[PATCH v2 1/6] s390/vfio-ap: always filter entire AP matrix

[PATCH v2 1/6] s390/vfio-ap: always filter entire AP matrix

[Tony Krowiak]

The vfio_ap_mdev_filter_matrix function is called whenever a new adapter or
domain is assigned to the mdev. The purpose of the function is to update
the guest's AP configuration by filtering the matrix of adapters and
domains assigned to the mdev. When an adapter or domain is assigned, only
the APQNs associated with the APID of the new adapter or APQI of the new
domain are inspected. If an APQN does not reference a queue device bound to
the vfio_ap device driver, then it's APID will be filtered from the mdev's
matrix when updating the guest's AP configuration.

Inspecting only the APID of the new adapter or APQI of the new domain will
result in passing AP queues through to a guest that are not bound to the
vfio_ap device driver under certain circumstances. Consider the following:

guest's AP configuration (all also assigned to the mdev's matrix):
14.0004
14.0005
14.0006
16.0004
16.0005
16.0006

unassign domain 4
unbind queue 16.0005
assign domain 4

When domain 4 is re-assigned, since only domain 4 will be inspected, the
APQNs that will be examined will be:
14.0004
16.0004

Since both of those APQNs reference queue devices that are bound to the
vfio_ap device driver, nothing will get filtered from the mdev's matrix
when updating the guest's AP configuration. Consequently, queue 16.0005
will get passed through despite not being bound to the driver. This
violates the linux device model requirement that a guest shall only be
given access to devices bound to the device driver facilitating their
pass-through.

To resolve this problem, every adapter and domain assigned to the mdev will
be inspected when filtering the mdev's matrix.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: 48cae940c31d ("s390/vfio-ap: refresh guest's APCB by filtering AP resources assigned to mdev")
Cc: <stable@vger.kernel.org>
---
 drivers/s390/crypto/vfio_ap_ops.c | 57 +++++++++----------------------
 1 file changed, 17 insertions(+), 40 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 4db538a55192..9382b32e5bd1 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -670,8 +670,7 @@ static bool vfio_ap_mdev_filter_cdoms(struct ap_matrix_mdev *matrix_mdev)
  * Return: a boolean value indicating whether the KVM guest's APCB was changed
  *	   by the filtering or not.
  */
-static bool vfio_ap_mdev_filter_matrix(unsigned long *apm, unsigned long *aqm,
-				       struct ap_matrix_mdev *matrix_mdev)
+static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev)
 {
 	unsigned long apid, apqi, apqn;
 	DECLARE_BITMAP(prev_shadow_apm, AP_DEVICES);
@@ -692,8 +691,8 @@ static bool vfio_ap_mdev_filter_matrix(unsigned long *apm, unsigned long *aqm,
 	bitmap_and(matrix_mdev->shadow_apcb.aqm, matrix_mdev->matrix.aqm,
 		   (unsigned long *)matrix_dev->info.aqm, AP_DOMAINS);
 
-	for_each_set_bit_inv(apid, apm, AP_DEVICES) {
-		for_each_set_bit_inv(apqi, aqm, AP_DOMAINS) {
+	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
+		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
 			/*
 			 * If the APQN is not bound to the vfio_ap device
 			 * driver, then we can't assign it to the guest's
@@ -958,7 +957,6 @@ static ssize_t assign_adapter_store(struct device *dev,
 {
 	int ret;
 	unsigned long apid;
-	DECLARE_BITMAP(apm_delta, AP_DEVICES);
 	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&ap_perms_mutex);
@@ -987,11 +985,8 @@ static ssize_t assign_adapter_store(struct device *dev,
 	}
 
 	vfio_ap_mdev_link_adapter(matrix_mdev, apid);
-	memset(apm_delta, 0, sizeof(apm_delta));
-	set_bit_inv(apid, apm_delta);
 
-	if (vfio_ap_mdev_filter_matrix(apm_delta,
-				       matrix_mdev->matrix.aqm, matrix_mdev))
+	if (vfio_ap_mdev_filter_matrix(matrix_mdev))
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 
 	ret = count;
@@ -1167,7 +1162,6 @@ static ssize_t assign_domain_store(struct device *dev,
 {
 	int ret;
 	unsigned long apqi;
-	DECLARE_BITMAP(aqm_delta, AP_DOMAINS);
 	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&ap_perms_mutex);
@@ -1196,11 +1190,8 @@ static ssize_t assign_domain_store(struct device *dev,
 	}
 
 	vfio_ap_mdev_link_domain(matrix_mdev, apqi);
-	memset(aqm_delta, 0, sizeof(aqm_delta));
-	set_bit_inv(apqi, aqm_delta);
 
-	if (vfio_ap_mdev_filter_matrix(matrix_mdev->matrix.apm, aqm_delta,
-				       matrix_mdev))
+	if (vfio_ap_mdev_filter_matrix(matrix_mdev))
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 
 	ret = count;
@@ -2091,9 +2082,7 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
 	if (matrix_mdev) {
 		vfio_ap_mdev_link_queue(matrix_mdev, q);
 
