[PATCH v11 07/14] s390/vfio-ap: sysfs attribute to display the guest's matrix

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

The matrix of adapters and domains configured in a guest's APCB may
differ from the matrix of adapters and domains assigned to the matrix mdev,
so this patch introduces a sysfs attribute to display the matrix of a guest
using the matrix mdev. For a matrix mdev denoted by $uuid, the crycb for a
guest using the matrix mdev can be displayed as follows:

   cat /sys/devices/vfio_ap/matrix/$uuid/guest_matrix

If a guest is not using the matrix mdev at the time the crycb is displayed,
an error (ENODEV) will be returned.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c | 54 +++++++++++++++++++++++--------
 1 file changed, 40 insertions(+), 14 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 9791761aa7fd..7bad70d7bcef 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1073,29 +1073,24 @@ static ssize_t control_domains_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(control_domains);
 
-static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
-			   char *buf)
+static ssize_t vfio_ap_mdev_matrix_show(struct ap_matrix *matrix, char *buf)
 {
-	struct mdev_device *mdev = mdev_from_dev(dev);
-	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
 	char *bufpos = buf;
 	unsigned long apid;
 	unsigned long apqi;
 	unsigned long apid1;
 	unsigned long apqi1;
-	unsigned long napm_bits = matrix_mdev->matrix.apm_max + 1;
-	unsigned long naqm_bits = matrix_mdev->matrix.aqm_max + 1;
+	unsigned long napm_bits = matrix->apm_max + 1;
+	unsigned long naqm_bits = matrix->aqm_max + 1;
 	int nchars = 0;
 	int n;
 
-	apid1 = find_first_bit_inv(matrix_mdev->matrix.apm, napm_bits);
-	apqi1 = find_first_bit_inv(matrix_mdev->matrix.aqm, naqm_bits);
-
-	mutex_lock(&matrix_dev->lock);
+	apid1 = find_first_bit_inv(matrix->apm, napm_bits);
+	apqi1 = find_first_bit_inv(matrix->aqm, naqm_bits);
 
 	if ((apid1 < napm_bits) && (apqi1 < naqm_bits)) {
-		for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, napm_bits) {
-			for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,
+		for_each_set_bit_inv(apid, matrix->apm, napm_bits) {
+			for_each_set_bit_inv(apqi, matrix->aqm,
 					     naqm_bits) {
 				n = sprintf(bufpos, "%02lx.%04lx\n", apid,
 					    apqi);
@@ -1104,25 +1099,55 @@ static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
 			}
 		}
 	} else if (apid1 < napm_bits) {
-		for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, napm_bits) {
+		for_each_set_bit_inv(apid, matrix->apm, napm_bits) {
 			n = sprintf(bufpos, "%02lx.\n", apid);
 			bufpos += n;
 			nchars += n;
 		}
 	} else if (apqi1 < naqm_bits) {
-		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, naqm_bits) {
+		for_each_set_bit_inv(apqi, matrix->aqm, naqm_bits) {
 			n = sprintf(bufpos, ".%04lx\n", apqi);
 			bufpos += n;
 			nchars += n;
 		}
 	}
 
+	return nchars;
+}
+
+static ssize_t matrix_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	ssize_t nchars;
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	mutex_lock(&matrix_dev->lock);
+	nchars = vfio_ap_mdev_matrix_show(&matrix_mdev->matrix, buf);
 	mutex_unlock(&matrix_dev->lock);
 
 	return nchars;
 }
 static DEVICE_ATTR_RO(matrix);
 
+static ssize_t guest_matrix_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	ssize_t nchars;
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	if (!vfio_ap_mdev_has_crycb(matrix_mdev))
+		return -ENODEV;
+
+	mutex_lock(&matrix_dev->lock);
+	nchars = vfio_ap_mdev_matrix_show(&matrix_mdev->shadow_apcb, buf);
+	mutex_unlock(&matrix_dev->lock);
+
+	return nchars;
+}
+static DEVICE_ATTR_RO(guest_matrix);
+
 static struct attribute *vfio_ap_mdev_attrs[] = {
 	&dev_attr_assign_adapter.attr,
 	&dev_attr_unassign_adapter.attr,
@@ -1132,6 +1157,7 @@ static struct attribute *vfio_ap_mdev_attrs[] = {
 	&dev_attr_unassign_control_domain.attr,
 	&dev_attr_control_domains.attr,
 	&dev_attr_matrix.attr,
+	&dev_attr_guest_matrix.attr,
 	NULL,
 };
 
-- 
2.21.1