[PATCH v2 32/46] KVM: SVM: Stuff save->dr6 at during VMSA sync, not at RESET/INIT
From: Sean Christopherson
Date: Tue Jul 13 2021 - 12:35:32 EST
Move code to stuff vmcb->save.dr6 to its architectural init value from
svm_vcpu_reset() into sev_es_sync_vmsa(). Except for protected guests,
a.k.a. SEV-ES guests, vmcb->save.dr6 is set during VM-Enter, i.e. the
extra write is unnecessary. For SEV-ES, stuffing save->dr6 handles a
theoretical case where the VMSA could be encrypted before the first
KVM_RUN.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/svm/sev.c | 1 +
arch/x86/kvm/svm/svm.c | 1 -
2 files changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8d36f0c73071..e34ee60fc9d7 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -583,6 +583,7 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
save->xcr0 = svm->vcpu.arch.xcr0;
save->pkru = svm->vcpu.arch.pkru;
save->xss = svm->vcpu.arch.ia32_xss;
+ save->dr6 = svm->vcpu.arch.dr6;
/*
* SEV-ES will use a VMSA that is pointed to by the VMCB, not
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 6eff7f1a4672..251b230b2fef 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1265,7 +1265,6 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
svm_set_cr0(vcpu, X86_CR0_NW | X86_CR0_CD | X86_CR0_ET);
svm_set_cr4(vcpu, 0);
svm_set_efer(vcpu, 0);
- save->dr6 = 0xffff0ff0;
kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
vcpu->arch.regs[VCPU_REGS_RIP] = 0x0000fff0;
--
2.32.0.93.g670b81a890-goog