Commit graph

230 commits

Author SHA1 Message Date
Oliver Upton
3318e42b81 Merge branch 'kvm-arm64/doublefault2' into kvmarm/next
* kvm-arm64/doublefault2: (33 commits)
  : NV Support for FEAT_RAS + DoubleFault2
  :
  : Delegate the vSError context to the guest hypervisor when in a nested
  : state, including registers related to ESR propagation. Additionally,
  : catch up KVM's external abort infrastructure to the architecture,
  : implementing the effects of FEAT_DoubleFault2.
  :
  : This has some impact on non-nested guests, as SErrors deemed unmasked at
  : the time they're made pending are now immediately injected with an
  : emulated exception entry rather than using the VSE bit.
  KVM: arm64: Make RAS registers UNDEF when RAS isn't advertised
  KVM: arm64: Filter out HCR_EL2 bits when running in hypervisor context
  KVM: arm64: Check for SYSREGS_ON_CPU before accessing the CPU state
  KVM: arm64: Commit exceptions from KVM_SET_VCPU_EVENTS immediately
  KVM: arm64: selftests: Test ESR propagation for vSError injection
  KVM: arm64: Populate ESR_ELx.EC for emulated SError injection
  KVM: arm64: selftests: Catch up set_id_regs with the kernel
  KVM: arm64: selftests: Add SCTLR2_EL1 to get-reg-list
  KVM: arm64: selftests: Test SEAs are taken to SError vector when EASE=1
  KVM: arm64: selftests: Add basic SError injection test
  KVM: arm64: Don't retire MMIO instruction w/ pending (emulated) SError
  KVM: arm64: Advertise support for FEAT_DoubleFault2
  KVM: arm64: Advertise support for FEAT_SCTLR2
  KVM: arm64: nv: Enable vSErrors when HCRX_EL2.TMEA is set
  KVM: arm64: nv: Honor SError routing effects of SCTLR2_ELx.NMEA
  KVM: arm64: nv: Take "masked" aborts to EL2 when HCRX_EL2.TMEA is set
  KVM: arm64: Route SEAs to the SError vector when EASE is set
  KVM: arm64: nv: Ensure Address size faults affect correct ESR
  KVM: arm64: Factor out helper for selecting exception target EL
  KVM: arm64: Describe SCTLR2_ELx RESx masks
  ...

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-26 08:47:22 -07:00
Oliver Upton
77ee70a073 KVM: arm64: nv: Honor SError exception routing / masking
To date KVM has used HCR_EL2.VSE to track the state of a pending SError
for the guest. With this bit set, hardware respects the EL1 exception
routing / masking rules and injects the vSError when appropriate.

This isn't correct for NV guests as hardware is oblivious to vEL2's
intentions for SErrors. Better yet, with FEAT_NV2 the guest can change
the routing behind our back as HCR_EL2 is redirected to memory. Cope
with this mess by:

 - Using a flag (instead of HCR_EL2.VSE) to track the pending SError
   state when SErrors are unconditionally masked for the current context

 - Resampling the routing / masking of a pending SError on every guest
   entry/exit

 - Emulating exception entry when SError routing implies a translation
   regime change

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 11:36:31 -07:00
Oliver Upton
9aba641b9e KVM: arm64: nv: Respect exception routing rules for SEAs
Synchronous external aborts are taken to EL2 if ELIsInHost() or
HCR_EL2.TEA=1. Rework the SEA injection plumbing to respect the imposed
routing of the guest hypervisor and opportunistically rephrase things to
make their function a bit more obvious.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 11:35:54 -07:00
Ankit Agrawal
0c67288e0c KVM: arm64: Allow cacheable stage 2 mapping using VMA flags
KVM currently forces non-cacheable memory attributes (either Normal-NC
or Device-nGnRE) for a region based on pfn_is_map_memory(), i.e. whether
or not the kernel has a cacheable alias for it. This is necessary in
situations where KVM needs to perform CMOs on the region but is
unnecessarily restrictive when hardware obviates the need for CMOs.

KVM doesn't need to perform any CMOs on hardware with FEAT_S2FWB and
CTR_EL0.DIC. As luck would have it, there are implementations in the
wild that need to map regions of a device with cacheable attributes to
function properly. An example of this is Nvidia's Grace Hopper/Blackwell
systems where GPU memory is interchangeable with DDR and retains
properties such as cacheability, unaligned accesses, atomics and
handling of executable faults. Of course, for this to work in a VM the
GPU memory needs to have a cacheable mapping at stage-2.

Allow cacheable stage-2 mappings to be created on supporting hardware
when the VMA has cacheable memory attributes. Check these preconditions
during memslot creation (in addition to fault handling) to potentially
'fail-fast' as a courtesy to userspace.

CC: Oliver Upton <oliver.upton@linux.dev>
CC: Sean Christopherson <seanjc@google.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Tested-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250705071717.5062-6-ankita@nvidia.com
[ Oliver: refine changelog, squash kvm_supports_cacheable_pfnmap() patch ]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-07 16:54:19 -07:00
Ankit Agrawal
2a8dfab266 KVM: arm64: Block cacheable PFNMAP mapping
Fixes a security bug due to mismatched attributes between S1 and
S2 mapping.

Currently, it is possible for a region to be cacheable in the userspace
VMA, but mapped non cached in S2. This creates a potential issue where
the VMM may sanitize cacheable memory across VMs using cacheable stores,
ensuring it is zeroed. However, if KVM subsequently assigns this memory
to a VM as uncached, the VM could end up accessing stale, non-zeroed data
from a previous VM, leading to unintended data exposure. This is a security
risk.

Block such mismatch attributes case by returning EINVAL when userspace
try to map PFNMAP cacheable. Only allow NORMAL_NC and DEVICE_*.

CC: Oliver Upton <oliver.upton@linux.dev>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Sean Christopherson <seanjc@google.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250705071717.5062-4-ankita@nvidia.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-07 16:43:27 -07:00
Ankit Agrawal
216887f79d KVM: arm64: Assume non-PFNMAP/MIXEDMAP VMAs can be mapped cacheable
Despite its name, kvm_is_device_pfn() is actually used to determine if a
given PFN has a kernel mapping that can be used to perform cache
maintenance, as it calls pfn_is_map_memory() internally.

Expand the helper into its single callsite and further condition the
check on the VMA having either VM_PFNMAP or VM_MIXEDMAP set. VMAs that
set neither of these flags must always contain Normal, struct page
backed memory with valid aliases in the kernel address space.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250705071717.5062-3-ankita@nvidia.com
[ Oliver: fixed typos, refined changelog ]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-07 07:50:20 -07:00
Ankit Agrawal
8cc9dc1ae4 KVM: arm64: Rename the device variable to s2_force_noncacheable
To perform cache maintenance on a region of memory, KVM/arm64 relies on
that region having a cacheable alias in the kernel's address space which
can be used with CMO instructions.

The 'device' variable is somewhat of a misnomer, as it actually
indicates whether or not the stage-2 alias is allowed to have cacheable
memory attributes. The resulting stage-2 memory attributes are further
modified by VM_ALLOW_ANY_UNCACHED, selecting between Normal-NC or
Device-nGnRE depending on what the endpoint supports.

Rename the to s2_force_noncacheable such that its purpose is a bit more
obvious.

