On 12/26/2022 7:17 PM, Like Xu wrote:
From: Like Xu <likexu@xxxxxxxxxxx>
When the PMU is disabled, don't bother sharing the PMU MSRs with
userspace through KVM_GET_MSR_INDEX_LIST. Instead, filter them out
so userspace doesn't have to keep track of them.
Note that 'enable_pmu' is read-only, so userspace has no control over
whether the PMU MSRs are included in the list or not.
Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Co-developed-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 22 ++++++++++++++++++++--
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f35f1ff4427b..2ed710b393eb 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -514,6 +514,7 @@ struct kvm_pmc {
#define MSR_ARCH_PERFMON_PERFCTR_MAX (MSR_ARCH_PERFMON_PERFCTR0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
#define MSR_ARCH_PERFMON_EVENTSEL_MAX (MSR_ARCH_PERFMON_EVENTSEL0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
#define KVM_PMC_MAX_FIXED 3
+#define MSR_ARCH_PERFMON_FIXED_CTR_MAX (MSR_ARCH_PERFMON_FIXED_CTR0 + KVM_PMC_MAX_FIXED - 1)
#define KVM_AMD_PMC_MAX_GENERIC 6
struct kvm_pmu {
unsigned nr_arch_gp_counters;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5c3ce39cdccb..f570367463c8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7054,15 +7054,32 @@ static void kvm_init_msr_list(void)
continue;
break;
case MSR_ARCH_PERFMON_PERFCTR0 ... MSR_ARCH_PERFMON_PERFCTR_MAX:
- if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_PERFCTR0 >=
+ if (!enable_pmu || msrs_to_save_all[i] - MSR_ARCH_PERFMON_PERFCTR0 >=
min(KVM_INTEL_PMC_MAX_GENERIC, kvm_pmu_cap.num_counters_gp))
continue;
break;
case MSR_ARCH_PERFMON_EVENTSEL0 ... MSR_ARCH_PERFMON_EVENTSEL_MAX:
- if (msrs_to_save_all[i] - MSR_ARCH_PERFMON_EVENTSEL0 >=
+ if (!enable_pmu || msrs_to_save_all[i] - MSR_ARCH_PERFMON_EVENTSEL0 >=
min(KVM_INTEL_PMC_MAX_GENERIC, kvm_pmu_cap.num_counters_gp))
continue;
break;
+ case MSR_ARCH_PERFMON_FIXED_CTR0 ... MSR_ARCH_PERFMON_FIXED_CTR_MAX:
+ if (!enable_pmu || msrs_to_save_all[i] - MSR_ARCH_PERFMON_FIXED_CTR0 >=
+ min(KVM_PMC_MAX_FIXED, kvm_pmu_cap.num_counters_fixed))
+ continue;
+ break;
+ case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5:
+ case MSR_K7_EVNTSEL0 ... MSR_K7_PERFCTR3:
+ case MSR_CORE_PERF_FIXED_CTR_CTRL:
+ case MSR_CORE_PERF_GLOBAL_STATUS:
+ case MSR_CORE_PERF_GLOBAL_CTRL:
+ case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
+ case MSR_IA32_DS_AREA:
+ case MSR_IA32_PEBS_ENABLE:
+ case MSR_PEBS_DATA_CFG:
+ if (!enable_pmu)
+ continue;
+ break;
I prefer use a helper to wrap the hunk of PMU msr checks and move the
helper to
the "default" branch of switch, it makes the code looks nicer:
default:
if(!enable_pmu && !kvm_pmu_valid_msrlist(msr))
continue;
case MSR_IA32_XFD:
case MSR_IA32_XFD_ERR:
if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
@@ -13468,3 +13485,4 @@ static void __exit kvm_x86_exit(void)
*/
}
module_exit(kvm_x86_exit);
+
Extra newline.
