Reject KVM_SEV_INIT and KVM_SEV_ES_INIT if they are attempted after one
or more vCPUs have been created. KVM assumes a VM is tagged SEV/SEV-ES
prior to vCPU creation, e.g. init_vmcb() needs to mark the VMCB as SEV
enabled, and svm_create_vcpu() needs to allocate the VMSA. At best,
creating vCPUs before SEV/SEV-ES init will lead to unexpected errors
and/or behavior, and at worst it will crash the host, e.g.
sev_launch_update_vmsa() will dereference a null svm->vmsa pointer.
Fixes:
1654efcbc431 ("KVM: SVM: Add KVM_SEV_INIT command")
Fixes:
ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest")
Cc: stable@vger.kernel.org
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <
20210331031936.2495277-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
bool es_active = argp->id == KVM_SEV_ES_INIT;
int asid, ret;
+ if (kvm->created_vcpus)
+ return -EINVAL;
+
ret = -EBUSY;
if (unlikely(sev->active))
return ret;