From cbbd1aa891398e9ddbdd05bc4e40a988175f22af Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Jan 2024 15:02:22 -0800 Subject: 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 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 Reviewed-by: Jim Mattson Reviewed-by: Kan Liang Tested-by: Dapeng Mi Link: https://lore.kernel.org/r/20240109230250.424295-3-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/pmu.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/kvm/pmu.h') 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); -- cgit v1.2.3