Commit graph

723 commits

Author SHA1 Message Date
Sean Christopherson
baeb4de7ad x86/reboot: KVM: Disable SVM during reboot via virt/KVM reboot callback
Use the virt callback to disable SVM (and set GIF=1) during an emergency
instead of blindly attempting to disable SVM.  Like the VMX case, if a
hypervisor, i.e. KVM, isn't loaded/active, SVM can't be in use.

Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-08-03 15:37:14 -07:00
Sean Christopherson
a85cd52d72 KVM: SVM: Use svm_get_lbr_vmcb() helper to handle writes to DEBUGCTL
Use the recently introduced svm_get_lbr_vmcb() instead an open coded
equivalent to retrieve the target VMCB when emulating writes to
MSR_IA32_DEBUGCTLMSR.

No functional change intended.

Link: https://lore.kernel.org/r/20230607203519.1570167-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-08-02 16:41:55 -07:00
Sean Christopherson
41dfb5f13e KVM: SVM: Clean up handling of LBR virtualization enabled
Clean up the enable_lbrv computation in svm_update_lbrv() to consolidate
the logic for computing enable_lbrv into a single statement, and to remove
the coding style violations (lack of curly braces on nested if).

No functional change intended.

Link: https://lore.kernel.org/r/20230607203519.1570167-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-08-02 16:41:54 -07:00
Sean Christopherson
d518f8cc10 KVM: SVM: Fix dead KVM_BUG() code in LBR MSR virtualization
Refactor KVM's handling of LBR MSRs on SVM to avoid a second layer of
case statements, and thus eliminate a dead KVM_BUG() call, which (a) will
never be hit in the current code base and (b) if a future commit breaks
things, will never fire as KVM passes "false" instead "true" or '1' for
the KVM_BUG() condition.

Reported-by: Michal Luczaj <mhal@rbox.co>
Cc: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20230607203519.1570167-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-08-02 16:41:54 -07:00
Sean Christopherson
26a0652cb4 KVM: x86: Disallow KVM_SET_SREGS{2} if incoming CR0 is invalid
Reject KVM_SET_SREGS{2} with -EINVAL if the incoming CR0 is invalid,
e.g. due to setting bits 63:32, illegal combinations, or to a value that
isn't allowed in VMX (non-)root mode.  The VMX checks in particular are
"fun" as failure to disallow Real Mode for an L2 that is configured with
unrestricted guest disabled, when KVM itself has unrestricted guest
enabled, will result in KVM forcing VM86 mode to virtual Real Mode for
L2, but then fail to unwind the related metadata when synthesizing a
nested VM-Exit back to L1 (which has unrestricted guest enabled).

Opportunistically fix a benign typo in the prototype for is_valid_cr4().

Cc: stable@vger.kernel.org
Reported-by: syzbot+5feef0b9ee9c8e9e5689@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000f316b705fdf6e2b4@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230613203037.1968489-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-07-29 11:05:31 -04:00
Sean Christopherson
b439eb8ab5 Revert "KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid"
Now that handle_fastpath_set_msr_irqoff() acquires kvm->srcu, i.e. allows
dereferencing memslots during WRMSR emulation, drop the requirement that
"next RIP" is valid.  In hindsight, acquiring kvm->srcu would have been a
better fix than avoiding the pastpath, but at the time it was thought that
accessing SRCU-protected data in the fastpath was a one-off edge case.

This reverts commit 5c30e8101e.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230721224337.2335137-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-07-29 11:05:27 -04:00
Sean Christopherson
a6bb570902 KVM: SVM: Don't try to pointlessly single-step SEV-ES guests for NMI window
Bail early from svm_enable_nmi_window() for SEV-ES guests without trying
to enable single-step of the guest, as single-stepping an SEV-ES guest is
impossible and the guest is responsible for *telling* KVM when it is ready
for an new NMI to be injected.

Functionally, setting TF and RF in svm->vmcb->save.rflags is benign as the
field is ignored by hardware, but it's all kinds of confusing.

Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-10-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-07-28 16:13:43 -07:00
Sean Christopherson
389fbbec26 KVM: SVM: Don't defer NMI unblocking until next exit for SEV-ES guests
Immediately mark NMIs as unmasked in response to #VMGEXIT(NMI complete)
instead of setting awaiting_iret_completion and waiting until the *next*
VM-Exit to unmask NMIs.  The whole point of "NMI complete" is that the
guest is responsible for telling the hypervisor when it's safe to inject
an NMI, i.e. there's no need to wait.  And because there's no IRET to
single-step, the next VM-Exit could be a long time coming, i.e. KVM could
incorrectly hold an NMI pending for far longer than what is required and
expected.

Opportunistically fix a stale reference to HF_IRET_MASK.

Fixes: 916b54a768 ("KVM: x86: Move HF_NMI_MASK and HF_IRET_MASK into "struct vcpu_svm"")
Fixes: 4444dfe405 ("KVM: SVM: Add NMI support for an SEV-ES guest")
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-9-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-07-28 16:13:18 -07:00
Alexey Kardashevskiy
c2690b5f01 KVM: SVM/SEV/SEV-ES: Rework intercepts
Currently SVM setup is done sequentially in
init_vmcb() -> sev_init_vmcb() -> sev_es_init_vmcb()
and tries keeping SVM/SEV/SEV-ES bits separated. One of the exceptions
is DR intercepts which is for SEV-ES before sev_es_init_vmcb() runs.

Move the SEV-ES intercept setup to sev_es_init_vmcb(). From now on
set_dr_intercepts()/clr_dr_intercepts() handle SVM/SEV only.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-6-aik@amd.com
[sean: drop comment about intercepting DR7]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-07-28 16:12:06 -07:00
Alexey Kardashevskiy
2837dd00f8 KVM: SEV-ES: explicitly disable debug
SVM/SEV enable debug registers intercepts to skip swapping DRs
on entering/exiting the guest. When the guest is in control of
debug registers (vcpu->guest_debug == 0), there is an optimisation to
reduce the number of context switches: intercepts are cleared and
the KVM_DEBUGREG_WONT_EXIT flag is set to tell KVM to do swapping
on guest enter/exit.

The same code also executes for SEV-ES, however it has no effect as
- it always takes (vcpu->guest_debug == 0) branch;
- KVM_DEBUGREG_WONT_EXIT is set but DR7 intercept is not cleared;
- vcpu_enter_guest() writes DRs but VMRUN for SEV-ES swaps them
with the values from _encrypted_ VMSA.

Be explicit about SEV-ES not supporting debug:
- return right away from dr_interception() and skip unnecessary processing;
- return an error right away from the KVM_SEV_LAUNCH_UPDATE_VMSA handler
if debugging was already enabled.
KVM_SET_GUEST_DEBUG are failing already after KVM_SEV_LAUNCH_UPDATE_VMSA
is finished due to vcpu->arch.guest_state_protected set to true.

