From: Sean Christopherson seanjc@google.com
commit 79b11142763791bdead8b6460052cbdde8e08e2f upstream.
Reject COPY_ENC_CONTEXT_FROM if the destination VM has created vCPUs. KVM relies on SEV activation to occur before vCPUs are created, e.g. to set VMCB flags and intercepts correctly.
Fixes: 54526d1fd593 ("KVM: x86: Support KVM VMs sharing SEV context") Cc: stable@vger.kernel.org Cc: Peter Gonda pgonda@google.com Cc: Marc Orr marcorr@google.com Cc: Sean Christopherson seanjc@google.com Cc: Nathan Tempelman natet@google.com Cc: Brijesh Singh brijesh.singh@amd.com Cc: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20211109215101.2211373-2-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/svm/sev.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1787,7 +1787,12 @@ int svm_vm_copy_asid_from(struct kvm *kv mutex_unlock(&source_kvm->lock); mutex_lock(&kvm->lock);
- if (sev_guest(kvm)) { + /* + * 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. + */ + if (sev_guest(kvm) || kvm->created_vcpus) { ret = -EINVAL; goto e_mirror_unlock; }