CC: Catalin Marinas <catalin.marinas@arm.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250705071717.5062-2-ankita@nvidia.com
[ Oliver: addressed typos, wound up rewriting changelog ]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-07 07:30:32 -07:00
Paolo Bonzini
4d526b02df KVM/arm64 updates for 6.16
* New features:
 
   - Add large stage-2 mapping support for non-protected pKVM guests,
     clawing back some performance.
 
   - Add UBSAN support to the standalone EL2 object used in nVHE/hVHE and
     protected modes.
 
   - Enable nested virtualisation support on systems that support it
     (yes, it has been a long time coming), though it is disabled by
     default.
 
 * Improvements, fixes and cleanups:
 
   - Large rework of the way KVM tracks architecture features and links
     them with the effects of control bits. This ensures correctness of
     emulation (the data is automatically extracted from the published
     JSON files), and helps dealing with the evolution of the
     architecture.
 
   - Significant changes to the way pKVM tracks ownership of pages,
     avoiding page table walks by storing the state in the hypervisor's
     vmemmap. This in turn enables the THP support described above.
 
   - New selftest checking the pKVM ownership transition rules
 
   - Fixes for FEAT_MTE_ASYNC being accidentally advertised to guests
     even if the host didn't have it.
 
   - Fixes for the address translation emulation, which happened to be
     rather buggy in some specific contexts.
 
   - Fixes for the PMU emulation in NV contexts, decoupling PMCR_EL0.N
     from the number of counters exposed to a guest and addressing a
     number of issues in the process.
 
   - Add a new selftest for the SVE host state being corrupted by a
     guest.
 
   - Keep HCR_EL2.xMO set at all times for systems running with the
     kernel at EL2, ensuring that the window for interrupts is slightly
     bigger, and avoiding a pretty bad erratum on the AmpereOne HW.
 
   - Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers
     from a pretty bad case of TLB corruption unless accesses to HCR_EL2
     are heavily synchronised.
 
   - Add a per-VM, per-ITS debugfs entry to dump the state of the ITS
     tables in a human-friendly fashion.
 
   - and the usual random cleanups.
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Merge tag 'kvmarm-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 6.16

* New features:

  - Add large stage-2 mapping support for non-protected pKVM guests,
    clawing back some performance.

  - Add UBSAN support to the standalone EL2 object used in nVHE/hVHE and
    protected modes.

  - Enable nested virtualisation support on systems that support it
    (yes, it has been a long time coming), though it is disabled by
    default.

* Improvements, fixes and cleanups:

  - Large rework of the way KVM tracks architecture features and links
    them with the effects of control bits. This ensures correctness of
    emulation (the data is automatically extracted from the published
    JSON files), and helps dealing with the evolution of the
    architecture.

  - Significant changes to the way pKVM tracks ownership of pages,
    avoiding page table walks by storing the state in the hypervisor's
    vmemmap. This in turn enables the THP support described above.

  - New selftest checking the pKVM ownership transition rules

  - Fixes for FEAT_MTE_ASYNC being accidentally advertised to guests
    even if the host didn't have it.

  - Fixes for the address translation emulation, which happened to be
    rather buggy in some specific contexts.

  - Fixes for the PMU emulation in NV contexts, decoupling PMCR_EL0.N
    from the number of counters exposed to a guest and addressing a
    number of issues in the process.

  - Add a new selftest for the SVE host state being corrupted by a
    guest.

  - Keep HCR_EL2.xMO set at all times for systems running with the
    kernel at EL2, ensuring that the window for interrupts is slightly
    bigger, and avoiding a pretty bad erratum on the AmpereOne HW.

  - Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers
    from a pretty bad case of TLB corruption unless accesses to HCR_EL2
    are heavily synchronised.

  - Add a per-VM, per-ITS debugfs entry to dump the state of the ITS
    tables in a human-friendly fashion.

  - and the usual random cleanups.
2025-05-26 16:19:46 -04:00
Vincent Donnefort
db14091d8f KVM: arm64: Stage-2 huge mappings for np-guests
Now np-guests hypercalls with range are supported, we can let the
hypervisor to install block mappings whenever the Stage-1 allows it,
that is when backed by either Hugetlbfs or THPs. The size of those block
mappings is limited to PMD_SIZE.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-10-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Sebastian Ott
157dbc4a32 KVM: arm64: Fix uninitialized memcache pointer in user_mem_abort()
Commit fce886a602 ("KVM: arm64: Plumb the pKVM MMU in KVM") made the
initialization of the local memcache variable in user_mem_abort()
conditional, leaving a codepath where it is used uninitialized via
kvm_pgtable_stage2_map().

This can fail on any path that requires a stage-2 allocation
without transition via a permission fault or dirty logging.

Fix this by making sure that memcache is always valid.

Fixes: fce886a602 ("KVM: arm64: Plumb the pKVM MMU in KVM")
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/kvmarm/3f5db4c7-ccce-fb95-595c-692fa7aad227@redhat.com/
Link: https://lore.kernel.org/r/20250505173148.33900-1-sebott@redhat.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-05-05 12:12:27 -07:00
Oliver Upton
26fbdf3692 KVM: arm64: Don't translate FAR if invalid/unsafe
Don't re-walk the page tables if an SEA occurred during the faulting
page table walk to avoid taking a fatal exception in the hyp.
Additionally, check that FAR_EL2 is valid for SEAs not taken on PTW
as the architecture doesn't guarantee it contains the fault VA.

Finally, fix up the rest of the abort path by checking for SEAs early
and bugging the VM if we get further along with an UNKNOWN fault IPA.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250402201725.2963645-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-04-03 00:28:51 -07:00
Vincent Donnefort
79ea662315 KVM: arm64: Count pKVM stage-2 usage in secondary pagetable stats
Count the pages used by pKVM for the guest stage-2 in memory stats under
secondary pagetable, similarly to what the VHE mode does.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250313114038.1502357-4-vdonnefort@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-14 00:56:30 -07:00
Vincent Donnefort
cf2d228da9 KVM: arm64: Add flags to kvm_hyp_memcache
Add flags to kvm_hyp_memcache and propagate the latter to the allocation
and free callbacks. This will later allow to account for memory, based
on the memcache configuration.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250313114038.1502357-2-vdonnefort@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-14 00:56:29 -07:00
Marc Zyngier
fa5e4043e9 Merge branch kvm-arm64/misc-6.14 into kvmarm-master/next
* kvm-arm64/misc-6.14:
  : .
  : Misc KVM/arm64 changes for 6.14
  :
  : - Don't expose AArch32 EL0 capability when NV is enabled
  :
  : - Update documentation to reflect the full gamut of kvm-arm.mode
  :   behaviours
  :
  : - Use the hypervisor VA bit width when dumping stacktraces
  :
  : - Decouple the hypervisor stack size from PAGE_SIZE, at least
  :   on the surface...
  :
  : - Make use of str_enabled_disabled() when advertising GICv4.1 support
  :
  : - Explicitly handle BRBE traps as UNDEFINED
  : .
  KVM: arm64: Explicitly handle BRBE traps as UNDEFINED
  KVM: arm64: vgic: Use str_enabled_disabled() in vgic_v3_probe()
  arm64: kvm: Introduce nvhe stack size constants
  KVM: arm64: Fix nVHE stacktrace VA bits mask
  Documentation: Update the behaviour of "kvm-arm.mode"
  KVM: arm64: nv: Advertise the lack of AArch32 EL0 support

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-01-17 11:06:50 +00:00
Kalesh Singh
38f9e4b905 arm64: kvm: Introduce nvhe stack size constants
Refactor nvhe stack code to use NVHE_STACK_SIZE/SHIFT constants,
instead of directly using PAGE_SIZE/SHIFT. This makes the code a bit
easier to read, without introducing any functional changes.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Link: https://lore.kernel.org/r/20241112003336.1375584-1-kaleshsingh@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-01-08 11:25:28 +00:00
Vincent Donnefort
68344037b7 KVM: arm64: Fix nVHE stacktrace VA bits mask
The hypervisor VA space size depends on both the ID map's
(IDMAP_VA_BITS) and the kernel stage-1 (VA_BITS). However, the
hypervisor stacktrace decoding is solely relying on VA_BITS. This is
especially an issue when VA_BITS < IDMAP_VA_BITS (i.e. VA_BITS is
39-bit): the hypervisor may have addresses bigger than the stacktrace is
masking.

