Commit graph

820 commits

Author SHA1 Message Date
Linus Torvalds
509f806f7f more s390 updates for 6.13 merge window
- Add swap entry for hugetlbfs support
 
 - Add PTE_MARKER support for hugetlbs mappings; this fixes a regression
   (possible page fault loop) which was introduced when support for
   UFFDIO_POISON for hugetlbfs was added
 
 - Add ARCH_HAS_PREEMPT_LAZY and PREEMPT_DYNAMIC support
 
 - Mark IRQ entries in entry code, so that stack tracers can filter out the
   non-IRQ parts of stack traces. This fixes stack depot capacity limit
   warnings, since without filtering the number of unique stack traces is
   huge
 
 - In PCI code fix leak of struct zpci_dev object, and fix potential double
   remove of hotplug slot
 
 - Fix pagefault_disable() / pagefault_enable() unbalance in
   arch_stack_user_walk_common()
 
 - A couple of inline assembly optimizations, more cmpxchg() to
   try_cmpxchg() conversions, and removal of usages of xchg() and cmpxchg()
   on one and two byte memory areas
 
 - Various other small improvements and cleanups
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Merge tag 's390-6.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull more s390 updates from Heiko Carstens:

 - Add swap entry for hugetlbfs support

 - Add PTE_MARKER support for hugetlbs mappings; this fixes a regression
   (possible page fault loop) which was introduced when support for
   UFFDIO_POISON for hugetlbfs was added

 - Add ARCH_HAS_PREEMPT_LAZY and PREEMPT_DYNAMIC support

 - Mark IRQ entries in entry code, so that stack tracers can filter out
   the non-IRQ parts of stack traces. This fixes stack depot capacity
   limit warnings, since without filtering the number of unique stack
   traces is huge

 - In PCI code fix leak of struct zpci_dev object, and fix potential
   double remove of hotplug slot

 - Fix pagefault_disable() / pagefault_enable() unbalance in
   arch_stack_user_walk_common()

 - A couple of inline assembly optimizations, more cmpxchg() to
   try_cmpxchg() conversions, and removal of usages of xchg() and
   cmpxchg() on one and two byte memory areas

 - Various other small improvements and cleanups

* tag 's390-6.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (27 commits)
  Revert "s390/mm: Allow large pages for KASAN shadow mapping"
  s390/spinlock: Use flag output constraint for arch_cmpxchg_niai8()
  s390/spinlock: Use R constraint for arch_load_niai4()
  s390/spinlock: Generate shorter code for arch_spin_unlock()
  s390/spinlock: Remove condition code clobber from arch_spin_unlock()
  s390/spinlock: Use symbolic names in inline assemblies
  s390: Support PREEMPT_DYNAMIC
  s390/pci: Fix potential double remove of hotplug slot
  s390/pci: Fix leak of struct zpci_dev when zpci_add_device() fails
  s390/mm/hugetlbfs: Add missing includes
  s390/mm: Add PTE_MARKER support for hugetlbfs mappings
  s390/mm: Introduce region-third and segment table swap entries
  s390/mm: Introduce region-third and segment table entry present bits
  s390/mm: Rearrange region-third and segment table entry SW bits
  KVM: s390: Increase size of union sca_utility to four bytes
  KVM: s390: Remove one byte cmpxchg() usage
  KVM: s390: Use try_cmpxchg() instead of cmpxchg() loops
  s390/ap: Replace xchg() with WRITE_ONCE()
  s390/mm: Allow large pages for KASAN shadow mapping
  s390: Add ARCH_HAS_PREEMPT_LAZY support
  ...
2024-11-29 10:40:52 -08:00
Heiko Carstens
5618c53d96 KVM: s390: Use try_cmpxchg() instead of cmpxchg() loops
Convert all cmpxchg() loops to try_cmpxchg() loops. With gcc 14 and the
usage of flag output operands in try_cmpxchg() this allows the compiler to
generate slightly better code.

Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20241126102515.3178914-2-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-11-27 12:55:15 +01:00
Linus Torvalds
9f16d5e6f2 The biggest change here is eliminating the awful idea that KVM had, of
essentially guessing which pfns are refcounted pages.  The reason to
 do so was that KVM needs to map both non-refcounted pages (for example
 BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP VMAs that contain
 refcounted pages.  However, the result was security issues in the past,
 and more recently the inability to map VM_IO and VM_PFNMAP memory
 that _is_ backed by struct page but is not refcounted.  In particular
 this broke virtio-gpu blob resources (which directly map host graphics
 buffers into the guest as "vram" for the virtio-gpu device) with the
 amdgpu driver, because amdgpu allocates non-compound higher order pages
 and the tail pages could not be mapped into KVM.
 
 This requires adjusting all uses of struct page in the per-architecture
 code, to always work on the pfn whenever possible.  The large series that
 did this, from David Stevens and Sean Christopherson, also cleaned up
 substantially the set of functions that provided arch code with the
 pfn for a host virtual addresses.  The previous maze of twisty little
 passages, all different, is replaced by five functions (__gfn_to_page,
 __kvm_faultin_pfn, the non-__ versions of these two, and kvm_prefetch_pages)
 saving almost 200 lines of code.
 
 ARM:
 
 * Support for stage-1 permission indirection (FEAT_S1PIE) and
   permission overlays (FEAT_S1POE), including nested virt + the
   emulated page table walker
 
 * Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call
   was introduced in PSCIv1.3 as a mechanism to request hibernation,
   similar to the S4 state in ACPI
 
 * Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
   part of it, introduce trivial initialization of the host's MPAM
   context so KVM can use the corresponding traps
 
 * PMU support under nested virtualization, honoring the guest
   hypervisor's trap configuration and event filtering when running a
   nested guest
 
 * Fixes to vgic ITS serialization where stale device/interrupt table
   entries are not zeroed when the mapping is invalidated by the VM
 
 * Avoid emulated MMIO completion if userspace has requested synchronous
   external abort injection
 
 * Various fixes and cleanups affecting pKVM, vCPU initialization, and
   selftests
 
 LoongArch:
 
 * Add iocsr and mmio bus simulation in kernel.
 
 * Add in-kernel interrupt controller emulation.
 
 * Add support for virtualization extensions to the eiointc irqchip.
 
 PPC:
 
 * Drop lingering and utterly obsolete references to PPC970 KVM, which was
   removed 10 years ago.
 
 * Fix incorrect documentation references to non-existing ioctls
 
 RISC-V:
 
 * Accelerate KVM RISC-V when running as a guest
 
 * Perf support to collect KVM guest statistics from host side
 
 s390:
 
 * New selftests: more ucontrol selftests and CPU model sanity checks
 
 * Support for the gen17 CPU model
 
 * List registers supported by KVM_GET/SET_ONE_REG in the documentation
 
 x86:
 
 * Cleanup KVM's handling of Accessed and Dirty bits to dedup code, improve
   documentation, harden against unexpected changes.  Even if the hardware
   A/D tracking is disabled, it is possible to use the hardware-defined A/D
   bits to track if a PFN is Accessed and/or Dirty, and that removes a lot
   of special cases.
 
 * Elide TLB flushes when aging secondary PTEs, as has been done in x86's
   primary MMU for over 10 years.
 
 * Recover huge pages in-place in the TDP MMU when dirty page logging is
   toggled off, instead of zapping them and waiting until the page is
   re-accessed to create a huge mapping.  This reduces vCPU jitter.
 
 * Batch TLB flushes when dirty page logging is toggled off.  This reduces
   the time it takes to disable dirty logging by ~3x.
 
 * Remove the shrinker that was (poorly) attempting to reclaim shadow page
   tables in low-memory situations.
 
 * Clean up and optimize KVM's handling of writes to MSR_IA32_APICBASE.
 
 * Advertise CPUIDs for new instructions in Clearwater Forest
 
 * Quirk KVM's misguided behavior of initialized certain feature MSRs to
   their maximum supported feature set, which can result in KVM creating
   invalid vCPU state.  E.g. initializing PERF_CAPABILITIES to a non-zero
   value results in the vCPU having invalid state if userspace hides PDCM
   from the guest, which in turn can lead to save/restore failures.
 
 * Fix KVM's handling of non-canonical checks for vCPUs that support LA57
   to better follow the "architecture", in quotes because the actual
   behavior is poorly documented.  E.g. most MSR writes and descriptor
   table loads ignore CR4.LA57 and operate purely on whether the CPU
   supports LA57.
 
 * Bypass the register cache when querying CPL from kvm_sched_out(), as
   filling the cache from IRQ context is generally unsafe; harden the
   cache accessors to try to prevent similar issues from occuring in the
   future.  The issue that triggered this change was already fixed in 6.12,
   but was still kinda latent.
 
 * Advertise AMD_IBPB_RET to userspace, and fix a related bug where KVM
   over-advertises SPEC_CTRL when trying to support cross-vendor VMs.
 
 * Minor cleanups
 
 * Switch hugepage recovery thread to use vhost_task.  These kthreads can
   consume significant amounts of CPU time on behalf of a VM or in response
   to how the VM behaves (for example how it accesses its memory); therefore
   KVM tried to place the thread in the VM's cgroups and charge the CPU
   time consumed by that work to the VM's container.  However the kthreads
   did not process SIGSTOP/SIGCONT, and therefore cgroups which had KVM
   instances inside could not complete freezing.  Fix this by replacing the
   kthread with a PF_USER_WORKER thread, via the vhost_task abstraction.
   Another 100+ lines removed, with generally better behavior too like
   having these threads properly parented in the process tree.
 
 * Revert a workaround for an old CPU erratum (Nehalem/Westmere) that didn't
   really work; there was really nothing to work around anyway: the broken
   patch was meant to fix nested virtualization, but the PERF_GLOBAL_CTRL
   MSR is virtualized and therefore unaffected by the erratum.
 
 * Fix 6.12 regression where CONFIG_KVM will be built as a module even
   if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is 'y'.
 
 x86 selftests:
 
 * x86 selftests can now use AVX.
 
 Documentation:
 
 * Use rST internal links
 
 * Reorganize the introduction to the API document
 
 Generic:
 
 * Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock instead
   of RCU, so that running a vCPU on a different task doesn't encounter long
   due to having to wait for all CPUs become quiescent.  In general both reads
   and writes are rare, but userspace that supports confidential computing is
   introducing the use of "helper" vCPUs that may jump from one host processor
   to another.  Those will be very happy to trigger a synchronize_rcu(), and
   the effect on performance is quite the disaster.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "The biggest change here is eliminating the awful idea that KVM had of
  essentially guessing which pfns are refcounted pages.

  The reason to do so was that KVM needs to map both non-refcounted
  pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP
  VMAs that contain refcounted pages.

  However, the result was security issues in the past, and more recently
  the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by
  struct page but is not refcounted. In particular this broke virtio-gpu
  blob resources (which directly map host graphics buffers into the
  guest as "vram" for the virtio-gpu device) with the amdgpu driver,
  because amdgpu allocates non-compound higher order pages and the tail
  pages could not be mapped into KVM.

  This requires adjusting all uses of struct page in the
  per-architecture code, to always work on the pfn whenever possible.
  The large series that did this, from David Stevens and Sean
  Christopherson, also cleaned up substantially the set of functions
  that provided arch code with the pfn for a host virtual addresses.

  The previous maze of twisty little passages, all different, is
  replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the
  non-__ versions of these two, and kvm_prefetch_pages) saving almost
  200 lines of code.

  ARM:

   - Support for stage-1 permission indirection (FEAT_S1PIE) and
     permission overlays (FEAT_S1POE), including nested virt + the
     emulated page table walker

   - Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This
     call was introduced in PSCIv1.3 as a mechanism to request
     hibernation, similar to the S4 state in ACPI

   - Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
     part of it, introduce trivial initialization of the host's MPAM
     context so KVM can use the corresponding traps

   - PMU support under nested virtualization, honoring the guest
     hypervisor's trap configuration and event filtering when running a
     nested guest

   - Fixes to vgic ITS serialization where stale device/interrupt table
     entries are not zeroed when the mapping is invalidated by the VM

   - Avoid emulated MMIO completion if userspace has requested
     synchronous external abort injection

   - Various fixes and cleanups affecting pKVM, vCPU initialization, and
     selftests

  LoongArch:

   - Add iocsr and mmio bus simulation in kernel.

   - Add in-kernel interrupt controller emulation.

   - Add support for virtualization extensions to the eiointc irqchip.

