| 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 |
| |
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 <brijesh.singh@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 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
|