[PATCH 3/3] s390/vfio-ap: Add write support to sysfs attr ap_config

[Jason J. Herne]

Allow writing a complete set of masks to ap_config. Doing so will
cause the vfio-ap driver to replace the vfio-ap mediated device's entire
state with the given set of masks. If the given state cannot be set, then
no changes are made to the vfio-ap mediated device.

The format of the data written to ap_config is as follows:
{amask},{dmask},{cmask}\n

\n is a newline character.

amask, dmask, and cmask are masks identifying which adapters, domains,
and control domains should be assigned to the mediated device.

The format of a mask is	as follows:
0xNN..NN

Where NN..NN is 64 hexadecimal characters representing a 256-bit value.
The leftmost (highest order) bit represents adapter/domain 0.

For an example set of masks that represent your mdev's current
configuration, simply cat ap_config.

This attribute is intended to be used by an mdevctl callout script
supporting the mdev type vfio_ap-passthrough to atomically update a
vfio-ap mediated device's state.

Signed-off-by: Jason J. Herne <jjherne@xxxxxxxxxxxxx>
---
 Documentation/arch/s390/vfio-ap.rst   |  27 ++++
 drivers/s390/crypto/vfio_ap_ops.c     | 188 +++++++++++++++++++++++---
 drivers/s390/crypto/vfio_ap_private.h |   6 +-
 3 files changed, 197 insertions(+), 24 deletions(-)

diff --git a/Documentation/arch/s390/vfio-ap.rst b/Documentation/arch/s390/vfio-ap.rst
index 929ee1c1c940..a94f13916dea 100644
--- a/Documentation/arch/s390/vfio-ap.rst
+++ b/Documentation/arch/s390/vfio-ap.rst
@@ -380,6 +380,33 @@ matrix device.
     control_domains:
       A read-only file for displaying the control domain numbers assigned to the
       vfio_ap mediated device.
+    ap_config:
+      A read/write file that, when written to, allows the entire vfio_ap mediated
+      device's ap configuration to be replaced in one shot. Three masks are given,
+      one for adapters, one for domains, and one for control domains. If the
+      given state cannot be set, then no changes are made to the vfio-ap
+      mediated device.
+
+      The format of the data written to ap_config is as follows:
+      {amask},{dmask},{cmask}\n
+
+      \n is a newline character.
+
+      amask, dmask, and cmask are masks identifying which adapters, domains,
+      and control domains should be assigned to the mediated device.
+
+      The format of a mask is as follows:
+      0xNN..NN
+
+      Where NN..NN is 64 hexadecimal characters representing a 256-bit value.
+      The leftmost (highest order) bit represents adapter/domain 0.
+
+      For an example set of masks that represent your mdev's current
+      configuration, simply cat ap_config.
+
+      This attribute is intended to be used by automation. End users would be
+      better served using the respective assign/unassign attributes for adapters
+      and domains.
 
 * functions:
 
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 96293683b939..5ad134c1d5e6 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -764,10 +764,11 @@ static int vfio_ap_mdev_probe(struct mdev_device *mdev)
 static void vfio_ap_mdev_link_queue(struct ap_matrix_mdev *matrix_mdev,
 				    struct vfio_ap_queue *q)
 {
-	if (q) {
-		q->matrix_mdev = matrix_mdev;
-		hash_add(matrix_mdev->qtable.queues, &q->mdev_qnode, q->apqn);
-	}
+	if (!q || vfio_ap_mdev_get_queue(matrix_mdev, q->apqn))
+		return;
+
+	q->matrix_mdev = matrix_mdev;
+	hash_add(matrix_mdev->qtable.queues, &q->mdev_qnode, q->apqn);
 }
 
 static void vfio_ap_mdev_link_apqn(struct ap_matrix_mdev *matrix_mdev, int apqn)
@@ -1048,21 +1049,25 @@ static void vfio_ap_mdev_unlink_adapter(struct ap_matrix_mdev *matrix_mdev,
 	}
 }
 
-static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
-					    unsigned long apid)
+static void vfio_ap_mdev_hot_unplug_adapters(struct ap_matrix_mdev *matrix_mdev,
+					    unsigned long *apids)
 {
-	int loop_cursor;
-	struct vfio_ap_queue *q;
 	struct ap_queue_table *qtable = kzalloc(sizeof(*qtable), GFP_KERNEL);
+	struct vfio_ap_queue *q;
+	unsigned long apid;
+	int loop_cursor;
 
 	hash_init(qtable->queues);
-	vfio_ap_mdev_unlink_adapter(matrix_mdev, apid, qtable);
 
