kvm: sev: Fail KVM_SEV_INIT if already initialized

By code inspection, it was found that multiple calls to KVM_SEV_INIT could deplete asid bits and overwrite kvm_sev_info's regions_list. Multiple calls to KVM_SVM_INIT is not likely to occur with QEMU, but this should likely be fixed anyway. This code is serialized by kvm->lock. Fixes: 1654efc ("KVM: SVM: Add KVM_SEV_INIT command") Reported-by: Cfir Cohen <[email protected]> Signed-off-by: David Rientjes <[email protected]> Signed-off-by: Radim Krčmář <[email protected]>
josf · Jan 11, 2019 · 3f14a89 · 3f14a89
1 parent 98938aa
commit 3f14a89
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
@@ -6278,6 +6278,9 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	int asid, ret;
 
 	ret = -EBUSY;
+	if (unlikely(sev->active))
+		return ret;
+
 	asid = sev_asid_new();
 	if (asid < 0)
 		return ret;