  PPC:

   - Drop lingering and utterly obsolete references to PPC970 KVM, which
     was removed 10 years ago.

   - Fix incorrect documentation references to non-existing ioctls

  RISC-V:

   - Accelerate KVM RISC-V when running as a guest

   - Perf support to collect KVM guest statistics from host side

  s390:

   - New selftests: more ucontrol selftests and CPU model sanity checks

   - Support for the gen17 CPU model

   - List registers supported by KVM_GET/SET_ONE_REG in the
     documentation

  x86:

   - Cleanup KVM's handling of Accessed and Dirty bits to dedup code,
     improve documentation, harden against unexpected changes.

     Even if the hardware A/D tracking is disabled, it is possible to
     use the hardware-defined A/D bits to track if a PFN is Accessed
     and/or Dirty, and that removes a lot of special cases.

   - Elide TLB flushes when aging secondary PTEs, as has been done in
     x86's primary MMU for over 10 years.

   - Recover huge pages in-place in the TDP MMU when dirty page logging
     is toggled off, instead of zapping them and waiting until the page
     is re-accessed to create a huge mapping. This reduces vCPU jitter.

   - Batch TLB flushes when dirty page logging is toggled off. This
     reduces the time it takes to disable dirty logging by ~3x.

   - Remove the shrinker that was (poorly) attempting to reclaim shadow
     page tables in low-memory situations.

   - Clean up and optimize KVM's handling of writes to
     MSR_IA32_APICBASE.

   - Advertise CPUIDs for new instructions in Clearwater Forest

   - Quirk KVM's misguided behavior of initialized certain feature MSRs
     to their maximum supported feature set, which can result in KVM
     creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to
     a non-zero value results in the vCPU having invalid state if
     userspace hides PDCM from the guest, which in turn can lead to
     save/restore failures.

   - Fix KVM's handling of non-canonical checks for vCPUs that support
     LA57 to better follow the "architecture", in quotes because the
     actual behavior is poorly documented. E.g. most MSR writes and
     descriptor table loads ignore CR4.LA57 and operate purely on
     whether the CPU supports LA57.

   - Bypass the register cache when querying CPL from kvm_sched_out(),
     as filling the cache from IRQ context is generally unsafe; harden
     the cache accessors to try to prevent similar issues from occuring
     in the future. The issue that triggered this change was already
     fixed in 6.12, but was still kinda latent.

   - Advertise AMD_IBPB_RET to userspace, and fix a related bug where
     KVM over-advertises SPEC_CTRL when trying to support cross-vendor
     VMs.

   - Minor cleanups

   - Switch hugepage recovery thread to use vhost_task.

     These kthreads can consume significant amounts of CPU time on
     behalf of a VM or in response to how the VM behaves (for example
     how it accesses its memory); therefore KVM tried to place the
     thread in the VM's cgroups and charge the CPU time consumed by that
     work to the VM's container.

     However the kthreads did not process SIGSTOP/SIGCONT, and therefore
     cgroups which had KVM instances inside could not complete freezing.

     Fix this by replacing the kthread with a PF_USER_WORKER thread, via
     the vhost_task abstraction. Another 100+ lines removed, with
     generally better behavior too like having these threads properly
     parented in the process tree.

   - Revert a workaround for an old CPU erratum (Nehalem/Westmere) that
     didn't really work; there was really nothing to work around anyway:
     the broken patch was meant to fix nested virtualization, but the
     PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the
     erratum.

   - Fix 6.12 regression where CONFIG_KVM will be built as a module even
     if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is
     'y'.

  x86 selftests:

   - x86 selftests can now use AVX.

  Documentation:

   - Use rST internal links

   - Reorganize the introduction to the API document

  Generic:

   - Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock
     instead of RCU, so that running a vCPU on a different task doesn't
     encounter long due to having to wait for all CPUs become quiescent.

     In general both reads and writes are rare, but userspace that
     supports confidential computing is introducing the use of "helper"
     vCPUs that may jump from one host processor to another. Those will
     be very happy to trigger a synchronize_rcu(), and the effect on
     performance is quite the disaster"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits)
  KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD
  KVM: x86: add back X86_LOCAL_APIC dependency
  Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()"
  KVM: x86: switch hugepage recovery thread to vhost_task
  KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR
  x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest
  Documentation: KVM: fix malformed table
  irqchip/loongson-eiointc: Add virt extension support
  LoongArch: KVM: Add irqfd support
  LoongArch: KVM: Add PCHPIC user mode read and write functions
  LoongArch: KVM: Add PCHPIC read and write functions
  LoongArch: KVM: Add PCHPIC device support
  LoongArch: KVM: Add EIOINTC user mode read and write functions
  LoongArch: KVM: Add EIOINTC read and write functions
  LoongArch: KVM: Add EIOINTC device support
  LoongArch: KVM: Add IPI user mode read and write function
  LoongArch: KVM: Add IPI read and write function
  LoongArch: KVM: Add IPI device support
  LoongArch: KVM: Add iocsr and mmio bus simulation in kernel
  KVM: arm64: Pass on SVE mapping failures
  ...
2024-11-23 16:00:50 -08:00
Heiko Carstens
4e20996f0d s390/kvm: Convert to use flag output macros
Use flag output macros in inline asm to allow for better code generation if
the compiler has support for the flag output constraint.

Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-11-13 14:31:33 +01:00
Hendrik Brueckner
85a9e680d4 KVM: s390: add gen17 facilities to CPU model
Add gen17 facilities and let KVM_CAP_S390_VECTOR_REGISTERS handle
the enablement of the vector extension facilities.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20241107152319.77816-4-brueckner@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20241107152319.77816-4-brueckner@linux.ibm.com>
2024-11-11 12:07:51 +00:00
Hendrik Brueckner
2c2cc82738 KVM: s390: add msa11 to cpu model
Message-security-assist 11 introduces pckmo subfunctions to encrypt
hmac keys.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20241107152319.77816-3-brueckner@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20241107152319.77816-3-brueckner@linux.ibm.com>
2024-11-11 12:07:51 +00:00
Hendrik Brueckner
66ff6bf59b KVM: s390: add concurrent-function facility to cpu model
Adding support for concurrent-functions facility which provides
additional subfunctions.

Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20241107152319.77816-2-brueckner@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20241107152319.77816-2-brueckner@linux.ibm.com>
2024-11-11 12:07:51 +00:00
Claudio Imbrenda
34fb045edd s390/kvm: Mask extra bits from program interrupt code
The program interrupt code has some extra bits that are sometimes set
by hardware for various reasons; those bits should be ignored when the
program interrupt number is needed for interrupt handling.

Fixes: 05066cafa9 ("s390/mm/fault: Handle guest-related program interrupts in KVM")
Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20241031120316.25462-1-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-11-07 10:23:43 +01:00
Claudio Imbrenda
64844729a6 s390/kvm: Initialize uninitialized flags variable
The flags variable was being used uninitialized.
Initialize it to 0 as expected.

For some reason neither gcc nor clang reported a warning.

Fixes: 05066cafa9 ("s390/mm/fault: Handle guest-related program interrupts in KVM")
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20241030161906.85476-1-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-10-31 10:50:07 +01:00
Claudio Imbrenda
8cdebf47ed s390/kvm: Stop using gmap_{en,dis}able()
Stop using gmap_enable(), gmap_disable(), gmap_get_enabled().

The correct guest ASCE is passed as a parameter of sie64a(), there is
no need to save the current gmap in lowcore.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20241022120601.167009-7-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-10-29 11:49:19 +01:00
Claudio Imbrenda
05066cafa9 s390/mm/fault: Handle guest-related program interrupts in KVM
Any program interrupt that happens in the host during the execution of
a KVM guest will now short circuit the fault handler and return to KVM
immediately. Guest fault handling (including pfault) will happen
entirely inside KVM.

When sie64a() returns zero, current->thread.gmap_int_code will contain
the program interrupt number that caused the exit, or zero if the exit
was not caused by a host program interrupt.

KVM will now take care of handling all guest faults in vcpu_post_run().

Since gmap faults will not be visible by the rest of the kernel, remove
GMAP_FAULT, the linux fault handlers for secure execution faults, the
exception table entries for the sie instruction, the nop padding after
the sie instruction, and all other references to guest faults from the
s390 code.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Co-developed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20241022120601.167009-6-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-10-29 11:49:18 +01:00
Claudio Imbrenda
ca3c6dc3a9 s390/kvm: Remove kvm_arch_fault_in_page()
kvm_arch_fault_in_page() is a useless wrapper around gmap_fault(); just
use gmap_fault() directly instead.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20241022120601.167009-3-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-10-29 11:49:18 +01:00
Hariharan Mari
09c38ad044 KVM: s390: Fix SORTL and DFLTCC instruction format error in __insn32_query
The __insn32_query() function incorrectly uses the RRF instruction format
for both the SORTL (RRE format) and DFLTCC (RRF format) instructions.
To fix this issue, add separate query functions for SORTL and DFLTCC that
use the appropriate instruction formats.

Additionally pass the query operand as a pointer to the entire array
of 32 elements to slightly optimize performance and readability.

Fixes: d668139718 ("KVM: s390: provide query function for instructions returning 32 byte")
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Hariharan Mari <hari55@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2024-08-19 07:51:14 +00:00
Linus Torvalds
2c9b351240 ARM:
* Initial infrastructure for shadow stage-2 MMUs, as part of nested
   virtualization enablement
 
 * Support for userspace changes to the guest CTR_EL0 value, enabling
   (in part) migration of VMs between heterogenous hardware
 
 * Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of
   the protocol
 
 * FPSIMD/SVE support for nested, including merged trap configuration
   and exception routing
 
 * New command-line parameter to control the WFx trap behavior under KVM
 
 * Introduce kCFI hardening in the EL2 hypervisor
 
 * Fixes + cleanups for handling presence/absence of FEAT_TCRX
 
 * Miscellaneous fixes + documentation updates
 
 LoongArch:
 
 * Add paravirt steal time support.
 
 * Add support for KVM_DIRTY_LOG_INITIALLY_SET.
 
 * Add perf kvm-stat support for loongarch.
 
 RISC-V:
 
 * Redirect AMO load/store access fault traps to guest
 
 * perf kvm stat support
 
 * Use guest files for IMSIC virtualization, when available
 
 ONE_REG support for the Zimop, Zcmop, Zca, Zcf, Zcd, Zcb and Zawrs ISA
 extensions is coming through the RISC-V tree.
 
 s390:
 
 * Assortment of tiny fixes which are not time critical
 
 x86:
 
 * Fixes for Xen emulation.
 
 * Add a global struct to consolidate tracking of host values, e.g. EFER
 
 * Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC
   bus frequency, because TDX.
 
 * Print the name of the APICv/AVIC inhibits in the relevant tracepoint.
 
 * Clean up KVM's handling of vendor specific emulation to consistently act on
   "compatible with Intel/AMD", versus checking for a specific vendor.
 
 * Drop MTRR virtualization, and instead always honor guest PAT on CPUs
   that support self-snoop.
 
 * Update to the newfangled Intel CPU FMS infrastructure.
 
 * Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads
   '0' and writes from userspace are ignored.
 
 * Misc cleanups
 
 x86 - MMU:
 
 * Small cleanups, renames and refactoring extracted from the upcoming
   Intel TDX support.
 
 * Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't
   hold leafs SPTEs.
 
 * Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager
   page splitting, to avoid stalling vCPUs when splitting huge pages.
 
 * Bug the VM instead of simply warning if KVM tries to split a SPTE that is
   non-present or not-huge.  KVM is guaranteed to end up in a broken state
   because the callers fully expect a valid SPTE, it's all but dangerous
   to let more MMU changes happen afterwards.
 
 x86 - AMD:
 
 * Make per-CPU save_area allocations NUMA-aware.
 
 * Force sev_es_host_save_area() to be inlined to avoid calling into an
   instrumentable function from noinstr code.
 
 * Base support for running SEV-SNP guests.  API-wise, this includes
   a new KVM_X86_SNP_VM type, encrypting/measure the initial image into
   guest memory, and finalizing it before launching it.  Internally,
   there are some gmem/mmu hooks needed to prepare gmem-allocated pages
   before mapping them into guest private memory ranges.
 
   This includes basic support for attestation guest requests, enough to
   say that KVM supports the GHCB 2.0 specification.
 