Align this mask with hyp_va_bits.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250107112821.416591-1-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-01-08 11:18:39 +00:00
Quentin Perret
fce886a602 KVM: arm64: Plumb the pKVM MMU in KVM
Introduce the KVM_PGT_CALL() helper macro to allow switching from the
traditional pgtable code to the pKVM version easily in mmu.c. The cost
of this 'indirection' is expected to be very minimal due to
is_protected_kvm_enabled() being backed by a static key.

With this, everything is in place to allow the delegation of
non-protected guest stage-2 page-tables to pKVM, so let's stop using the
host's kvm_s2_mmu from EL2 and enjoy the ride.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-19-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-12-20 09:44:00 +00:00
Quentin Perret
e279c25d78 KVM: arm64: Pass walk flags to kvm_pgtable_stage2_relax_perms
kvm_pgtable_stage2_relax_perms currently assumes that it is being called
from a 'shared' walker, which will not be true once called from pKVM. To
allow for the re-use of that function, make the walk flags one of its
parameters.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-7-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-12-20 09:44:00 +00:00
Quentin Perret
5398ddc5c9 KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung
kvm_pgtable_stage2_mkyoung currently assumes that it is being called
from a 'shared' walker, which will not be true once called from pKVM.
To allow for the re-use of that function, make the walk flags one of
its parameters.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-6-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-12-20 09:43:59 +00:00
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
Linus Torvalds
ba1f9c8fe3 arm64 updates for 6.13:
* Support for running Linux in a protected VM under the Arm Confidential
   Compute Architecture (CCA)
 
 * Guarded Control Stack user-space support. Current patches follow the
   x86 ABI of implicitly creating a shadow stack on clone(). Subsequent
   patches (already on the list) will add support for clone3() allowing
   finer-grained control of the shadow stack size and placement from libc
 
 * AT_HWCAP3 support (not running out of HWCAP2 bits yet but we are
   getting close with the upcoming dpISA support)
 
 * Other arch features:
 
   - In-kernel use of the memcpy instructions, FEAT_MOPS (previously only
     exposed to user; uaccess support not merged yet)
 
   - MTE: hugetlbfs support and the corresponding kselftests
 
   - Optimise CRC32 using the PMULL instructions
 
   - Support for FEAT_HAFT enabling ARCH_HAS_NONLEAF_PMD_YOUNG
 
   - Optimise the kernel TLB flushing to use the range operations
 
   - POE/pkey (permission overlays): further cleanups after bringing the
     signal handler in line with the x86 behaviour for 6.12
 
 * arm64 perf updates:
 
   - Support for the NXP i.MX91 PMU in the existing IMX driver
 
   - Support for Ampere SoCs in the Designware PCIe PMU driver
 
   - Support for Marvell's 'PEM' PCIe PMU present in the 'Odyssey' SoC
 
   - Support for Samsung's 'Mongoose' CPU PMU
 
   - Support for PMUv3.9 finer-grained userspace counter access control
 
   - Switch back to platform_driver::remove() now that it returns 'void'
 
   - Add some missing events for the CXL PMU driver
 
 * Miscellaneous arm64 fixes/cleanups:
 
   - Page table accessors cleanup: type updates, drop unused macros,
     reorganise arch_make_huge_pte() and clean up pte_mkcont(), sanity
     check addresses before runtime P4D/PUD folding
 
   - Command line override for ID_AA64MMFR0_EL1.ECV (advertising the
     FEAT_ECV for the generic timers) allowing Linux to boot with
     firmware deployments that don't set SCTLR_EL3.ECVEn
 
   - ACPI/arm64: tighten the check for the array of platform timer
     structures and adjust the error handling procedure in
     gtdt_parse_timer_block()
 
   - Optimise the cache flush for the uprobes xol slot (skip if no
     change) and other uprobes/kprobes cleanups
 
   - Fix the context switching of tpidrro_el0 when kpti is enabled
 
   - Dynamic shadow call stack fixes
 
   - Sysreg updates
 
   - Various arm64 kselftest improvements
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:

 - Support for running Linux in a protected VM under the Arm
   Confidential Compute Architecture (CCA)

 - Guarded Control Stack user-space support. Current patches follow the
   x86 ABI of implicitly creating a shadow stack on clone(). Subsequent
   patches (already on the list) will add support for clone3() allowing
   finer-grained control of the shadow stack size and placement from
   libc

 - AT_HWCAP3 support (not running out of HWCAP2 bits yet but we are
   getting close with the upcoming dpISA support)

 - Other arch features:

     - In-kernel use of the memcpy instructions, FEAT_MOPS (previously
       only exposed to user; uaccess support not merged yet)

     - MTE: hugetlbfs support and the corresponding kselftests

     - Optimise CRC32 using the PMULL instructions

     - Support for FEAT_HAFT enabling ARCH_HAS_NONLEAF_PMD_YOUNG

     - Optimise the kernel TLB flushing to use the range operations

     - POE/pkey (permission overlays): further cleanups after bringing
       the signal handler in line with the x86 behaviour for 6.12

 - arm64 perf updates:

     - Support for the NXP i.MX91 PMU in the existing IMX driver

     - Support for Ampere SoCs in the Designware PCIe PMU driver

     - Support for Marvell's 'PEM' PCIe PMU present in the 'Odyssey' SoC

     - Support for Samsung's 'Mongoose' CPU PMU

     - Support for PMUv3.9 finer-grained userspace counter access
       control

     - Switch back to platform_driver::remove() now that it returns
       'void'

     - Add some missing events for the CXL PMU driver

 - Miscellaneous arm64 fixes/cleanups:

     - Page table accessors cleanup: type updates, drop unused macros,
       reorganise arch_make_huge_pte() and clean up pte_mkcont(), sanity
       check addresses before runtime P4D/PUD folding

     - Command line override for ID_AA64MMFR0_EL1.ECV (advertising the
       FEAT_ECV for the generic timers) allowing Linux to boot with
       firmware deployments that don't set SCTLR_EL3.ECVEn

     - ACPI/arm64: tighten the check for the array of platform timer
       structures and adjust the error handling procedure in
       gtdt_parse_timer_block()

     - Optimise the cache flush for the uprobes xol slot (skip if no
       change) and other uprobes/kprobes cleanups

