KVM: x86/pmu: Track mediated PMU counters with mode-specific enables

Instead of always checking of a counter needs to be disabled for
mode-specific reasons (e.g. Host-Only/Guest-Only bits in SVM), add a
bitmap to track such counters. Set the bit for counters using either
Host-Only or Guest-Only bits in EVENTSEL on SVM.

This bitmap will also be reused in following changes to selectively
apply changes to such counters.

Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260527234711.4175166-12-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index dd761073d618d14ff3e49e1987a91951e6415d9d..5934cc3994c58d7293bebf7c0c96a8531ce60795 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -612,6 +612,8 @@ struct kvm_pmu {
        DECLARE_BITMAP(pmc_counting_instructions, X86_PMC_IDX_MAX);
        DECLARE_BITMAP(pmc_counting_branches, X86_PMC_IDX_MAX);
 
+       DECLARE_BITMAP(pmc_has_mode_specific_enables, X86_PMC_IDX_MAX);
+
        u64 ds_area;
        u64 pebs_enable;
        u64 pebs_enable_rsvd;

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 8159b07e9bc2078991d9f9dc9cf51e7627bdebed..84c834ad2cd473cb03acad85f3476526b3c981a8 100644 (file)
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -936,6 +936,7 @@ static void kvm_pmu_reset(struct kvm_vcpu *vcpu)
        pmu->need_cleanup = false;
 
        bitmap_zero(pmu->reprogram_pmi, X86_PMC_IDX_MAX);
+       bitmap_zero(pmu->pmc_has_mode_specific_enables, X86_PMC_IDX_MAX);
 
        kvm_for_each_pmc(pmu, pmc, i, pmu->all_valid_pmc_idx) {
                pmc_stop_counter(pmc);

diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 71c7853e8ae5fd4138833d7e61a7f79ee046e642..34c3c6913ef6279677d541e7e154ebfa8951a53f 100644 (file)
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -202,8 +202,13 @@ static inline bool pmc_is_locally_enabled(struct kvm_pmc *pmc)
                                        pmc->idx - KVM_FIXED_PMC_BASE_IDX) &
                                        (INTEL_FIXED_0_KERNEL | INTEL_FIXED_0_USER);
 
-       return (pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE) &&
-              !kvm_pmu_call(pmc_is_disabled_in_current_mode)(pmc);
+       if (!(pmc->eventsel & ARCH_PERFMON_EVENTSEL_ENABLE))
+               return false;
+
+       if (!test_bit(pmc->idx, pmu->pmc_has_mode_specific_enables))
+               return true;
+
+       return !kvm_pmu_call(pmc_is_disabled_in_current_mode)(pmc);
 }
 
 extern struct x86_pmu_capability kvm_pmu_cap;

diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 41ee6532290e9299253a5bbb2058dc0559a6c20f..b892a25ea4ca9b4bfbdeadc23dd69277364f66a8 100644 (file)
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -168,6 +168,12 @@ static int amd_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
                        pmc->eventsel = data;
                        pmc->eventsel_hw = (data & ~AMD64_EVENTSEL_HOSTONLY) |
                                           AMD64_EVENTSEL_GUESTONLY;
+
+                       if (data & AMD64_EVENTSEL_HOST_GUEST_MASK)
+                               __set_bit(pmc->idx, pmu->pmc_has_mode_specific_enables);
+                       else
+                               __clear_bit(pmc->idx, pmu->pmc_has_mode_specific_enables);
+
                        kvm_pmu_request_counter_reprogram(pmc);
                }
                return 0;