   There is no support yet for loading into the firmware those signing
   keys to be used for attestation requests, and therefore no need yet
   for the host to provide certificate data for those keys.  To support
   fetching certificate data from userspace, a new KVM exit type will be
   needed to handle fetching the certificate from userspace. An attempt to
   define a new KVM_EXIT_COCO/KVM_EXIT_COCO_REQ_CERTS exit type to handle
   this was introduced in v1 of this patchset, but is still being discussed
   by community, so for now this patchset only implements a stub version
   of SNP Extended Guest Requests that does not provide certificate data.
 
 x86 - Intel:
 
 * Remove an unnecessary EPT TLB flush when enabling hardware.
 
 * Fix a series of bugs that cause KVM to fail to detect nested pending posted
   interrupts as valid wake eents for a vCPU executing HLT in L2 (with
   HLT-exiting disable by L1).
 
 * KVM: x86: Suppress MMIO that is triggered during task switch emulation
 
   Explicitly suppress userspace emulated MMIO exits that are triggered when
   emulating a task switch as KVM doesn't support userspace MMIO during
   complex (multi-step) emulation.  Silently ignoring the exit request can
   result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to
   userspace for some other reason prior to purging mmio_needed.
 
   See commit 0dc902267c ("KVM: x86: Suppress pending MMIO write exits if
   emulator detects exception") for more details on KVM's limitations with
   respect to emulated MMIO during complex emulator flows.
 
 Generic:
 
 * Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE,
   because the special casing needed by these pages is not due to just
   unmovability (and in fact they are only unmovable because the CPU cannot
   access them).
 
 * New ioctl to populate the KVM page tables in advance, which is useful to
   mitigate KVM page faults during guest boot or after live migration.
   The code will also be used by TDX, but (probably) not through the ioctl.
 
 * Enable halt poll shrinking by default, as Intel found it to be a clear win.
 
 * Setup empty IRQ routing when creating a VM to avoid having to synchronize
   SRCU when creating a split IRQCHIP on x86.
 
 * Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
   that arch code can use for hooking both sched_in() and sched_out().
 
 * Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
   truncating a bogus value from userspace, e.g. to help userspace detect bugs.
 
 * Mark a vCPU as preempted if and only if it's scheduled out while in the
   KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
   memory when retrieving guest state during live migration blackout.
 
 Selftests:
 
 * Remove dead code in the memslot modification stress test.
 
 * Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs.
 
 * Print the guest pseudo-RNG seed only when it changes, to avoid spamming the
   log for tests that create lots of VMs.
 
 * Make the PMU counters test less flaky when counting LLC cache misses by
   doing CLFLUSH{OPT} in every loop iteration.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "ARM:

   - Initial infrastructure for shadow stage-2 MMUs, as part of nested
     virtualization enablement

   - Support for userspace changes to the guest CTR_EL0 value, enabling
     (in part) migration of VMs between heterogenous hardware

   - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1
     of the protocol

   - FPSIMD/SVE support for nested, including merged trap configuration
     and exception routing

   - New command-line parameter to control the WFx trap behavior under
     KVM

   - Introduce kCFI hardening in the EL2 hypervisor

   - Fixes + cleanups for handling presence/absence of FEAT_TCRX

   - Miscellaneous fixes + documentation updates

  LoongArch:

   - Add paravirt steal time support

   - Add support for KVM_DIRTY_LOG_INITIALLY_SET

   - Add perf kvm-stat support for loongarch

  RISC-V:

   - Redirect AMO load/store access fault traps to guest

   - perf kvm stat support

   - Use guest files for IMSIC virtualization, when available

  s390:

   - Assortment of tiny fixes which are not time critical

  x86:

   - Fixes for Xen emulation

   - Add a global struct to consolidate tracking of host values, e.g.
     EFER

   - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the
     effective APIC bus frequency, because TDX

   - Print the name of the APICv/AVIC inhibits in the relevant
     tracepoint

   - Clean up KVM's handling of vendor specific emulation to
     consistently act on "compatible with Intel/AMD", versus checking
     for a specific vendor

   - Drop MTRR virtualization, and instead always honor guest PAT on
     CPUs that support self-snoop

   - Update to the newfangled Intel CPU FMS infrastructure

   - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as
     it reads '0' and writes from userspace are ignored

   - Misc cleanups

  x86 - MMU:

   - Small cleanups, renames and refactoring extracted from the upcoming
     Intel TDX support

   - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages
     that can't hold leafs SPTEs

   - Unconditionally drop mmu_lock when allocating TDP MMU page tables
     for eager page splitting, to avoid stalling vCPUs when splitting
     huge pages

   - Bug the VM instead of simply warning if KVM tries to split a SPTE
     that is non-present or not-huge. KVM is guaranteed to end up in a
     broken state because the callers fully expect a valid SPTE, it's
     all but dangerous to let more MMU changes happen afterwards

  x86 - AMD:

   - Make per-CPU save_area allocations NUMA-aware

   - Force sev_es_host_save_area() to be inlined to avoid calling into
     an instrumentable function from noinstr code

   - Base support for running SEV-SNP guests. API-wise, this includes a
     new KVM_X86_SNP_VM type, encrypting/measure the initial image into
     guest memory, and finalizing it before launching it. Internally,
     there are some gmem/mmu hooks needed to prepare gmem-allocated
     pages before mapping them into guest private memory ranges

     This includes basic support for attestation guest requests, enough
     to say that KVM supports the GHCB 2.0 specification

     There is no support yet for loading into the firmware those signing
     keys to be used for attestation requests, and therefore no need yet
     for the host to provide certificate data for those keys.

     To support fetching certificate data from userspace, a new KVM exit
     type will be needed to handle fetching the certificate from
     userspace.

     An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS
     exit type to handle this was introduced in v1 of this patchset, but
     is still being discussed by community, so for now this patchset
     only implements a stub version of SNP Extended Guest Requests that
     does not provide certificate data

  x86 - Intel:

   - Remove an unnecessary EPT TLB flush when enabling hardware

   - Fix a series of bugs that cause KVM to fail to detect nested
     pending posted interrupts as valid wake eents for a vCPU executing
     HLT in L2 (with HLT-exiting disable by L1)

   - KVM: x86: Suppress MMIO that is triggered during task switch
     emulation

     Explicitly suppress userspace emulated MMIO exits that are
     triggered when emulating a task switch as KVM doesn't support
     userspace MMIO during complex (multi-step) emulation

     Silently ignoring the exit request can result in the
     WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace
     for some other reason prior to purging mmio_needed

     See commit 0dc902267c ("KVM: x86: Suppress pending MMIO write
     exits if emulator detects exception") for more details on KVM's
     limitations with respect to emulated MMIO during complex emulator
     flows

  Generic:

   - Rename the AS_UNMOVABLE flag that was introduced for KVM to
     AS_INACCESSIBLE, because the special casing needed by these pages
     is not due to just unmovability (and in fact they are only
     unmovable because the CPU cannot access them)

   - New ioctl to populate the KVM page tables in advance, which is
     useful to mitigate KVM page faults during guest boot or after live
     migration. The code will also be used by TDX, but (probably) not
     through the ioctl

   - Enable halt poll shrinking by default, as Intel found it to be a
     clear win

   - Setup empty IRQ routing when creating a VM to avoid having to
     synchronize SRCU when creating a split IRQCHIP on x86

   - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with
     a flag that arch code can use for hooking both sched_in() and
     sched_out()

   - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
     truncating a bogus value from userspace, e.g. to help userspace
     detect bugs

   - Mark a vCPU as preempted if and only if it's scheduled out while in
     the KVM_RUN loop, e.g. to avoid marking it preempted and thus
     writing guest memory when retrieving guest state during live
     migration blackout

  Selftests:

   - Remove dead code in the memslot modification stress test

   - Treat "branch instructions retired" as supported on all AMD Family
     17h+ CPUs

   - Print the guest pseudo-RNG seed only when it changes, to avoid
     spamming the log for tests that create lots of VMs

   - Make the PMU counters test less flaky when counting LLC cache
     misses by doing CLFLUSH{OPT} in every loop iteration"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits)
  crypto: ccp: Add the SNP_VLEK_LOAD command
  KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops
  KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops
  KVM: x86: Replace static_call_cond() with static_call()
  KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event
  x86/sev: Move sev_guest.h into common SEV header
  KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event
  KVM: x86: Suppress MMIO that is triggered during task switch emulation
  KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro
  KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE
  KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY
  KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory()
  KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level
  KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault"
  KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler
  KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory
  KVM: Document KVM_PRE_FAULT_MEMORY ioctl
  mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE
  perf kvm: Add kvm-stat for loongarch64
  LoongArch: KVM: Add PV steal time support in guest side
  ...
2024-07-20 12:41:03 -07:00
Linus Torvalds
1c7d0c3af5 s390 updates for 6.11 merge window
- Remove restrictions on PAI NNPA and crypto counters, enabling
   concurrent per-task and system-wide sampling and counting events
 
 - Switch to GENERIC_CPU_DEVICES by setting up the CPU present mask in
   the architecture code and letting the generic code handle CPU bring-up
 
 - Add support for the diag204 busy indication facility to prevent
   undesirable blocking during hypervisor logical CPU utilization
   queries. Implement results caching
 
 - Improve the handling of Store Data SCLP events by suppressing
   unnecessary warning, preventing buffer release in I/O during failures,
   and adding timeout handling for Store Data requests to address potential
   firmware issues
 
 - Provide optimized __arch_hweight*() implementations
 
 - Remove the unnecessary CPU KOBJ_CHANGE uevents generated during topology
   updates, as they are unused and also not present on other architectures
 
 - Cleanup atomic_ops, optimize __atomic_set() for small values and
   __atomic_cmpxchg_bool() for compilers supporting flag output constraint
 
 - Couple of cleanups for KVM:
   - Move and improve KVM struct definitions for DAT tables from gaccess.c
     to a new header
   - Pass the asce as parameter to sie64a()
 
 - Make the crdte() and cspg() page table handling wrappers return a
   boolean to indicate success, like the other existing "compare and swap"
   wrappers
 
 - Add documentation for HWCAP flags
 
 - Switch to obtaining total RAM pages from memblock instead of
   totalram_pages() during mm init, to ensure correct calculation of zero
   page size, when defer_init is enabled
 
 - Refactor lowcore access and switch to using the get_lowcore() function
   instead of the S390_lowcore macro
 
 - Cleanups for PG_arch_1 and folio handling in UV and hugetlb code
 
 - Add missing MODULE_DESCRIPTION() macros
 
 - Fix VM_FAULT_HWPOISON handling in do_exception()
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Merge tag 's390-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Vasily Gorbik:

 - Remove restrictions on PAI NNPA and crypto counters, enabling
   concurrent per-task and system-wide sampling and counting events

 - Switch to GENERIC_CPU_DEVICES by setting up the CPU present mask in
   the architecture code and letting the generic code handle CPU
   bring-up

 - Add support for the diag204 busy indication facility to prevent
   undesirable blocking during hypervisor logical CPU utilization
   queries. Implement results caching

 - Improve the handling of Store Data SCLP events by suppressing
   unnecessary warning, preventing buffer release in I/O during
   failures, and adding timeout handling for Store Data requests to
   address potential firmware issues

 - Provide optimized __arch_hweight*() implementations

 - Remove the unnecessary CPU KOBJ_CHANGE uevents generated during
   topology updates, as they are unused and also not present on other
   architectures

 - Cleanup atomic_ops, optimize __atomic_set() for small values and
   __atomic_cmpxchg_bool() for compilers supporting flag output
   constraint

 - Couple of cleanups for KVM:
     - Move and improve KVM struct definitions for DAT tables from
       gaccess.c to a new header
     - Pass the asce as parameter to sie64a()

 - Make the crdte() and cspg() page table handling wrappers return a
   boolean to indicate success, like the other existing "compare and
   swap" wrappers

 - Add documentation for HWCAP flags

 - Switch to obtaining total RAM pages from memblock instead of
   totalram_pages() during mm init, to ensure correct calculation of
   zero page size, when defer_init is enabled

 - Refactor lowcore access and switch to using the get_lowcore()
   function instead of the S390_lowcore macro

 - Cleanups for PG_arch_1 and folio handling in UV and hugetlb code

 - Add missing MODULE_DESCRIPTION() macros

 - Fix VM_FAULT_HWPOISON handling in do_exception()

* tag 's390-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (54 commits)
  s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()
  s390/kvm: Move bitfields for dat tables
  s390/entry: Pass the asce as parameter to sie64a()
  s390/sthyi: Use cached data when diag is busy
  s390/sthyi: Move diag operations
  s390/hypfs_diag: Diag204 busy loop
  s390/diag: Add busy-indication-facility requirements
  s390/diag: Diag204 add busy return errno
  s390/diag: Return errno's from diag204
  s390/sclp: Diag204 busy indication facility detection
  s390/atomic_ops: Make use of flag output constraint
  s390/atomic_ops: Improve __atomic_set() for small values
  s390/atomic_ops: Use symbolic names
  s390/smp: Switch to GENERIC_CPU_DEVICES
  s390/hwcaps: Add documentation for HWCAP flags
  s390/pgtable: Make crdte() and cspg() return a value
  s390/topology: Remove CPU KOBJ_CHANGE uevents
  s390/sclp: Add timeout to Store Data requests
  s390/sclp: Prevent release of buffer in I/O
  s390/sclp: Suppress unnecessary Store Data warning
  ...
2024-07-18 15:41:45 -07:00
Paolo Bonzini
86014c1e20 KVM generic changes for 6.11
- Enable halt poll shrinking by default, as Intel found it to be a clear win.
 