     - Fix the context switching of tpidrro_el0 when kpti is enabled

     - Dynamic shadow call stack fixes

     - Sysreg updates

     - Various arm64 kselftest improvements

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (168 commits)
  arm64: tls: Fix context-switching of tpidrro_el0 when kpti is enabled
  kselftest/arm64: Try harder to generate different keys during PAC tests
  kselftest/arm64: Don't leak pipe fds in pac.exec_sign_all()
  arm64/ptrace: Clarify documentation of VL configuration via ptrace
  kselftest/arm64: Corrupt P0 in the irritator when testing SSVE
  acpi/arm64: remove unnecessary cast
  arm64/mm: Change protval as 'pteval_t' in map_range()
  kselftest/arm64: Fix missing printf() argument in gcs/gcs-stress.c
  kselftest/arm64: Add FPMR coverage to fp-ptrace
  kselftest/arm64: Expand the set of ZA writes fp-ptrace does
  kselftets/arm64: Use flag bits for features in fp-ptrace assembler code
  kselftest/arm64: Enable build of PAC tests with LLVM=1
  kselftest/arm64: Check that SVCR is 0 in signal handlers
  selftests/mm: Fix unused function warning for aarch64_write_signal_pkey()
  kselftest/arm64: Fix printf() compiler warnings in the arm64 syscall-abi.c tests
  kselftest/arm64: Fix printf() warning in the arm64 MTE prctl() test
  kselftest/arm64: Fix printf() compiler warnings in the arm64 fp tests
  kselftest/arm64: Fix build with stricter assemblers
  arm64/scs: Drop unused prototype __pi_scs_patch_vmlinux()
  arm64/scs: Deal with 64-bit relative offsets in FDE frames
  ...
2024-11-18 18:10:37 -08:00
Sean Christopherson
2362506f7c KVM: arm64: Don't mark "struct page" accessed when making SPTE young
Don't mark pages/folios as accessed in the primary MMU when making a SPTE
young in KVM's secondary MMU, as doing so relies on
kvm_pfn_to_refcounted_page(), and generally speaking is unnecessary and
wasteful.  KVM participates in page aging via mmu_notifiers, so there's no
need to push "accessed" updates to the primary MMU.

Dropping use of kvm_set_pfn_accessed() also paves the way for removing
kvm_pfn_to_refcounted_page() and all its users.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-84-seanjc@google.com>
2024-10-25 13:01:35 -04:00
Sean Christopherson
85c7869e30 KVM: arm64: Use __kvm_faultin_pfn() to handle memory aborts
Convert arm64 to use __kvm_faultin_pfn()+kvm_release_faultin_page().
Three down, six to go.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-57-seanjc@google.com>
2024-10-25 13:00:48 -04:00
Sean Christopherson
28991c91d5 KVM: arm64: Mark "struct page" pfns accessed/dirty before dropping mmu_lock
Mark pages/folios accessed+dirty prior to dropping mmu_lock, as marking a
page/folio dirty after it has been written back can make some filesystems
unhappy (backing KVM guests will such filesystem files is uncommon, and
the race is minuscule, hence the lack of complaints).

While scary sounding, practically speaking the worst case scenario is that
KVM would trigger this WARN in filemap_unaccount_folio():

        /*
         * At this point folio must be either written or cleaned by
         * truncate.  Dirty folio here signals a bug and loss of
         * unwritten data - on ordinary filesystems.
         *
         * But it's harmless on in-memory filesystems like tmpfs; and can
         * occur when a driver which did get_user_pages() sets page dirty
         * before putting it, while the inode is being finally evicted.
         *
         * Below fixes dirty accounting after removing the folio entirely
         * but leaves the dirty flag set: it has no effect for truncated
         * folio and anyway will be cleared before returning folio to
         * buddy allocator.
         */
        if (WARN_ON_ONCE(folio_test_dirty(folio) &&
                         mapping_can_writeback(mapping)))
                folio_account_cleaned(folio, inode_to_wb(mapping->host));

KVM won't actually write memory because the stage-2 mappings are protected
by the mmu_notifier, i.e. there is no risk of loss of data, even if the
VM were backed by memory that needs writeback.

See the link below for additional details.

This will also allow converting arm64 to kvm_release_faultin_page(), which
requires that mmu_lock be held (for the aforementioned reason).

Link: https://lore.kernel.org/all/cover.1683044162.git.lstoakes@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-56-seanjc@google.com>
2024-10-25 13:00:48 -04:00
Sean Christopherson
cccefb0a0d KVM: Drop unused "hva" pointer from __gfn_to_pfn_memslot()
Drop @hva from __gfn_to_pfn_memslot() now that all callers pass NULL.

No functional change intended.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-19-seanjc@google.com>
2024-10-25 12:57:58 -04:00
Sean Christopherson
e2d2ca71ac KVM: Drop @atomic param from gfn=>pfn and hva=>pfn APIs
Drop @atomic from the myriad "to_pfn" APIs now that all callers pass
"false", and remove a comment blurb about KVM running only the "GUP fast"
part in atomic context.

No functional change intended.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-13-seanjc@google.com>
2024-10-25 12:57:58 -04:00
Yang Shi
25c17c4b55 hugetlb: arm64: add mte support
Enable MTE support for hugetlb.

The MTE page flags will be set on the folio only.  When copying
hugetlb folio (for example, CoW), the tags for all subpages will be copied
when copying the first subpage.

When freeing hugetlb folio, the MTE flags will be cleared.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20241001225220.271178-1-yang@os.amperecomputing.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-16 14:50:47 +01:00
Oliver Upton
3c164eb946 KVM: arm64: nv: Do not block when unmapping stage-2 if disallowed
Right now the nested code allows unmap operations on a shadow stage-2 to
block unconditionally. This is wrong in a couple places, such as a
non-blocking MMU notifier or on the back of a sched_in() notifier as
part of shadow MMU recycling.

Carry through whether or not blocking is allowed to
kvm_pgtable_stage2_unmap(). This 'fixes' an issue where stage-2 MMU
reclaim would precipitate a stack overflow from a pile of kvm_sched_in()
callbacks, all trying to recycle a stage-2 MMU.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-3-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-10-08 10:40:27 +01:00
Oliver Upton
1d8c3c23a6 KVM: arm64: Ensure canonical IPA is hugepage-aligned when handling fault
Zenghui reports that VMs backed by hugetlb pages are no longer booting
after commit fd276e71d1 ("KVM: arm64: nv: Handle shadow stage 2 page
faults").

Support for shadow stage-2 MMUs introduced the concept of a fault IPA
and canonical IPA to stage-2 fault handling. These are identical in the
non-nested case, as the hardware stage-2 context is always that of the
canonical IPA space.

Both addresses need to be hugepage-aligned when preparing to install a
hugepage mapping to ensure that KVM uses the correct GFN->PFN translation
and installs that at the correct IPA for the current stage-2.

And now I'm feeling thirsty after all this talk of IPAs...

Fixes: fd276e71d1 ("KVM: arm64: nv: Handle shadow stage 2 page faults")
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240822071710.2291690-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-08-22 07:41:00 +00:00
Marc Zyngier
b1a3a94812 KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level
Populate bits [56:55] of the leaf entry with the level provided
by the guest's S2 translation. This will allow us to better scope
the invalidation by remembering the mapping size.

Of course, this assume that the guest will issue an invalidation
with an address that falls into the same leaf. If the guest doesn't,
we'll over-invalidate.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-13-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-19 08:14:38 +00:00
Christoffer Dall
ec14c27240 KVM: arm64: nv: Unmap/flush shadow stage 2 page tables
Unmap/flush shadow stage 2 page tables for the nested VMs as well as the
stage 2 page table for the guest hypervisor.