Add WARN_ON to kvm_x86::sync_dirty_debug_regs() (saves guest DRs on
guest exit) to signify that SEV-ES won't hit that path.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-5-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-07-28 15:58:53 -07:00
Alexey Kardashevskiy
29de732cc9 KVM: SEV: Move SEV's GP_VECTOR intercept setup to SEV
Currently SVM setup is done sequentially in
init_vmcb() -> sev_init_vmcb() -> sev_es_init_vmcb() and tries
keeping SVM/SEV/SEV-ES bits separated. One of the exceptions
is #GP intercept which init_vmcb() skips setting for SEV guests and
then sev_es_init_vmcb() needlessly clears it.

Remove the SEV check from init_vmcb(). Clear the #GP intercept in
sev_init_vmcb(). SEV-ES will use the SEV setting.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-3-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-07-28 15:58:53 -07:00
Alexey Kardashevskiy
b265ee7bae KVM: SEV: move set_dr_intercepts/clr_dr_intercepts from the header
Static functions set_dr_intercepts() and clr_dr_intercepts() are only
called from SVM so move them to .c.

No functional change intended.

Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Santosh Shukla <santosh.shukla@amd.com>
Link: https://lore.kernel.org/r/20230615063757.3039121-2-aik@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-07-28 15:58:53 -07:00
Borislav Petkov (AMD)
d893832d0e x86/srso: Add IBPB on VMEXIT
Add the option to flush IBPB only on VMEXIT in order to protect from
malicious guests but one otherwise trusts the software that runs on the
hypervisor.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2023-07-27 11:07:19 +02:00
Paolo Bonzini
24975ce8b2 KVM SVM changes for 6.5:
- Drop manual TR/TSS load after VM-Exit now that KVM uses VMLOAD for host state
 
  - Fix a not-yet-problematic missing call to trace_kvm_exit() for VM-Exits that
    are handled in the fastpath
 
  - Print more descriptive information about the status of SEV and SEV-ES during
    module load
 
  - Assert that misc_cg_set_capacity() doesn't fail to avoid should-be-impossible
    memory leaks
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Merge tag 'kvm-x86-svm-6.5' of https://github.com/kvm-x86/linux into HEAD

KVM SVM changes for 6.5:

 - Drop manual TR/TSS load after VM-Exit now that KVM uses VMLOAD for host state

 - Fix a not-yet-problematic missing call to trace_kvm_exit() for VM-Exits that
   are handled in the fastpath

 - Print more descriptive information about the status of SEV and SEV-ES during
   module load

 - Assert that misc_cg_set_capacity() doesn't fail to avoid should-be-impossible
   memory leaks
2023-07-01 07:19:42 -04:00
Paolo Bonzini
751d77fefa KVM x86/pmu changes for 6.5:
- Add support for AMD PerfMonV2, with a variety of cleanups and minor fixes
    included along the way
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Merge tag 'kvm-x86-pmu-6.5' of https://github.com/kvm-x86/linux into HEAD

KVM x86/pmu changes for 6.5:

 - Add support for AMD PerfMonV2, with a variety of cleanups and minor fixes
   included along the way
2023-07-01 07:18:51 -04:00
Paolo Bonzini
36b68d360a KVM x86 changes for 6.5:
- Move handling of PAT out of MTRR code and dedup SVM+VMX code
 
  - Fix output of PIC poll command emulation when there's an interrupt
 
  - Fix a longstanding bug in the reporting of the number of entries returned by
    KVM_GET_CPUID2
 
  - Add a maintainer's handbook to document KVM x86 processes, preferred coding
    style, testing expectations, etc.
 
  - Misc cleanups
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Merge tag 'kvm-x86-misc-6.5' of https://github.com/kvm-x86/linux into HEAD

KVM x86 changes for 6.5:

* Move handling of PAT out of MTRR code and dedup SVM+VMX code

* Fix output of PIC poll command emulation when there's an interrupt

* Add a maintainer's handbook to document KVM x86 processes, preferred coding
  style, testing expectations, etc.

* Misc cleanups
2023-07-01 07:08:59 -04:00
Like Xu
94cdeebd82 KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022
CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some new
performance monitoring features for AMD processors.

Bit 0 of EAX indicates support for Performance Monitoring Version 2
(PerfMonV2) features. If found to be set during PMU initialization,
the EBX bits of the same CPUID function can be used to determine
the number of available PMCs for different PMU types.

Expose the relevant bits via KVM_GET_SUPPORTED_CPUID so that
guests can make use of the PerfMonV2 features.

Co-developed-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230603011058.1038821-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-06 17:31:44 -07:00
Like Xu
d338d8789e KVM: x86/pmu: Advertise PERFCTR_CORE iff the min nr of counters is met
Enable and advertise PERFCTR_CORE if and only if the minimum number of
required counters are available, i.e. if perf says there are less than six
general purpose counters.

Opportunistically, use kvm_cpu_cap_check_and_set() instead of open coding
the check for host support.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
[sean: massage shortlog and changelog]
Link: https://lore.kernel.org/r/20230603011058.1038821-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-06 17:31:44 -07:00
Michal Luczaj
e12fa4b92a KVM: x86: Clean up: remove redundant bool conversions
As test_bit() returns bool, explicitly converting result to bool is
unnecessary. Get rid of '!!'.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Link: https://lore.kernel.org/r/20230605200158.118109-1-mhal@rbox.co
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-06 17:13:55 -07:00
Sean Christopherson
791a089861 KVM: SVM: Invoke trace_kvm_exit() for fastpath VM-Exits
Move SVM's call to trace_kvm_exit() from the "slow" VM-Exit handler to
svm_vcpu_run() so that KVM traces fastpath VM-Exits that re-enter the
guest without bouncing through the slow path.  This bug is benign in the
current code base as KVM doesn't currently support any such exits on SVM.

Fixes: a9ab13ff6e ("KVM: X86: Improve latency for single target IPI fastpath")
Link: https://lore.kernel.org/r/20230602011920.787844-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-02 16:40:27 -07:00
Maciej S. Szmigiero
b2ce899788 KVM: SVM: vNMI pending bit is V_NMI_PENDING_MASK not V_NMI_BLOCKING_MASK
While testing Hyper-V enabled Windows Server 2019 guests on Zen4 hardware
I noticed that with vCPU count large enough (> 16) they sometimes froze at
boot.
With vCPU count of 64 they never booted successfully - suggesting some kind
of a race condition.

Since adding "vnmi=0" module parameter made these guests boot successfully
it was clear that the problem is most likely (v)NMI-related.

Running kvm-unit-tests quickly showed failing NMI-related tests cases, like
"multiple nmi" and "pending nmi" from apic-split, x2apic and xapic tests
and the NMI parts of eventinj test.

The issue was that once one NMI was being serviced no other NMI was allowed
to be set pending (NMI limit = 0), which was traced to
svm_is_vnmi_pending() wrongly testing for the "NMI blocked" flag rather
than for the "NMI pending" flag.

Fix this by testing for the right flag in svm_is_vnmi_pending().
Once this is done, the NMI-related kvm-unit-tests pass successfully and
the Windows guest no longer freezes at boot.