  - Setup empty IRQ routing when creating a VM to avoid having to synchronize
    SRCU when creating a split IRQCHIP on x86.
 
  - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
    that arch code can use for hooking both sched_in() and sched_out().
 
  - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
    truncating a bogus value from userspace, e.g. to help userspace detect bugs.
 
  - Mark a vCPU as preempted if and only if it's scheduled out while in the
    KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
    memory when retrieving guest state during live migration blackout.
 
  - A few minor cleanups
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Merge tag 'kvm-x86-generic-6.11' of https://github.com/kvm-x86/linux into HEAD

KVM generic changes for 6.11

 - Enable halt poll shrinking by default, as Intel found it to be a clear win.

 - Setup empty IRQ routing when creating a VM to avoid having to synchronize
   SRCU when creating a split IRQCHIP on x86.

 - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
   that arch code can use for hooking both sched_in() and sched_out().

 - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
   truncating a bogus value from userspace, e.g. to help userspace detect bugs.

 - Mark a vCPU as preempted if and only if it's scheduled out while in the
   KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
   memory when retrieving guest state during live migration blackout.

 - A few minor cleanups
2024-07-16 09:51:36 -04:00
Paolo Bonzini
c8b8b8190a LoongArch KVM changes for v6.11
1. Add ParaVirt steal time support.
 2. Add some VM migration enhancement.
 3. Add perf kvm-stat support for loongarch.
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Merge tag 'loongarch-kvm-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD

LoongArch KVM changes for v6.11

1. Add ParaVirt steal time support.
2. Add some VM migration enhancement.
3. Add perf kvm-stat support for loongarch.
2024-07-12 11:24:12 -04:00
Claudio Imbrenda
723ac2d6ba s390/entry: Pass the asce as parameter to sie64a()
Pass the guest ASCE explicitly as parameter, instead of having sie64a()
take it from lowcore.

This removes hidden state from lowcore, and makes things look cleaner.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Link: https://lore.kernel.org/r/20240703155900.103783-2-imbrenda@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-07-10 19:50:45 +02:00
Christoph Schlameuss
7816e58967 kvm: s390: Reject memory region operations for ucontrol VMs
This change rejects the KVM_SET_USER_MEMORY_REGION and
KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM.
This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and
would thus result in a null pointer dereference further in.
Memory management needs to be performed in userspace and using the
ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP.

Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION
and KVM_SET_USER_MEMORY_REGION2.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Fixes: 27e0393f15 ("KVM: s390: ucontrol: per vcpu address spaces")
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20240624095902.29375-1-schlameuss@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
[frankja@linux.ibm.com: commit message spelling fix, subject prefix fix]
Message-ID: <20240624095902.29375-1-schlameuss@linux.ibm.com>
2024-07-04 09:07:24 +02:00
Christian Borntraeger
4c6abb7f7b KVM: s390: fix LPSWEY handling
in rare cases, e.g. for injecting a machine check we do intercept all
load PSW instructions via ICTL_LPSW. With facility 193 a new variant
LPSWEY was added. KVM needs to handle that as well.

Fixes: a3efa84292 ("KVM: s390: gen_facilities: allow facilities 165, 193, 194 and 196")
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Message-ID: <20240628163547.2314-1-borntraeger@linux.ibm.com>
2024-07-01 14:31:15 +02:00
David Matlack
a6816314af KVM: Introduce vcpu->wants_to_run
Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run
loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit
was not set.

Replace all references to vcpu->run->immediate_exit with
!vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a
malicious userspace could invoked KVM_RUN with immediate_exit=true and
then after KVM reads it to set wants_to_run=false, flip it to false.
This would result in the vCPU running in KVM_RUN with
wants_to_run=false. This wouldn't cause any real bugs today but is a
dangerous landmine.

Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-06-18 09:20:01 -07:00
Sven Schnelle
208da1d5fc s390: Replace S390_lowcore by get_lowcore()
Replace all S390_lowcore usages in arch/s390/ by get_lowcore().

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-06-18 17:01:33 +02:00
Yi Wang
c4201bd24f KVM: s390: Don't re-setup dummy routing when KVM_CREATE_IRQCHIP
Now that KVM sets up empty irq routing in kvm_create_vm(), there's
no need to setup dummy routing when KVM_CREATE_IRQCHIP.

Note, userspace could very theoretically use KVM_CREATE_IRQCHIP after
KVM_SET_GSI_ROUTING to reset to empty IRQ routing, but it's extremely
unlikely any VMM does that, e.g. the main reason s390 does anything for
KVM_CREATE_IRQCHIP is to that s390 doesn't need to be special cased by the
VMM.

Signed-off-by: Yi Wang <foxywang@tencent.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20240506101751.3145407-4-foxywang@tencent.com
[sean: keep use_irqchip check, call out KVM_SET_GSI_ROUTING impact]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-06-11 14:18:41 -07:00
Linus Torvalds
d65e1a0f30 - Store AP Query Configuration Information in a static buffer
- Rework the AP initialization and add missing cleanups to the error path
 
 - Swap IRQ and AP bus/device registration to avoid race conditions
 
 - Export prot_virt_guest symbol
 
 - Introduce AP configuration changes notifier interface to facilitate
   modularization of the AP bus
 
 - Add CONFIG_AP kernel configuration option to allow modularization of
   the AP bus
 
 - Rework CONFIG_ZCRYPT_DEBUG kernel configuration option description and
   dependency and rename it to CONFIG_AP_DEBUG
 
 - Convert sprintf() and snprintf() to sysfs_emit() in CIO code
 
 - Adjust indentation of RELOCS command build step
 
 - Make crypto performance counters upward compatible
 
 - Convert make_page_secure() and gmap_make_secure() to use folio
 
 - Rework channel-utilization-block (CUB) handling in preparation of
   introducing additional CUBs
 
 - Use attribute groups to simplify registration, removal and extension
   of measurement-related channel-path sysfs attributes
 
 - Add a per-channel-path binary "ext_measurement" sysfs attribute that
   provides access to extended channel-path measurement data
 
 - Export measurement data for all channel-measurement-groups (CMG), not
   only for a specific ones. This enables support of new CMG data formats
   in userspace without the need for kernel changes
 
 - Add a per-channel-path sysfs attribute "speed_bps" that provides the
   operating speed in bits per second or 0 if the operating speed is not
   available
 
 - The CIO tracepoint subchannel-type field "st" is incorrectly set to
   the value of subchannel-enabled SCHIB "ena" field. Fix that
 
 - Do not forcefully limit vmemmap starting address to MAX_PHYSMEM_BITS
 
 - Consider the maximum physical address available to a DCSS segment
   (512GB) when memory layout is set up
 
 - Simplify the virtual memory layout setup by reducing the size of
   identity mapping vs vmemmap overlap
 
 - Swap vmalloc and Lowcore/Real Memory Copy areas in virtual memory.
   This will allow to place the kernel image next to kernel modules
 
 - Move everyting KASLR related from <asm/setup.h> to <asm/page.h>
 
 - Put virtual memory layout information into a structure to improve
   code generation
 
 - Currently __kaslr_offset is the kernel offset in both physical and
   virtual memory spaces. Uncouple these offsets to allow uncoupling
   of the addresses spaces
 
 - Currently the identity mapping base address is implicit and is always
   set to zero. Make it explicit by putting into __identity_base persistent
   boot variable and use it in proper context
 
 - Introduce .amode31 section start and end macros AMODE31_START and
   AMODE31_END
 
 - Introduce OS_INFO entries that do not reference any data in memory,
   but rather provide only values
 
 - Store virtual memory layout in OS_INFO. It is read out by makedumpfile,
   crash and other tools
 
 - Store virtual memory layout in VMCORE_INFO. It is read out by crash and
   other tools when /proc/kcore device is used
 
 - Create additional PT_LOAD ELF program header that covers kernel image
   only, so that vmcore tools could locate kernel text and data when virtual
   and physical memory spaces are uncoupled
 
 - Uncouple physical and virtual address spaces
 
 - Map kernel at fixed location when KASLR mode is disabled. The location is
   defined by CONFIG_KERNEL_IMAGE_BASE kernel configuration value.
 
 - Rework deployment of kernel image for both compressed and uncompressed
   variants as defined by CONFIG_KERNEL_UNCOMPRESSED kernel configuration
   value
 
 - Move .vmlinux.relocs section in front of the compressed kernel.
   The interim section rescue step is avoided as result
 
 - Correct modules thunk offset calculation when branch target is more
   than 2GB away
 
 - Kernel modules contain their own set of expoline thunks. Now that the
   kernel modules area is less than 4GB away from kernel expoline thunks,
   make modules use kernel expolines. Also make EXPOLINE_EXTERN the default
   if the compiler supports it
 
 - userfaultfd can insert shared zeropages into processes running VMs,
   but that is not allowed for s390. Fallback to allocating a fresh
   zeroed anonymous folio and insert that instead
 
 - Re-enable shared zeropages for non-PV and non-skeys KVM guests
 
 - Rename hex2bitmap() to ap_hex2bitmap() and export it for external use
 
 - Add ap_config sysfs attribute to provide the means for setting or
   displaying adapters, domains and control domains assigned to a vfio-ap
   mediated device in a single operation
 
 - Make vfio_ap_mdev_link_queue() ignore duplicate link requests
 
 - Add write support to ap_config sysfs attribute to allow atomic update
   a vfio-ap mediated device state
 
 - Document ap_config sysfs attribute
 
 - Function os_info_old_init() is expected to be called only from a regular
   kdump kernel. Enable it to be called from a stand-alone dump kernel
 
 - Address gcc -Warray-bounds warning and fix array size in struct os_info
 
 - s390 does not support SMBIOS, so drop unneeded CONFIG_DMI checks
 
 - Use unwinder instead of __builtin_return_address() with ftrace to
   prevent returning of undefined values
 
 - Sections .hash and .gnu.hash are only created when CONFIG_PIE_BUILD
   kernel is enabled. Drop these for the case CONFIG_PIE_BUILD is disabled
 
 - Compile kernel with -fPIC and link with -no-pie to allow kpatch feature
   always succeed and drop the whole CONFIG_PIE_BUILD option-enabled code
 
 - Add missing virt_to_phys() converter for VSIE facility and crypto
   control blocks
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Merge tag 's390-6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Alexander Gordeev:

 - Store AP Query Configuration Information in a static buffer

 - Rework the AP initialization and add missing cleanups to the error
   path

 - Swap IRQ and AP bus/device registration to avoid race conditions

 - Export prot_virt_guest symbol

 - Introduce AP configuration changes notifier interface to facilitate
   modularization of the AP bus

 - Add CONFIG_AP kernel configuration option to allow modularization of
   the AP bus

 - Rework CONFIG_ZCRYPT_DEBUG kernel configuration option description
   and dependency and rename it to CONFIG_AP_DEBUG

 - Convert sprintf() and snprintf() to sysfs_emit() in CIO code

 - Adjust indentation of RELOCS command build step

 - Make crypto performance counters upward compatible

 - Convert make_page_secure() and gmap_make_secure() to use folio

 - Rework channel-utilization-block (CUB) handling in preparation of
   introducing additional CUBs

