Merge branch 'ap-driver-override' into features

Harald Freudenberger says:

====================

Support for driver override on AP queues.

Add a new sysfs attribute driver_override the AP queue's directory. Writing
in a string overrides the default driver determination and the drivers are
matched against this string instead. This overrules the driver binding
determined by the apmask/aqmask bitmask fields. With the write to the
attribute a check is done if the queue is in use by an mdev device.
If this is true, the write is aborted and EBUSY is returned.

As there exists some tooling for this kind of driver_override
(see package driverctl) the AP bus behavior for re-binding
should be compatible to this. The steps for a driver_override are:
 1) unbind the current driver from the device. For example
    echo "17.0005" > /sys/devices/ap/card17/17.0005/driver/unbind
 2) set the new driver for this device in the sysfs
    driver_override attribute. For example
    echo "vfio_ap" > /sys//devices/ap/card17/17.0005/driver_override
 3) trigger a bus reprobe of this device. For example
    echo "17.0005" > /sys/bus/ap/drivers_probe
With the driverctl package this is more comfortable and
the settings get persisted:
  driverctl -b ap set-override 17.0005 vfio_ap
and unset with
  driverctl -b ap unset-override 17.0005

====================

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Author: hcahca

drivers/s390/crypto/ap_bus.c

@@ -86,8 +86,17 @@ DEFINE_SPINLOCK(ap_queues_lock);
 /* Default permissions (ioctl, card and domain masking) */
 struct ap_perms ap_perms;
 EXPORT_SYMBOL(ap_perms);
-DEFINE_MUTEX(ap_perms_mutex);
-EXPORT_SYMBOL(ap_perms_mutex);
+/* true if apmask and/or aqmask are NOT default */
+bool ap_apmask_aqmask_in_use;
+/* counter for how many driver_overrides are currently active */
+int ap_driver_override_ctr;
+/*
+ * Mutex for consistent read and write of the ap_perms struct,
+ * ap_apmask_aqmask_in_use, ap_driver_override_ctr
+ * and the ap bus sysfs attributes apmask and aqmask.
+ */
+DEFINE_MUTEX(ap_attr_mutex);
+EXPORT_SYMBOL(ap_attr_mutex);
 
 /* # of bindings complete since init */
 static atomic64_t ap_bindings_complete_count = ATOMIC64_INIT(0);
@@ -853,20 +862,38 @@ static int __ap_revise_reserved(struct device *dev, void *dummy)
 	int rc, card, queue, devres, drvres;
 
 	if (is_queue_dev(dev)) {
-		card = AP_QID_CARD(to_ap_queue(dev)->qid);
-		queue = AP_QID_QUEUE(to_ap_queue(dev)->qid);
-		mutex_lock(&ap_perms_mutex);
-		devres = test_bit_inv(card, ap_perms.apm) &&
-			test_bit_inv(queue, ap_perms.aqm);
-		mutex_unlock(&ap_perms_mutex);
-		drvres = to_ap_drv(dev->driver)->flags
-			& AP_DRIVER_FLAG_DEFAULT;
-		if (!!devres != !!drvres) {
-			pr_debug("reprobing queue=%02x.%04x\n", card, queue);
-			rc = device_reprobe(dev);
-			if (rc)
-				AP_DBF_WARN("%s reprobing queue=%02x.%04x failed\n",
-					    __func__, card, queue);
+		struct ap_driver *ap_drv = to_ap_drv(dev->driver);
+		struct ap_queue *aq = to_ap_queue(dev);
+		struct ap_device *ap_dev = &aq->ap_dev;
+
+		card = AP_QID_CARD(aq->qid);
+		queue = AP_QID_QUEUE(aq->qid);
+
+		if (ap_dev->driver_override) {
+			if (strcmp(ap_dev->driver_override,
+				   ap_drv->driver.name)) {
+				pr_debug("reprobing queue=%02x.%04x\n", card, queue);
+				rc = device_reprobe(dev);
+				if (rc) {
+					AP_DBF_WARN("%s reprobing queue=%02x.%04x failed\n",
+						    __func__, card, queue);
+				}
+			}
+		} else {
+			mutex_lock(&ap_attr_mutex);
+			devres = test_bit_inv(card, ap_perms.apm) &&
+				test_bit_inv(queue, ap_perms.aqm);
+			mutex_unlock(&ap_attr_mutex);
+			drvres = to_ap_drv(dev->driver)->flags
+				& AP_DRIVER_FLAG_DEFAULT;
+			if (!!devres != !!drvres) {
+				pr_debug("reprobing queue=%02x.%04x\n", card, queue);
+				rc = device_reprobe(dev);
+				if (rc) {
+					AP_DBF_WARN("%s reprobing queue=%02x.%04x failed\n",
+						    __func__, card, queue);
+				}
+			}
 		}
 	}
 
