On 6/9/2022 1:26 am, Jim Mattson wrote:
On Mon, Sep 5, 2022 at 5:45 AM Like Xu <like.xu.linux@xxxxxxxxx> wrote:From: Like Xu <likexu@xxxxxxxxxxx> The AMD PerfMonV2 specification allows for a maximum of 16 GP counters, which is clearly not supported with zero code effort in the current KVM. A local macro (named like INTEL_PMC_MAX_GENERIC) is introduced to take back control of this virt capability, which also makes it easier to statically partition all available counters between hosts and guests. Signed-off-by: Like Xu <likexu@xxxxxxxxxxx> --- arch/x86/kvm/pmu.h | 2 ++ arch/x86/kvm/svm/pmu.c | 7 ++++--- arch/x86/kvm/x86.c | 2 ++ 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index 847e7112a5d3..e3a3813b6a38 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -18,6 +18,8 @@ #define VMWARE_BACKDOOR_PMC_REAL_TIME 0x10001 #define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002 +#define KVM_AMD_PMC_MAX_GENERIC AMD64_NUM_COUNTERS_CORE + struct kvm_event_hw_type_mapping { u8 eventsel; u8 unit_mask; diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c index 2ec420b85d6a..f99f2c869664 100644 --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -192,9 +192,10 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu) struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); int i; - BUILD_BUG_ON(AMD64_NUM_COUNTERS_CORE > INTEL_PMC_MAX_GENERIC); + BUILD_BUG_ON(AMD64_NUM_COUNTERS_CORE > KVM_AMD_PMC_MAX_GENERIC); + BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > INTEL_PMC_MAX_GENERIC); - for (i = 0; i < AMD64_NUM_COUNTERS_CORE ; i++) { + for (i = 0; i < KVM_AMD_PMC_MAX_GENERIC ; i++) { pmu->gp_counters[i].type = KVM_PMC_GP; pmu->gp_counters[i].vcpu = vcpu; pmu->gp_counters[i].idx = i; @@ -207,7 +208,7 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu) struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); int i; - for (i = 0; i < AMD64_NUM_COUNTERS_CORE; i++) { + for (i = 0; i < KVM_AMD_PMC_MAX_GENERIC; i++) { struct kvm_pmc *pmc = &pmu->gp_counters[i]; pmc_stop_counter(pmc); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 43a6a7efc6ec..b9738efd8425 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1444,12 +1444,14 @@ static const u32 msrs_to_save_all[] = { MSR_ARCH_PERFMON_EVENTSEL0 + 16, MSR_ARCH_PERFMON_EVENTSEL0 + 17,IIRC, the effective maximum on the Intel side is 18, despite what INTEL_PMC_MAX_GENERIC says, due to collisions with other existing MSR
Emm, check https://lore.kernel.org/kvm/20220906081604.24035-1-likexu@xxxxxxxxxxx/
indices. That's why the Intel list stops here. Should we introduce a KVM_INTEL_PMC_MAX_GENERIC as well?
Yes, this suggestion will be applied in the next version.
MSR_IA32_PEBS_ENABLE, MSR_IA32_DS_AREA, MSR_PEBS_DATA_CFG, + /* This part of MSRs should match KVM_AMD_PMC_MAX_GENERIC. */Perhaps the comment above should be moved down two lines, since the next two lines deal with the legacy counters.
Applied, thanks.
MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3, MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3, MSR_F15H_PERF_CTL0, MSR_F15H_PERF_CTL1, MSR_F15H_PERF_CTL2, MSR_F15H_PERF_CTL3, MSR_F15H_PERF_CTL4, MSR_F15H_PERF_CTL5, MSR_F15H_PERF_CTR0, MSR_F15H_PERF_CTR1, MSR_F15H_PERF_CTR2, MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,At some point, we may want to consider populating the PMU MSR list dynamically, rather than statically enumerating all of them (for both AMD and Intel).
The uncertainty of msrs_to_save_all[] may cause troubles for legacy user spaces. I had draft patches to rewrite pmu msr accesses for host-initiated as first move.
Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx>
