[RFC 08/19] s390/zcrypt: support for assigning adapters to matrix mdev

[Tony Krowiak]

Provides the sysfs interfaces for assigning an adapter to
and unassigning an AP adapter from a mediated matrix device.

The IDs of the AP adapters assigned to the mediated matrix
device are stored in a bit mask. The bits in the mask, from
left to right, correspond to AP adapter numbers 0 to 255. The
bit corresponding to the ID of the adapter being assigned will
be set in the bit mask.

The relevant sysfs structures are:

/sys/devices/ap_matrix
... [matrix]
...... [mdev_supported_types]
......... [ap_matrix-passthrough]
............ [devices]
...............[$uuid]
.................. adapters
.................. assign_adapter
.................. unassign_adapter

To assign an adapter to the $uuid mediated matrix device, write
ID of the adapter (hex value) to the assign_adapter file. To
unassign an adapter, write the ID of the adapter (hex value)
to the unassign_adapter file. The list of adapters that have
been assigned can be viewed by displaying the contents of the
adapters file.

For example, to assign adapter 0xad to mediated matrix device
$uuid:

	echo ad > assign_adapter

To unassign adapter 0xad:

	echo ad > unassign_adapter

To see the list of adapters assigned:

	cat adapters

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>
---
 arch/s390/include/asm/ap-config.h        |   13 +++
 drivers/s390/crypto/vfio_ap_matrix_ops.c |  147 ++++++++++++++++++++++++++++++
 2 files changed, 160 insertions(+), 0 deletions(-)

diff --git a/arch/s390/include/asm/ap-config.h b/arch/s390/include/asm/ap-config.h
index 8491b5f..3064215 100644
--- a/arch/s390/include/asm/ap-config.h
+++ b/arch/s390/include/asm/ap-config.h
@@ -9,4 +9,17 @@
 #ifndef _ASM_KVM_AP_CONFIG_H_
 #define _ASM_KVM_AP_CONFIG_H_
 
+#include <linux/types.h>
+
+#define AP_MATRIX_MAX_MASK_BITS		256
+#define AP_MATRIX_MASK_INDICES		(AP_MATRIX_MAX_MASK_BITS / \
+					(sizeof(u64) * 8))
+#define AP_MATRIX_MAX_MASK_BYTES	(AP_MATRIX_MASK_INDICES * sizeof(u64))
+
+struct ap_config_masks {
+	u64 apm[AP_MATRIX_MASK_INDICES];
+	u64 aqm[AP_MATRIX_MASK_INDICES];
+	u64 adm[AP_MATRIX_MASK_INDICES];
+};
+
 #endif /* _ASM_KVM_AP_CONFIG_H_ */
diff --git a/drivers/s390/crypto/vfio_ap_matrix_ops.c b/drivers/s390/crypto/vfio_ap_matrix_ops.c
index 7d01f18..e4b1236 100644
--- a/drivers/s390/crypto/vfio_ap_matrix_ops.c
+++ b/drivers/s390/crypto/vfio_ap_matrix_ops.c
@@ -23,6 +23,7 @@
 struct ap_matrix_mdev {
 	struct mdev_device *mdev;
 	struct list_head node;
+	struct ap_config_masks masks;
 };
 
 struct ap_matrix	*matrix;
@@ -136,9 +137,155 @@ static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
 	NULL,
 };
 