@@ -884,22 +911,37 @@ static void ap_bus_revise_bindings(void)
  * @card: the APID of the adapter card to check
  * @queue: the APQI of the queue to check
  *
- * Note: the ap_perms_mutex must be locked by the caller of this function.
+ * Note: the ap_attr_mutex must be locked by the caller of this function.
  *
  * Return: an int specifying whether the AP adapter is reserved for the host (1)
  *	   or not (0).
  */
 int ap_owned_by_def_drv(int card, int queue)
 {
+	struct ap_queue *aq;
 	int rc = 0;
 
 	if (card < 0 || card >= AP_DEVICES || queue < 0 || queue >= AP_DOMAINS)
 		return -EINVAL;
 
+	aq = ap_get_qdev(AP_MKQID(card, queue));
+	if (aq) {
+		const struct device_driver *drv = aq->ap_dev.device.driver;
+		const struct ap_driver *ap_drv = to_ap_drv(drv);
+		bool override = !!aq->ap_dev.driver_override;
+
+		if (override && drv && ap_drv->flags & AP_DRIVER_FLAG_DEFAULT)
+			rc = 1;
+		put_device(&aq->ap_dev.device);
+		if (override)
+			goto out;
+	}
+
 	if (test_bit_inv(card, ap_perms.apm) &&
 	    test_bit_inv(queue, ap_perms.aqm))
 		rc = 1;
 
+out:
 	return rc;
 }
 EXPORT_SYMBOL(ap_owned_by_def_drv);
@@ -911,7 +953,7 @@ EXPORT_SYMBOL(ap_owned_by_def_drv);
  * @apm: a bitmap specifying a set of APIDs comprising the APQNs to check
  * @aqm: a bitmap specifying a set of APQIs comprising the APQNs to check
  *
- * Note: the ap_perms_mutex must be locked by the caller of this function.
+ * Note: the ap_attr_mutex must be locked by the caller of this function.
  *
  * Return: an int specifying whether each APQN is reserved for the host (1) or
  *	   not (0)
@@ -922,12 +964,10 @@ int ap_apqn_in_matrix_owned_by_def_drv(unsigned long *apm,
 	int card, queue, rc = 0;
 
 	for (card = 0; !rc && card < AP_DEVICES; card++)
-		if (test_bit_inv(card, apm) &&
-		    test_bit_inv(card, ap_perms.apm))
+		if (test_bit_inv(card, apm))
 			for (queue = 0; !rc && queue < AP_DOMAINS; queue++)
-				if (test_bit_inv(queue, aqm) &&
-				    test_bit_inv(queue, ap_perms.aqm))
-					rc = 1;
+				if (test_bit_inv(queue, aqm))
+					rc = ap_owned_by_def_drv(card, queue);
 
 	return rc;
 }
@@ -951,13 +991,19 @@ static int ap_device_probe(struct device *dev)
 		 */
 		card = AP_QID_CARD(to_ap_queue(dev)->qid);
 		queue = AP_QID_QUEUE(to_ap_queue(dev)->qid);
-		mutex_lock(&ap_perms_mutex);
-		devres = test_bit_inv(card, ap_perms.apm) &&
-			test_bit_inv(queue, ap_perms.aqm);
-		mutex_unlock(&ap_perms_mutex);
-		drvres = ap_drv->flags & AP_DRIVER_FLAG_DEFAULT;
-		if (!!devres != !!drvres)
-			goto out;
+		if (ap_dev->driver_override) {
+			if (strcmp(ap_dev->driver_override,
+				   ap_drv->driver.name))
+				goto out;
+		} else {
+			mutex_lock(&ap_attr_mutex);
+			devres = test_bit_inv(card, ap_perms.apm) &&
+				test_bit_inv(queue, ap_perms.aqm);
+			mutex_unlock(&ap_attr_mutex);
+			drvres = ap_drv->flags & AP_DRIVER_FLAG_DEFAULT;
+			if (!!devres != !!drvres)
+				goto out;
+		}
 	}
 
