[PATCH 2/3] KVM: x86/pmu: Don't pre-set the pmu->global_ctrl when refreshing

From: Like Xu
Date: Mon May 09 2022 - 06:24:01 EST


From: Like Xu <likexu@xxxxxxxxxxx>

Assigning a value to pmu->global_ctrl just to set the value of
pmu->global_ctrl_mask in a more readable way leaves a side effect of
not conforming to the specification. The global_ctrl is reset to zero on
Power up and Reset but keeps unchanged on INIT, like an ordinary MSR.

Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
arch/x86/kvm/vmx/pmu_intel.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index cff03baf8921..4d6cc95bc770 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -525,9 +525,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
setup_fixed_pmc_eventsel(pmu);
}

- pmu->global_ctrl = ((1ull << pmu->nr_arch_gp_counters) - 1) |
+ pmu->global_ctrl_mask = ~((1ull << pmu->nr_arch_gp_counters) - 1) |
(((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED);
- pmu->global_ctrl_mask = ~pmu->global_ctrl;
pmu->global_ovf_ctrl_mask = pmu->global_ctrl_mask
& ~(MSR_CORE_PERF_GLOBAL_OVF_CTRL_OVF_BUF |
MSR_CORE_PERF_GLOBAL_OVF_CTRL_COND_CHGD);
--
2.36.1