 - Use attribute groups to simplify registration, removal and extension
   of measurement-related channel-path sysfs attributes

 - Add a per-channel-path binary "ext_measurement" sysfs attribute that
   provides access to extended channel-path measurement data

 - Export measurement data for all channel-measurement-groups (CMG), not
   only for a specific ones. This enables support of new CMG data
   formats in userspace without the need for kernel changes

 - Add a per-channel-path sysfs attribute "speed_bps" that provides the
   operating speed in bits per second or 0 if the operating speed is not
   available

 - The CIO tracepoint subchannel-type field "st" is incorrectly set to
   the value of subchannel-enabled SCHIB "ena" field. Fix that

 - Do not forcefully limit vmemmap starting address to MAX_PHYSMEM_BITS

 - Consider the maximum physical address available to a DCSS segment
   (512GB) when memory layout is set up

 - Simplify the virtual memory layout setup by reducing the size of
   identity mapping vs vmemmap overlap

 - Swap vmalloc and Lowcore/Real Memory Copy areas in virtual memory.
   This will allow to place the kernel image next to kernel modules

 - Move everyting KASLR related from <asm/setup.h> to <asm/page.h>

 - Put virtual memory layout information into a structure to improve
   code generation

 - Currently __kaslr_offset is the kernel offset in both physical and
   virtual memory spaces. Uncouple these offsets to allow uncoupling of
   the addresses spaces

 - Currently the identity mapping base address is implicit and is always
   set to zero. Make it explicit by putting into __identity_base
   persistent boot variable and use it in proper context

 - Introduce .amode31 section start and end macros AMODE31_START and
   AMODE31_END

 - Introduce OS_INFO entries that do not reference any data in memory,
   but rather provide only values

 - Store virtual memory layout in OS_INFO. It is read out by
   makedumpfile, crash and other tools

 - Store virtual memory layout in VMCORE_INFO. It is read out by crash
   and other tools when /proc/kcore device is used

 - Create additional PT_LOAD ELF program header that covers kernel image
   only, so that vmcore tools could locate kernel text and data when
   virtual and physical memory spaces are uncoupled

 - Uncouple physical and virtual address spaces

 - Map kernel at fixed location when KASLR mode is disabled. The
   location is defined by CONFIG_KERNEL_IMAGE_BASE kernel configuration
   value.

 - Rework deployment of kernel image for both compressed and
   uncompressed variants as defined by CONFIG_KERNEL_UNCOMPRESSED kernel
   configuration value

 - Move .vmlinux.relocs section in front of the compressed kernel. The
   interim section rescue step is avoided as result

 - Correct modules thunk offset calculation when branch target is more
   than 2GB away

 - Kernel modules contain their own set of expoline thunks. Now that the
   kernel modules area is less than 4GB away from kernel expoline
   thunks, make modules use kernel expolines. Also make EXPOLINE_EXTERN
   the default if the compiler supports it

 - userfaultfd can insert shared zeropages into processes running VMs,
   but that is not allowed for s390. Fallback to allocating a fresh
   zeroed anonymous folio and insert that instead

 - Re-enable shared zeropages for non-PV and non-skeys KVM guests

 - Rename hex2bitmap() to ap_hex2bitmap() and export it for external use

 - Add ap_config sysfs attribute to provide the means for setting or
   displaying adapters, domains and control domains assigned to a
   vfio-ap mediated device in a single operation

 - Make vfio_ap_mdev_link_queue() ignore duplicate link requests

 - Add write support to ap_config sysfs attribute to allow atomic update
   a vfio-ap mediated device state

 - Document ap_config sysfs attribute

 - Function os_info_old_init() is expected to be called only from a
   regular kdump kernel. Enable it to be called from a stand-alone dump
   kernel

 - Address gcc -Warray-bounds warning and fix array size in struct
   os_info

 - s390 does not support SMBIOS, so drop unneeded CONFIG_DMI checks

 - Use unwinder instead of __builtin_return_address() with ftrace to
   prevent returning of undefined values

 - Sections .hash and .gnu.hash are only created when CONFIG_PIE_BUILD
   kernel is enabled. Drop these for the case CONFIG_PIE_BUILD is
   disabled

 - Compile kernel with -fPIC and link with -no-pie to allow kpatch
   feature always succeed and drop the whole CONFIG_PIE_BUILD
   option-enabled code

 - Add missing virt_to_phys() converter for VSIE facility and crypto
   control blocks

* tag 's390-6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (54 commits)
  Revert "s390: Relocate vmlinux ELF data to virtual address space"
  KVM: s390: vsie: Use virt_to_phys for crypto control block
  s390: Relocate vmlinux ELF data to virtual address space
  s390: Compile kernel with -fPIC and link with -no-pie
  s390: vmlinux.lds.S: Drop .hash and .gnu.hash for !CONFIG_PIE_BUILD
  s390/ftrace: Use unwinder instead of __builtin_return_address()
  s390/pci: Drop unneeded reference to CONFIG_DMI
  s390/os_info: Fix array size in struct os_info
  s390/os_info: Initialize old os_info in standalone dump kernel
  docs: Update s390 vfio-ap doc for ap_config sysfs attribute
  s390/vfio-ap: Add write support to sysfs attr ap_config
  s390/vfio-ap: Ignore duplicate link requests in vfio_ap_mdev_link_queue
  s390/vfio-ap: Add sysfs attr, ap_config, to export mdev state
  s390/ap: Externalize AP bus specific bitmap reading function
  s390/mm: Re-enable the shared zeropage for !PV and !skeys KVM guests
  mm/userfaultfd: Do not place zeropages when zeropages are disallowed
  s390/expoline: Make modules use kernel expolines
  s390/nospec: Correct modules thunk offset calculation
  s390/boot: Do not rescue .vmlinux.relocs section
  s390/boot: Rework deployment of the kernel image
  ...
2024-05-13 08:33:52 -07:00
Jean-Philippe Brucker
175f2f5bcd KVM: s390: Check kvm pointer when testing KVM_CAP_S390_HPAGE_1M
KVM allows issuing the KVM_CHECK_EXTENSION ioctl either on the /dev/kvm
fd or the VM fd. In the first case, kvm_vm_ioctl_check_extension() is
called with kvm==NULL. Ensure we don't dereference the pointer in that
case.

Fixes: 40ebdb8e59 ("KVM: s390: Make huge pages unavailable in ucontrol VMs")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Message-ID: <20240419160723.320910-2-jean-philippe@linaro.org>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
2024-05-02 09:41:38 +02:00
David Hildenbrand
06201e00ee s390/mm: Re-enable the shared zeropage for !PV and !skeys KVM guests
commit fa41ba0d08 ("s390/mm: avoid empty zero pages for KVM guests to
avoid postcopy hangs") introduced an undesired side effect when combined
with memory ballooning and VM migration: memory part of the inflated
memory balloon will consume memory.

Assuming we have a 100GiB VM and inflated the balloon to 40GiB. Our VM
will consume ~60GiB of memory. If we now trigger a VM migration,
hypervisors like QEMU will read all VM memory. As s390x does not support
the shared zeropage, we'll end up allocating for all previously-inflated
memory part of the memory balloon: 50 GiB. So we might easily
(unexpectedly) crash the VM on the migration source.

Even worse, hypervisors like QEMU optimize for zeropage migration to not
consume memory on the migration destination: when migrating a
"page full of zeroes", on the migration destination they check whether the
target memory is already zero (by reading the destination memory) and avoid
writing to the memory to not allocate memory: however, s390x will also
allocate memory here, implying that also on the migration destination, we
will end up allocating all previously-inflated memory part of the memory
balloon.

This is especially bad if actual memory overcommit was not desired, when
memory ballooning is used for dynamic VM memory resizing, setting aside
some memory during boot that can be added later on demand. Alternatives
like virtio-mem that would avoid this issue are not yet available on
s390x.

There could be ways to optimize some cases in user space: before reading
memory in an anonymous private mapping on the migration source, check via
/proc/self/pagemap if anything is already populated. Similarly check on
the migration destination before reading. While that would avoid
populating tables full of shared zeropages on all architectures, it's
harder to get right and performant, and requires user space changes.

Further, with posctopy live migration we must place a page, so there,
"avoid touching memory to avoid allocating memory" is not really
possible. (Note that a previously we would have falsely inserted
shared zeropages into processes using UFFDIO_ZEROPAGE where
mm_forbids_zeropage() would have actually forbidden it)

PV is currently incompatible with memory ballooning, and in the common
case, KVM guests don't make use of storage keys. Instead of zapping
zeropages when enabling storage keys / PV, that turned out to be
problematic in the past, let's do exactly the same we do with KSM pages:
trigger unsharing faults to replace the shared zeropages by proper
anonymous folios.

What about added latency when enabling storage kes? Having a lot of
zeropages in applicable environments (PV, legacy guests, unittests) is
unexpected. Further, KSM could today already unshare the zeropages
and unmerging KSM pages when enabling storage kets would unshare the
KSM-placed zeropages in the same way, resulting in the same latency.

[ agordeev: Fixed sparse and checkpatch complaints and error handling ]

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Fixes: fa41ba0d08 ("s390/mm: avoid empty zero pages for KVM guests to avoid postcopy hangs")
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20240411161441.910170-3-david@redhat.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-04-18 15:02:53 +02:00
Linus Torvalds
4f712ee0cb S390:
* Changes to FPU handling came in via the main s390 pull request
 
 * Only deliver to the guest the SCLP events that userspace has
   requested.
 
 * More virtual vs physical address fixes (only a cleanup since
   virtual and physical address spaces are currently the same).
 
 * Fix selftests undefined behavior.
 
 x86:
 
 * Fix a restriction that the guest can't program a PMU event whose
   encoding matches an architectural event that isn't included in the
   guest CPUID.  The enumeration of an architectural event only says
   that if a CPU supports an architectural event, then the event can be
   programmed *using the architectural encoding*.  The enumeration does
   NOT say anything about the encoding when the CPU doesn't report support
   the event *in general*.  It might support it, and it might support it
   using the same encoding that made it into the architectural PMU spec.
 
 * Fix a variety of bugs in KVM's emulation of RDPMC (more details on
   individual commits) and add a selftest to verify KVM correctly emulates
   RDMPC, counter availability, and a variety of other PMC-related
   behaviors that depend on guest CPUID and therefore are easier to
   validate with selftests than with custom guests (aka kvm-unit-tests).
 
 * Zero out PMU state on AMD if the virtual PMU is disabled, it does not
   cause any bug but it wastes time in various cases where KVM would check
   if a PMC event needs to be synthesized.
 
 * Optimize triggering of emulated events, with a nice ~10% performance
   improvement in VM-Exit microbenchmarks when a vPMU is exposed to the
   guest.
 
 * Tighten the check for "PMI in guest" to reduce false positives if an NMI
   arrives in the host while KVM is handling an IRQ VM-Exit.
 
 * Fix a bug where KVM would report stale/bogus exit qualification information
   when exiting to userspace with an internal error exit code.
 
 * Add a VMX flag in /proc/cpuinfo to report 5-level EPT support.
 
 * Rework TDP MMU root unload, free, and alloc to run with mmu_lock held for
   read, e.g. to avoid serializing vCPUs when userspace deletes a memslot.
 
 * Tear down TDP MMU page tables at 4KiB granularity (used to be 1GiB).  KVM
   doesn't support yielding in the middle of processing a zap, and 1GiB
   granularity resulted in multi-millisecond lags that are quite impolite
   for CONFIG_PREEMPT kernels.
 
 * Allocate write-tracking metadata on-demand to avoid the memory overhead when
   a kernel is built with i915 virtualization support but the workloads use
   neither shadow paging nor i915 virtualization.
 
 * Explicitly initialize a variety of on-stack variables in the emulator that
   triggered KMSAN false positives.
 
 * Fix the debugregs ABI for 32-bit KVM.
 
 * Rework the "force immediate exit" code so that vendor code ultimately decides
   how and when to force the exit, which allowed some optimization for both
   Intel and AMD.
 
 * Fix a long-standing bug where kvm_has_noapic_vcpu could be left elevated if
   vCPU creation ultimately failed, causing extra unnecessary work.
 
 * Cleanup the logic for checking if the currently loaded vCPU is in-kernel.
 