 	/*
@@ -983,8 +1029,17 @@ static int ap_device_probe(struct device *dev)
 	}
 
 out:
-	if (rc)
+	if (rc) {
 		put_device(dev);
+	} else {
+		if (is_queue_dev(dev)) {
+			pr_debug("queue=%02x.%04x new driver=%s\n",
+				 card, queue, ap_drv->driver.name);
+		} else {
+			pr_debug("card=%02x new driver=%s\n",
+				 to_ap_card(dev)->id, ap_drv->driver.name);
+		}
+	}
 	return rc;
 }
 
@@ -1437,12 +1492,12 @@ static ssize_t apmask_show(const struct bus_type *bus, char *buf)
 {
 	int rc;
 
-	if (mutex_lock_interruptible(&ap_perms_mutex))
+	if (mutex_lock_interruptible(&ap_attr_mutex))
 		return -ERESTARTSYS;
 	rc = sysfs_emit(buf, "0x%016lx%016lx%016lx%016lx\n",
 			ap_perms.apm[0], ap_perms.apm[1],
 			ap_perms.apm[2], ap_perms.apm[3]);
-	mutex_unlock(&ap_perms_mutex);
+	mutex_unlock(&ap_attr_mutex);
 
 	return rc;
 }
@@ -1452,6 +1507,7 @@ static int __verify_card_reservations(struct device_driver *drv, void *data)
 	int rc = 0;
 	struct ap_driver *ap_drv = to_ap_drv(drv);
 	unsigned long *newapm = (unsigned long *)data;
+	unsigned long aqm_any[BITS_TO_LONGS(AP_DOMAINS)];
 
 	/*
 	 * increase the driver's module refcounter to be sure it is not
@@ -1461,7 +1517,8 @@ static int __verify_card_reservations(struct device_driver *drv, void *data)
 		return 0;
 
 	if (ap_drv->in_use) {
-		rc = ap_drv->in_use(newapm, ap_perms.aqm);
+		bitmap_fill(aqm_any, AP_DOMAINS);
+		rc = ap_drv->in_use(newapm, aqm_any);
 		if (rc)
 			rc = -EBUSY;
 	}
@@ -1490,18 +1547,31 @@ static int apmask_commit(unsigned long *newapm)
 
 	memcpy(ap_perms.apm, newapm, APMASKSIZE);
 
+	/*
+	 * Update ap_apmask_aqmask_in_use. Note that the
+	 * ap_attr_mutex has to be obtained here.
+	 */
+	ap_apmask_aqmask_in_use =
+		bitmap_full(ap_perms.apm, AP_DEVICES) &&
+		bitmap_full(ap_perms.aqm, AP_DOMAINS) ?
+		false : true;
+
 	return 0;
 }
 
 static ssize_t apmask_store(const struct bus_type *bus, const char *buf,
 			    size_t count)
 {
-	int rc, changes = 0;
 	DECLARE_BITMAP(newapm, AP_DEVICES);
+	int rc = -EINVAL, changes = 0;
 
-	if (mutex_lock_interruptible(&ap_perms_mutex))
+	if (mutex_lock_interruptible(&ap_attr_mutex))
 		return -ERESTARTSYS;
 
+	/* Do not allow apmask/aqmask if driver override is active */
+	if (ap_driver_override_ctr)
+		goto done;
+
 	rc = ap_parse_bitmap_str(buf, ap_perms.apm, AP_DEVICES, newapm);
 	if (rc)
 		goto done;
@@ -1511,7 +1581,7 @@ static ssize_t apmask_store(const struct bus_type *bus, const char *buf,
 		rc = apmask_commit(newapm);
 
 done:
-	mutex_unlock(&ap_perms_mutex);
+	mutex_unlock(&ap_attr_mutex);
 	if (rc)
 		return rc;
 
@@ -1529,12 +1599,12 @@ static ssize_t aqmask_show(const struct bus_type *bus, char *buf)
 {
 	int rc;
 