Note: A bunch of the code in mmu.c relating to MMU notifiers is
currently dealt with in an extremely abrupt way, for example by clearing
out an entire shadow stage-2 table. This will be handled in a more
efficient way using the reverse mapping feature in a later version of
the patch series.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-19 08:13:49 +00:00
Marc Zyngier
fd276e71d1 KVM: arm64: nv: Handle shadow stage 2 page faults
If we are faulting on a shadow stage 2 translation, we first walk the
guest hypervisor's stage 2 page table to see if it has a mapping. If
not, we inject a stage 2 page fault to the virtual EL2. Otherwise, we
create a mapping in the shadow stage 2 page table.

Note that we have to deal with two IPAs when we got a shadow stage 2
page fault. One is the address we faulted on, and is in the L2 guest
phys space. The other is from the guest stage-2 page table walk, and is
in the L1 guest phys space.  To differentiate them, we rename variables
so that fault_ipa is used for the former and ipa is used for the latter.

When mapping a page in a shadow stage-2, special care must be taken not
to be more permissive than the guest is.

Co-developed-by: Christoffer Dall <christoffer.dall@linaro.org>
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-19 08:13:49 +00:00
Marc Zyngier
4f128f8e1a KVM: arm64: nv: Support multiple nested Stage-2 mmu structures
Add Stage-2 mmu data structures for virtual EL2 and for nested guests.
We don't yet populate shadow Stage-2 page tables, but we now have a
framework for getting to a shadow Stage-2 pgd.

We allocate twice the number of vcpus as Stage-2 mmu structures because
that's sufficient for each vcpu running two translation regimes without
having to flush the Stage-2 page tables.

Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-06-19 08:13:49 +00:00
Paolo Bonzini
e5f62e27b1 KVM/arm64 updates for Linux 6.10
- Move a lot of state that was previously stored on a per vcpu
   basis into a per-CPU area, because it is only pertinent to the
   host while the vcpu is loaded. This results in better state
   tracking, and a smaller vcpu structure.
 
 - Add full handling of the ERET/ERETAA/ERETAB instructions in
   nested virtualisation. The last two instructions also require
   emulating part of the pointer authentication extension.
   As a result, the trap handling of pointer authentication has
   been greattly simplified.
 
 - Turn the global (and not very scalable) LPI translation cache
   into a per-ITS, scalable cache, making non directly injected
   LPIs much cheaper to make visible to the vcpu.
 
 - A batch of pKVM patches, mostly fixes and cleanups, as the
   upstreaming process seems to be resuming. Fingers crossed!
 
 - Allocate PPIs and SGIs outside of the vcpu structure, allowing
   for smaller EL2 mapping and some flexibility in implementing
   more or less than 32 private IRQs.
 
 - Purge stale mpidr_data if a vcpu is created after the MPIDR
   map has been created.
 
 - Preserve vcpu-specific ID registers across a vcpu reset.
 
 - Various minor cleanups and improvements.
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Merge tag 'kvmarm-6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for Linux 6.10

- Move a lot of state that was previously stored on a per vcpu
  basis into a per-CPU area, because it is only pertinent to the
  host while the vcpu is loaded. This results in better state
  tracking, and a smaller vcpu structure.

- Add full handling of the ERET/ERETAA/ERETAB instructions in
  nested virtualisation. The last two instructions also require
  emulating part of the pointer authentication extension.
  As a result, the trap handling of pointer authentication has
  been greattly simplified.

- Turn the global (and not very scalable) LPI translation cache
  into a per-ITS, scalable cache, making non directly injected
  LPIs much cheaper to make visible to the vcpu.

- A batch of pKVM patches, mostly fixes and cleanups, as the
  upstreaming process seems to be resuming. Fingers crossed!

- Allocate PPIs and SGIs outside of the vcpu structure, allowing
  for smaller EL2 mapping and some flexibility in implementing
  more or less than 32 private IRQs.

- Purge stale mpidr_data if a vcpu is created after the MPIDR
  map has been created.

- Preserve vcpu-specific ID registers across a vcpu reset.

- Various minor cleanups and improvements.
2024-05-12 03:15:53 -04:00
Marc Zyngier
8540bd1b99 Merge branch kvm-arm64/pkvm-6.10 into kvmarm-master/next
* kvm-arm64/pkvm-6.10: (25 commits)
  : .
  : At last, a bunch of pKVM patches, courtesy of Fuad Tabba.
  : From the cover letter:
  :
  : "This series is a bit of a bombay-mix of patches we've been
  : carrying. There's no one overarching theme, but they do improve
  : the code by fixing existing bugs in pKVM, refactoring code to
  : make it more readable and easier to re-use for pKVM, or adding
  : functionality to the existing pKVM code upstream."
  : .
  KVM: arm64: Force injection of a data abort on NISV MMIO exit
  KVM: arm64: Restrict supported capabilities for protected VMs
  KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap()
  KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst
  KVM: arm64: Rename firmware pseudo-register documentation file
  KVM: arm64: Reformat/beautify PTP hypercall documentation
  KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit
  KVM: arm64: Introduce and use predicates that check for protected VMs
  KVM: arm64: Add is_pkvm_initialized() helper
  KVM: arm64: Simplify vgic-v3 hypercalls
  KVM: arm64: Move setting the page as dirty out of the critical section
  KVM: arm64: Change kvm_handle_mmio_return() return polarity
  KVM: arm64: Fix comment for __pkvm_vcpu_init_traps()
  KVM: arm64: Prevent kmemleak from accessing .hyp.data
  KVM: arm64: Do not map the host fpsimd state to hyp in pKVM
  KVM: arm64: Rename __tlb_switch_to_{guest,host}() in VHE
  KVM: arm64: Support TLB invalidation in guest context
  KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE
  KVM: arm64: Check for PTE validity when checking for executable/cacheable
  KVM: arm64: Avoid BUG-ing from the host abort path
  ...

Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-03 11:39:52 +01:00
Fuad Tabba
9c30fc615d KVM: arm64: Move setting the page as dirty out of the critical section
Move the unlock earlier in user_mem_abort() to shorten the
critical section. This also helps for future refactoring and
reuse of similar code.

This moves out marking the page as dirty outside of the critical
section. That code does not interact with the stage-2 page
tables, which the read lock in the critical section protects.

Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-16-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-05-01 16:48:14 +01:00
Paolo Bonzini
f3b65bbaed KVM: delete .change_pte MMU notifier callback
The .change_pte() MMU notifier callback was intended as an
optimization. The original point of it was that KSM could tell KVM to flip
its secondary PTE to a new location without having to first zap it. At
the time there was also an .invalidate_page() callback; both of them were
*not* bracketed by calls to mmu_notifier_invalidate_range_{start,end}(),
and .invalidate_page() also doubled as a fallback implementation of
.change_pte().

Later on, however, both callbacks were changed to occur within an
invalidate_range_start/end() block.

In the case of .change_pte(), commit 6bdb913f0a ("mm: wrap calls to
set_pte_at_notify with invalidate_range_start and invalidate_range_end",
2012-10-09) did so to remove the fallback from .invalidate_page() to
.change_pte() and allow sleepable .invalidate_page() hooks.

