diff options
| author | Like Xu <likexu@tencent.com> | 2022-01-11 15:38:23 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-01-17 12:56:03 -0500 |
| commit | 4732f2444acd9b7eabc744f20eb5cc9694c0bfbd (patch) | |
| tree | 66dab7a1b1d173842630ce98a8e67a63f0fc2291 /arch/x86/kvm/vmx | |
| parent | ecebb966acaab2466d9857d1cc435ee1fc9eee50 (diff) | |
| download | linux-4732f2444acd9b7eabc744f20eb5cc9694c0bfbd.tar.bz2 | |
KVM: x86: Making the module parameter of vPMU more common
The new module parameter to control PMU virtualization should apply
to Intel as well as AMD, for situations where userspace is not trusted.
If the module parameter allows PMU virtualization, there could be a
new KVM_CAP or guest CPUID bits whereby userspace can enable/disable
PMU virtualization on a per-VM basis.
If the module parameter does not allow PMU virtualization, there
should be no userspace override, since we have no precedent for
authorizing that kind of override. If it's false, other counter-based
profiling features (such as LBR including the associated CPUID bits
if any) will not be exposed.
Change its name from "pmu" to "enable_pmu" as we have temporary
variables with the same name in our code like "struct kvm_pmu *pmu".
Fixes: b1d66dad65dc ("KVM: x86/svm: Add module param to control PMU virtualization")
Suggested-by : Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20220111073823.21885-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx')
| -rw-r--r-- | arch/x86/kvm/vmx/capabilities.h | 4 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 2 |
2 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h index c8029b7845b6..959b59d13b5a 100644 --- a/arch/x86/kvm/vmx/capabilities.h +++ b/arch/x86/kvm/vmx/capabilities.h @@ -5,6 +5,7 @@ #include <asm/vmx.h> #include "lapic.h" +#include "x86.h" extern bool __read_mostly enable_vpid; extern bool __read_mostly flexpriority_enabled; @@ -389,6 +390,9 @@ static inline u64 vmx_get_perf_capabilities(void) { u64 perf_cap = 0; + if (!enable_pmu) + return perf_cap; + if (boot_cpu_has(X86_FEATURE_PDCM)) rdmsrl(MSR_IA32_PERF_CAPABILITIES, perf_cap); diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index ffccfd9823c0..466d18fc0c5d 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -487,7 +487,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->reserved_bits = 0xffffffff00200000ull; entry = kvm_find_cpuid_entry(vcpu, 0xa, 0); - if (!entry) + if (!entry || !enable_pmu) return; eax.full = entry->eax; edx.full = entry->edx; |