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 and the
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.
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: "Radim Krčmář" <rkrc...@redhat.com>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Borislav Petkov <b...@suse.de>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: x...@kernel.org
Cc: k...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Borislav Petkov <b...@suse.de>
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
---
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 b9906cb59238..d997f63c765d 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1437,8 +1437,10 @@ static void init_vmcb(struct vcpu_svm *svm)
svm->vmcb->control.int_ctl |= V_GIF_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);
--
2.9.5
