From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brijesh Singh Subject: [RFC Part2 PATCH v3 25/26] KVM: SVM: Do not install #UD intercept when SEV is enabled Date: Mon, 24 Jul 2017 15:03:02 -0500 Message-ID: <20170724200303.12197-26-brijesh.singh@amd.com> References: <20170724200303.12197-1-brijesh.singh@amd.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Thomas Gleixner , Borislav Petkov , Joerg Roedel , "Michael S . Tsirkin" , Paolo Bonzini , =?UTF-8?q?=5C=22Radim=20Kr=C4=8Dm=C3=A1=C5=99=5C=22?= , Tom Lendacky , Brijesh Singh To: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org Return-path: In-Reply-To: <20170724200303.12197-1-brijesh.singh@amd.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On #UD, x86_emulate_instruction() fetches the data from guest memory and decodes the instruction bytes to assist further. When SEV is enabled, the instruction bytes will be encrypted using the guest-specific key, hypervisor will no longer able to fetch the instruction bytes to assist UD handling. By not installing intercept we let the guest receive and handle #UD. Signed-off-by: Brijesh Singh --- arch/x86/kvm/svm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 64b9f60..4581d03 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1432,8 +1432,10 @@ static void init_vmcb(struct vcpu_svm *svm) svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK; } - if (sev_guest(svm->vcpu.kvm)) + if (sev_guest(svm->vcpu.kvm)) { svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ENABLE; + clr_exception_intercept(svm, UD_VECTOR); + } mark_all_dirty(svm->vmcb); -- 2.9.4