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| author | Sean Christopherson <seanjc@google.com> | 2024-01-10 02:02:22 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-01-31 02:28:02 +0300 |
| commit | cbbd1aa891398e9ddbdd05bc4e40a988175f22af (patch) | |
| tree | b9f4066508570c3704700937ce701b46ee9d7cc3 /arch/x86/kvm/svm/pmu.c | |
| parent | 5eb7fcbdea63fc91685ac0c89ceb42d3becc96d2 (diff) | |
| download | linux-cbbd1aa891398e9ddbdd05bc4e40a988175f22af.tar.xz | |
KVM: x86/pmu: Allow programming events that match unsupported arch events
Remove KVM's bogus restriction that the guest can't program an event whose
encoding matches an unsupported architectural event. 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 architectural event.
Preventing the guest from counting events whose encoding happens to match
an architectural event breaks existing functionality whenever Intel adds
an architectural encoding that was *ever* used for a CPU that doesn't
enumerate support for the architectural event, even if the encoding is for
the exact same event!
E.g. the architectural encoding for Top-Down Slots is 0x01a4. Broadwell
CPUs, which do not support the Top-Down Slots architectural event, 0x01a4
is a valid, model-specific event. Denying guest usage of 0x01a4 if/when
KVM adds support for Top-Down slots would break any Broadwell-based guest.
Reported-by: Kan Liang <kan.liang@linux.intel.com>
Closes: https://lore.kernel.org/all/2004baa6-b494-462c-a11f-8104ea152c6a@linux.intel.com
Fixes: a21864486f7e ("KVM: x86/pmu: Fix available_event_types check for REF_CPU_CYCLES event")
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Link: https://lore.kernel.org/r/20240109230250.424295-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/svm/pmu.c')
| -rw-r--r-- | arch/x86/kvm/svm/pmu.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index b6a7ad4d6914..1475d47c821c 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -73,11 +73,6 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr, return amd_pmc_idx_to_pmc(pmu, idx); } -static bool amd_hw_event_available(struct kvm_pmc *pmc) -{ - return true; -} - static bool amd_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); @@ -233,7 +228,6 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu) } struct kvm_pmu_ops amd_pmu_ops __initdata = { - .hw_event_available = amd_hw_event_available, .pmc_idx_to_pmc = amd_pmc_idx_to_pmc, .rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc, .msr_idx_to_pmc = amd_msr_idx_to_pmc, |