Fixes: fa4c027a79 ("KVM: x86: Add support for SVM's Virtual NMI")
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/be4ca192eb0c1e69a210db3009ca984e6a54ae69.1684495380.git.maciej.szmigiero@oracle.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-02 16:34:20 -07:00
Sean Christopherson
dee321977a KVM: x86: Move common handling of PAT MSR writes to kvm_set_msr_common()
Move the common check-and-set handling of PAT MSR writes out of vendor
code and into kvm_set_msr_common().  This aligns writes with reads, which
are already handled in common code, i.e. makes the handling of reads and
writes symmetrical in common code.

Alternatively, the common handling in kvm_get_msr_common() could be moved
to vendor code, but duplicating code is generally undesirable (even though
the duplicatated code is trivial in this case), and guest writes to PAT
should be rare, i.e. the overhead of the extra function call is a
non-issue in practice.

Suggested-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230511233351.635053-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01 13:41:06 -07:00
Ke Guo
7aeae02761 KVM: SVM: Use kvm_pat_valid() directly instead of kvm_mtrr_valid()
Use kvm_pat_valid() directly instead of bouncing through kvm_mtrr_valid().
The PAT is not an MTRR, and kvm_mtrr_valid() just redirects to
kvm_pat_valid(), i.e. is exempt from KVM's "zap SPTEs" logic that's
needed to honor guest MTRRs when the VM has a passthrough device with
non-coherent DMA (KVM does NOT set "ignore guest PAT" in this case, and so
enables hardware virtualization of the guest's PAT, i.e. doesn't need to
manually emulate the PAT memtype).

Signed-off-by: Ke Guo <guoke@uniontech.com>
[sean: massage changelog]
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230511233351.635053-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01 13:41:05 -07:00
Mingwei Zhang
0d3518d2f8 KVM: SVM: Remove TSS reloading code after VMEXIT
Remove the dedicated post-VMEXIT TSS reloading code now that KVM uses
VMLOAD to load host segment state, which includes TSS state.

Fixes: e79b91bb3c ("KVM: SVM: use vmsave/vmload for saving/restoring additional host state")
Reported-by: Venkatesh Srinivas <venkateshs@google.com>
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230523165635.4002711-1-mizhang@google.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-06-01 13:38:16 -07:00
Linus Torvalds
c8c655c34e s390:
* More phys_to_virt conversions
 
 * Improvement of AP management for VSIE (nested virtualization)
 
 ARM64:
 
 * Numerous fixes for the pathological lock inversion issue that
   plagued KVM/arm64 since... forever.
 
 * New framework allowing SMCCC-compliant hypercalls to be forwarded
   to userspace, hopefully paving the way for some more features
   being moved to VMMs rather than be implemented in the kernel.
 
 * Large rework of the timer code to allow a VM-wide offset to be
   applied to both virtual and physical counters as well as a
   per-timer, per-vcpu offset that complements the global one.
   This last part allows the NV timer code to be implemented on
   top.
 
 * A small set of fixes to make sure that we don't change anything
   affecting the EL1&0 translation regime just after having having
   taken an exception to EL2 until we have executed a DSB. This
   ensures that speculative walks started in EL1&0 have completed.
 
 * The usual selftest fixes and improvements.
 
 KVM x86 changes for 6.4:
 
 * Optimize CR0.WP toggling by avoiding an MMU reload when TDP is enabled,
   and by giving the guest control of CR0.WP when EPT is enabled on VMX
   (VMX-only because SVM doesn't support per-bit controls)
 
 * Add CR0/CR4 helpers to query single bits, and clean up related code
   where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long" return
   as a bool
 
 * Move AMD_PSFD to cpufeatures.h and purge KVM's definition
 
 * Avoid unnecessary writes+flushes when the guest is only adding new PTEs
 
 * Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s optimizations
   when emulating invalidations
 
 * Clean up the range-based flushing APIs
 
 * Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a single
   A/D bit using a LOCK AND instead of XCHG, and skip all of the "handle
   changed SPTE" overhead associated with writing the entire entry
 
 * Track the number of "tail" entries in a pte_list_desc to avoid having
   to walk (potentially) all descriptors during insertion and deletion,
   which gets quite expensive if the guest is spamming fork()
 
 * Disallow virtualizing legacy LBRs if architectural LBRs are available,
   the two are mutually exclusive in hardware
 
 * Disallow writes to immutable feature MSRs (notably PERF_CAPABILITIES)
   after KVM_RUN, similar to CPUID features
 
 * Overhaul the vmx_pmu_caps selftest to better validate PERF_CAPABILITIES
 
 * Apply PMU filters to emulated events and add test coverage to the
   pmu_event_filter selftest
 
 x86 AMD:
 
 * Add support for virtual NMIs
 
 * Fixes for edge cases related to virtual interrupts
 
 x86 Intel:
 
 * Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if XTILE_DATA is
   not being reported due to userspace not opting in via prctl()
 
 * Fix a bug in emulation of ENCLS in compatibility mode
 
 * Allow emulation of NOP and PAUSE for L2
 
 * AMX selftests improvements
 
 * Misc cleanups
 
 MIPS:
 
 * Constify MIPS's internal callbacks (a leftover from the hardware enabling
   rework that landed in 6.3)
 
 Generic:
 
 * Drop unnecessary casts from "void *" throughout kvm_main.c
 
 * Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the struct
   size by 8 bytes on 64-bit kernels by utilizing a padding hole
 
 Documentation:
 
 * Fix goof introduced by the conversion to rST
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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:

   - More phys_to_virt conversions

   - Improvement of AP management for VSIE (nested virtualization)

  ARM64:

   - Numerous fixes for the pathological lock inversion issue that
     plagued KVM/arm64 since... forever.

   - New framework allowing SMCCC-compliant hypercalls to be forwarded
     to userspace, hopefully paving the way for some more features being
     moved to VMMs rather than be implemented in the kernel.

   - Large rework of the timer code to allow a VM-wide offset to be
     applied to both virtual and physical counters as well as a
     per-timer, per-vcpu offset that complements the global one. This
     last part allows the NV timer code to be implemented on top.

   - A small set of fixes to make sure that we don't change anything
     affecting the EL1&0 translation regime just after having having
     taken an exception to EL2 until we have executed a DSB. This
     ensures that speculative walks started in EL1&0 have completed.