This however made KVM's usage of the .change_pte() callback completely
moot, because KVM unmaps the sPTEs during .invalidate_range_start()
and therefore .change_pte() has no hope of finding a sPTE to change.
Drop the generic KVM code that dispatches to kvm_set_spte_gfn(), as
well as all the architecture specific implementations.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Anup Patel <anup@brainfault.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Message-ID: <20240405115815.3226315-2-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11 13:18:27 -04:00
Wujie Duan
f5fe0adeed KVM: arm64: Fix out-of-IPA space translation fault handling
Commit 11e5ea5242 ("KVM: arm64: Use helpers to classify exception
types reported via ESR") tried to abstract the translation fault
check when handling an out-of IPA space condition, but incorrectly
replaced it with a permission fault check.

Restore the previous translation fault check.

Fixes: 11e5ea5242 ("KVM: arm64: Use helpers to classify exception types reported via ESR")
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Wujie Duan <wjduan@linx-info.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/kvmarm/864jd3269g.wl-maz@kernel.org/
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-03-26 01:51:44 -07:00
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
Oliver Upton
4a09ddb833 Merge branch kvm-arm64/kerneldoc into kvmarm/next
* kvm-arm64/kerneldoc:
  : kerneldoc warning fixes, courtesy of Randy Dunlap
  :
  : Fixes addressing the widespread misuse of kerneldoc-style comments
  : throughout KVM/arm64.
  KVM: arm64: vgic: fix a kernel-doc warning
  KVM: arm64: vgic-its: fix kernel-doc warnings
  KVM: arm64: vgic-init: fix a kernel-doc warning
  KVM: arm64: sys_regs: fix kernel-doc warnings
  KVM: arm64: PMU: fix kernel-doc warnings
  KVM: arm64: mmu: fix a kernel-doc warning
  KVM: arm64: vhe: fix a kernel-doc warning
  KVM: arm64: hyp/aarch32: fix kernel-doc warnings
  KVM: arm64: guest: fix kernel-doc warnings
  KVM: arm64: debug: fix kernel-doc warnings

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-03-07 00:56:16 +00:00
Ankit Agrawal
8c47ce3e1d KVM: arm64: Set io memory s2 pte as normalnc for vfio pci device
To provide VM with the ability to get device IO memory with NormalNC
property, map device MMIO in KVM for ARM64 at stage2 as NormalNC.
Having NormalNC S2 default puts guests in control (based on [1],
"Combining stage 1 and stage 2 memory type attributes") of device
MMIO regions memory mappings. The rules are summarized below:
([(S1) - stage1], [(S2) - stage 2])

S1           |  S2           | Result
NORMAL-WB    |  NORMAL-NC    | NORMAL-NC
NORMAL-WT    |  NORMAL-NC    | NORMAL-NC
NORMAL-NC    |  NORMAL-NC    | NORMAL-NC
DEVICE<attr> |  NORMAL-NC    | DEVICE<attr>

Still this cannot be generalized to non PCI devices such as GICv2.
There is insufficient information and uncertainity in the behavior
of non PCI driver. A driver must indicate support using the
new flag VM_ALLOW_ANY_UNCACHED.

Adapt KVM to make use of the flag VM_ALLOW_ANY_UNCACHED as indicator to
activate the S2 setting to NormalNc.

[1] section D8.5.5 of DDI0487J_a_a-profile_architecture_reference_manual.pdf

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Link: https://lore.kernel.org/r/20240224150546.368-4-ankita@nvidia.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-24 17:57:39 +00:00
Ard Biesheuvel
95e059b5db arm64: kvm: avoid CONFIG_PGTABLE_LEVELS for runtime levels
get_user_mapping_size() uses vabits_actual and CONFIG_PGTABLE_LEVELS to
provide the starting point for a table walk. This is fine for LVA, as
the number of translation levels is the same regardless of whether LVA
is enabled. However, with LPA2, this will no longer be the case, so
let's derive the number of levels from the number of VA bits directly.

Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-84-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-02-16 12:42:42 +00:00
Ard Biesheuvel
e6128a8e52 arm64: mm: Use 48-bit virtual addressing for the permanent ID map
Even though we support loading kernels anywhere in 48-bit addressable
physical memory, we create the ID maps based on the number of levels
that we happened to configure for the kernel VA and user VA spaces.

The reason for this is that the PGD/PUD/PMD based classification of
translation levels, along with the associated folding when the number of
levels is less than 5, does not permit creating a page table hierarchy
of a set number of levels. This means that, for instance, on 39-bit VA
kernels we need to configure an additional level above PGD level on the
fly, and 36-bit VA kernels still only support 47-bit virtual addressing
with this trick applied.

Now that we have a separate helper to populate page table hierarchies
that does not define the levels in terms of PUDS/PMDS/etc at all, let's
reuse it to create the permanent ID map with a fixed VA size of 48 bits.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-64-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-02-16 12:42:34 +00:00
Randy Dunlap
ffd9eaffa3 KVM: arm64: mmu: fix a kernel-doc warning
Use the correct function name in a kernel-doc comment to prevent
a warning:

arch/arm64/kvm/mmu.c:321: warning: expecting prototype for unmap_stage2_range(). Prototype was for __unmap_stage2_range() instead

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Zenghui Yu <yuzenghui@huawei.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.linux.dev
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20240117230714.31025-6-rdunlap@infradead.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-02-01 20:25:41 +00:00
Ard Biesheuvel
11e5ea5242 KVM: arm64: Use helpers to classify exception types reported via ESR
Currently, we rely on the fact that exceptions can be trivially
classified by applying a mask/value pair to the syndrome value reported
via the ESR register, but this will no longer be true once we enable
support for 5 level paging.

So introduce a couple of helpers that encapsulate this mask/value pair
matching, and wire them up in the code. No functional change intended,
the actual handling of translation level -1 will be added in a
subsequent patch.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
[maz: folded in changes suggested by Mark]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231128140400.3132145-2-ardb@google.com
2023-11-30 10:45:28 +00:00
Ryan Roberts
419edf48d7 KVM: arm64: Convert translation level parameter to s8
With the introduction of FEAT_LPA2, the Arm ARM adds a new level of
translation, level -1, so levels can now be in the range [-1;3]. 3 is
always the last level and the first level is determined based on the
number of VA bits in use.

Convert level variables to use a signed type in preparation for
supporting this new level -1.

Since the last level is always anchored at 3, and the first level varies
to suit the number of VA/IPA bits, take the opportunity to replace
KVM_PGTABLE_MAX_LEVELS with the 2 macros KVM_PGTABLE_FIRST_LEVEL and
KVM_PGTABLE_LAST_LEVEL. This removes the assumption from the code that
levels run from 0 to KVM_PGTABLE_MAX_LEVELS - 1, which will soon no
longer be true.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231127111737.1897081-9-ryan.roberts@arm.com
2023-11-27 15:03:50 +00:00
Linus Torvalds
6803bd7956 ARM:
* Generalized infrastructure for 'writable' ID registers, effectively
   allowing userspace to opt-out of certain vCPU features for its guest
 
 * Optimization for vSGI injection, opportunistically compressing MPIDR
   to vCPU mapping into a table
 
 * Improvements to KVM's PMU emulation, allowing userspace to select
   the number of PMCs available to a VM
 
 * Guest support for memory operation instructions (FEAT_MOPS)
 
 * Cleanups to handling feature flags in KVM_ARM_VCPU_INIT, squashing
   bugs and getting rid of useless code
 
 * Changes to the way the SMCCC filter is constructed, avoiding wasted
   memory allocations when not in use
 
 * Load the stage-2 MMU context at vcpu_load() for VHE systems, reducing
   the overhead of errata mitigations
 
 * Miscellaneous kernel and selftest fixes
 
 LoongArch:
 
 * New architecture.  The hardware uses the same model as x86, s390
   and RISC-V, where guest/host mode is orthogonal to supervisor/user
   mode.  The virtualization extensions are very similar to MIPS,
   therefore the code also has some similarities but it's been cleaned
   up to avoid some of the historical bogosities that are found in
   arch/mips.  The kernel emulates MMU, timer and CSR accesses, while
   interrupt controllers are only emulated in userspace, at least for
   now.
 