-		if (vfio_ap_mdev_filter_matrix(matrix_mdev->matrix.apm,
-					       matrix_mdev->matrix.aqm,
-					       matrix_mdev))
+		if (vfio_ap_mdev_filter_matrix(matrix_mdev))
 			vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 	}
 	dev_set_drvdata(&apdev->device, q);
@@ -2443,34 +2432,22 @@ void vfio_ap_on_cfg_changed(struct ap_config_info *cur_cfg_info,
 
 static void vfio_ap_mdev_hot_plug_cfg(struct ap_matrix_mdev *matrix_mdev)
 {
-	bool do_hotplug = false;
-	int filter_domains = 0;
-	int filter_adapters = 0;
-	DECLARE_BITMAP(apm, AP_DEVICES);
-	DECLARE_BITMAP(aqm, AP_DOMAINS);
+	bool filter_domains, filter_adapters, filter_cdoms, do_hotplug = false;
 
 	mutex_lock(&matrix_mdev->kvm->lock);
 	mutex_lock(&matrix_dev->mdevs_lock);
 
-	filter_adapters = bitmap_and(apm, matrix_mdev->matrix.apm,
-				     matrix_mdev->apm_add, AP_DEVICES);
-	filter_domains = bitmap_and(aqm, matrix_mdev->matrix.aqm,
-				    matrix_mdev->aqm_add, AP_DOMAINS);
-
-	if (filter_adapters && filter_domains)
-		do_hotplug |= vfio_ap_mdev_filter_matrix(apm, aqm, matrix_mdev);
-	else if (filter_adapters)
-		do_hotplug |=
-			vfio_ap_mdev_filter_matrix(apm,
-						   matrix_mdev->shadow_apcb.aqm,
-						   matrix_mdev);
-	else
-		do_hotplug |=
-			vfio_ap_mdev_filter_matrix(matrix_mdev->shadow_apcb.apm,
-						   aqm, matrix_mdev);
+	filter_adapters = bitmap_intersects(matrix_mdev->matrix.apm,
+					    matrix_mdev->apm_add, AP_DEVICES);
+	filter_domains = bitmap_intersects(matrix_mdev->matrix.aqm,
+					   matrix_mdev->aqm_add, AP_DOMAINS);
+	filter_cdoms = bitmap_intersects(matrix_mdev->matrix.adm,
+					 matrix_mdev->adm_add, AP_DOMAINS);
+
+	if (filter_adapters || filter_domains)
+		do_hotplug = vfio_ap_mdev_filter_matrix(matrix_mdev);
 
-	if (bitmap_intersects(matrix_mdev->matrix.adm, matrix_mdev->adm_add,
-			      AP_DOMAINS))
+	if (filter_cdoms)
 		do_hotplug |= vfio_ap_mdev_filter_cdoms(matrix_mdev);
 
 	if (do_hotplug)
-- 
2.43.0

[PATCH v2 2/6] s390/vfio-ap: loop over the shadow APCB when filtering guest's AP configuration

[Tony Krowiak]

While filtering the mdev matrix, it doesn't make sense - and will have
unexpected results - to filter an APID from the matrix if the APID or one
of the associated APQIs is not in the host's AP configuration. There are
two reasons for this:

1. An adapter or domain that is not in the host's AP configuration can be
   assigned to the matrix; this is known as over-provisioning. Queue
   devices, however, are only created for adapters and domains in the
   host's AP configuration, so there will be no queues associated with an
   over-provisioned adapter or domain to filter.

2. The adapter or domain may have been externally removed from the host's
   configuration via an SE or HMC attached to a DPM enabled LPAR. In this
   case, the vfio_ap device driver would have been notified by the AP bus
   via the on_config_changed callback and the adapter or domain would
   have already been filtered.

Since the matrix_mdev->shadow_apcb.apm and matrix_mdev->shadow_apcb.aqm are
copied from the mdev matrix sans the APIDs and APQIs not in the host's AP
configuration, let's loop over those bitmaps instead of those assigned to
the matrix.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: 48cae940c31d ("s390/vfio-ap: refresh guest's APCB by filtering AP resources assigned to mdev")
Cc: <stable@vger.kernel.org>
---
 drivers/s390/crypto/vfio_ap_ops.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 9382b32e5bd1..47232e19a50e 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -691,8 +691,9 @@ static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev)
 	bitmap_and(matrix_mdev->shadow_apcb.aqm, matrix_mdev->matrix.aqm,
 		   (unsigned long *)matrix_dev->info.aqm, AP_DOMAINS);
 
-	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
-		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
+	for_each_set_bit_inv(apid, matrix_mdev->shadow_apcb.apm, AP_DEVICES) {
+		for_each_set_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm,
+				     AP_DOMAINS) {
 			/*
 			 * If the APQN is not bound to the vfio_ap device
 			 * driver, then we can't assign it to the guest's
-- 
2.43.0

