diff mbox series

[RFC,v3,29/58] KVM: x86/pmu: Avoid legacy vPMU code when accessing global_ctrl in passthrough vPMU

Message ID 20240801045907.4010984-30-mizhang@google.com (mailing list archive)
State New, archived
Headers show
Series Mediated Passthrough vPMU 3.0 for x86 | expand

Commit Message

Mingwei Zhang Aug. 1, 2024, 4:58 a.m. UTC 
Avoid calling into legacy/emulated vPMU logic such as reprogram_counters()
when passthrough vPMU is enabled. Note that even when passthrough vPMU is
enabled, global_ctrl may still be intercepted if guest VM only sees a
subset of the counters.

Suggested-by: Xiong Zhang <xiong.y.zhang@linux.intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
---
 arch/x86/kvm/pmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index bd94f2d67f5c..e9047051489e 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -713,7 +713,8 @@  int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (pmu->global_ctrl != data) {
 			diff = pmu->global_ctrl ^ data;
 			pmu->global_ctrl = data;
-			reprogram_counters(pmu, diff);
+			if (!is_passthrough_pmu_enabled(vcpu))
+				reprogram_counters(pmu, diff);
 		}
 		break;
 	case MSR_CORE_PERF_GLOBAL_OVF_CTRL: