[PATCH v9 10/15] s390/vfio-ap: Add method to set a new guest AP configuration

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

Adds a new vfio_ap_set_new_config function to set a guest's AP
configuration. This is needed in order to set the state of the mdev when
it is migrated from a remote host system during the RESUMING phase.

Key changes:
* Refactored code from the ap_config_store function - handles changes to
  the sysfs ap_config attribute - into a new, non-static function which
  is callable from the ap_config_store function as well as the live guest
  migration code.

Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_ops.c     | 159 +++++++++++++++++++-------
 drivers/s390/crypto/vfio_ap_private.h |   3 +
 2 files changed, 118 insertions(+), 44 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index c951f289f305..5803207e9846 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -981,8 +981,7 @@ static void vfio_ap_mdev_link_adapter(struct ap_matrix_mdev *matrix_mdev,
 	unsigned long apqi;
 
 	for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS)
-		vfio_ap_mdev_link_apqn(matrix_mdev,
-				       AP_MKQID(apid, apqi));
+		vfio_ap_mdev_link_apqn(matrix_mdev, AP_MKQID(apid, apqi));
 }
 
 static void collect_queues_to_reset(struct ap_matrix_mdev *matrix_mdev,
@@ -1692,54 +1691,98 @@ static void ap_matrix_copy(struct ap_matrix *dst, struct ap_matrix *src)
 	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)
+static void get_removed_matrixes(struct ap_matrix *m_removed,
+				 struct ap_matrix *m_old,
+				 struct ap_matrix *m_new)
 {
-	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
-	struct ap_matrix m_new, m_old, m_added, m_removed;
+	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_removed->adm, m_old->adm, m_new->adm, AP_DOMAINS);
+}
+
+static void get_added_matrixes(struct ap_matrix *m_added,
+			       struct ap_matrix *m_old,
+			       struct ap_matrix *m_new)
+{
+	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);
+	bitmap_andnot(m_added->adm, m_new->adm, m_old->adm, AP_DOMAINS);
+}
+
+static int validate_new_state(struct ap_matrix_mdev *matrix_mdev)
+{
+	int rc;
+
+	/* Ensure new state is valid, else undo new state */
+	rc = vfio_ap_mdev_validate_masks(matrix_mdev);
+	if (rc)
+		return rc;
+
+	rc = ap_matrix_overflow_check(matrix_mdev);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static void link_new_queues(struct ap_matrix_mdev *matrix_mdev,
+			    struct ap_matrix *m_added)
+{
+	unsigned long apid, apqi;
+
+	for_each_set_bit_inv(apid, m_added->apm, AP_DEVICES)
+		vfio_ap_mdev_link_adapter(matrix_mdev, apid);
+
+	for_each_set_bit_inv(apqi, m_added->aqm, AP_DOMAINS)
+		vfio_ap_mdev_link_domain(matrix_mdev, apqi);
+}
+
+/**
+ * vfio_ap_set_new_guest_config:
+ *
+ * Set a new AP configuration for a guest.
+ *
+ * @matrix_mdev: Object used to maintain the AP configuration for a guest
+ * @m_new:		 Object used to set the new AP configuration
+ *
+ * Returns: zero (0) if the new AP configuration is successfully set; otherwise,
+ *	    returns an error:
+ *
+ *	    ~ EADDRNOTAVAIL One or more APQNs are reserved for host use
+ *	    ~ EADDRINUSE    One or more APQNs are assigned to another mdev
+ *	    ~ ENODEV	    An adapter, domain or control domain in the new
+ *			    AP configuration exceeds the max architected value
+ */
+int vfio_ap_set_new_guest_config(struct ap_matrix_mdev *matrix_mdev,
+				 struct ap_matrix *m_new)
+{
+	struct ap_matrix m_old, m_added, m_removed;
 	DECLARE_BITMAP(apm_filtered, AP_DEVICES);
-	unsigned long newbit;
-	char *newbuf, *rest;
-	int rc = count;
 	bool do_update;
+	int rc;
 
-	newbuf = kstrndup(buf, AP_CONFIG_STRLEN, GFP_KERNEL);
-	if (!newbuf)
-		return -ENOMEM;
-	rest = newbuf;
-
-	mutex_lock(&ap_attr_mutex);
-	get_update_locks_for_mdev(matrix_mdev);
+	lockdep_assert_held(&ap_attr_mutex);
+	assert_has_update_locks_for_mdev(matrix_mdev);
 
-	/* Save old state */
+	/* Save the old matrix to restore it if validation fails */
 	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);
+	/*
+	 * Get the adapters, domains and control domains added and/or removed
+	 * from the existing configuration
+	 */
+	get_removed_matrixes(&m_removed, &m_old, m_new);
+	get_added_matrixes(&m_added, &m_old, m_new);
 
 	/* Need new bitmaps in matrix_mdev for validation */
-	ap_matrix_copy(&matrix_mdev->matrix, &m_new);
+	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_overflow_check(matrix_mdev);
+	rc = validate_new_state(matrix_mdev);
 	if (rc) {
 		ap_matrix_copy(&matrix_mdev->matrix, &m_old);
-		goto out;
+		return rc;
 	}
-	rc = count;
 
 	/* Need old bitmaps in matrix_mdev for unplug/unlink */
 	ap_matrix_copy(&matrix_mdev->matrix, &m_old);
@@ -1749,14 +1792,10 @@ static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr
 	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);
+	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);
+	/* Link queues associated with the newly added adapters and domains */
+	link_new_queues(matrix_mdev, &m_added);
 
 	/* filter resources not bound to vfio-ap */
 	do_update = vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered);
@@ -1767,7 +1806,39 @@ static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 		reset_queues_for_apids(matrix_mdev, apm_filtered);
 	}
-out:
+
+	return 0;
+}
+
+static ssize_t ap_config_store(struct device *dev, struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
+	struct ap_matrix m_new;
+	char *newbuf, *rest;
+	ssize_t rc;
+
+	newbuf = kstrndup(buf, AP_CONFIG_STRLEN, GFP_KERNEL);
+	if (!newbuf)
+		return -ENOMEM;
+	rest = newbuf;
+
+	mutex_lock(&ap_attr_mutex);
+	get_update_locks_for_mdev(matrix_mdev);
+
+	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)) {
+		kfree(newbuf);
+		release_update_locks_for_mdev(matrix_mdev);
+		mutex_unlock(&ap_attr_mutex);
+		return -EINVAL;
+	}
+
+	rc = vfio_ap_set_new_guest_config(matrix_mdev, &m_new);
+	if (!rc)
+		rc = count;
+
 	release_update_locks_for_mdev(matrix_mdev);
 	mutex_unlock(&ap_attr_mutex);
 	kfree(newbuf);
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 9044ef4408c8..f506c4b07b46 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -235,4 +235,7 @@ assert_has_update_locks_for_mdev(struct ap_matrix_mdev *matrix_mdev)
 
 void vfio_ap_matrix_init(struct ap_config_info *info, struct ap_matrix *matrix);
 
+int vfio_ap_set_new_guest_config(struct ap_matrix_mdev *matrix_mdev,
+				 struct ap_matrix *m_new);
+
 #endif /* _VFIO_AP_PRIVATE_H_ */
-- 
2.53.0