[RESEND v13 03/10] KVM: x86/pmu: Use IA32_PERF_CAPABILITIES to adjust features visibility

[Like Xu]

On Intel platforms, KVM agent could configure MSR_IA32_PERF_CAPABILITIES
(such as unmask some vmx-supported bits in vcpu->arch.perf_capabilities)
to adjust the visibility of guest PMU features for vPMU-enabled guests.

Once MSR_IA32_PERF_CAPABILITIES is changed via vmx_set_msr() validly,
the adjustment in intel_pmu_refresh() will be triggered. To ensure the
sustainability of the new value, the default initialization path is
moved to intel_pmu_init().

Signed-off-by: Like Xu <like...@linux.intel.com>
Reviewed-by: Andi Kleen <a...@linux.intel.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 6 +++---
 arch/x86/kvm/vmx/vmx.c       | 5 +++++
 arch/x86/kvm/x86.c           | 2 +-
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index a886a47daebd..f8083ecf8c7b 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -327,7 +327,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
        pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
        pmu->version = 0;
        pmu->reserved_bits = 0xffffffff00200000ull;
-       vcpu->arch.perf_capabilities = 0;
 
        entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
        if (!entry)
@@ -340,8 +339,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
                return;
 
        perf_get_x86_pmu_capability(&x86_pmu);
-       if (guest_cpuid_has(vcpu, X86_FEATURE_PDCM))
-               vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
 
        pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
                                         x86_pmu.num_counters_gp);
@@ -401,6 +398,9 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
                pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
                pmu->fixed_counters[i].current_config = 0;
        }
+
+       vcpu->arch.perf_capabilities = guest_cpuid_has(vcpu, X86_FEATURE_PDCM) ?
+               vmx_get_perf_capabilities() : 0;
 }
 
 static void intel_pmu_reset(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 035bd6d279a4..085a14579bbe 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2209,6 +2209,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct 
msr_data *msr_info)
                if ((data >> 32) != 0)
                        return 1;
                goto find_uret_msr;
+       case MSR_IA32_PERF_CAPABILITIES:
+               if (data && !vcpu_to_pmu(vcpu)->version)
+                       return 1;
+               ret = kvm_set_msr_common(vcpu, msr_info);
+               break;
 
        default:
        find_uret_msr:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c765fd72a66c..a1b251ae648a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3037,7 +3037,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct 
msr_data *msr_info)
                        return 1;
 
                vcpu->arch.perf_capabilities = data;
-
+               kvm_pmu_refresh(vcpu);
                return 0;
                }
        case MSR_EFER:
-- 
2.29.2