linux-kernel - [PATCH v3 08/15] KVM: nSVM: Use KVM-governed feature framework to track "NRIPS enabled"

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Message-ID: <20230815203653.519297-9-seanjc@google.com>
Date:   Tue, 15 Aug 2023 13:36:46 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Zeng Guang <guang.zeng@...el.com>,
        Yuan Yao <yuan.yao@...el.com>
Subject: [PATCH v3 08/15] KVM: nSVM: Use KVM-governed feature framework to
 track "NRIPS enabled"

Track "NRIPS exposed to L1" via a governed feature flag instead of using
a dedicated bit/flag in vcpu_svm.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/governed_features.h | 1 +
 arch/x86/kvm/svm/nested.c        | 6 +++---
 arch/x86/kvm/svm/svm.c           | 4 +---
 arch/x86/kvm/svm/svm.h           | 1 -
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index 22446614bf49..722b66af412c 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -8,6 +8,7 @@ BUILD_BUG()
 KVM_GOVERNED_X86_FEATURE(GBPAGES)
 KVM_GOVERNED_X86_FEATURE(XSAVES)
 KVM_GOVERNED_X86_FEATURE(VMX)
+KVM_GOVERNED_X86_FEATURE(NRIPS)
 
 #undef KVM_GOVERNED_X86_FEATURE
 #undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 3342cc4a5189..9092f3f8dccf 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -716,7 +716,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
 	 * what a nrips=0 CPU would do (L1 is responsible for advancing RIP
 	 * prior to injecting the event).
 	 */
-	if (svm->nrips_enabled)
+	if (guest_can_use(vcpu, X86_FEATURE_NRIPS))
 		vmcb02->control.next_rip    = svm->nested.ctl.next_rip;
 	else if (boot_cpu_has(X86_FEATURE_NRIPS))
 		vmcb02->control.next_rip    = vmcb12_rip;
@@ -726,7 +726,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
 		svm->soft_int_injected = true;
 		svm->soft_int_csbase = vmcb12_csbase;
 		svm->soft_int_old_rip = vmcb12_rip;
-		if (svm->nrips_enabled)
+		if (guest_can_use(vcpu, X86_FEATURE_NRIPS))
 			svm->soft_int_next_rip = svm->nested.ctl.next_rip;
 		else
 			svm->soft_int_next_rip = vmcb12_rip;
@@ -1026,7 +1026,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	if (vmcb12->control.exit_code != SVM_EXIT_ERR)
 		nested_save_pending_event_to_vmcb12(svm, vmcb12);
 
-	if (svm->nrips_enabled)
+	if (guest_can_use(vcpu, X86_FEATURE_NRIPS))
 		vmcb12->control.next_rip  = vmcb02->control.next_rip;
 
 	vmcb12->control.int_ctl           = svm->nested.ctl.int_ctl;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d67f6e23dcd2..c8b97cb3138c 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4288,9 +4288,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	    guest_cpuid_has(vcpu, X86_FEATURE_XSAVE))
 		kvm_governed_feature_set(vcpu, X86_FEATURE_XSAVES);
 
-	/* Update nrips enabled cache */
-	svm->nrips_enabled = kvm_cpu_cap_has(X86_FEATURE_NRIPS) &&
-			     guest_cpuid_has(vcpu, X86_FEATURE_NRIPS);
+	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_NRIPS);
 
 	svm->tsc_scaling_enabled = tsc_scaling && guest_cpuid_has(vcpu, X86_FEATURE_TSCRATEMSR);
 	svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 5115b35a4d31..e147f2046ffa 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -259,7 +259,6 @@ struct vcpu_svm {
 	bool soft_int_injected;
 
 	/* optional nested SVM features that are enabled for this guest  */
-	bool nrips_enabled                : 1;
 	bool tsc_scaling_enabled          : 1;
 	bool v_vmload_vmsave_enabled      : 1;
 	bool lbrv_enabled                 : 1;
-- 
2.41.0.694.ge786442a9b-goog