From 79b11142763791bdead8b6460052cbdde8e08e2f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 9 Nov 2021 21:50:56 +0000 Subject: [PATCH] KVM: SEV: Disallow COPY_ENC_CONTEXT_FROM if target has created vCPUs 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 Cc: Marc Orr Cc: Sean Christopherson Cc: Nathan Tempelman Cc: Brijesh Singh Cc: Tom Lendacky Signed-off-by: Sean Christopherson Message-Id: <20211109215101.2211373-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/sev.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 3e27698..eeec499 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1775,7 +1775,12 @@ int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd) 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; } -- 2.7.4