Reply-To: Sean Christopherson <seanjc@google.com>
Date:   Fri, 17 Feb 2023 15:10:19 -0800
In-Reply-To: <20230217231022.816138-1-seanjc@google.com>
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References: <20230217231022.816138-1-seanjc@google.com>
Message-ID: <20230217231022.816138-10-seanjc@google.com>
Subject: [PATCH 09/12] KVM: nSVM: Use KVM-governed feature framework to track
 "LBRv enabled"
From:   Sean Christopherson <seanjc@google.com>
To:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Track "LBR virtualization 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@google.com>
---
 arch/x86/kvm/governed_features.h |  1 +
 arch/x86/kvm/svm/nested.c        | 23 +++++++++++++----------
 arch/x86/kvm/svm/svm.c           |  7 +++++--
 arch/x86/kvm/svm/svm.h           |  1 -
 4 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index b66b9d550f33..16c58d61bdf6 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -10,6 +10,7 @@ KVM_GOVERNED_X86_FEATURE(XSAVES)
 KVM_GOVERNED_X86_FEATURE(NRIPS)
 KVM_GOVERNED_X86_FEATURE(TSCRATEMSR)
 KVM_GOVERNED_X86_FEATURE(V_VMSAVE_VMLOAD)
+KVM_GOVERNED_X86_FEATURE(LBRV)
 
 #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 6a96058c0e48..9e210b03e635 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -540,6 +540,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
 	bool new_vmcb12 = false;
 	struct vmcb *vmcb01 = svm->vmcb01.ptr;
 	struct vmcb *vmcb02 = svm->nested.vmcb02.ptr;
+	struct kvm_vcpu *vcpu = &svm->vcpu;
 
 	nested_vmcb02_compute_g_pat(svm);
 
@@ -565,18 +566,18 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
 		vmcb_mark_dirty(vmcb02, VMCB_DT);
 	}
 
-	kvm_set_rflags(&svm->vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED);
+	kvm_set_rflags(vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED);
 
-	svm_set_efer(&svm->vcpu, svm->nested.save.efer);
+	svm_set_efer(vcpu, svm->nested.save.efer);
 
-	svm_set_cr0(&svm->vcpu, svm->nested.save.cr0);
-	svm_set_cr4(&svm->vcpu, svm->nested.save.cr4);
+	svm_set_cr0(vcpu, svm->nested.save.cr0);
+	svm_set_cr4(vcpu, svm->nested.save.cr4);
 
 	svm->vcpu.arch.cr2 = vmcb12->save.cr2;
 
-	kvm_rax_write(&svm->vcpu, vmcb12->save.rax);
-	kvm_rsp_write(&svm->vcpu, vmcb12->save.rsp);
-	kvm_rip_write(&svm->vcpu, vmcb12->save.rip);
+	kvm_rax_write(vcpu, vmcb12->save.rax);
+	kvm_rsp_write(vcpu, vmcb12->save.rsp);
+	kvm_rip_write(vcpu, vmcb12->save.rip);
 
 	/* In case we don't even reach vcpu_run, the fields are not updated */
 	vmcb02->save.rax = vmcb12->save.rax;
@@ -590,7 +591,8 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
 		vmcb_mark_dirty(vmcb02, VMCB_DR);
 	}
 
-	if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+	if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) &&
+		     (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
 		/*
 		 * Reserved bits of DEBUGCTL are ignored.  Be consistent with
 		 * svm_set_msr's definition of reserved bits.
@@ -712,7 +714,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
 
 	vmcb02->control.virt_ext            = vmcb01->control.virt_ext &
 					      LBR_CTL_ENABLE_MASK;
-	if (svm->lbrv_enabled)
+	if (guest_can_use(vcpu, X86_FEATURE_LBRV))
 		vmcb02->control.virt_ext  |=
 			(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
 
@@ -1021,7 +1023,8 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 
 	svm_switch_vmcb(svm, &svm->vmcb01);
 
-	if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+	if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) &&
+		     (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
 		svm_copy_lbrs(vmcb12, vmcb02);
 		svm_update_lbrv(vcpu);
 	} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b3f0271c73b9..42591c77f98a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -994,9 +994,11 @@ void svm_update_lbrv(struct kvm_vcpu *vcpu)
 	bool current_enable_lbrv = !!(svm->vmcb->control.virt_ext &
 				      LBR_CTL_ENABLE_MASK);
 
-	if (unlikely(is_guest_mode(vcpu) && svm->lbrv_enabled))
+	if (unlikely(is_guest_mode(vcpu) &&
+		     guest_can_use(vcpu, X86_FEATURE_LBRV))) {
 		if (unlikely(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))
 			enable_lbrv = true;
+	}
 
 	if (enable_lbrv == current_enable_lbrv)
 		return;
@@ -4149,7 +4151,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	if (tsc_scaling)
 		kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_TSCRATEMSR);
 
-	svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
+	if (lbrv)
+		kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_LBRV);
 
 	if (vls && !guest_cpuid_is_intel(vcpu))
 		kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 1e3e7462b1d7..60817ff346b0 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -258,7 +258,6 @@ struct vcpu_svm {
 	bool soft_int_injected;
 
 	/* optional nested SVM features that are enabled for this guest  */
-	bool lbrv_enabled                 : 1;
 	bool pause_filter_enabled         : 1;
 	bool pause_threshold_enabled      : 1;
 	bool vgif_enabled                 : 1;
-- 
2.39.2.637.g21b0678d19-goog