 RISC-V:
 
 * Support for the Smstateen and Zicond extensions
 
 * Support for virtualizing senvcfg
 
 * Support for virtualized SBI debug console (DBCN)
 
 S390:
 
 * Nested page table management can be monitored through tracepoints
   and statistics
 
 x86:
 
 * Fix incorrect handling of VMX posted interrupt descriptor in KVM_SET_LAPIC,
   which could result in a dropped timer IRQ
 
 * Avoid WARN on systems with Intel IPI virtualization
 
 * Add CONFIG_KVM_MAX_NR_VCPUS, to allow supporting up to 4096 vCPUs without
   forcing more common use cases to eat the extra memory overhead.
 
 * Add virtualization support for AMD SRSO mitigation (IBPB_BRTYPE and
   SBPB, aka Selective Branch Predictor Barrier).
 
 * Fix a bug where restoring a vCPU snapshot that was taken within 1 second of
   creating the original vCPU would cause KVM to try to synchronize the vCPU's
   TSC and thus clobber the correct TSC being set by userspace.
 
 * Compute guest wall clock using a single TSC read to avoid generating an
   inaccurate time, e.g. if the vCPU is preempted between multiple TSC reads.
 
 * "Virtualize" HWCR.TscFreqSel to make Linux guests happy, which complain
   about a "Firmware Bug" if the bit isn't set for select F/M/S combos.
   Likewise "virtualize" (ignore) MSR_AMD64_TW_CFG to appease Windows Server
   2022.
 
 * Don't apply side effects to Hyper-V's synthetic timer on writes from
   userspace to fix an issue where the auto-enable behavior can trigger
   spurious interrupts, i.e. do auto-enabling only for guest writes.
 
 * Remove an unnecessary kick of all vCPUs when synchronizing the dirty log
   without PML enabled.
 
 * Advertise "support" for non-serializing FS/GS base MSR writes as appropriate.
 
 * Harden the fast page fault path to guard against encountering an invalid
   root when walking SPTEs.
 
 * Omit "struct kvm_vcpu_xen" entirely when CONFIG_KVM_XEN=n.
 
 * Use the fast path directly from the timer callback when delivering Xen
   timer events, instead of waiting for the next iteration of the run loop.
   This was not done so far because previously proposed code had races,
   but now care is taken to stop the hrtimer at critical points such as
   restarting the timer or saving the timer information for userspace.
 
 * Follow the lead of upstream Xen and ignore the VCPU_SSHOTTMR_future flag.
 
 * Optimize injection of PMU interrupts that are simultaneous with NMIs.
 
 * Usual handful of fixes for typos and other warts.
 
 x86 - MTRR/PAT fixes and optimizations:
 
 * Clean up code that deals with honoring guest MTRRs when the VM has
   non-coherent DMA and host MTRRs are ignored, i.e. EPT is enabled.
 
 * Zap EPT entries when non-coherent DMA assignment stops/start to prevent
   using stale entries with the wrong memtype.
 
 * Don't ignore guest PAT for CR0.CD=1 && KVM_X86_QUIRK_CD_NW_CLEARED=y.
   This was done as a workaround for virtual machine BIOSes that did not
   bother to clear CR0.CD (because ancient KVM/QEMU did not bother to
   set it, in turn), and there's zero reason to extend the quirk to
   also ignore guest PAT.
 
 x86 - SEV fixes:
 
 * Report KVM_EXIT_SHUTDOWN instead of EINVAL if KVM intercepts SHUTDOWN while
   running an SEV-ES guest.
 
 * Clean up the recognition of emulation failures on SEV guests, when KVM would
   like to "skip" the instruction but it had already been partially emulated.
   This makes it possible to drop a hack that second guessed the (insufficient)
   information provided by the emulator, and just do the right thing.
 
 Documentation:
 
 * Various updates and fixes, mostly for x86
 
 * MTRR and PAT fixes and optimizations:
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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:

   - Generalized infrastructure for 'writable' ID registers, effectively
     allowing userspace to opt-out of certain vCPU features for its
     guest

   - Optimization for vSGI injection, opportunistically compressing
     MPIDR to vCPU mapping into a table

   - Improvements to KVM's PMU emulation, allowing userspace to select
     the number of PMCs available to a VM

   - Guest support for memory operation instructions (FEAT_MOPS)

   - Cleanups to handling feature flags in KVM_ARM_VCPU_INIT, squashing
     bugs and getting rid of useless code

   - Changes to the way the SMCCC filter is constructed, avoiding wasted
     memory allocations when not in use

   - Load the stage-2 MMU context at vcpu_load() for VHE systems,
     reducing the overhead of errata mitigations

   - Miscellaneous kernel and selftest fixes

  LoongArch:

   - New architecture for kvm.

     The hardware uses the same model as x86, s390 and RISC-V, where
     guest/host mode is orthogonal to supervisor/user mode. The
     virtualization extensions are very similar to MIPS, therefore the
     code also has some similarities but it's been cleaned up to avoid
     some of the historical bogosities that are found in arch/mips. The
     kernel emulates MMU, timer and CSR accesses, while interrupt
     controllers are only emulated in userspace, at least for now.

  RISC-V:

   - Support for the Smstateen and Zicond extensions

   - Support for virtualizing senvcfg

   - Support for virtualized SBI debug console (DBCN)

  S390:

   - Nested page table management can be monitored through tracepoints
     and statistics

  x86:

   - Fix incorrect handling of VMX posted interrupt descriptor in
     KVM_SET_LAPIC, which could result in a dropped timer IRQ

   - Avoid WARN on systems with Intel IPI virtualization

   - Add CONFIG_KVM_MAX_NR_VCPUS, to allow supporting up to 4096 vCPUs
     without forcing more common use cases to eat the extra memory
     overhead.

   - Add virtualization support for AMD SRSO mitigation (IBPB_BRTYPE and
     SBPB, aka Selective Branch Predictor Barrier).

   - Fix a bug where restoring a vCPU snapshot that was taken within 1
     second of creating the original vCPU would cause KVM to try to
     synchronize the vCPU's TSC and thus clobber the correct TSC being
     set by userspace.

   - Compute guest wall clock using a single TSC read to avoid
     generating an inaccurate time, e.g. if the vCPU is preempted
     between multiple TSC reads.

   - "Virtualize" HWCR.TscFreqSel to make Linux guests happy, which
     complain about a "Firmware Bug" if the bit isn't set for select
     F/M/S combos. Likewise "virtualize" (ignore) MSR_AMD64_TW_CFG to
     appease Windows Server 2022.

   - Don't apply side effects to Hyper-V's synthetic timer on writes
     from userspace to fix an issue where the auto-enable behavior can
     trigger spurious interrupts, i.e. do auto-enabling only for guest
     writes.

