selftests: sev_migrate_tests: add tests for KVM_CAP_VM_COPY_ENC_CONTEXT_FROM

I am putting the tests in sev_migrate_tests because the failure conditions are
very similar and some of the setup code can be reused, too.

The tests cover both successful creation of a mirror VM, and error
conditions.

Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Message-Id: <20211123005036.2954379-9-pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

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

@@ -54,12 +54,15 @@ static struct kvm_vm *sev_vm_create(bool es)
 	return vm;
 }
 
-static struct kvm_vm *__vm_create(void)
+static struct kvm_vm *aux_vm_create(bool with_vcpus)
 {
 	struct kvm_vm *vm;
 	int i;
 
 	vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
+	if (!with_vcpus)
+		return vm;
+
 	for (i = 0; i < NR_MIGRATE_TEST_VCPUS; ++i)
 		vm_vcpu_add(vm, i);
 
@@ -93,7 +96,7 @@ static void test_sev_migrate_from(bool es)
 
 	src_vm = sev_vm_create(es);
 	for (i = 0; i < NR_MIGRATE_TEST_VMS; ++i)
-		dst_vms[i] = __vm_create();
+		dst_vms[i] = aux_vm_create(true);
 
 	/* Initial migration from the src to the first dst. */
 	sev_migrate_from(dst_vms[0]->fd, src_vm->fd);
@@ -162,7 +165,7 @@ static void test_sev_migrate_parameters(void)
 	sev_vm = sev_vm_create(/* es= */ false);
 	sev_es_vm = sev_vm_create(/* es= */ true);
 	vm_no_vcpu = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
-	vm_no_sev = __vm_create();
+	vm_no_sev = aux_vm_create(true);
 	sev_es_vm_no_vmsa = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
 	sev_ioctl(sev_es_vm_no_vmsa->fd, KVM_SEV_ES_INIT, NULL);
 	vm_vcpu_add(sev_es_vm_no_vmsa, 1);
@@ -203,11 +206,106 @@ static void test_sev_migrate_parameters(void)
 	kvm_vm_free(vm_no_sev);
 }
 
+static int __sev_mirror_create(int dst_fd, int src_fd)
+{
+	struct kvm_enable_cap cap = {
+		.cap = KVM_CAP_VM_COPY_ENC_CONTEXT_FROM,
+		.args = { src_fd }
+	};
+
+	return ioctl(dst_fd, KVM_ENABLE_CAP, &cap);
+}
+
+
+static void sev_mirror_create(int dst_fd, int src_fd)
+{
+	int ret;
+
+	ret = __sev_mirror_create(dst_fd, src_fd);
+	TEST_ASSERT(!ret, "Copying context failed, ret: %d, errno: %d\n", ret, errno);
+}
+
+static void test_sev_mirror(bool es)
+{
+	struct kvm_vm *src_vm, *dst_vm;
+	struct kvm_sev_launch_start start = {
+		.policy = es ? SEV_POLICY_ES : 0
+	};
+	int i;
+
+	src_vm = sev_vm_create(es);
+	dst_vm = aux_vm_create(false);
+
+	sev_mirror_create(dst_vm->fd, src_vm->fd);
+
+	/* Check that we can complete creation of the mirror VM.  */
+	for (i = 0; i < NR_MIGRATE_TEST_VCPUS; ++i)
+		vm_vcpu_add(dst_vm, i);
+	sev_ioctl(dst_vm->fd, KVM_SEV_LAUNCH_START, &start);
+	if (es)
+		sev_ioctl(dst_vm->fd, KVM_SEV_LAUNCH_UPDATE_VMSA, NULL);
+
+	kvm_vm_free(src_vm);
+	kvm_vm_free(dst_vm);
+}
+
+static void test_sev_mirror_parameters(void)
+{
+	struct kvm_vm *sev_vm, *sev_es_vm, *vm_no_vcpu, *vm_with_vcpu;
+	int ret;
+
+	sev_vm = sev_vm_create(/* es= */ false);
+	sev_es_vm = sev_vm_create(/* es= */ true);
+	vm_with_vcpu = aux_vm_create(true);
+	vm_no_vcpu = aux_vm_create(false);
+
+	ret = __sev_mirror_create(sev_vm->fd, sev_vm->fd);
+	TEST_ASSERT(
+		ret == -1 && errno == EINVAL,
+		"Should not be able copy context to self. ret: %d, errno: %d\n",
+		ret, errno);
+
+	ret = __sev_mirror_create(sev_vm->fd, sev_es_vm->fd);
+	TEST_ASSERT(
+		ret == -1 && errno == EINVAL,
+		"Should not be able copy context to SEV enabled VM. ret: %d, errno: %d\n",
+		ret, errno);
+
+	ret = __sev_mirror_create(sev_es_vm->fd, sev_vm->fd);
+	TEST_ASSERT(
+		ret == -1 && errno == EINVAL,
+		"Should not be able copy context to SEV-ES enabled VM. ret: %d, errno: %d\n",
+		ret, errno);
+
+	ret = __sev_mirror_create(vm_no_vcpu->fd, vm_with_vcpu->fd);
+	TEST_ASSERT(ret == -1 && errno == EINVAL,
+		    "Copy context requires SEV enabled. ret %d, errno: %d\n", ret,
+		    errno);
+
+	ret = __sev_mirror_create(vm_with_vcpu->fd, sev_vm->fd);
+	TEST_ASSERT(
+		ret == -1 && errno == EINVAL,
+		"SEV copy context requires no vCPUS on the destination. ret: %d, errno: %d\n",
+		ret, errno);
+
+	kvm_vm_free(sev_vm);
+	kvm_vm_free(sev_es_vm);
+	kvm_vm_free(vm_with_vcpu);
+	kvm_vm_free(vm_no_vcpu);
+}
+
 int main(int argc, char *argv[])
 {
-	test_sev_migrate_from(/* es= */ false);
-	test_sev_migrate_from(/* es= */ true);
-	test_sev_migrate_locking();
-	test_sev_migrate_parameters();
+	if (kvm_check_cap(KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM)) {
+		test_sev_migrate_from(/* es= */ false);
+		test_sev_migrate_from(/* es= */ true);
+		test_sev_migrate_locking();
+		test_sev_migrate_parameters();
+	}
+	if (kvm_check_cap(KVM_CAP_VM_COPY_ENC_CONTEXT_FROM)) {
+		test_sev_mirror(/* es= */ false);
+		test_sev_mirror(/* es= */ true);
+		test_sev_mirror_parameters();
+	}
 	return 0;
 }