From: Atish Patra Date: Tue, 2 Jun 2026 22:36:32 +0000 (-0700) Subject: KVM: SEV: Do not allow intra-host migration/mirroring of SNP VMs X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6ee4140788234a6fabf59e6a50e38cdb936008cd;p=thirdparty%2Fkernel%2Flinux.git KVM: SEV: Do not allow intra-host migration/mirroring of SNP VMs The intra-host migration/mirroring feature is not fully implemented for SEV-SNP VMs. The proper migration requires additional SNP-specific state such as guest_req_mutex, guest_req_buf, and guest_resp_buf to be transferred or initialized on the destination. The SNP VM mirroring requires vmsa features to be copied as well otherwise ASID would be bound to SNP range while VM is detected as a SEV VM. Reject SNP source VMs in migration/mirroring until proper SNP state transfer is implemented. Fixes: 1dfe571c12cf ("KVM: SEV: Add initial SEV-SNP support") Reported-by: Chris Mason Reported-by: Sashiko Assisted-by: Claude:claude-opus-4-6 Reviewed-by: Tom Lendacky Signed-off-by: Atish Patra Link: https://patch.msgid.link/20260602-sev_snp_fixes-v3-1-24bfd3ae047c@meta.com Cc: stable@vger.kernel.org [sean: let lines poke past 80 chars, tag for stable] Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 427229347876..944aaea6501f 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2129,8 +2129,9 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) if (ret) return ret; + /* Do not allow SNP VM migration until additional state transfer is implemented */ if (kvm->arch.vm_type != source_kvm->arch.vm_type || - sev_guest(kvm) || !sev_guest(source_kvm)) { + sev_guest(kvm) || !sev_guest(source_kvm) || sev_snp_guest(source_kvm)) { ret = -EINVAL; goto out_unlock; } @@ -2851,8 +2852,9 @@ int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd) * disallow out-of-band SEV/SEV-ES init if the target is already an * SEV guest, or if vCPUs have been created. KVM relies on vCPUs being * created after SEV/SEV-ES initialization, e.g. to init intercepts. + * Also do not allow SNP VM mirroring until additional state transfer is implemented. */ - if (sev_guest(kvm) || !sev_guest(source_kvm) || + if (sev_guest(kvm) || !sev_guest(source_kvm) || sev_snp_guest(source_kvm) || is_mirroring_enc_context(source_kvm) || kvm->created_vcpus) { ret = -EINVAL; goto e_unlock;