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authorPaolo Bonzini <pbonzini@redhat.com>2024-01-08 16:10:08 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2024-01-08 16:10:08 +0300
commit01edb1cfbdb984ebe7b490cce544e908c402e859 (patch)
tree009ffd0c9e2645a61773c90b4a36d9ebc44a767e /arch/x86/include
parent33d0403fdad8f4f6a1ccf552bdc31a0170f665b8 (diff)
parentfd89499a5151d197ba30f7b801f6d8f4646cf446 (diff)
downloadlinux-01edb1cfbdb984ebe7b490cce544e908c402e859.tar.xz
Merge tag 'kvm-x86-pmu-6.8' of https://github.com/kvm-x86/linux into HEAD
KVM x86 PMU changes for 6.8: - Fix a variety of bugs where KVM fail to stop/reset counters and other state prior to refreshing the vPMU model. - Fix a double-overflow PMU bug by tracking emulated counter events using a dedicated field instead of snapshotting the "previous" counter. If the hardware PMC count triggers overflow that is recognized in the same VM-Exit that KVM manually bumps an event count, KVM would pend PMIs for both the hardware-triggered overflow and for KVM-triggered overflow.
Diffstat (limited to 'arch/x86/include')
-rw-r--r--arch/x86/include/asm/kvm-x86-pmu-ops.h2
-rw-r--r--arch/x86/include/asm/kvm_host.h17
2 files changed, 17 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm-x86-pmu-ops.h b/arch/x86/include/asm/kvm-x86-pmu-ops.h
index 6c98f4bb4228..058bc636356a 100644
--- a/arch/x86/include/asm/kvm-x86-pmu-ops.h
+++ b/arch/x86/include/asm/kvm-x86-pmu-ops.h
@@ -22,7 +22,7 @@ KVM_X86_PMU_OP(get_msr)
KVM_X86_PMU_OP(set_msr)
KVM_X86_PMU_OP(refresh)
KVM_X86_PMU_OP(init)
-KVM_X86_PMU_OP(reset)
+KVM_X86_PMU_OP_OPTIONAL(reset)
KVM_X86_PMU_OP_OPTIONAL(deliver_pmi)
KVM_X86_PMU_OP_OPTIONAL(cleanup)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b093c2191cd3..c17e38ac8b7a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -500,8 +500,23 @@ struct kvm_pmc {
u8 idx;
bool is_paused;
bool intr;
+ /*
+ * Base value of the PMC counter, relative to the *consumed* count in
+ * the associated perf_event. This value includes counter updates from
+ * the perf_event and emulated_count since the last time the counter
+ * was reprogrammed, but it is *not* the current value as seen by the
+ * guest or userspace.
+ *
+ * The count is relative to the associated perf_event so that KVM
+ * doesn't need to reprogram the perf_event every time the guest writes
+ * to the counter.
+ */
u64 counter;
- u64 prev_counter;
+ /*
+ * PMC events triggered by KVM emulation that haven't been fully
+ * processed, i.e. haven't undergone overflow detection.
+ */
+ u64 emulated_counter;
u64 eventsel;
struct perf_event *perf_event;
struct kvm_vcpu *vcpu;