[RFC 13/19] s390/zcrypt: validate control domain assignment

[Tony Krowiak <akrowiak@linux.vnet.ibm.com>]

The AP control domain being assigned to the mediated
matrix driver must be assigned to the LPAR.

Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
---
 drivers/s390/crypto/vfio_ap_matrix_ops.c |   33 ++++++++++++++++++++++++++++++
 1 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_matrix_ops.c b/drivers/s390/crypto/vfio_ap_matrix_ops.c
index 2387916..10a006c 100644
--- a/drivers/s390/crypto/vfio_ap_matrix_ops.c
+++ b/drivers/s390/crypto/vfio_ap_matrix_ops.c
@@ -469,12 +469,41 @@ static ssize_t ap_matrix_domains_show(struct device *dev,
 static DEVICE_ATTR(domains, 0644, ap_matrix_domains_show,
 		   NULL);
 
+static int
+ap_matrix_validate_control_domains(struct ap_matrix_mdev *matrix_mdev,
+				   unsigned long id)
+{
+	int ret;
+	struct ap_config_info config;
+
+	memset(&config, 0, sizeof(config));
+
+	ret = ap_query_configuration(&config);
+	if (ret == -EOPNOTSUPP)
+		return 0;
+
+	if (ret) {
+		pr_err("%s: query AP configuration failed with rc %d",
+		       VFIO_AP_MATRIX_MODULE_NAME, ret);
+		return ret;
+	}
+
+	if (!test_bit_inv(id, (unsigned long *)config.adm)) {
+		pr_err("%s: control domain %04lx is not installed on the lpar",
+		       VFIO_AP_MATRIX_MODULE_NAME, id);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
 static ssize_t ap_matrix_control_domain_assign(struct device *dev,
 					       struct device_attribute *attr,
 					       const char *buf, size_t count)
 {
 	int ret;
 	unsigned int id;
+
 	struct mdev_device *mdev = mdev_from_dev(dev);
 	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 
@@ -482,6 +511,10 @@ static ssize_t ap_matrix_control_domain_assign(struct device *dev,
 	if (ret)
 		return ret;
 
+	ret = ap_matrix_validate_control_domains(matrix_mdev, id);
+	if (ret)
+		return ret;
+
 	set_bit_inv((unsigned long)id,
 		    (unsigned long *)matrix_mdev->masks.adm);
 
-- 
1.7.1