-	if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm)) {
-		clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
-		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+	for_each_set_bit_inv(apid, apids, AP_DEVICES) {
+		vfio_ap_mdev_unlink_adapter(matrix_mdev, apid, qtable);
+
+		if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm))
+			clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
 	}
 
+	vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+
 	vfio_ap_mdev_reset_queues(qtable);
 
 	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
@@ -1073,6 +1078,15 @@ static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
 	kfree(qtable);
 }
 
+static void vfio_ap_mdev_hot_unplug_adapter(struct ap_matrix_mdev *matrix_mdev,
+					    unsigned long apid)
+{
+	DECLARE_BITMAP(apids, AP_DEVICES);
+
+	set_bit_inv(apid, apids);
+	vfio_ap_mdev_hot_unplug_adapters(matrix_mdev, apids);
+}
+
 /**
  * unassign_adapter_store - parses the APID from @buf and clears the
  * corresponding bit in the mediated matrix device's APM
@@ -1235,21 +1249,24 @@ static void vfio_ap_mdev_unlink_domain(struct ap_matrix_mdev *matrix_mdev,
 	}
 }
 
-static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
-					   unsigned long apqi)
+static void vfio_ap_mdev_hot_unplug_domains(struct ap_matrix_mdev *matrix_mdev,
+					   unsigned long *apqis)
 {
-	int loop_cursor;
-	struct vfio_ap_queue *q;
 	struct ap_queue_table *qtable = kzalloc(sizeof(*qtable), GFP_KERNEL);
+	struct vfio_ap_queue *q;
+	unsigned long apqi;
+	int loop_cursor;
 
 	hash_init(qtable->queues);
-	vfio_ap_mdev_unlink_domain(matrix_mdev, apqi, qtable);
 
-	if (test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm)) {
-		clear_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm);
-		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+	for_each_set_bit_inv(apqi, apqis, AP_DOMAINS) {
+		vfio_ap_mdev_unlink_domain(matrix_mdev, apqi, qtable);
+
+		if (test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm))
+			clear_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm);
 	}
 
+	vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 	vfio_ap_mdev_reset_queues(qtable);
 
 	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
@@ -1260,6 +1277,15 @@ static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
 	kfree(qtable);
 }
 
+static void vfio_ap_mdev_hot_unplug_domain(struct ap_matrix_mdev *matrix_mdev,
+					   unsigned long apqi)
+{
+	DECLARE_BITMAP(apqis, AP_DOMAINS);
+
+	set_bit_inv(apqi, apqis);
+	vfio_ap_mdev_hot_unplug_domains(matrix_mdev, apqis);
+}
+
 /**
  * unassign_domain_store - parses the APQI from @buf and clears the
  * corresponding bit in the mediated matrix device's AQM
@@ -1527,10 +1553,130 @@ static ssize_t ap_config_show(struct device *dev, struct device_attribute *attr,
 	return idx;
 }
 
