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authorLike Xu <likexu@tencent.com>2022-01-11 15:38:23 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2022-01-17 12:56:03 -0500
commit4732f2444acd9b7eabc744f20eb5cc9694c0bfbd (patch)
tree66dab7a1b1d173842630ce98a8e67a63f0fc2291 /arch/x86/kvm/vmx
parentecebb966acaab2466d9857d1cc435ee1fc9eee50 (diff)
downloadlinux-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.h4
-rw-r--r--arch/x86/kvm/vmx/pmu_intel.c2
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;