From: Sean Christopherson seanjc@google.com
commit 0b0be065b7563ac708aaa9f69dd4941c80b3446d upstream.
Never intercept #GP for SEV guests as reading SEV guest private memory will return cyphertext, i.e. emulating on #GP can't work as intended.
Cc: stable@vger.kernel.org Cc: Tom Lendacky thomas.lendacky@amd.com Cc: Brijesh Singh brijesh.singh@amd.com Signed-off-by: Sean Christopherson seanjc@google.com Reviewed-by: Liam Merwick liam.merwick@oracle.com Message-Id: 20220120010719.711476-4-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/svm.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -312,7 +312,11 @@ int svm_set_efer(struct kvm_vcpu *vcpu, return ret; }
- if (svm_gp_erratum_intercept) + /* + * Never intercept #GP for SEV guests, KVM can't + * decrypt guest memory to workaround the erratum. + */ + if (svm_gp_erratum_intercept && !sev_guest(vcpu->kvm)) set_exception_intercept(svm, GP_VECTOR); } } @@ -1238,9 +1242,10 @@ static void init_vmcb(struct kvm_vcpu *v * Guest access to VMware backdoor ports could legitimately * trigger #GP because of TSS I/O permission bitmap. * We intercept those #GP and allow access to them anyway - * as VMware does. + * as VMware does. Don't intercept #GP for SEV guests as KVM can't + * decrypt guest memory to decode the faulting instruction. */ - if (enable_vmware_backdoor) + if (enable_vmware_backdoor && !sev_guest(vcpu->kvm)) set_exception_intercept(svm, GP_VECTOR);
svm_set_intercept(svm, INTERCEPT_INTR);