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    Subject[PATCH 31/43] KVM: SVM: Stuff save->dr6 at during VMSA sync, not at RESET/INIT
    From
    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@google.com>
    ---
    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 a9d8d6aafdb8..b81ebeb4c426 100644
    --- a/arch/x86/kvm/svm/sev.c
    +++ b/arch/x86/kvm/svm/sev.c
    @@ -573,6 +573,7 @@ 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 558329f53709..996a6b03e338 100644
    --- a/arch/x86/kvm/svm/svm.c
    +++ b/arch/x86/kvm/svm/svm.c
    @@ -1207,7 +1207,6 @@ 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;

    --
    2.31.1.498.g6c1eba8ee3d-goog
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