-	if (mutex_lock_interruptible(&ap_perms_mutex))
+	if (mutex_lock_interruptible(&ap_attr_mutex))
 		return -ERESTARTSYS;
 	rc = sysfs_emit(buf, "0x%016lx%016lx%016lx%016lx\n",
 			ap_perms.aqm[0], ap_perms.aqm[1],
 			ap_perms.aqm[2], ap_perms.aqm[3]);
-	mutex_unlock(&ap_perms_mutex);
+	mutex_unlock(&ap_attr_mutex);
 
 	return rc;
 }
@@ -1544,6 +1614,7 @@ static int __verify_queue_reservations(struct device_driver *drv, void *data)
 	int rc = 0;
 	struct ap_driver *ap_drv = to_ap_drv(drv);
 	unsigned long *newaqm = (unsigned long *)data;
+	unsigned long apm_any[BITS_TO_LONGS(AP_DEVICES)];
 
 	/*
 	 * increase the driver's module refcounter to be sure it is not
@@ -1553,7 +1624,8 @@ static int __verify_queue_reservations(struct device_driver *drv, void *data)
 		return 0;
 
 	if (ap_drv->in_use) {
-		rc = ap_drv->in_use(ap_perms.apm, newaqm);
+		bitmap_fill(apm_any, AP_DEVICES);
+		rc = ap_drv->in_use(apm_any, newaqm);
 		if (rc)
 			rc = -EBUSY;
 	}
@@ -1582,18 +1654,31 @@ static int aqmask_commit(unsigned long *newaqm)
 
 	memcpy(ap_perms.aqm, newaqm, AQMASKSIZE);
 
+	/*
+	 * Update ap_apmask_aqmask_in_use. Note that the
+	 * ap_attr_mutex has to be obtained here.
+	 */
+	ap_apmask_aqmask_in_use =
+		bitmap_full(ap_perms.apm, AP_DEVICES) &&
+		bitmap_full(ap_perms.aqm, AP_DOMAINS) ?
+		false : true;
+
 	return 0;
 }
 
 static ssize_t aqmask_store(const struct bus_type *bus, const char *buf,
 			    size_t count)
 {
-	int rc, changes = 0;
 	DECLARE_BITMAP(newaqm, AP_DOMAINS);
+	int rc = -EINVAL, changes = 0;
 
-	if (mutex_lock_interruptible(&ap_perms_mutex))
+	if (mutex_lock_interruptible(&ap_attr_mutex))
 		return -ERESTARTSYS;
 
+	/* Do not allow apmask/aqmask if driver override is active */
+	if (ap_driver_override_ctr)
+		goto done;
+
 	rc = ap_parse_bitmap_str(buf, ap_perms.aqm, AP_DOMAINS, newaqm);
 	if (rc)
 		goto done;
@@ -1603,7 +1688,7 @@ static ssize_t aqmask_store(const struct bus_type *bus, const char *buf,
 		rc = aqmask_commit(newaqm);
 
 done:
-	mutex_unlock(&ap_perms_mutex);
+	mutex_unlock(&ap_attr_mutex);
 	if (rc)
 		return rc;
 
@@ -2474,14 +2559,14 @@ static void __init ap_perms_init(void)
 	if (apm_str) {
 		memset(&ap_perms.apm, 0, sizeof(ap_perms.apm));
 		ap_parse_mask_str(apm_str, ap_perms.apm, AP_DEVICES,
-				  &ap_perms_mutex);
+				  &ap_attr_mutex);
 	}
 
 	/* aqm kernel parameter string */
 	if (aqm_str) {
 		memset(&ap_perms.aqm, 0, sizeof(ap_perms.aqm));
 		ap_parse_mask_str(aqm_str, ap_perms.aqm, AP_DOMAINS,
-				  &ap_perms_mutex);
+				  &ap_attr_mutex);
 	}
 }
 

drivers/s390/crypto/ap_bus.h

@@ -166,6 +166,7 @@ void ap_driver_unregister(struct ap_driver *);
 struct ap_device {
 	struct device device;
 	int device_type;		/* AP device type. */
+	const char *driver_override;
 };
 
 #define to_ap_dev(x) container_of((x), struct ap_device, device)
@@ -280,7 +281,9 @@ struct ap_perms {
 };
 
 extern struct ap_perms ap_perms;
-extern struct mutex ap_perms_mutex;
+extern bool ap_apmask_aqmask_in_use;
+extern int ap_driver_override_ctr;
+extern struct mutex ap_attr_mutex;
 
 /*
  * Get ap_queue device for this qid.