path: root/arch/x86/kvm/svm/pmu.c
diff options
authorLike Xu <likexu@tencent.com>2021-11-17 16:03:04 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2021-12-08 04:24:58 -0500
commitb1d66dad65dcc8a6e5942db27027a086aa4f5c16 (patch)
tree345ceead7644d3f42c6b9e5a1a3839752c880aa5 /arch/x86/kvm/svm/pmu.c
parentbaed82c8e4893a3258267dad198e04691d2f7c09 (diff)
KVM: x86/svm: Add module param to control PMU virtualization
For Intel, the guest PMU can be disabled via clearing the PMU CPUID. For AMD, all hw implementations support the base set of four performance counters, with current mainstream hardware indicating the presence of two additional counters via X86_FEATURE_PERFCTR_CORE. In the virtualized world, the AMD guest driver may detect the presence of at least one counter MSR. Most hypervisor vendors would introduce a module param (like lbrv for svm) to disable PMU for all guests. Another control proposal per-VM is to pass PMU disable information via MSR_IA32_PERF_CAPABILITIES or one bit in CPUID Fn4000_00[FF:00]. Both of methods require some guest-side changes, so a module parameter may not be sufficiently granular, but practical enough. Signed-off-by: Like Xu <likexu@tencent.com> Message-Id: <20211117080304.38989-1-likexu@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm/pmu.c')
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index b4095dfeeee6..0cf05e4caa4c 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -16,6 +16,7 @@
#include "cpuid.h"
#include "lapic.h"
#include "pmu.h"
+#include "svm.h"
enum pmu_type {
@@ -100,6 +101,9 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr,
struct kvm_vcpu *vcpu = pmu_to_vcpu(pmu);
+ if (!pmu)
+ return NULL;
switch (msr) {
case MSR_F15H_PERF_CTL0:
case MSR_F15H_PERF_CTL1: