selftests: KVM: sev_migrate_tests: Add mirror command tests

Add tests to confirm mirror vms can only run correct subset of commands.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Marc Orr <marcorr@google.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Message-Id: <20211208191642.3792819-4-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/x86_64/sev_migrate_tests.c

@@ -21,7 +21,7 @@
 #define NR_LOCK_TESTING_THREADS 3
 #define NR_LOCK_TESTING_ITERATIONS 10000
 
-static void sev_ioctl(int vm_fd, int cmd_id, void *data)
+static int __sev_ioctl(int vm_fd, int cmd_id, void *data, __u32 *fw_error)
 {
 	struct kvm_sev_cmd cmd = {
 		.id = cmd_id,
@@ -30,11 +30,20 @@ static void sev_ioctl(int vm_fd, int cmd_id, void *data)
 	};
 	int ret;
 
-
 	ret = ioctl(vm_fd, KVM_MEMORY_ENCRYPT_OP, &cmd);
-	TEST_ASSERT(ret == 0 && cmd.error == SEV_RET_SUCCESS,
+	*fw_error = cmd.error;
+	return ret;
+}
+
+static void sev_ioctl(int vm_fd, int cmd_id, void *data)
+{
+	int ret;
+	__u32 fw_error;
+
+	ret = __sev_ioctl(vm_fd, cmd_id, data, &fw_error);
+	TEST_ASSERT(ret == 0 && fw_error == SEV_RET_SUCCESS,
 		    "%d failed: return code: %d, errno: %d, fw error: %d",
-		    cmd_id, ret, errno, cmd.error);
+		    cmd_id, ret, errno, fw_error);
 }
 
 static struct kvm_vm *sev_vm_create(bool es)
@@ -226,6 +235,42 @@ static void sev_mirror_create(int dst_fd, int src_fd)
 	TEST_ASSERT(!ret, "Copying context failed, ret: %d, errno: %d\n", ret, errno);
 }
 
+static void verify_mirror_allowed_cmds(int vm_fd)
+{
+	struct kvm_sev_guest_status status;
+
+	for (int cmd_id = KVM_SEV_INIT; cmd_id < KVM_SEV_NR_MAX; ++cmd_id) {
+		int ret;
+		__u32 fw_error;
+
+		/*
+		 * These commands are allowed for mirror VMs, all others are
+		 * not.
+		 */
+		switch (cmd_id) {
+		case KVM_SEV_LAUNCH_UPDATE_VMSA:
+		case KVM_SEV_GUEST_STATUS:
+		case KVM_SEV_DBG_DECRYPT:
+		case KVM_SEV_DBG_ENCRYPT:
+			continue;
+		default:
+			break;
+		}
+
+		/*
+		 * These commands should be disallowed before the data
+		 * parameter is examined so NULL is OK here.
+		 */
+		ret = __sev_ioctl(vm_fd, cmd_id, NULL, &fw_error);
+		TEST_ASSERT(
+			ret == -1 && errno == EINVAL,
+			"Should not be able call command: %d. ret: %d, errno: %d\n",
+			cmd_id, ret, errno);
+	}
+
+	sev_ioctl(vm_fd, KVM_SEV_GUEST_STATUS, &status);
+}
+
 static void test_sev_mirror(bool es)
 {
 	struct kvm_vm *src_vm, *dst_vm;
@@ -243,6 +288,8 @@ static void test_sev_mirror(bool es)
 	if (es)
 		sev_ioctl(dst_vm->fd, KVM_SEV_LAUNCH_UPDATE_VMSA, NULL);
 
+	verify_mirror_allowed_cmds(dst_vm->fd);
+
 	kvm_vm_free(src_vm);
 	kvm_vm_free(dst_vm);
 }