   - The usual selftest fixes and improvements.

  x86:

   - Optimize CR0.WP toggling by avoiding an MMU reload when TDP is
     enabled, and by giving the guest control of CR0.WP when EPT is
     enabled on VMX (VMX-only because SVM doesn't support per-bit
     controls)

   - Add CR0/CR4 helpers to query single bits, and clean up related code
     where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long"
     return as a bool

   - Move AMD_PSFD to cpufeatures.h and purge KVM's definition

   - Avoid unnecessary writes+flushes when the guest is only adding new
     PTEs

   - Overhaul .sync_page() and .invlpg() to utilize .sync_page()'s
     optimizations when emulating invalidations

   - Clean up the range-based flushing APIs

   - Revamp the TDP MMU's reaping of Accessed/Dirty bits to clear a
     single A/D bit using a LOCK AND instead of XCHG, and skip all of
     the "handle changed SPTE" overhead associated with writing the
     entire entry

   - Track the number of "tail" entries in a pte_list_desc to avoid
     having to walk (potentially) all descriptors during insertion and
     deletion, which gets quite expensive if the guest is spamming
     fork()

   - Disallow virtualizing legacy LBRs if architectural LBRs are
     available, the two are mutually exclusive in hardware

   - Disallow writes to immutable feature MSRs (notably
     PERF_CAPABILITIES) after KVM_RUN, similar to CPUID features

   - Overhaul the vmx_pmu_caps selftest to better validate
     PERF_CAPABILITIES

   - Apply PMU filters to emulated events and add test coverage to the
     pmu_event_filter selftest

   - AMD SVM:
       - Add support for virtual NMIs
       - Fixes for edge cases related to virtual interrupts

   - Intel AMX:
       - Don't advertise XTILE_CFG in KVM_GET_SUPPORTED_CPUID if
         XTILE_DATA is not being reported due to userspace not opting in
         via prctl()
       - Fix a bug in emulation of ENCLS in compatibility mode
       - Allow emulation of NOP and PAUSE for L2
       - AMX selftests improvements
       - Misc cleanups

  MIPS:

   - Constify MIPS's internal callbacks (a leftover from the hardware
     enabling rework that landed in 6.3)

  Generic:

   - Drop unnecessary casts from "void *" throughout kvm_main.c

   - Tweak the layout of "struct kvm_mmu_memory_cache" to shrink the
     struct size by 8 bytes on 64-bit kernels by utilizing a padding
     hole

  Documentation:

   - Fix goof introduced by the conversion to rST"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (211 commits)
  KVM: s390: pci: fix virtual-physical confusion on module unload/load
  KVM: s390: vsie: clarifications on setting the APCB
  KVM: s390: interrupt: fix virtual-physical confusion for next alert GISA
  KVM: arm64: Have kvm_psci_vcpu_on() use WRITE_ONCE() to update mp_state
  KVM: arm64: Acquire mp_state_lock in kvm_arch_vcpu_ioctl_vcpu_init()
  KVM: selftests: Test the PMU event "Instructions retired"
  KVM: selftests: Copy full counter values from guest in PMU event filter test
  KVM: selftests: Use error codes to signal errors in PMU event filter test
  KVM: selftests: Print detailed info in PMU event filter asserts
  KVM: selftests: Add helpers for PMC asserts in PMU event filter test
  KVM: selftests: Add a common helper for the PMU event filter guest code
  KVM: selftests: Fix spelling mistake "perrmited" -> "permitted"
  KVM: arm64: vhe: Drop extra isb() on guest exit
  KVM: arm64: vhe: Synchronise with page table walker on MMU update
  KVM: arm64: pkvm: Document the side effects of kvm_flush_dcache_to_poc()
  KVM: arm64: nvhe: Synchronise with page table walker on TLBI
  KVM: arm64: Handle 32bit CNTPCTSS traps
  KVM: arm64: nvhe: Synchronise with page table walker on vcpu run
  KVM: arm64: vgic: Don't acquire its_lock before config_lock
  KVM: selftests: Add test to verify KVM's supported XCR0
  ...
2023-05-01 12:06:20 -07:00
Linus Torvalds
f20730efbd SMP cross-CPU function-call updates for v6.4:
- Remove diagnostics and adjust config for CSD lock diagnostics
 
  - Add a generic IPI-sending tracepoint, as currently there's no easy
    way to instrument IPI origins: it's arch dependent and for some
    major architectures it's not even consistently available.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'smp-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull SMP cross-CPU function-call updates from Ingo Molnar:

 - Remove diagnostics and adjust config for CSD lock diagnostics

 - Add a generic IPI-sending tracepoint, as currently there's no easy
   way to instrument IPI origins: it's arch dependent and for some major
   architectures it's not even consistently available.

* tag 'smp-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  trace,smp: Trace all smp_function_call*() invocations
  trace: Add trace_ipi_send_cpu()
  sched, smp: Trace smp callback causing an IPI
  smp: reword smp call IPI comment
  treewide: Trace IPIs sent via smp_send_reschedule()
  irq_work: Trace self-IPIs sent via arch_irq_work_raise()
  smp: Trace IPIs sent via arch_send_call_function_ipi_mask()
  sched, smp: Trace IPIs sent via send_call_function_single_ipi()
  trace: Add trace_ipi_send_cpumask()
  kernel/smp: Make csdlock_debug= resettable
  locking/csd_lock: Remove per-CPU data indirection from CSD lock debugging
  locking/csd_lock: Remove added data from CSD lock debugging
  locking/csd_lock: Add Kconfig option for csd_debug default
2023-04-28 15:03:43 -07:00
Paolo Bonzini
4a5fd41995 KVM SVM changes for 6.4:
- Add support for virtual NMIs
 
  - Fixes for edge cases related to virtual interrupts
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Merge tag 'kvm-x86-svm-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM SVM changes for 6.4:

 - Add support for virtual NMIs

 - Fixes for edge cases related to virtual interrupts
2023-04-26 15:56:27 -04:00
Paolo Bonzini
48b1893ae3 KVM x86 PMU changes for 6.4:
- Disallow virtualizing legacy LBRs if architectural LBRs are available,
    the two are mutually exclusive in hardware
 
  - Disallow writes to immutable feature MSRs (notably PERF_CAPABILITIES)
    after KVM_RUN, and overhaul the vmx_pmu_caps selftest to better
    validate PERF_CAPABILITIES
 
  - Apply PMU filters to emulated events and add test coverage to the
    pmu_event_filter selftest
 
  - Misc cleanups and fixes
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Merge tag 'kvm-x86-pmu-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM x86 PMU changes for 6.4:

 - Disallow virtualizing legacy LBRs if architectural LBRs are available,
   the two are mutually exclusive in hardware

 - Disallow writes to immutable feature MSRs (notably PERF_CAPABILITIES)
   after KVM_RUN, and overhaul the vmx_pmu_caps selftest to better
   validate PERF_CAPABILITIES

 - Apply PMU filters to emulated events and add test coverage to the
   pmu_event_filter selftest

 - Misc cleanups and fixes
2023-04-26 15:53:36 -04:00
Paolo Bonzini
a1c288f87d KVM x86 changes for 6.4:
- Optimize CR0.WP toggling by avoiding an MMU reload when TDP is enabled,
    and by giving the guest control of CR0.WP when EPT is enabled on VMX
    (VMX-only because SVM doesn't support per-bit controls)
 
  - Add CR0/CR4 helpers to query single bits, and clean up related code
    where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long" return
    as a bool
 
  - Move AMD_PSFD to cpufeatures.h and purge KVM's definition
 
  - Misc cleanups
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Merge tag 'kvm-x86-misc-6.4' of https://github.com/kvm-x86/linux into HEAD

KVM x86 changes for 6.4:

 - Optimize CR0.WP toggling by avoiding an MMU reload when TDP is enabled,
   and by giving the guest control of CR0.WP when EPT is enabled on VMX
   (VMX-only because SVM doesn't support per-bit controls)

 - Add CR0/CR4 helpers to query single bits, and clean up related code
   where KVM was interpreting kvm_read_cr4_bits()'s "unsigned long" return
   as a bool

 - Move AMD_PSFD to cpufeatures.h and purge KVM's definition

 - Misc cleanups
2023-04-26 15:49:23 -04:00
Sean Christopherson
5757f5b956 KVM: x86: Add macros to track first...last VMX feature MSRs
Add macros to track the range of VMX feature MSRs that are emulated by
KVM to reduce the maintenance cost of extending the set of emulated MSRs.

