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

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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@xxxxxxxxxxxxxxx>
Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
Tested-by: Yongwei Ma <yongwei.ma@xxxxxxxxx>
---
 arch/x86/kvm/pmu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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:
-- 
2.46.0.rc1.232.g9752f9e123-goog





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