Copying an ASID into new vCPUs will not work for SEV-ES since the vCPUs VMSAs need to be setup and measured before SEV_LAUNCH_FINISH. Return an error if a users tries to KVM_CAP_VM_COPY_ENC_CONTEXT_FROM from an SEV-ES guest. The destination VM is already checked for SEV and SEV-ES with sev_guest(), so this ioctl already fails if the destination is SEV enabled.
Enabling mirroring a VM or copying its encryption context with an SEV-ES VM is more involved and should happen in its own feature patch if that's needed. This is because the vCPUs of SEV-ES VMs need to be updated with LAUNCH_UPDATE_VMSA before LAUNCH_FINISH. This needs KVM changes because the mirror VM has all its SEV ioctls blocked and the original VM doesn't know about the mirrors vCPUs.
Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context")
V2: * Updated changelog with more information and added stable CC.
Signed-off-by: Peter Gonda pgonda@google.com Cc: Marc Orr marcorr@google.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Sean Christopherson seanjc@google.com Cc: Nathan Tempelman natet@google.com Cc: Brijesh Singh brijesh.singh@amd.com Cc: kvm@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- arch/x86/kvm/svm/sev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 75e0b21ad07c..8a279027425f 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1728,7 +1728,7 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd) source_kvm = source_kvm_file->private_data; mutex_lock(&source_kvm->lock);
- if (!sev_guest(source_kvm)) { + if (!sev_guest(source_kvm) || sev_es_guest(source_kvm)) { ret = -EINVAL; goto e_source_unlock; }