Note, KVM doesn't necessarily emulate all known/consumed VMX MSRs, e.g.
PROCBASED_CTLS3 is consumed by KVM to enable IPI virtualization, but is
not emulated as KVM doesn't emulate/virtualize IPI virtualization for
nested guests.

No functional change intended.

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20230311004618.920745-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-04-06 14:57:22 -07:00
Sean Christopherson
400d213228 KVM: SVM: Return the local "r" variable from svm_set_msr()
Rename "r" to "ret" and actually return it from svm_set_msr() to reduce
the probability of repeating the mistake of commit 723d5fb0ff ("kvm:
svm: Add IA32_FLUSH_CMD guest support"), which set "r" thinking that it
would be propagated to the caller.

Alternatively, the declaration of "r" could be moved into the handling of
MSR_TSC_AUX, but that risks variable shadowing in the future.  A wrapper
for kvm_set_user_return_msr() would allow eliding a local variable, but
that feels like delaying the inevitable.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:37 -04:00
Sean Christopherson
da3db168fb KVM: x86: Virtualize FLUSH_L1D and passthrough MSR_IA32_FLUSH_CMD
Virtualize FLUSH_L1D so that the guest can use the performant L1D flush
if one of the many mitigations might require a flush in the guest, e.g.
Linux provides an option to flush the L1D when switching mms.

Passthrough MSR_IA32_FLUSH_CMD for write when it's supported in hardware
and exposed to the guest, i.e. always let the guest write it directly if
FLUSH_L1D is fully supported.

Forward writes to hardware in host context on the off chance that KVM
ends up emulating a WRMSR, or in the really unlikely scenario where
userspace wants to force a flush.  Restrict these forwarded WRMSRs to
the known command out of an abundance of caution.  Passing through the
MSR means the guest can throw any and all values at hardware, but doing
so in host context is arguably a bit more dangerous.

Link: https://lkml.kernel.org/r/CALMp9eTt3xzAEoQ038bJQ9LN0ZOXrSWsN7xnNUD%2B0SS%3DWwF7Pg%40mail.gmail.com
Link: https://lore.kernel.org/all/20230201132905.549148-2-eesposit@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:37 -04:00
Sean Christopherson
903358c7ed KVM: x86: Move MSR_IA32_PRED_CMD WRMSR emulation to common code
Dedup the handling of MSR_IA32_PRED_CMD across VMX and SVM by moving the
logic to kvm_set_msr_common().  Now that the MSR interception toggling is
handled as part of setting guest CPUID, the VMX and SVM paths are
identical.

Opportunistically massage the code to make it a wee bit denser.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20230322011440.2195485-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:36 -04:00
Sean Christopherson
bff903e8cd KVM: SVM: Passthrough MSR_IA32_PRED_CMD based purely on host+guest CPUID
Passthrough MSR_IA32_PRED_CMD based purely on whether or not the MSR is
supported and enabled, i.e. don't wait until the first write.  There's no
benefit to deferred passthrough, and the extra logic only adds complexity.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322011440.2195485-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:36 -04:00
Sean Christopherson
52887af565 KVM: x86: Revert MSR_IA32_FLUSH_CMD.FLUSH_L1D enabling
Revert the recently added virtualizing of MSR_IA32_FLUSH_CMD, as both
the VMX and SVM are fatally buggy to guests that use MSR_IA32_FLUSH_CMD or
MSR_IA32_PRED_CMD, and because the entire foundation of the logic is
flawed.

The most immediate problem is an inverted check on @cmd that results in
rejecting legal values.  SVM doubles down on bugs and drops the error,
i.e. silently breaks all guest mitigations based on the command MSRs.

The next issue is that neither VMX nor SVM was updated to mark
MSR_IA32_FLUSH_CMD as being a possible passthrough MSR,
which isn't hugely problematic, but does break MSR filtering and triggers
a WARN on VMX designed to catch this exact bug.

The foundational issues stem from the MSR_IA32_FLUSH_CMD code reusing
logic from MSR_IA32_PRED_CMD, which in turn was likely copied from KVM's
support for MSR_IA32_SPEC_CTRL.  The copy+paste from MSR_IA32_SPEC_CTRL
was misguided as MSR_IA32_PRED_CMD (and MSR_IA32_FLUSH_CMD) is a
write-only MSR, i.e. doesn't need the same "deferred passthrough"
shenanigans as MSR_IA32_SPEC_CTRL.

Revert all MSR_IA32_FLUSH_CMD enabling in one fell swoop so that there is
no point where KVM advertises, but does not support, L1D_FLUSH.

This reverts commits 45cf86f261,
723d5fb0ff, and
a807b78ad0.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lkml.kernel.org/r/20230317190432.GA863767%40dev-arch.thelio-3990X
Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Mathias Krause <minipli@grsecurity.net>
Message-Id: <20230322011440.2195485-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-04-06 13:37:35 -04:00
Jeremi Piotrowski
e5c972c1fa KVM: SVM: Flush Hyper-V TLB when required
The Hyper-V "EnlightenedNptTlb" enlightenment is always enabled when KVM
is running on top of Hyper-V and Hyper-V exposes support for it (which
is always). On AMD CPUs this enlightenment results in ASID invalidations
not flushing TLB entries derived from the NPT. To force the underlying
(L0) hypervisor to rebuild its shadow page tables, an explicit hypercall
is needed.

The original KVM implementation of Hyper-V's "EnlightenedNptTlb" on SVM
only added remote TLB flush hooks. This worked out fine for a while, as
sufficient remote TLB flushes where being issued in KVM to mask the
problem. Since v5.17, changes in the TDP code reduced the number of
flushes and the out-of-sync TLB prevents guests from booting
successfully.

Split svm_flush_tlb_current() into separate callbacks for the 3 cases
(guest/all/current), and issue the required Hyper-V hypercall when a
Hyper-V TLB flush is needed. The most important case where the TLB flush
was missing is when loading a new PGD, which is followed by what is now
svm_flush_tlb_current().

