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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/pmu.h | |
| 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/pmu.h')
| -rw-r--r-- | arch/x86/kvm/pmu.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 7caeb3d8d4fd..87ecf22f5b25 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -19,7 +19,6 @@ #define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002 struct kvm_pmu_ops { - bool (*hw_event_available)(struct kvm_pmc *pmc); struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx); struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu, unsigned int idx, u64 *mask); |