+static int ap_matrix_id_is_xnum(char *id)
+{
+	size_t i;
+
+	for (i = 0; i < strlen(id); i++) {
+		if (!isxdigit(id[i]))
+			return 0;
+	}
+
+	return 1;
+}
+
+static int ap_matrix_parse_id(const char *buf, unsigned int *id)
+{
+	int ret;
+	char *bufcpy;
+	char *id_str;
+
+	if ((strlen(buf) == 0) || (*buf == '\n')) {
+		pr_err("%s: input buffer '%s' contains no valid hex values",
+		       VFIO_AP_MATRIX_MODULE_NAME, buf);
+		return -EINVAL;
+	}
+
+	bufcpy = kzalloc(strlen(buf) + 1, GFP_KERNEL);
+	if (!bufcpy)
+		return -ENOMEM;
+
+	strcpy(bufcpy, buf);
+	id_str = strim(bufcpy);
+
+	if (!ap_matrix_id_is_xnum(id_str)) {
+		pr_err("%s: input id '%s' contains an invalid hex value '%s'",
+		       VFIO_AP_MATRIX_MODULE_NAME, buf, id_str);
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = kstrtouint (id_str, 16, id);
+	if (ret || (*id >= AP_MATRIX_MAX_MASK_BITS)) {
+		pr_err("%s: input id '%s' is not a value from 0 to %x",
+		       VFIO_AP_MATRIX_MODULE_NAME, buf,
+		       AP_MATRIX_MAX_MASK_BITS);
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = 0;
+
+done:
+	kfree(bufcpy);
+	return ret;
+}
+
+static ssize_t ap_matrix_adapters_assign(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	int ret;
+	unsigned int apid;
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	ret = ap_matrix_parse_id(buf, &apid);
+	if (ret)
+		return ret;
+
+	set_bit_inv((unsigned long)apid,
+		    (unsigned long *)matrix_mdev->masks.apm);
+
+	return count;
+}
+static DEVICE_ATTR(assign_adapter, 0644, NULL, ap_matrix_adapters_assign);
+
+static ssize_t ap_matrix_adapters_unassign(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t count)
+{
+	int ret;
+	unsigned int apid;
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+
+	ret = ap_matrix_parse_id(buf, &apid);
+	if (ret)
+		return ret;
+
+	clear_bit_inv((unsigned long)apid,
+		      (unsigned long *)matrix_mdev->masks.apm);
+
+	return count;
+}
+static DEVICE_ATTR(unassign_adapter, 0644, NULL, ap_matrix_adapters_unassign);
+
+static ssize_t ap_matrix_adapters_show(struct device *dev,
+				       struct device_attribute *attr,
+				       char *buf)
+{
+	struct mdev_device *mdev = mdev_from_dev(dev);
+	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
+	unsigned long *apm = (unsigned long *)matrix_mdev->masks.apm;
+	unsigned long id;
+	unsigned long nbits = 256;
+	char *bufpos = buf;
+	int nchars = 0;
+	int n;
+
+	id = find_first_bit_inv(apm, nbits);
+	while (id < nbits) {
+		if (nchars) {
+			n = sprintf(bufpos, ",");
+			bufpos += n;
+			nchars += n;
+		}
+
+		n = sprintf(bufpos, "%02lx", id);
+		bufpos += n;
+		nchars += n;
+		id = find_next_bit_inv(apm, nbits, id + 1);
+	}
+
+	n = sprintf(bufpos, "\n");
+	bufpos += n;
+	nchars += n;
+
+	return nchars;
+}
+static DEVICE_ATTR(adapters, 0644, ap_matrix_adapters_show, NULL);
+
+static struct attribute *ap_matrix_mdev_attrs[] = {
+	&dev_attr_assign_adapter.attr,
+	&dev_attr_unassign_adapter.attr,
+	&dev_attr_adapters.attr,
+	NULL
+};
+
+static struct attribute_group ap_matrix_mdev_attr_group = {
+	.attrs = ap_matrix_mdev_attrs
+};
+
+static const struct attribute_group *ap_matrix_mdev_attr_groups[] = {
+	&ap_matrix_mdev_attr_group,
+	NULL
+};
+
 static const struct mdev_parent_ops vfio_ap_matrix_ops = {
 	.owner                  = THIS_MODULE,
 	.supported_type_groups  = ap_matrix_mdev_type_groups,
+	.mdev_attr_groups	= ap_matrix_mdev_attr_groups,
 	.create                 = ap_matrix_mdev_create,
 	.remove                 = ap_matrix_mdev_remove,
 };
-- 
1.7.1