Cc: stable@vger.kernel.org # v5.17+
Fixes: 1e0c7d4075 ("KVM: SVM: hyper-v: Remote TLB flush for SVM")
Link: https://lore.kernel.org/lkml/43980946-7bbf-dcef-7e40-af904c456250@linux.microsoft.com/
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20230324145233.4585-1-jpiotrowski@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-03-27 10:10:26 -04:00
Valentin Schneider
4c8c3c7f70 treewide: Trace IPIs sent via smp_send_reschedule()
To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Changes to include the declaration of the tracepoint were driven by the
following coccinelle script:

  @func_use@
  @@
  smp_send_reschedule(...);

  @include@
  @@
  #include <trace/events/ipi.h>

  @no_include depends on func_use && !include@
  @@
    #include <...>
  +
  + #include <trace/events/ipi.h>

[csky bits]
[riscv bits]
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230307143558.294354-6-vschneid@redhat.com
2023-03-24 11:01:28 +01:00
Santosh Shukla
0977cfac6e KVM: nSVM: Implement support for nested VNMI
Allow L1 to use vNMI to accelerate its injection of NMI to L2 by
propagating vNMI int_ctl bits from/to vmcb12 to/from vmcb02.

To handle both the case where vNMI is enabled for L1 and L2, and where
vNMI is enabled for L1 but _not_ L2, move pending L1 vNMIs to nmi_pending
on nested VM-Entry and raise KVM_REQ_EVENT, i.e. rely on existing code to
route the NMI to the correct domain.

On nested VM-Exit, reverse the process and set/clear V_NMI_PENDING for L1
based one whether nmi_pending is zero or non-zero.  There is no need to
consider vmcb02 in this case, as V_NMI_PENDING can be set in vmcb02 if
vNMI is disabled for L2, and if vNMI is enabled for L2, then L1 and L2
have different NMI contexts.

Co-developed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
Link: https://lore.kernel.org/r/20230227084016.3368-12-santosh.shukla@amd.com
[sean: massage changelog to match the code]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 17:43:45 -07:00
Santosh Shukla
fa4c027a79 KVM: x86: Add support for SVM's Virtual NMI
Add support for SVM's Virtual NMIs implementation, which adds proper
tracking of virtual NMI blocking, and an intr_ctrl flag that software can
set to mark a virtual NMI as pending.  Pending virtual NMIs are serviced
by hardware if/when virtual NMIs become unblocked, i.e. act more or less
like real NMIs.

Introduce two new kvm_x86_ops callbacks so to support SVM's vNMI, as KVM
needs to treat a pending vNMI as partially injected.  Specifically, if
two NMIs (for L1) arrive concurrently in KVM's software model, KVM's ABI
is to inject one and pend the other.  Without vNMI, KVM manually tracks
the pending NMI and uses NMI windows to detect when the NMI should be
injected.

With vNMI, the pending NMI is simply stuffed into the VMCB and handed
off to hardware.  This means that KVM needs to be able to set a vNMI
pending on-demand, and also query if a vNMI is pending, e.g. to honor the
"at most one NMI pending" rule and to preserve all NMIs across save and
restore.

Warn if KVM attempts to open an NMI window when vNMI is fully enabled,
as the above logic should prevent KVM from ever getting to
kvm_check_and_inject_events() with two NMIs pending _in software_, and
the "at most one NMI pending" logic should prevent having an NMI pending
in hardware and an NMI pending in software if NMIs are also blocked, i.e.
if KVM can't immediately inject the second NMI.

Signed-off-by: Santosh Shukla <Santosh.Shukla@amd.com>
Co-developed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20230227084016.3368-11-santosh.shukla@amd.com
[sean: rewrite shortlog and changelog, massage code comments]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 17:43:22 -07:00
Maxim Levitsky
772f254d4d KVM: SVM: add wrappers to enable/disable IRET interception
SEV-ES guests don't use IRET interception for the detection of
an end of a NMI.

Therefore it makes sense to create a wrapper to avoid repeating
the check for the SEV-ES.

No functional change is intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
[Renamed iret intercept API of style svm_{clr,set}_iret_intercept()]
Signed-off-by: Santosh Shukla <Santosh.Shukla@amd.com>
Link: https://lore.kernel.org/r/20230227084016.3368-5-santosh.shukla@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 12:34:32 -07:00
Santosh Shukla
7334ede457 KVM: nSVM: Disable intercept of VINTR if saved L1 host RFLAGS.IF is 0
Disable intercept of virtual interrupts (used to detect interrupt windows)
if the saved host (L1) RFLAGS.IF is '0', as the effective RFLAGS.IF for L1
interrupts will never be set while L2 is running (L2's RFLAGS.IF doesn't
affect L1 IRQs when virtual interrupts are enabled).

Suggested-by: Sean Christopherson <seanjc@google.com>
Link: https://lkml.kernel.org/r/Y9hybI65So5X2LFg%40google.com
Signed-off-by: Santosh Shukla <Santosh.Shukla@amd.com>
Link: https://lore.kernel.org/r/20230227084016.3368-3-santosh.shukla@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 12:19:40 -07:00
Binbin Wu
627778bfcf KVM: SVM: Use kvm_is_cr4_bit_set() to query SMAP/SMEP in "can emulate"
Use kvm_is_cr4_bit_set() to query SMAP and SMEP when determining whether
or not AMD's SMAP+SEV errata prevents KVM from emulating an instruction.
This eliminates an implicit cast from ulong to bool and makes the code
slightly more readable.

Note, any overhead from making multiple calls to kvm_read_cr4_bits() is
negligible, not to mention the code is question is encountered only in
rare situations, i.e. is not a remotely hot path.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20230322045824.22970-4-binbin.wu@linux.intel.com
[sean: keep local smap/smep variables, massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 10:18:18 -07:00
Binbin Wu
bede6eb4db KVM: x86: Use boolean return value for is_{pae,pse,paging}()
Convert is_{pae,pse,paging}() to use kvm_is_cr{0,4}_bit_set() and return
bools.  Returning an "int" requires not one, but two implicit casts, first
from "unsigned long" to "int", and then again to a "bool".  Both casts are
more than a bit dangerous; the ulong=>int casts would drop a bit on 64-bit
kernels _if_ the bits in question weren't in the lower 32 bits, and the
int=>bool cast can result in false negatives/positives, e.g. see commit
0c928ff26b ("KVM: SVM: Fix benign "bool vs. int" comparison in
svm_set_cr0()").

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Link: https://lore.kernel.org/r/20230322045824.22970-3-binbin.wu@linux.intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 10:18:11 -07:00
Sean Christopherson
0c928ff26b KVM: SVM: Fix benign "bool vs. int" comparison in svm_set_cr0()
Explicitly convert the return from is_paging() to a bool when comparing
against old_paging, which is also a boolean.  is_paging() sneakily uses
kvm_read_cr0_bits() and returns an int, i.e. returns X86_CR0_PG or 0, not
1 or 0.

Luckily, the bug is benign as it only results in a false positive, not a
false negative, i.e. only causes a spurious refresh of CR4 when paging is
enabled in both the old and new.