 * Harden against underflowing the active mmu_notifier invalidation
   count, so that "bad" invalidations (usually due to bugs elsehwere in the
   kernel) are detected earlier and are less likely to hang the kernel.
 
 x86 Xen emulation:
 
 * Overlay pages can now be cached based on host virtual address,
   instead of guest physical addresses.  This removes the need to
   reconfigure and invalidate the cache if the guest changes the
   gpa but the underlying host virtual address remains the same.
 
 * When possible, use a single host TSC value when computing the deadline for
   Xen timers in order to improve the accuracy of the timer emulation.
 
 * Inject pending upcall events when the vCPU software-enables its APIC to fix
   a bug where an upcall can be lost (and to follow Xen's behavior).
 
 * Fall back to the slow path instead of warning if "fast" IRQ delivery of Xen
   events fails, e.g. if the guest has aliased xAPIC IDs.
 
 RISC-V:
 
 * Support exception and interrupt handling in selftests
 
 * New self test for RISC-V architectural timer (Sstc extension)
 
 * New extension support (Ztso, Zacas)
 
 * Support userspace emulation of random number seed CSRs.
 
 ARM:
 
 * Infrastructure for building KVM's trap configuration based on the
   architectural features (or lack thereof) advertised in the VM's ID
   registers
 
 * Support for mapping vfio-pci BARs as Normal-NC (vaguely similar to
   x86's WC) at stage-2, improving the performance of interacting with
   assigned devices that can tolerate it
 
 * Conversion of KVM's representation of LPIs to an xarray, utilized to
   address serialization some of the serialization on the LPI injection
   path
 
 * Support for _architectural_ VHE-only systems, advertised through the
   absence of FEAT_E2H0 in the CPU's ID register
 
 * Miscellaneous cleanups, fixes, and spelling corrections to KVM and
   selftests
 
 LoongArch:
 
 * Set reserved bits as zero in CPUCFG.
 
 * Start SW timer only when vcpu is blocking.
 
 * Do not restart SW timer when it is expired.
 
 * Remove unnecessary CSR register saving during enter guest.
 
 * Misc cleanups and fixes as usual.
 
 Generic:
 
 * cleanup Kconfig by removing CONFIG_HAVE_KVM, which was basically always
   true on all architectures except MIPS (where Kconfig determines the
   available depending on CPU capabilities).  It is replaced either by
   an architecture-dependent symbol for MIPS, and IS_ENABLED(CONFIG_KVM)
   everywhere else.
 
 * Factor common "select" statements in common code instead of requiring
   each architecture to specify it
 
 * Remove thoroughly obsolete APIs from the uapi headers.
 
 * Move architecture-dependent stuff to uapi/asm/kvm.h
 
 * Always flush the async page fault workqueue when a work item is being
   removed, especially during vCPU destruction, to ensure that there are no
   workers running in KVM code when all references to KVM-the-module are gone,
   i.e. to prevent a very unlikely use-after-free if kvm.ko is unloaded.
 
 * Grab a reference to the VM's mm_struct in the async #PF worker itself instead
   of gifting the worker a reference, so that there's no need to remember
   to *conditionally* clean up after the worker.
 
 Selftests:
 
 * Reduce boilerplate especially when utilize selftest TAP infrastructure.
 
 * Add basic smoke tests for SEV and SEV-ES, along with a pile of library
   support for handling private/encrypted/protected memory.
 
 * Fix benign bugs where tests neglect to close() guest_memfd files.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "S390:

   - Changes to FPU handling came in via the main s390 pull request

   - Only deliver to the guest the SCLP events that userspace has
     requested

   - More virtual vs physical address fixes (only a cleanup since
     virtual and physical address spaces are currently the same)

   - Fix selftests undefined behavior

  x86:

   - Fix a restriction that the guest can't program a PMU event whose
     encoding matches an architectural event that isn't included in the
     guest CPUID. The enumeration of an architectural event only says
     that if a CPU supports an architectural event, then the event can
     be programmed *using the architectural encoding*. The enumeration
     does NOT say anything about the encoding when the CPU doesn't
     report support the event *in general*. It might support it, and it
     might support it using the same encoding that made it into the
     architectural PMU spec

   - Fix a variety of bugs in KVM's emulation of RDPMC (more details on
     individual commits) and add a selftest to verify KVM correctly
     emulates RDMPC, counter availability, and a variety of other
     PMC-related behaviors that depend on guest CPUID and therefore are
     easier to validate with selftests than with custom guests (aka
     kvm-unit-tests)

   - Zero out PMU state on AMD if the virtual PMU is disabled, it does
     not cause any bug but it wastes time in various cases where KVM
     would check if a PMC event needs to be synthesized

   - Optimize triggering of emulated events, with a nice ~10%
     performance improvement in VM-Exit microbenchmarks when a vPMU is
     exposed to the guest

   - Tighten the check for "PMI in guest" to reduce false positives if
     an NMI arrives in the host while KVM is handling an IRQ VM-Exit

   - Fix a bug where KVM would report stale/bogus exit qualification
     information when exiting to userspace with an internal error exit
     code

   - Add a VMX flag in /proc/cpuinfo to report 5-level EPT support

   - Rework TDP MMU root unload, free, and alloc to run with mmu_lock
     held for read, e.g. to avoid serializing vCPUs when userspace
     deletes a memslot

   - Tear down TDP MMU page tables at 4KiB granularity (used to be
     1GiB). KVM doesn't support yielding in the middle of processing a
     zap, and 1GiB granularity resulted in multi-millisecond lags that
     are quite impolite for CONFIG_PREEMPT kernels

   - Allocate write-tracking metadata on-demand to avoid the memory
     overhead when a kernel is built with i915 virtualization support
     but the workloads use neither shadow paging nor i915 virtualization

   - Explicitly initialize a variety of on-stack variables in the
     emulator that triggered KMSAN false positives

   - Fix the debugregs ABI for 32-bit KVM

   - Rework the "force immediate exit" code so that vendor code
     ultimately decides how and when to force the exit, which allowed
     some optimization for both Intel and AMD

   - Fix a long-standing bug where kvm_has_noapic_vcpu could be left
     elevated if vCPU creation ultimately failed, causing extra
     unnecessary work

   - Cleanup the logic for checking if the currently loaded vCPU is
     in-kernel

   - Harden against underflowing the active mmu_notifier invalidation
     count, so that "bad" invalidations (usually due to bugs elsehwere
     in the kernel) are detected earlier and are less likely to hang the
     kernel

  x86 Xen emulation:

   - Overlay pages can now be cached based on host virtual address,
     instead of guest physical addresses. This removes the need to
     reconfigure and invalidate the cache if the guest changes the gpa
     but the underlying host virtual address remains the same

   - When possible, use a single host TSC value when computing the
     deadline for Xen timers in order to improve the accuracy of the
     timer emulation

   - Inject pending upcall events when the vCPU software-enables its
     APIC to fix a bug where an upcall can be lost (and to follow Xen's
     behavior)

   - Fall back to the slow path instead of warning if "fast" IRQ
     delivery of Xen events fails, e.g. if the guest has aliased xAPIC
     IDs

  RISC-V:

   - Support exception and interrupt handling in selftests

   - New self test for RISC-V architectural timer (Sstc extension)

   - New extension support (Ztso, Zacas)

   - Support userspace emulation of random number seed CSRs

  ARM:

   - Infrastructure for building KVM's trap configuration based on the
     architectural features (or lack thereof) advertised in the VM's ID
     registers

   - Support for mapping vfio-pci BARs as Normal-NC (vaguely similar to
     x86's WC) at stage-2, improving the performance of interacting with
     assigned devices that can tolerate it

   - Conversion of KVM's representation of LPIs to an xarray, utilized
     to address serialization some of the serialization on the LPI
     injection path

   - Support for _architectural_ VHE-only systems, advertised through
     the absence of FEAT_E2H0 in the CPU's ID register

   - Miscellaneous cleanups, fixes, and spelling corrections to KVM and
     selftests

  LoongArch:

   - Set reserved bits as zero in CPUCFG

   - Start SW timer only when vcpu is blocking

   - Do not restart SW timer when it is expired

   - Remove unnecessary CSR register saving during enter guest

   - Misc cleanups and fixes as usual

  Generic:

   - Clean up Kconfig by removing CONFIG_HAVE_KVM, which was basically
     always true on all architectures except MIPS (where Kconfig
     determines the available depending on CPU capabilities). It is
     replaced either by an architecture-dependent symbol for MIPS, and
     IS_ENABLED(CONFIG_KVM) everywhere else

   - Factor common "select" statements in common code instead of
     requiring each architecture to specify it

   - Remove thoroughly obsolete APIs from the uapi headers

   - Move architecture-dependent stuff to uapi/asm/kvm.h

   - Always flush the async page fault workqueue when a work item is
     being removed, especially during vCPU destruction, to ensure that
     there are no workers running in KVM code when all references to
     KVM-the-module are gone, i.e. to prevent a very unlikely
     use-after-free if kvm.ko is unloaded

   - Grab a reference to the VM's mm_struct in the async #PF worker
     itself instead of gifting the worker a reference, so that there's
     no need to remember to *conditionally* clean up after the worker

  Selftests:

   - Reduce boilerplate especially when utilize selftest TAP
     infrastructure

   - Add basic smoke tests for SEV and SEV-ES, along with a pile of
     library support for handling private/encrypted/protected memory

   - Fix benign bugs where tests neglect to close() guest_memfd files"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (246 commits)
  selftests: kvm: remove meaningless assignments in Makefiles
  KVM: riscv: selftests: Add Zacas extension to get-reg-list test
  RISC-V: KVM: Allow Zacas extension for Guest/VM
  KVM: riscv: selftests: Add Ztso extension to get-reg-list test
  RISC-V: KVM: Allow Ztso extension for Guest/VM
  RISC-V: KVM: Forward SEED CSR access to user space
  KVM: riscv: selftests: Add sstc timer test
  KVM: riscv: selftests: Change vcpu_has_ext to a common function
  KVM: riscv: selftests: Add guest helper to get vcpu id
  KVM: riscv: selftests: Add exception handling support
  LoongArch: KVM: Remove unnecessary CSR register saving during enter guest
  LoongArch: KVM: Do not restart SW timer when it is expired
  LoongArch: KVM: Start SW timer only when vcpu is blocking
  LoongArch: KVM: Set reserved bits as zero in CPUCFG
  KVM: selftests: Explicitly close guest_memfd files in some gmem tests
  KVM: x86/xen: fix recursive deadlock in timer injection
  KVM: pfncache: simplify locking and make more self-contained
  KVM: x86/xen: remove WARN_ON_ONCE() with false positives in evtchn delivery
  KVM: x86/xen: inject vCPU upcall vector when local APIC is enabled
  KVM: x86/xen: improve accuracy of Xen timers
  ...
2024-03-15 13:03:13 -07:00
Paolo Bonzini
17193ced2d - Memop selftest rotate fix
- SCLP event bits over indication fix
 - Missing virt_to_phys for the CRYCB fix
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Merge tag 'kvm-s390-next-6.9-1' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

- Memop selftest rotate fix
- SCLP event bits over indication fix
- Missing virt_to_phys for the CRYCB fix
2024-03-14 14:47:56 -04:00
Eric Farman
01be7f53df KVM: s390: fix access register usage in ioctls
The routine ar_translation() can be reached by both the instruction
intercept path (where the access registers had been loaded with the
guest register contents), and the MEM_OP ioctls (which hadn't).
Since this routine saves the current registers to vcpu->run,
this routine erroneously saves host registers into the guest space.

Introduce a boolean in the kvm_vcpu_arch struct to indicate whether
the registers contain guest contents. If they do (the instruction
intercept path), the save can be performed and the AR translation
is done just as it is today. If they don't (the MEM_OP path), the
AR can be read from vcpu->run without stashing the current contents.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20240220211211.3102609-2-farman@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-22 16:06:56 +01:00
Janosch Frank
4a59932874 KVM: s390: introduce kvm_s390_fpu_(store|load)
It's a bit nicer than having multiple lines and will help if there's
another re-work since we'll only have to change one location.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-21 15:09:13 +01:00
Sean Christopherson
9e7325acb3 KVM: s390: Refactor kvm_is_error_gpa() into kvm_is_gpa_in_memslot()
Rename kvm_is_error_gpa() to kvm_is_gpa_in_memslot() and invert the
polarity accordingly in order to (a) free up kvm_is_error_gpa() to match
with kvm_is_error_{hva,page}(), and (b) to make it more obvious that the
helper is doing a memslot lookup, i.e. not simply checking for INVALID_GPA.

