linux-kernel - [PATCH 2/3] KVM: SVM: keep DR6 synchronized with vcpu->arch.dr6

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Message-Id: <20200504155558.401468-3-pbonzini@redhat.com>
Date:   Mon,  4 May 2020 11:55:57 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH 2/3] KVM: SVM: keep DR6 synchronized with vcpu->arch.dr6

Ensure that the current value of DR6 is always available in vcpu->arch.dr6,
so that the get_dr6 callback can just access vcpu->arch.dr6 and becomes
redundant.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/svm.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index dbcf4198a9fe..6b65c75b6816 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1654,7 +1654,7 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd)
 
 static u64 svm_get_dr6(struct kvm_vcpu *vcpu)
 {
-	return to_svm(vcpu)->vmcb->save.dr6;
+	return vcpu->arch.dr6;
 }
 
 static void svm_set_dr6(struct kvm_vcpu *vcpu, unsigned long value)
@@ -1673,7 +1673,7 @@ static void svm_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
 	get_debugreg(vcpu->arch.db[1], 1);
 	get_debugreg(vcpu->arch.db[2], 2);
 	get_debugreg(vcpu->arch.db[3], 3);
-	vcpu->arch.dr6 = svm_get_dr6(vcpu);
+	vcpu->arch.dr6 = svm->vmcb->save.dr6;
 	vcpu->arch.dr7 = svm->vmcb->save.dr7;
 
 	vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_WONT_EXIT;
@@ -1719,6 +1719,7 @@ static int db_interception(struct vcpu_svm *svm)
 	if (!(svm->vcpu.guest_debug &
 	      (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) &&
 		!svm->nmi_singlestep) {
+		vcpu->arch.dr6 = svm->vmcb->save.dr6;
 		kvm_queue_exception(&svm->vcpu, DB_VECTOR);
 		return 1;
 	}
-- 
2.18.2