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Subject[RFC v1 7/9] KVM: X86: Expose PDCM cpuid to guest
Date
PDCM (Perfmon and Debug Capability) indicates the processor
supports the performance and debug feature indication
MSR IA32_PERF_CAPABILITIES.

PEBS enabling in KVM guest depend on PEBS via PT, and
PEBS via PT is detected by IA32_PERF_CAPABILITIES[Bit16].

Signed-off-by: Luwei Kang <luwei.kang@intel.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/cpuid.c | 3 ++-
arch/x86/kvm/svm.c | 6 ++++++
arch/x86/kvm/vmx/capabilities.h | 10 ++++++++++
arch/x86/kvm/vmx/vmx.c | 1 +
5 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 07d3b21..2d9b0f9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1129,6 +1129,7 @@ struct kvm_x86_ops {
bool (*xsaves_supported)(void);
bool (*umip_emulated)(void);
bool (*pt_supported)(void);
+ bool (*pdcm_supported)(void);

int (*check_nested_events)(struct kvm_vcpu *vcpu, bool external_intr);
void (*request_immediate_exit)(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 22c2720..d12e7af 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -430,6 +430,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
+ unsigned f_pdcm = kvm_x86_ops->pdcm_supported() ? F(PDCM) : 0;

/* cpuid 1.edx */
const u32 kvm_cpuid_1_edx_x86_features =
@@ -458,7 +459,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
0 /* DS-CPL, VMX, SMX, EST */ |
0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
- F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
+ F(FMA) | F(CX16) | 0 /* xTPR Update */ | f_pdcm |
F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index e036807..8ae6716 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6005,6 +6005,11 @@ static bool svm_pt_supported(void)
return false;
}

+static bool svm_pdcm_supported(void)
+{
+ return false;
+}
+
static bool svm_has_wbinvd_exit(void)
{
return true;
@@ -7293,6 +7298,7 @@ static bool svm_need_emulation_on_page_fault(struct kvm_vcpu *vcpu)
.xsaves_supported = svm_xsaves_supported,
.umip_emulated = svm_umip_emulated,
.pt_supported = svm_pt_supported,
+ .pdcm_supported = svm_pdcm_supported,

.set_supported_cpuid = svm_set_supported_cpuid,

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index 4bcb6b4..82ca51d 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -353,4 +353,14 @@ static inline bool cpu_has_vmx_pebs_output_pt(void)
(perf_cap & MSR_IA32_PERF_CAP_PEBS_OUTPUT_PT));
}

+static inline bool vmx_pebs_supported(void)
+{
+ return (cpu_has_vmx_pebs_output_pt() && pt_mode == PT_MODE_HOST_GUEST);
+}
+
+static inline bool vmx_pdcm_supported(void)
+{
+ return boot_cpu_has(X86_FEATURE_PDCM) && vmx_pebs_supported();
+}
+
#endif /* __KVM_X86_VMX_CAPS_H */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4090c08..dbff8f0 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7768,6 +7768,7 @@ static __exit void hardware_unsetup(void)
.xsaves_supported = vmx_xsaves_supported,
.umip_emulated = vmx_umip_emulated,
.pt_supported = vmx_pt_supported,
+ .pdcm_supported = vmx_pdcm_supported,

.request_immediate_exit = vmx_request_immediate_exit,

--
1.8.3.1
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