+/* Number of characters needed for a complete hex mask representing the bits in ..  */
+#define AP_DEVICES_STRLEN	(AP_DEVICES/4 + 3)
+#define AP_DOMAINS_STRLEN	(AP_DOMAINS/4 + 3)
+#define AP_CONFIG_STRLEN	(AP_DEVICES_STRLEN + 2 * AP_DOMAINS_STRLEN)
+
+static int parse_bitmap(char **strbufptr, unsigned long *bitmap, int nbits)
+{
+	char *curmask;
+
+	curmask = strsep(strbufptr, ",\n");
+	if (!curmask)
+		return -EINVAL;
+
+	bitmap_clear(bitmap, 0, nbits);
+	return ap_hex2bitmap(curmask, bitmap, nbits);
+}
+
+static int ap_matrix_length_check(struct ap_matrix_mdev *matrix_mdev)
+{
+	unsigned long bit;
+
+	for_each_set_bit_inv(bit, matrix_mdev->matrix.apm, AP_DEVICES) {
+		if (bit > matrix_mdev->matrix.apm_max)
+			return -ENODEV;
+	}
+
+	for_each_set_bit_inv(bit, matrix_mdev->matrix.aqm, AP_DOMAINS) {
+		if (bit > matrix_mdev->matrix.aqm_max)
+			return -ENODEV;
+	}
+
+	for_each_set_bit_inv(bit, matrix_mdev->matrix.adm, AP_DOMAINS) {
+		if (bit > matrix_mdev->matrix.adm_max)
+			return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void ap_matrix_copy(struct ap_matrix *dst, struct ap_matrix *src)
+{
+	bitmap_copy(dst->apm, src->apm, AP_DEVICES);
+	bitmap_copy(dst->aqm, src->aqm, AP_DOMAINS);
+	bitmap_copy(dst->adm, src->adm, AP_DOMAINS);
+}
+
 static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr,
 			       const char *buf, size_t count)
 {
-	return count;
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
+	struct ap_matrix m_new, m_old, m_added, m_removed;
+	unsigned long newbit;
+	char *newbuf, *rest;
+	int rc = count;
+	bool do_update;
+
+	newbuf = rest = kstrndup(buf, AP_CONFIG_STRLEN, GFP_KERNEL);
+	if (!newbuf)
+		return -ENOMEM;
+
+	mutex_lock(&ap_perms_mutex);
+	get_update_locks_for_mdev(matrix_mdev);
+
+	/* Save old state */
+	ap_matrix_copy(&m_old, &matrix_mdev->matrix);
+
+	if (parse_bitmap(&rest, m_new.apm, AP_DEVICES) ||
+	    parse_bitmap(&rest, m_new.aqm, AP_DOMAINS) ||
+		parse_bitmap(&rest, m_new.adm, AP_DOMAINS)) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	bitmap_andnot(m_removed.apm, m_old.apm, m_new.apm, AP_DEVICES);
+	bitmap_andnot(m_removed.aqm, m_old.aqm, m_new.aqm, AP_DOMAINS);
+	bitmap_andnot(m_added.apm, m_new.apm, m_old.apm, AP_DEVICES);
+	bitmap_andnot(m_added.aqm, m_new.aqm, m_old.aqm, AP_DOMAINS);
+
+	/* Need new bitmaps in matrix_mdev for validation */
+	ap_matrix_copy(&matrix_mdev->matrix, &m_new);
+
+	/* Ensure new state is valid, else undo new state */
+	rc = vfio_ap_mdev_validate_masks(matrix_mdev);
+	if (rc) {
+		ap_matrix_copy(&matrix_mdev->matrix, &m_old);
+		goto out;
+	}
+	rc = ap_matrix_length_check(matrix_mdev);
+	if (rc) {
+		ap_matrix_copy(&matrix_mdev->matrix, &m_old);
+		goto out;
+	}
+	rc = count;
+
+	/* Need old bitmaps in matrix_mdev for unplug/unlink */
+	ap_matrix_copy(&matrix_mdev->matrix, &m_old);
+
+	/* Unlink removed adapters/domains */
+	vfio_ap_mdev_hot_unplug_adapters(matrix_mdev, m_removed.apm);
+	vfio_ap_mdev_hot_unplug_domains(matrix_mdev, m_removed.aqm);
+
+	/* Need new bitmaps in matrix_mdev for linking new adapters/domains */
+	ap_matrix_copy(&matrix_mdev->matrix, &m_new);
+
+	/* Link newly added adapters */
+	for_each_set_bit_inv(newbit, m_added.apm, AP_DEVICES)
+		vfio_ap_mdev_link_adapter(matrix_mdev, newbit);
+
+	for_each_set_bit_inv(newbit, m_added.aqm, AP_DOMAINS)
+		vfio_ap_mdev_link_domain(matrix_mdev, newbit);
+
+	/* filter resources not bound to vfio-ap */
+	do_update = vfio_ap_mdev_filter_matrix(matrix_mdev->matrix.apm,
+				matrix_mdev->matrix.aqm, matrix_mdev);
+	do_update |= vfio_ap_mdev_filter_cdoms(matrix_mdev);
+
+	/* Apply changes to shadow apbc if things changed */
+	if (do_update)
+		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+out:
+	release_update_locks_for_mdev(matrix_mdev);
+	mutex_unlock(&ap_perms_mutex);
+	kfree(newbuf);
+	return rc;
 }
 static DEVICE_ATTR_RW(ap_config);
 
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 88aff8b81f2f..e2cf07c184bf 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -75,11 +75,11 @@ extern struct ap_matrix_dev *matrix_dev;
  */
 struct ap_matrix {
 	unsigned long apm_max;
-	DECLARE_BITMAP(apm, 256);
+	DECLARE_BITMAP(apm, AP_DEVICES);
 	unsigned long aqm_max;
-	DECLARE_BITMAP(aqm, 256);
+	DECLARE_BITMAP(aqm, AP_DOMAINS);
 	unsigned long adm_max;
-	DECLARE_BITMAP(adm, 256);
+	DECLARE_BITMAP(adm, AP_DOMAINS);
 };
 
 /**
-- 
2.41.0