Cc: Maxim Levitsky <mlevitsk@redhat.com>
Fixes: c53bbe2145 ("KVM: x86: SVM: don't passthrough SMAP/SMEP/PKE bits in !NPT && !gCR0.PG case")
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 10:10:37 -07:00
Emanuele Giuseppe Esposito
723d5fb0ff kvm: svm: Add IA32_FLUSH_CMD guest support
Expose IA32_FLUSH_CMD to the guest if the guest CPUID enumerates
support for this MSR. As with IA32_PRED_CMD, permission for
unintercepted writes to this MSR will be granted to the guest after
the first non-zero write.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20230201132905.549148-3-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-03-16 10:18:04 -04:00
Linus Torvalds
49d5759268 ARM:
- Provide a virtual cache topology to the guest to avoid
   inconsistencies with migration on heterogenous systems. Non secure
   software has no practical need to traverse the caches by set/way in
   the first place.
 
 - Add support for taking stage-2 access faults in parallel. This was an
   accidental omission in the original parallel faults implementation,
   but should provide a marginal improvement to machines w/o FEAT_HAFDBS
   (such as hardware from the fruit company).
 
 - A preamble to adding support for nested virtualization to KVM,
   including vEL2 register state, rudimentary nested exception handling
   and masking unsupported features for nested guests.
 
 - Fixes to the PSCI relay that avoid an unexpected host SVE trap when
   resuming a CPU when running pKVM.
 
 - VGIC maintenance interrupt support for the AIC
 
 - Improvements to the arch timer emulation, primarily aimed at reducing
   the trap overhead of running nested.
 
 - Add CONFIG_USERFAULTFD to the KVM selftests config fragment in the
   interest of CI systems.
 
 - Avoid VM-wide stop-the-world operations when a vCPU accesses its own
   redistributor.
 
 - Serialize when toggling CPACR_EL1.SMEN to avoid unexpected exceptions
   in the host.
 
 - Aesthetic and comment/kerneldoc fixes
 
 - Drop the vestiges of the old Columbia mailing list and add [Oliver]
   as co-maintainer
 
 This also drags in arm64's 'for-next/sme2' branch, because both it and
 the PSCI relay changes touch the EL2 initialization code.
 
 RISC-V:
 
 - Fix wrong usage of PGDIR_SIZE instead of PUD_SIZE
 
 - Correctly place the guest in S-mode after redirecting a trap to the guest
 
 - Redirect illegal instruction traps to guest
 
 - SBI PMU support for guest
 
 s390:
 
 - Two patches sorting out confusion between virtual and physical
   addresses, which currently are the same on s390.
 
 - A new ioctl that performs cmpxchg on guest memory
 
 - A few fixes
 
 x86:
 
 - Change tdp_mmu to a read-only parameter
 
 - Separate TDP and shadow MMU page fault paths
 
 - Enable Hyper-V invariant TSC control
 
 - Fix a variety of APICv and AVIC bugs, some of them real-world,
   some of them affecting architecurally legal but unlikely to
   happen in practice
 
 - Mark APIC timer as expired if its in one-shot mode and the count
   underflows while the vCPU task was being migrated
 
 - Advertise support for Intel's new fast REP string features
 
 - Fix a double-shootdown issue in the emergency reboot code
 
 - Ensure GIF=1 and disable SVM during an emergency reboot, i.e. give SVM
   similar treatment to VMX
 
 - Update Xen's TSC info CPUID sub-leaves as appropriate
 
 - Add support for Hyper-V's extended hypercalls, where "support" at this
   point is just forwarding the hypercalls to userspace
 
 - Clean up the kvm->lock vs. kvm->srcu sequences when updating the PMU and
   MSR filters
 
 - One-off fixes and cleanups
 
 - Fix and cleanup the range-based TLB flushing code, used when KVM is
   running on Hyper-V
 
 - Add support for filtering PMU events using a mask.  If userspace
   wants to restrict heavily what events the guest can use, it can now
   do so without needing an absurd number of filter entries
 
 - Clean up KVM's handling of "PMU MSRs to save", especially when vPMU
   support is disabled
 
 - Add PEBS support for Intel Sapphire Rapids
 
 - Fix a mostly benign overflow bug in SEV's send|receive_update_data()
 
 - Move several SVM-specific flags into vcpu_svm
 
 x86 Intel:
 
 - Handle NMI VM-Exits before leaving the noinstr region
 
 - A few trivial cleanups in the VM-Enter flows
 
 - Stop enabling VMFUNC for L1 purely to document that KVM doesn't support
   EPTP switching (or any other VM function) for L1
 
 - Fix a crash when using eVMCS's enlighted MSR bitmaps
 
 Generic:
 
 - Clean up the hardware enable and initialization flow, which was
   scattered around multiple arch-specific hooks.  Instead, just
   let the arch code call into generic code.  Both x86 and ARM should
   benefit from not having to fight common KVM code's notion of how
   to do initialization.
 
 - Account allocations in generic kvm_arch_alloc_vm()
 
 - Fix a memory leak if coalesced MMIO unregistration fails
 
 selftests:
 
 - On x86, cache the CPU vendor (AMD vs. Intel) and use the info to emit
   the correct hypercall instruction instead of relying on KVM to patch
   in VMMCALL
 
 - Use TAP interface for kvm_binary_stats_test and tsc_msrs_test
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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:

   - Provide a virtual cache topology to the guest to avoid
     inconsistencies with migration on heterogenous systems. Non secure
     software has no practical need to traverse the caches by set/way in
     the first place

   - Add support for taking stage-2 access faults in parallel. This was
     an accidental omission in the original parallel faults
     implementation, but should provide a marginal improvement to
     machines w/o FEAT_HAFDBS (such as hardware from the fruit company)

   - A preamble to adding support for nested virtualization to KVM,
     including vEL2 register state, rudimentary nested exception
     handling and masking unsupported features for nested guests

   - Fixes to the PSCI relay that avoid an unexpected host SVE trap when
     resuming a CPU when running pKVM

   - VGIC maintenance interrupt support for the AIC

   - Improvements to the arch timer emulation, primarily aimed at
     reducing the trap overhead of running nested

   - Add CONFIG_USERFAULTFD to the KVM selftests config fragment in the
     interest of CI systems

   - Avoid VM-wide stop-the-world operations when a vCPU accesses its
     own redistributor

   - Serialize when toggling CPACR_EL1.SMEN to avoid unexpected
     exceptions in the host

   - Aesthetic and comment/kerneldoc fixes

   - Drop the vestiges of the old Columbia mailing list and add [Oliver]
     as co-maintainer

  RISC-V:

   - Fix wrong usage of PGDIR_SIZE instead of PUD_SIZE

   - Correctly place the guest in S-mode after redirecting a trap to the
     guest

   - Redirect illegal instruction traps to guest

   - SBI PMU support for guest

  s390:

   - Sort out confusion between virtual and physical addresses, which
     currently are the same on s390

   - A new ioctl that performs cmpxchg on guest memory

   - A few fixes

  x86:

