Messages in this thread | | | Date | Fri, 10 Nov 2023 11:22:13 +0800 | Subject | Re: [PATCH v8 07/26] KVM: x86/pmu: Apply "fast" RDPMC only to Intel PMUs | From | "Mi, Dapeng" <> |
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On 11/10/2023 10:12 AM, Sean Christopherson wrote: > Move the handling of "fast" RDPMC instructions, which drop bits 63:31 of
63:32?
> the count, to Intel. The "fast" flag, and all flags for that matter, are > Intel-only and aren't supported by AMD. > > Opportunistically replace open coded bit crud with proper #defines. > > Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM") > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/kvm/pmu.c | 3 +-- > arch/x86/kvm/vmx/pmu_intel.c | 20 ++++++++++++++++---- > 2 files changed, 17 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c > index 99ed72966528..e3ba5e12c2e7 100644 > --- a/arch/x86/kvm/pmu.c > +++ b/arch/x86/kvm/pmu.c > @@ -499,10 +499,9 @@ static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) > > int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) > { > - bool fast_mode = idx & (1u << 31); > struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); > struct kvm_pmc *pmc; > - u64 mask = fast_mode ? ~0u : ~0ull; > + u64 mask = ~0ull; > > if (!pmu->version) > return 1; > diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c > index 3bac3b32b485..c6ea128ea7c8 100644 > --- a/arch/x86/kvm/vmx/pmu_intel.c > +++ b/arch/x86/kvm/vmx/pmu_intel.c > @@ -20,6 +20,10 @@ > #include "nested.h" > #include "pmu.h" > > +/* Perf's "BASE" is wildly misleading, this is a single-bit flag, not a base. */ > +#define INTEL_RDPMC_FIXED INTEL_PMC_FIXED_RDPMC_BASE > +#define INTEL_RDPMC_FAST BIT(31) > + > #define MSR_PMC_FULL_WIDTH_BIT (MSR_IA32_PMC0 - MSR_IA32_PERFCTR0) > > static void reprogram_fixed_counters(struct kvm_pmu *pmu, u64 data) > @@ -55,12 +59,17 @@ static struct kvm_pmc *intel_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx) > } > } > > +static u32 intel_rdpmc_get_masked_idx(struct kvm_pmu *pmu, u32 idx)
inline?
> +{ > + return idx & ~(INTEL_RDPMC_FIXED | INTEL_RDPMC_FAST); > +} > + > static bool intel_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx) > { > struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); > - bool fixed = idx & (1u << 30); > + bool fixed = idx & INTEL_RDPMC_FIXED; > > - idx &= ~(3u << 30); > + idx = intel_rdpmc_get_masked_idx(pmu, idx); > > return fixed ? idx < pmu->nr_arch_fixed_counters > : idx < pmu->nr_arch_gp_counters; > @@ -70,11 +79,14 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, > unsigned int idx, u64 *mask) > { > struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); > - bool fixed = idx & (1u << 30); > + bool fixed = idx & INTEL_RDPMC_FIXED; > struct kvm_pmc *counters; > unsigned int num_counters; > > - idx &= ~(3u << 30); > + if (idx & INTEL_RDPMC_FAST) > + *mask &= GENMASK_ULL(31, 0); > + > + idx = intel_rdpmc_get_masked_idx(pmu, idx); > if (fixed) { > counters = pmu->fixed_counters; > num_counters = pmu->nr_arch_fixed_counters; Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
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