linux-kernel - [PATCH 26/26] KVM: VMX: Directly query Intel PT mode when refreshing PMUs

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Date:   Wed, 29 Jan 2020 15:46:40 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 26/26] KVM: VMX: Directly query Intel PT mode when refreshing PMUs

Use vmx_pt_mode_is_host_guest() in intel_pmu_refresh() instead of
bouncing through kvm_x86_ops->pt_supported and remove ->pt_supported()
as the PMU code was the last remaining user.

Opportunistically clean up the wording of a comment that referenced
kvm_x86_ops->pt_supported().

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/include/asm/kvm_host.h | 1 -
 arch/x86/kvm/svm.c              | 6 ------
 arch/x86/kvm/vmx/pmu_intel.c    | 2 +-
 arch/x86/kvm/vmx/vmx.c          | 6 ------
 arch/x86/kvm/x86.c              | 7 +++----
 5 files changed, 4 insertions(+), 18 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ea076debe6f8..3106abbf5ac2 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1164,7 +1164,6 @@ struct kvm_x86_ops {
 		enum exit_fastpath_completion *exit_fastpath);
 
 	bool (*umip_emulated)(void);
-	bool (*pt_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/svm.c b/arch/x86/kvm/svm.c
index a08ee7b2dddb..dd616cac6e67 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6108,11 +6108,6 @@ static bool svm_umip_emulated(void)
 	return false;
 }
 
-static bool svm_pt_supported(void)
-{
-	return false;
-}
-
 static bool svm_has_wbinvd_exit(void)
 {
 	return true;
@@ -7474,7 +7469,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.cpuid_update = svm_cpuid_update,
 
 	.umip_emulated = svm_umip_emulated,
-	.pt_supported = svm_pt_supported,
 
 	.set_supported_cpuid = svm_set_supported_cpuid,
 
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 34a3a17bb6d7..d8f5cb312b9d 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -330,7 +330,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	pmu->global_ovf_ctrl_mask = pmu->global_ctrl_mask
 			& ~(MSR_CORE_PERF_GLOBAL_OVF_CTRL_OVF_BUF |
 			    MSR_CORE_PERF_GLOBAL_OVF_CTRL_COND_CHGD);
-	if (kvm_x86_ops->pt_supported())
+	if (vmx_pt_mode_is_host_guest())
 		pmu->global_ovf_ctrl_mask &=
 				~MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI;
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 10c31aa40730..75842b574e26 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6318,11 +6318,6 @@ static bool vmx_has_emulated_msr(u32 index)
 	}
 }
 
-static bool vmx_pt_supported(void)
-{
-	return vmx_pt_mode_is_host_guest();
-}
-
 static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
 {
 	u32 exit_intr_info;
@@ -7914,7 +7909,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 	.check_intercept = vmx_check_intercept,
 	.handle_exit_irqoff = vmx_handle_exit_irqoff,
 	.umip_emulated = vmx_umip_emulated,
-	.pt_supported = vmx_pt_supported,
 
 	.request_immediate_exit = vmx_request_immediate_exit,
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 03e656d05c15..e889e83dbb78 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2805,10 +2805,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		    !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))
 			return 1;
 		/*
-		 * We do support PT if kvm_x86_ops->pt_supported(), but we do
-		 * not support IA32_XSS[bit 8]. Guests will have to use
-		 * RDMSR/WRMSR rather than XSAVES/XRSTORS to save/restore PT
-		 * MSRs.
+		 * KVM supports exposing PT to the guest, but does not support
+		 * IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than
+		 * XSAVES/XRSTORS to save/restore PT MSRs.
 		 */
 		if (data != 0)
 			return 1;
-- 
2.24.1