   - Change tdp_mmu to a read-only parameter

   - Separate TDP and shadow MMU page fault paths

   - Enable Hyper-V invariant TSC control

   - Fix a variety of APICv and AVIC bugs, some of them real-world, some
     of them affecting architecurally legal but unlikely to happen in
     practice

   - Mark APIC timer as expired if its in one-shot mode and the count
     underflows while the vCPU task was being migrated

   - Advertise support for Intel's new fast REP string features

   - Fix a double-shootdown issue in the emergency reboot code

   - Ensure GIF=1 and disable SVM during an emergency reboot, i.e. give
     SVM similar treatment to VMX

   - Update Xen's TSC info CPUID sub-leaves as appropriate

   - Add support for Hyper-V's extended hypercalls, where "support" at
     this point is just forwarding the hypercalls to userspace

   - Clean up the kvm->lock vs. kvm->srcu sequences when updating the
     PMU and MSR filters

   - One-off fixes and cleanups

   - Fix and cleanup the range-based TLB flushing code, used when KVM is
     running on Hyper-V

   - Add support for filtering PMU events using a mask. If userspace
     wants to restrict heavily what events the guest can use, it can now
     do so without needing an absurd number of filter entries

   - Clean up KVM's handling of "PMU MSRs to save", especially when vPMU
     support is disabled

   - Add PEBS support for Intel Sapphire Rapids

   - Fix a mostly benign overflow bug in SEV's
     send|receive_update_data()

   - Move several SVM-specific flags into vcpu_svm

  x86 Intel:

   - Handle NMI VM-Exits before leaving the noinstr region

   - A few trivial cleanups in the VM-Enter flows

   - Stop enabling VMFUNC for L1 purely to document that KVM doesn't
     support EPTP switching (or any other VM function) for L1

   - Fix a crash when using eVMCS's enlighted MSR bitmaps

  Generic:

   - Clean up the hardware enable and initialization flow, which was
     scattered around multiple arch-specific hooks. Instead, just let
     the arch code call into generic code. Both x86 and ARM should
     benefit from not having to fight common KVM code's notion of how to
     do initialization

   - Account allocations in generic kvm_arch_alloc_vm()

   - Fix a memory leak if coalesced MMIO unregistration fails

  selftests:

   - On x86, cache the CPU vendor (AMD vs. Intel) and use the info to
     emit the correct hypercall instruction instead of relying on KVM to
     patch in VMMCALL

   - Use TAP interface for kvm_binary_stats_test and tsc_msrs_test"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (325 commits)
  KVM: SVM: hyper-v: placate modpost section mismatch error
  KVM: x86/mmu: Make tdp_mmu_allowed static
  KVM: arm64: nv: Use reg_to_encoding() to get sysreg ID
  KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes
  KVM: arm64: nv: Filter out unsupported features from ID regs
  KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2
  KVM: arm64: nv: Allow a sysreg to be hidden from userspace only
  KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor
  KVM: arm64: nv: Add accessors for SPSR_EL1, ELR_EL1 and VBAR_EL1 from virtual EL2
  KVM: arm64: nv: Handle SMCs taken from virtual EL2
  KVM: arm64: nv: Handle trapped ERET from virtual EL2
  KVM: arm64: nv: Inject HVC exceptions to the virtual EL2
  KVM: arm64: nv: Support virtual EL2 exceptions
  KVM: arm64: nv: Handle HCR_EL2.NV system register traps
  KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state
  KVM: arm64: nv: Add EL2 system registers to vcpu context
  KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x
  KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set
  KVM: arm64: nv: Introduce nested virtualization VCPU feature
  KVM: arm64: Use the S2 MMU context to iterate over S2 table
  ...
2023-02-25 11:30:21 -08:00
Paolo Bonzini
4bc6dcaa15 KVM SVM changes for 6.3:
- Fix a mostly benign overflow bug in SEV's send|receive_update_data()
 
  - Move the SVM-specific "host flags" into vcpu_svm (extracted from the
    vNMI enabling series)
 
  - A handful for fixes and cleanups
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Merge tag 'kvm-x86-svm-6.3' of https://github.com/kvm-x86/linux into HEAD

KVM SVM changes for 6.3:

 - Fix a mostly benign overflow bug in SEV's send|receive_update_data()

 - Move the SVM-specific "host flags" into vcpu_svm (extracted from the
   vNMI enabling series)

 - A handful for fixes and cleanups
2023-02-15 12:23:06 -05:00
Maxim Levitsky
916b54a768 KVM: x86: Move HF_NMI_MASK and HF_IRET_MASK into "struct vcpu_svm"
Move HF_NMI_MASK and HF_IRET_MASK (a.k.a. "waiting for IRET") out of the
common "hflags" and into dedicated flags in "struct vcpu_svm".  The flags
are used only for the SVM and thus should not be in hflags.

Tracking NMI masking in software isn't SVM specific, e.g. VMX has a
similar flag (soft_vnmi_blocked), but that's much more of a hack as VMX
can't intercept IRET, is useful only for ancient CPUs, i.e. will
hopefully be removed at some point, and again the exact behavior is
vendor specific and shouldn't ever be referenced in common code.
converting VMX

No functional change is intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Santosh Shukla <Santosh.Shukla@amd.com>
Link: https://lore.kernel.org/r/20221129193717.513824-5-mlevitsk@redhat.com
[sean: split from HF_GIF_MASK patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-01-31 12:56:42 -08:00
Sean Christopherson
e76ae52747 KVM: x86/pmu: Gate all "unimplemented MSR" prints on report_ignored_msrs
Add helpers to print unimplemented MSR accesses and condition all such
prints on report_ignored_msrs, i.e. honor userspace's request to not
print unimplemented MSRs.  Even though vcpu_unimpl() is ratelimited,
printing can still be problematic, e.g. if a print gets stalled when host
userspace is writing MSRs during live migration, an effective stall can
result in very noticeable disruption in the guest.

E.g. the profile below was taken while calling KVM_SET_MSRS on the PMU
counters while the PMU was disabled in KVM.

  -   99.75%     0.00%  [.] __ioctl
   - __ioctl
      - 99.74% entry_SYSCALL_64_after_hwframe
           do_syscall_64
           sys_ioctl
         - do_vfs_ioctl
            - 92.48% kvm_vcpu_ioctl
               - kvm_arch_vcpu_ioctl
                  - 85.12% kvm_set_msr_ignored_check
                       svm_set_msr
                       kvm_set_msr_common
                       printk
                       vprintk_func
                       vprintk_default
                       vprintk_emit
                       console_unlock
                       call_console_drivers
                       univ8250_console_write
                       serial8250_console_write
                       uart_console_write

Reported-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20230124234905.3774678-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-01-26 18:03:42 -08:00
Kim Phillips
8c19b6f257 KVM: x86: Propagate the AMD Automatic IBRS feature to the guest
Add the AMD Automatic IBRS feature bit to those being propagated to the guest,
and enable the guest EFER bit.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-9-kim.phillips@amd.com
2023-01-25 17:21:40 +01:00