   - Remove an unnecessary kick of all vCPUs when synchronizing the
     dirty log without PML enabled.

   - Advertise "support" for non-serializing FS/GS base MSR writes as
     appropriate.

   - Harden the fast page fault path to guard against encountering an
     invalid root when walking SPTEs.

   - Omit "struct kvm_vcpu_xen" entirely when CONFIG_KVM_XEN=n.

   - Use the fast path directly from the timer callback when delivering
     Xen timer events, instead of waiting for the next iteration of the
     run loop. This was not done so far because previously proposed code
     had races, but now care is taken to stop the hrtimer at critical
     points such as restarting the timer or saving the timer information
     for userspace.

   - Follow the lead of upstream Xen and ignore the VCPU_SSHOTTMR_future
     flag.

   - Optimize injection of PMU interrupts that are simultaneous with
     NMIs.

   - Usual handful of fixes for typos and other warts.

  x86 - MTRR/PAT fixes and optimizations:

   - Clean up code that deals with honoring guest MTRRs when the VM has
     non-coherent DMA and host MTRRs are ignored, i.e. EPT is enabled.

   - Zap EPT entries when non-coherent DMA assignment stops/start to
     prevent using stale entries with the wrong memtype.

   - Don't ignore guest PAT for CR0.CD=1 && KVM_X86_QUIRK_CD_NW_CLEARED=y

     This was done as a workaround for virtual machine BIOSes that did
     not bother to clear CR0.CD (because ancient KVM/QEMU did not bother
     to set it, in turn), and there's zero reason to extend the quirk to
     also ignore guest PAT.

  x86 - SEV fixes:

   - Report KVM_EXIT_SHUTDOWN instead of EINVAL if KVM intercepts
     SHUTDOWN while running an SEV-ES guest.

   - Clean up the recognition of emulation failures on SEV guests, when
     KVM would like to "skip" the instruction but it had already been
     partially emulated. This makes it possible to drop a hack that
     second guessed the (insufficient) information provided by the
     emulator, and just do the right thing.

  Documentation:

   - Various updates and fixes, mostly for x86

   - MTRR and PAT fixes and optimizations"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (164 commits)
  KVM: selftests: Avoid using forced target for generating arm64 headers
  tools headers arm64: Fix references to top srcdir in Makefile
  KVM: arm64: Add tracepoint for MMIO accesses where ISV==0
  KVM: arm64: selftest: Perform ISB before reading PAR_EL1
  KVM: arm64: selftest: Add the missing .guest_prepare()
  KVM: arm64: Always invalidate TLB for stage-2 permission faults
  KVM: x86: Service NMI requests after PMI requests in VM-Enter path
  KVM: arm64: Handle AArch32 SPSR_{irq,abt,und,fiq} as RAZ/WI
  KVM: arm64: Do not let a L1 hypervisor access the *32_EL2 sysregs
  KVM: arm64: Refine _EL2 system register list that require trap reinjection
  arm64: Add missing _EL2 encodings
  arm64: Add missing _EL12 encodings
  KVM: selftests: aarch64: vPMU test for validating user accesses
  KVM: selftests: aarch64: vPMU register test for unimplemented counters
  KVM: selftests: aarch64: vPMU register test for implemented counters
  KVM: selftests: aarch64: Introduce vpmu_counter_access test
  tools: Import arm_pmuv3.h
  KVM: arm64: PMU: Allow userspace to limit PMCR_EL0.N for the guest
  KVM: arm64: Sanitize PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR} before first run
  KVM: arm64: Add {get,set}_user for PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}
  ...
2023-11-02 15:45:15 -10:00
Oliver Upton
df26b77915 Merge branch kvm-arm64/stage2-vhe-load into kvmarm/next
* kvm-arm64/stage2-vhe-load:
  : Setup stage-2 MMU from vcpu_load() for VHE
  :
  : Unlike nVHE, there is no need to switch the stage-2 MMU around on guest
  : entry/exit in VHE mode as the host is running at EL2. Despite this KVM
  : reloads the stage-2 on every guest entry, which is needless.
  :
  : This series moves the setup of the stage-2 MMU context to vcpu_load()
  : when running in VHE mode. This is likely to be a win across the board,
  : but also allows us to remove an ISB on the guest entry path for systems
  : with one of the speculative AT errata.
  KVM: arm64: Move VTCR_EL2 into struct s2_mmu
  KVM: arm64: Load the stage-2 MMU context in kvm_vcpu_load_vhe()
  KVM: arm64: Rename helpers for VHE vCPU load/put
  KVM: arm64: Reload stage-2 for VMID change on VHE
  KVM: arm64: Restore the stage-2 context in VHE's __tlb_switch_to_host()
  KVM: arm64: Don't zero VTTBR in __tlb_switch_to_host()

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-10-30 20:18:56 +00:00
Oliver Upton
054056bf98 Merge branch kvm-arm64/misc into kvmarm/next
* kvm-arm64/misc:
  : Miscellaneous updates
  :
  :  - Put an upper bound on the number of I-cache invalidations by
  :    cacheline to avoid soft lockups
  :
  :  - Get rid of bogus refererence count transfer for THP mappings
  :
  :  - Do a local TLB invalidation on permission fault race
  :
  :  - Fixes for page_fault_test KVM selftest
  :
  :  - Add a tracepoint for detecting MMIO instructions unsupported by KVM
  KVM: arm64: Add tracepoint for MMIO accesses where ISV==0
  KVM: arm64: selftest: Perform ISB before reading PAR_EL1
  KVM: arm64: selftest: Add the missing .guest_prepare()
  KVM: arm64: Always invalidate TLB for stage-2 permission faults
  KVM: arm64: Do not transfer page refcount for THP adjustment
  KVM: arm64: Avoid soft lockups due to I-cache maintenance
  arm64: tlbflush: Rename MAX_TLBI_OPS
  KVM: arm64: Don't use kerneldoc comment for arm64_check_features()

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-10-30 20:18:00 +00:00
Marc Zyngier
fe49fd940e KVM: arm64: Move VTCR_EL2 into struct s2_mmu
We currently have a global VTCR_EL2 value for each guest, even
if the guest uses NV. This implies that the guest's own S2 must
fit in the host's. This is odd, for multiple reasons:

- the PARange values and the number of IPA bits don't necessarily
  match: you can have 33 bits of IPA space, and yet you can only
  describe 32 or 36 bits of PARange

- When userspace set the IPA space, it creates a contract with the
  kernel saying "this is the IPA space I'm prepared to handle".
  At no point does it constraint the guest's own IPA space as
  long as the guest doesn't try to use a [I]PA outside of the
  IPA space set by userspace

- We don't even try to hide the value of ID_AA64MMFR0_EL1.PARange.

And then there is the consequence of the above: if a guest tries
to create a S2 that has for input address something that is larger
than the IPA space defined by the host, we inject a fatal exception.

This is no good. For all intent and purposes, a guest should be
able to have the S2 it really wants, as long as the *output* address
of that S2 isn't outside of the IPA space.

For that, we need to have a per-s2_mmu VTCR_EL2 setting, which
allows us to represent the full PARange. Move the vctr field into
the s2_mmu structure, which has no impact whatsoever, except for NV.

Note that once we are able to override ID_AA64MMFR0_EL1.PARange
from userspace, we'll also be able to restrict the size of the
shadow S2 that NV uses.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231012205108.3937270-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-10-23 18:48:46 +00:00