The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 0b0be065b7563ac708aaa9f69dd4941c80b3446d Mon Sep 17 00:00:00 2001 From: Sean Christopherson seanjc@google.com Date: Thu, 20 Jan 2022 01:07:13 +0000 Subject: [PATCH] KVM: SVM: Don't intercept #GP for SEV guests
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
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 37eb3168e0ea..defc91a8c04c 100644 --- 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, u64 efer) 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); } } @@ -1010,9 +1014,10 @@ static void init_vmcb(struct kvm_vcpu *vcpu) * 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);