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KVM: x86: Making the module parameter of vPMU more common

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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: b1d66dad65 ("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>
This commit is contained in:
Like Xu
2022-01-11 15:38:23 +08:00
committed by Paolo Bonzini
parent ecebb966ac
commit 4732f2444a
8 changed files with 17 additions and 12 deletions
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8
arch/x86/kvm/svm/svm.c
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@@ -192,10 +192,6 @@ module_param(vgif, int, 0444);
static int lbrv = true;
module_param(lbrv, int, 0444);
/* enable/disable PMU virtualization */
bool pmu = true;
module_param(pmu, bool, 0444);
static int tsc_scaling = true;
module_param(tsc_scaling, int, 0444);
@@ -957,7 +953,7 @@ static __init void svm_set_cpu_caps(void)
kvm_cpu_cap_set(X86_FEATURE_VIRT_SSBD);
/* AMD PMU PERFCTR_CORE CPUID */
if (pmu && boot_cpu_has(X86_FEATURE_PERFCTR_CORE))
if (enable_pmu && boot_cpu_has(X86_FEATURE_PERFCTR_CORE))
kvm_cpu_cap_set(X86_FEATURE_PERFCTR_CORE);
/* CPUID 0x8000001F (SME/SEV features) */
@@ -1093,7 +1089,7 @@ static __init int svm_hardware_setup(void)
pr_info("LBR virtualization supported\n");
}
if (!pmu)
if (!enable_pmu)
pr_info("PMU virtualization is disabled\n");
svm_set_cpu_caps();