No functional change intended.

Link: https://lore.kernel.org/r/20240215152916.1158-9-paul@xen.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-02-20 07:37:45 -08:00
Heiko Carstens
066c40918b s390/fpu: decrease stack usage for some cases
The kernel_fpu structure has a quite large size of 520 bytes. In order to
reduce stack footprint introduce several kernel fpu structures with
different and also smaller sizes. This way every kernel fpu user must use
the correct variant. A compile time check verifies that the correct variant
is used.

There are several users which use only 16 instead of all 32 vector
registers. For those users the new kernel_fpu_16 structure with a size of
only 266 bytes can be used.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-16 14:30:16 +01:00
Heiko Carstens
ed3a0a011a s390/kvm: convert to regular kernel fpu user
KVM modifies the kernel fpu's regs pointer to its own area to implement its
custom version of preemtible kernel fpu context. With general support for
preemptible kernel fpu context there is no need for the extra complexity in
KVM code anymore.

Therefore convert KVM to a regular kernel fpu user. In particular this
means that all TIF_FPU checks can be removed, since the fpu register
context will never be changed by other kernel fpu users, and also the fpu
register context will be restored if a thread is preempted.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-16 14:30:16 +01:00
Heiko Carstens
87c5c70036 s390/fpu: rename save_fpu_regs() to save_user_fpu_regs(), etc
Rename save_fpu_regs(), load_fpu_regs(), and struct thread_struct's fpu
member to save_user_fpu_regs(), load_user_fpu_regs(), and ufpu. This way
the function and variable names reflect for which context they are supposed
to be used.

This large and trivial conversion is a prerequisite for making the kernel
fpu usage preemptible.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-16 14:30:15 +01:00
Heiko Carstens
419abc4d38 s390/fpu: convert FPU CIF flag to regular TIF flag
The FPU state, as represented by the CIF_FPU flag reflects the FPU state of
a task, not the CPU it is running on. Therefore convert the flag to a
regular TIF flag.

This removes the magic in switch_to() where a save_fpu_regs() call for the
currently (previous) running task sets the per-cpu CIF_FPU flag, which is
required to restore FPU register contents of the next task, when it returns
to user space.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-16 14:30:15 +01:00
Heiko Carstens
fd2527f209 s390/fpu: move, rename, and merge header files
Move, rename, and merge the fpu and vx header files. This way fpu header
files have a consistent naming scheme (fpu*.h).

Also get rid of the fpu subdirectory and move header files to asm
directory, so that all fpu and vx header files can be found at the same
location.

Merge internal.h header file into other header files, since the internal
helpers are used at many locations. so those helper functions are really
not internal.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-16 14:30:14 +01:00
Alexander Gordeev
7b2411e793 KVM: s390: fix virtual vs physical address confusion
Fix virtual vs physical address confusion. This does not fix a bug
since virtual and physical address spaces are currently the same.

Suggested-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2024-02-14 16:25:29 +01:00
Heiko Carstens
304103736b s390/acrs: cleanup access register handling
save_access_regs() and restore_access_regs() are only available by
including switch_to.h. This is done by a couple of C files, which have
nothing to do with switch_to(), but only need these functions.

Move both functions to a new header file and improve the implementation:

- Get rid of typedef

- Add memory access instrumentation support

- Use long displacement instructions lamy/stamy instead of lam/stam - all
  current users end up with better code because of this

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2024-02-12 15:03:33 +01:00
Linus Torvalds
09d1c6a80f Generic:
- Use memdup_array_user() to harden against overflow.
 
 - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
 
 - Clean up Kconfigs that all KVM architectures were selecting
 
 - New functionality around "guest_memfd", a new userspace API that
   creates an anonymous file and returns a file descriptor that refers
   to it.  guest_memfd files are bound to their owning virtual machine,
   cannot be mapped, read, or written by userspace, and cannot be resized.
   guest_memfd files do however support PUNCH_HOLE, which can be used to
   switch a memory area between guest_memfd and regular anonymous memory.
 
 - New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify
   per-page attributes for a given page of guest memory; right now the
   only attribute is whether the guest expects to access memory via
   guest_memfd or not, which in Confidential SVMs backed by SEV-SNP,
   TDX or ARM64 pKVM is checked by firmware or hypervisor that guarantees
   confidentiality (AMD PSP, Intel TDX module, or EL2 in the case of pKVM).
 
 x86:
 
 - Support for "software-protected VMs" that can use the new guest_memfd
   and page attributes infrastructure.  This is mostly useful for testing,
   since there is no pKVM-like infrastructure to provide a meaningfully
   reduced TCB.
 
 - Fix a relatively benign off-by-one error when splitting huge pages during
   CLEAR_DIRTY_LOG.
 
 - Fix a bug where KVM could incorrectly test-and-clear dirty bits in non-leaf
   TDP MMU SPTEs if a racing thread replaces a huge SPTE with a non-huge SPTE.
 
 - Use more generic lockdep assertions in paths that don't actually care
   about whether the caller is a reader or a writer.
 
 - let Xen guests opt out of having PV clock reported as "based on a stable TSC",
   because some of them don't expect the "TSC stable" bit (added to the pvclock
   ABI by KVM, but never set by Xen) to be set.
 
 - Revert a bogus, made-up nested SVM consistency check for TLB_CONTROL.
 
 - Advertise flush-by-ASID support for nSVM unconditionally, as KVM always
   flushes on nested transitions, i.e. always satisfies flush requests.  This
   allows running bleeding edge versions of VMware Workstation on top of KVM.
 
 - Sanity check that the CPU supports flush-by-ASID when enabling SEV support.
 
 - On AMD machines with vNMI, always rely on hardware instead of intercepting
   IRET in some cases to detect unmasking of NMIs
 
 - Support for virtualizing Linear Address Masking (LAM)
 
 - Fix a variety of vPMU bugs where KVM fail to stop/reset counters and other state
   prior to refreshing the vPMU model.
 
 - Fix a double-overflow PMU bug by tracking emulated counter events using a
   dedicated field instead of snapshotting the "previous" counter.  If the
   hardware PMC count triggers overflow that is recognized in the same VM-Exit
   that KVM manually bumps an event count, KVM would pend PMIs for both the
   hardware-triggered overflow and for KVM-triggered overflow.
 
 - Turn off KVM_WERROR by default for all configs so that it's not
   inadvertantly enabled by non-KVM developers, which can be problematic for
   subsystems that require no regressions for W=1 builds.
 
 - Advertise all of the host-supported CPUID bits that enumerate IA32_SPEC_CTRL
   "features".
 
 - Don't force a masterclock update when a vCPU synchronizes to the current TSC
   generation, as updating the masterclock can cause kvmclock's time to "jump"
   unexpectedly, e.g. when userspace hotplugs a pre-created vCPU.
 
 - Use RIP-relative address to read kvm_rebooting in the VM-Enter fault paths,
   partly as a super minor optimization, but mostly to make KVM play nice with
   position independent executable builds.
 
 - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on
   CONFIG_HYPERV as a minor optimization, and to self-document the code.
 
 - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV "emulation"
   at build time.
 
 ARM64:
 
 - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB
   base granule sizes. Branch shared with the arm64 tree.
 
 - Large Fine-Grained Trap rework, bringing some sanity to the
   feature, although there is more to come. This comes with
   a prefix branch shared with the arm64 tree.
 
 - Some additional Nested Virtualization groundwork, mostly
   introducing the NV2 VNCR support and retargetting the NV
   support to that version of the architecture.
 
 - A small set of vgic fixes and associated cleanups.
 
 Loongarch:
 
 - Optimization for memslot hugepage checking
 
 - Cleanup and fix some HW/SW timer issues
 
 - Add LSX/LASX (128bit/256bit SIMD) support
 
 RISC-V:
 
 - KVM_GET_REG_LIST improvement for vector registers
 
 - Generate ISA extension reg_list using macros in get-reg-list selftest
 
 - Support for reporting steal time along with selftest
 
 s390:
 
 - Bugfixes
 
 Selftests:
 
 - Fix an annoying goof where the NX hugepage test prints out garbage
   instead of the magic token needed to run the test.
 
 - Fix build errors when a header is delete/moved due to a missing flag
   in the Makefile.
 
 - Detect if KVM bugged/killed a selftest's VM and print out a helpful
   message instead of complaining that a random ioctl() failed.
 
 - Annotate the guest printf/assert helpers with __printf(), and fix the
   various bugs that were lurking due to lack of said annotation.
 
 There are two non-KVM patches buried in the middle of guest_memfd support:
 
   fs: Rename anon_inode_getfile_secure() and anon_inode_getfd_secure()
   mm: Add AS_UNMOVABLE to mark mapping as completely unmovable
 
 The first is small and mostly suggested-by Christian Brauner; the second
 a bit less so but it was written by an mm person (Vlastimil Babka).
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "Generic:

   - Use memdup_array_user() to harden against overflow.

   - Unconditionally advertise KVM_CAP_DEVICE_CTRL for all
     architectures.

   - Clean up Kconfigs that all KVM architectures were selecting

   - New functionality around "guest_memfd", a new userspace API that
     creates an anonymous file and returns a file descriptor that refers
     to it. guest_memfd files are bound to their owning virtual machine,
     cannot be mapped, read, or written by userspace, and cannot be
     resized. guest_memfd files do however support PUNCH_HOLE, which can
     be used to switch a memory area between guest_memfd and regular
     anonymous memory.

   - New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify
     per-page attributes for a given page of guest memory; right now the
     only attribute is whether the guest expects to access memory via
     guest_memfd or not, which in Confidential SVMs backed by SEV-SNP,
     TDX or ARM64 pKVM is checked by firmware or hypervisor that
     guarantees confidentiality (AMD PSP, Intel TDX module, or EL2 in
     the case of pKVM).

  x86:

   - Support for "software-protected VMs" that can use the new
     guest_memfd and page attributes infrastructure. This is mostly
     useful for testing, since there is no pKVM-like infrastructure to
     provide a meaningfully reduced TCB.

   - Fix a relatively benign off-by-one error when splitting huge pages
     during CLEAR_DIRTY_LOG.

   - Fix a bug where KVM could incorrectly test-and-clear dirty bits in
     non-leaf TDP MMU SPTEs if a racing thread replaces a huge SPTE with
     a non-huge SPTE.

   - Use more generic lockdep assertions in paths that don't actually
     care about whether the caller is a reader or a writer.

   - let Xen guests opt out of having PV clock reported as "based on a
     stable TSC", because some of them don't expect the "TSC stable" bit
     (added to the pvclock ABI by KVM, but never set by Xen) to be set.

   - Revert a bogus, made-up nested SVM consistency check for
     TLB_CONTROL.

   - Advertise flush-by-ASID support for nSVM unconditionally, as KVM
     always flushes on nested transitions, i.e. always satisfies flush
     requests. This allows running bleeding edge versions of VMware
     Workstation on top of KVM.

   - Sanity check that the CPU supports flush-by-ASID when enabling SEV
     support.

   - On AMD machines with vNMI, always rely on hardware instead of
     intercepting IRET in some cases to detect unmasking of NMIs

   - Support for virtualizing Linear Address Masking (LAM)

   - Fix a variety of vPMU bugs where KVM fail to stop/reset counters
     and other state prior to refreshing the vPMU model.

   - Fix a double-overflow PMU bug by tracking emulated counter events
     using a dedicated field instead of snapshotting the "previous"
     counter. If the hardware PMC count triggers overflow that is
     recognized in the same VM-Exit that KVM manually bumps an event
     count, KVM would pend PMIs for both the hardware-triggered overflow
     and for KVM-triggered overflow.

   - Turn off KVM_WERROR by default for all configs so that it's not
     inadvertantly enabled by non-KVM developers, which can be
     problematic for subsystems that require no regressions for W=1
     builds.

   - Advertise all of the host-supported CPUID bits that enumerate
     IA32_SPEC_CTRL "features".

   - Don't force a masterclock update when a vCPU synchronizes to the
     current TSC generation, as updating the masterclock can cause
     kvmclock's time to "jump" unexpectedly, e.g. when userspace
     hotplugs a pre-created vCPU.

   - Use RIP-relative address to read kvm_rebooting in the VM-Enter
     fault paths, partly as a super minor optimization, but mostly to
     make KVM play nice with position independent executable builds.

   - Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on
     CONFIG_HYPERV as a minor optimization, and to self-document the
     code.

   - Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV
     "emulation" at build time.

  ARM64:

   - LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB base
     granule sizes. Branch shared with the arm64 tree.

   - Large Fine-Grained Trap rework, bringing some sanity to the
     feature, although there is more to come. This comes with a prefix
     branch shared with the arm64 tree.

   - Some additional Nested Virtualization groundwork, mostly
     introducing the NV2 VNCR support and retargetting the NV support to
     that version of the architecture.

   - A small set of vgic fixes and associated cleanups.

  Loongarch:

   - Optimization for memslot hugepage checking

   - Cleanup and fix some HW/SW timer issues

   - Add LSX/LASX (128bit/256bit SIMD) support

  RISC-V:

   - KVM_GET_REG_LIST improvement for vector registers

   - Generate ISA extension reg_list using macros in get-reg-list
     selftest

   - Support for reporting steal time along with selftest

  s390:

   - Bugfixes

  Selftests:

   - Fix an annoying goof where the NX hugepage test prints out garbage
     instead of the magic token needed to run the test.

   - Fix build errors when a header is delete/moved due to a missing
     flag in the Makefile.

   - Detect if KVM bugged/killed a selftest's VM and print out a helpful
     message instead of complaining that a random ioctl() failed.

   - Annotate the guest printf/assert helpers with __printf(), and fix
     the various bugs that were lurking due to lack of said annotation"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (185 commits)
  x86/kvm: Do not try to disable kvmclock if it was not enabled
  KVM: x86: add missing "depends on KVM"
  KVM: fix direction of dependency on MMU notifiers
  KVM: introduce CONFIG_KVM_COMMON
  KVM: arm64: Add missing memory barriers when switching to pKVM's hyp pgd
  KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
  RISC-V: KVM: selftests: Add get-reg-list test for STA registers
  RISC-V: KVM: selftests: Add steal_time test support
  RISC-V: KVM: selftests: Add guest_sbi_probe_extension
  RISC-V: KVM: selftests: Move sbi_ecall to processor.c
  RISC-V: KVM: Implement SBI STA extension
  RISC-V: KVM: Add support for SBI STA registers
  RISC-V: KVM: Add support for SBI extension registers
  RISC-V: KVM: Add SBI STA info to vcpu_arch
  RISC-V: KVM: Add steal-update vcpu request
  RISC-V: KVM: Add SBI STA extension skeleton
  RISC-V: paravirt: Implement steal-time support
  RISC-V: Add SBI STA extension definitions
  RISC-V: paravirt: Add skeleton for pv-time support
  RISC-V: KVM: Fix indentation in kvm_riscv_vcpu_set_reg_csr()
  ...
2024-01-17 13:03:37 -08:00
Heiko Carstens
18564756ab s390/fpu: get rid of MACHINE_HAS_VX
Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx() which is a
short readable wrapper for "test_facility(129)".

Facility bit 129 is set if the vector facility is present. test_facility()
returns also true for all bits which are set in the architecture level set
of the cpu that the kernel is compiled for. This means that
test_facility(129) is a compile time constant which returns true for z13
and later, since the vector facility bit is part of the z13 kernel ALS.

In result the compiled code will have less runtime checks, and less code.

Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-12-11 14:33:07 +01:00
Heiko Carstens
d7271ba401 KVM: s390: remove superfluous save_fpu_regs() call
The save_fpu_regs() call in kvm_arch_vcpu_ioctl_get_fpu() is pointless: it
will save the current user space fpu context to the thread's save area. But
the code is accessing only the vcpu's save are / mapped register area,
which in this case are not the same.

Therefore remove the confusing call.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-12-11 14:33:06 +01:00
Heiko Carstens
702644249d s390/fpu: get rid of test_fp_ctl()
It is quite subtle to use test_fp_ctl() correctly. Therefore remove it -
instead copy whatever new floating point control (fpc) register values are
supposed to be used into its save area.

Test the validity of the new value when loading it. If the new value is
invalid, load the fpc register with zero.

This seems to be a the best way to approach this problem. Even though this
changes behavior:

- sigreturn with an invalid fpc value on the stack will succeed, and
  continue with zero value, instead of returning with SIGSEGV

- ptraced processes will also use a zero value instead of letting the
  request fail with -EINVAL

However all of this seems to acceptable. After all testing of the value was
only implemented to avoid that user space can crash the kernel. It is not
there to test values for validity; and the assumption is that there is no
existing user space which is doing this.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-12-11 14:33:06 +01:00
Heiko Carstens
3b2e00f167 KVM: s390: use READ_ONCE() to read fpc register value
Use READ_ONCE() to read a vcpu's floating point register value from
the memory mapped area. This avoids that, depending on code
generation, a different value is tested for validity than the one that
is used, since user space can modify the area concurrently and the
compiler is free to generate code that reads the value multiple times.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-12-11 14:33:05 +01:00
Heiko Carstens
b988b1bb00 KVM: s390: fix setting of fpc register
kvm_arch_vcpu_ioctl_set_fpu() allows to set the floating point control
(fpc) register of a guest cpu. The new value is tested for validity by
temporarily loading it into the fpc register.

This may lead to corruption of the fpc register of the host process:
if an interrupt happens while the value is temporarily loaded into the fpc
register, and within interrupt context floating point or vector registers
are used, the current fp/vx registers are saved with save_fpu_regs()
assuming they belong to user space and will be loaded into fp/vx registers
when returning to user space.

test_fp_ctl() restores the original user space / host process fpc register
value, however it will be discarded, when returning to user space.

In result the host process will incorrectly continue to run with the value
that was supposed to be used for a guest cpu.

Fix this by simply removing the test. There is another test right before
the SIE context is entered which will handles invalid values.

This results in a change of behaviour: invalid values will now be accepted
instead of that the ioctl fails with -EINVAL. This seems to be acceptable,
given that this interface is most likely not used anymore, and this is in
addition the same behaviour implemented with the memory mapped interface
(replace invalid values with zero) - see sync_regs() in kvm-s390.c.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2023-12-11 14:33:05 +01:00
Wei Wang
63912245c1 KVM: move KVM_CAP_DEVICE_CTRL to the generic check
KVM_CAP_DEVICE_CTRL allows userspace to check if the kvm_device
framework (e.g. KVM_CREATE_DEVICE) is supported by KVM. Move
KVM_CAP_DEVICE_CTRL to the generic check for the two reasons:
1) it already supports arch agnostic usages (i.e. KVM_DEV_TYPE_VFIO).
For example, userspace VFIO implementation may needs to create
KVM_DEV_TYPE_VFIO on x86, riscv, or arm etc. It is simpler to have it
checked at the generic code than at each arch's code.
2) KVM_CREATE_DEVICE has been added to the generic code.

Link: https://lore.kernel.org/all/20221215115207.14784-1-wei.w.wang@intel.com
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Acked-by: Anup Patel <anup@brainfault.org> (riscv)
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lore.kernel.org/r/20230315101606.10636-1-wei.w.wang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-11-30 13:09:43 -08:00
Linus Torvalds
e392ea4d4d s390 updates for the 6.7 merge window
- Get rid of private VM_FAULT flags
 
 - Add word-at-a-time implementation
 
 - Add DCACHE_WORD_ACCESS support
 
 - Cleanup control register handling
 
 - Disallow CPU hotplug of CPU 0 to simplify its handling complexity,
   following a similar restriction in x86
 
 - Optimize pai crypto map allocation
 
 - Update the list of crypto express EP11 coprocessor operation modes
 
 - Fixes and improvements for secure guests AP pass-through
 
 - Several fixes to address incorrect page marking for address translation
   with the "cmma no-dat" feature, preventing potential incorrect guest
   TLB flushes
 
 - Fix early IPI handling
 
 - Several virtual vs physical address confusion fixes
 
 - Various small fixes and improvements all over the code
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Merge tag 's390-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Vasily Gorbik:

 - Get rid of private VM_FAULT flags

 - Add word-at-a-time implementation

 - Add DCACHE_WORD_ACCESS support

 - Cleanup control register handling

 - Disallow CPU hotplug of CPU 0 to simplify its handling complexity,
   following a similar restriction in x86

 - Optimize pai crypto map allocation

 - Update the list of crypto express EP11 coprocessor operation modes

 - Fixes and improvements for secure guests AP pass-through

 - Several fixes to address incorrect page marking for address
   translation with the "cmma no-dat" feature, preventing potential
   incorrect guest TLB flushes

 - Fix early IPI handling

 - Several virtual vs physical address confusion fixes

 - Various small fixes and improvements all over the code

* tag 's390-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (74 commits)
  s390/cio: replace deprecated strncpy with strscpy
  s390/sclp: replace deprecated strncpy with strtomem
  s390/cio: fix virtual vs physical address confusion
  s390/cio: export CMG value as decimal
  s390: delete the unused store_prefix() function
  s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir
  s390/cmma: fix detection of DAT pages
  s390/sclp: handle default case in sclp memory notifier
  s390/pai_crypto: remove per-cpu variable assignement in event initialization
  s390/pai: initialize event count once at initialization
  s390/pai_crypto: use PERF_ATTACH_TASK define for per task detection
  s390/mm: add missing arch_set_page_dat() call to gmap allocations
  s390/mm: add missing arch_set_page_dat() call to vmem_crst_alloc()
  s390/cmma: fix initial kernel address space page table walk
  s390/diag: add missing virt_to_phys() translation to diag224()
  s390/mm,fault: move VM_FAULT_ERROR handling to do_exception()
  s390/mm,fault: remove VM_FAULT_BADMAP and VM_FAULT_BADACCESS
  s390/mm,fault: remove VM_FAULT_SIGNAL
  s390/mm,fault: remove VM_FAULT_BADCONTEXT
  s390/mm,fault: simplify kfence fault handling
  ...
2023-11-03 10:17:22 -10:00
Nico Boehr
70fea30195 KVM: s390: add tracepoint in gmap notifier
The gmap notifier is called for changes in table entries with the
notifier bit set. To diagnose performance issues, it can be useful to
see what causes certain changes in the gmap.

Hence, add a tracepoint in the gmap notifier.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20231009093304.2555344-3-nrb@linux.ibm.com
Message-Id: <20231009093304.2555344-3-nrb@linux.ibm.com>
2023-10-16 14:54:29 +02:00
Nico Boehr
c3235e2dd6 KVM: s390: add stat counter for shadow gmap events
The shadow gmap tracks memory of nested guests (guest-3). In certain
scenarios, the shadow gmap needs to be rebuilt, which is a costly operation
since it involves a SIE exit into guest-1 for every entry in the respective
shadow level.

Add kvm stat counters when new shadow structures are created at various
levels. Also add a counter gmap_shadow_create when a completely fresh
shadow gmap is created as well as a counter gmap_shadow_reuse when an
existing gmap is being reused.

Note that when several levels are shadowed at once, counters on all
affected levels will be increased.

Also note that not all page table levels need to be present and a ASCE
can directly point to e.g. a segment table. In this case, a new segment
table will always be equivalent to a new shadow gmap and hence will be
counted as gmap_shadow_create and not as gmap_shadow_segment.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20231009093304.2555344-2-nrb@linux.ibm.com
Message-Id: <20231009093304.2555344-2-nrb@linux.ibm.com>
2023-10-16 14:54:29 +02:00
Heiko Carstens
99441a38c3 s390: use control register bit defines
Use control register bit defines instead of plain numbers where
possible.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2023-09-19 13:26:57 +02:00
Heiko Carstens
8d5e98f8d6 s390/ctlreg: add local and system prefix to some functions
Add local and system prefix to some functions to clarify they change
control register contents on either the local CPU or the on all CPUs.

This results in the following API:

Two defines which load and save multiple control registers.
The defines correlate with the following C prototypes:

void __local_ctl_load(unsigned long *, unsigned int cr_low, unsigned int cr_high);
void __local_ctl_store(unsigned long *, unsigned int cr_low, unsigned int cr_high);

Two functions which locally set or clear one bit for a specified
control register:

void local_ctl_set_bit(unsigned int cr, unsigned int bit);
void local_ctl_clear_bit(unsigned int cr, unsigned int bit);

Two functions which set or clear one bit for a specified control
register on all CPUs:

void system_ctl_set_bit(unsigned int cr, unsigned int bit);
void system_ctl_clear_bit(unsigend int cr, unsigned int bit);

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2023-09-19 13:26:56 +02:00