[PATCH V10 17/18] KVM: x86/cpuid: Refactor host/guest CPU model consistency check

From: Zhu Lingshan
Date: Fri Aug 06 2021 - 09:40:01 EST


From: Like Xu <like.xu@xxxxxxxxxxxxxxx>

For the same purpose, the leagcy intel_pmu_lbr_is_compatible() can be
renamed for reuse by more callers, and remove the comment about LBR
use case can be deleted by the way.

Signed-off-by: Like Xu <like.xu@xxxxxxxxxxxxxxx>
Signed-off-by: Zhu Lingshan <lingshan.zhu@xxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/kvm/cpuid.h | 5 +++++
arch/x86/kvm/vmx/pmu_intel.c | 12 +-----------
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/vmx/vmx.h | 1 -
4 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index c99edfff7f82..439ce776b9a0 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -143,6 +143,11 @@ static inline int guest_cpuid_model(struct kvm_vcpu *vcpu)
return x86_model(best->eax);
}

+static inline bool cpuid_model_is_consistent(struct kvm_vcpu *vcpu)
+{
+ return boot_cpu_data.x86_model == guest_cpuid_model(vcpu);
+}
+
static inline int guest_cpuid_stepping(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 05bc218c08df..a77d5a5f2ba5 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -173,16 +173,6 @@ static inline struct kvm_pmc *get_fw_gp_pmc(struct kvm_pmu *pmu, u32 msr)
return get_gp_pmc(pmu, msr, MSR_IA32_PMC0);
}

-bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu)
-{
- /*
- * As a first step, a guest could only enable LBR feature if its
- * cpu model is the same as the host because the LBR registers
- * would be pass-through to the guest and they're model specific.
- */
- return boot_cpu_data.x86_model == guest_cpuid_model(vcpu);
-}
-
bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu)
{
struct x86_pmu_lbr *lbr = vcpu_to_lbr_records(vcpu);
@@ -578,7 +568,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)

nested_vmx_pmu_entry_exit_ctls_update(vcpu);

- if (intel_pmu_lbr_is_compatible(vcpu))
+ if (cpuid_model_is_consistent(vcpu))
x86_perf_get_lbr(&lbr_desc->records);
else
lbr_desc->records.nr = 0;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d8552dbece6f..d0af51c1389d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2221,7 +2221,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if ((data & PMU_CAP_LBR_FMT) !=
(vmx_get_perf_capabilities() & PMU_CAP_LBR_FMT))
return 1;
- if (!intel_pmu_lbr_is_compatible(vcpu))
+ if (!cpuid_model_is_consistent(vcpu))
return 1;
}
ret = kvm_set_msr_common(vcpu, msr_info);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 86fa1a08feca..bd2922c8046f 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -95,7 +95,6 @@ union vmx_exit_reason {
#define vcpu_to_lbr_records(vcpu) (&to_vmx(vcpu)->lbr_desc.records)

void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu);
-bool intel_pmu_lbr_is_compatible(struct kvm_vcpu *vcpu);
bool intel_pmu_lbr_is_enabled(struct kvm_vcpu *vcpu);

int intel_pmu_create_guest_lbr_event(struct kvm_vcpu *vcpu);
--
2.27.0