[PATCH v2] KVM: x86/pmu: Don't pre-set the pmu->global_ctrl when refreshing

From: Like Xu
Date: Tue May 10 2022 - 00:44:19 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 value 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>
---
v1 -> v2 Changelog:
- Explicitly add parentheses around;

arch/x86/kvm/vmx/pmu_intel.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index b82b6709d7a8..7829ec457b28 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -522,9 +522,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
setup_fixed_pmc_eventsel(pmu);
}

- pmu->global_ctrl = ((1ull << pmu->nr_arch_gp_counters) - 1) |
- (((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED);
- pmu->global_ctrl_mask = ~pmu->global_ctrl;
+ pmu->global_ctrl_mask = ~(((1ull << pmu->nr_arch_gp_counters) - 1) |
+ (((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED));
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