[PATCH v2 4/6] s390/vfio-ap: reset queues filtered from the guest's AP config

[Tony Krowiak]

When filtering the adapters from the configuration profile for a guest to
create or update a guest's AP configuration, if the APID of an adapter and
the APQI of a domain identify a queue device that is not bound to the
vfio_ap device driver, the APID of the adapter will be filtered because an
individual APQN can not be filtered due to the fact the APQNs are assigned
to an AP configuration as a matrix of APIDs and APQIs. Consequently, a
guest will not have access to all of the queues associated with the
filtered adapter. If the queues are subsequently made available again to
the guest, they should re-appear in a reset state; so, let's make sure all
queues associated with an adapter unplugged from the guest are reset.

In order to identify the set of queues that need to be reset, let's allow a
vfio_ap_queue object to be simultaneously stored in both a hashtable and a
list: A hashtable used to store all of the queues assigned
to a matrix mdev; and/or, a list used to store a subset of the queues that
need to be reset. For example, when an adapter is hot unplugged from a
guest, all guest queues associated with that adapter must be reset. Since
that may be a subset of those assigned to the matrix mdev, they can be
stored in a list that can be passed to the vfio_ap_mdev_reset_queues
function.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: 48cae940c31d ("s390/vfio-ap: refresh guest's APCB by filtering AP resources assigned to mdev")
Cc: <stable@vger.kernel.org>
---
 drivers/s390/crypto/vfio_ap_ops.c     | 171 +++++++++++++++++++-------
 drivers/s390/crypto/vfio_ap_private.h |  11 +-
 2 files changed, 133 insertions(+), 49 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 26bd4aca497a..11f8f0bcc7ed 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -32,7 +32,8 @@
 
 #define AP_RESET_INTERVAL		20	/* Reset sleep interval (20ms)		*/
 
-static int vfio_ap_mdev_reset_queues(struct ap_queue_table *qtable);
+static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev);
+static int vfio_ap_mdev_reset_qlist(struct list_head *qlist);
 static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);
 static const struct vfio_device_ops vfio_ap_matrix_dev_ops;
 static void vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q);
@@ -661,16 +662,23 @@ static bool vfio_ap_mdev_filter_cdoms(struct ap_matrix_mdev *matrix_mdev)
  *				device driver.
  *
  * @matrix_mdev: the matrix mdev whose matrix is to be filtered.
+ * @apm_filtered: a 256-bit bitmap for storing the APIDs filtered from the
+ *		  guest's AP configuration that are still in the host's AP
+ *		  configuration.
  *
  * Note: If an APQN referencing a queue device that is not bound to the vfio_ap
  *	 driver, its APID will be filtered from the guest's APCB. The matrix
  *	 structure precludes filtering an individual APQN, so its APID will be
- *	 filtered.
+ *	 filtered. Consequently, all queues associated with the adapter that
+ *	 are in the host's AP configuration must be reset. If queues are
+ *	 subsequently made available again to the guest, they should re-appear
+ *	 in a reset state
  *
  * Return: a boolean value indicating whether the KVM guest's APCB was changed
  *	   by the filtering or not.
  */
-static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev)
+static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev,
+				       unsigned long *apm_filtered)
 {
 	unsigned long apid, apqi, apqn;
 	DECLARE_BITMAP(prev_shadow_apm, AP_DEVICES);
@@ -680,6 +688,7 @@ static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev)
 	bitmap_copy(prev_shadow_apm, matrix_mdev->shadow_apcb.apm, AP_DEVICES);
 	bitmap_copy(prev_shadow_aqm, matrix_mdev->shadow_apcb.aqm, AP_DOMAINS);
 	vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->shadow_apcb);
+	bitmap_clear(apm_filtered, 0, AP_DEVICES);
 
 	/*
 	 * Copy the adapters, domains and control domains to the shadow_apcb
@@ -705,8 +714,16 @@ static bool vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev *matrix_mdev)
 			apqn = AP_MKQID(apid, apqi);
 			q = vfio_ap_mdev_get_queue(matrix_mdev, apqn);
 			if (!q || q->reset_status.response_code) {
-				clear_bit_inv(apid,
-					      matrix_mdev->shadow_apcb.apm);
+				clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
+
+				/*
+				 * If the adapter was previously plugged into
+				 * the guest, let's let the caller know that
+				 * the APID was filtered.
+				 */
+				if (test_bit_inv(apid, prev_shadow_apm))
+					set_bit_inv(apid, apm_filtered);
+
 				break;
 			}
 		}
@@ -808,7 +825,7 @@ static void vfio_ap_mdev_remove(struct mdev_device *mdev)
 
 	mutex_lock(&matrix_dev->guests_lock);
 	mutex_lock(&matrix_dev->mdevs_lock);
-	vfio_ap_mdev_reset_queues(&matrix_mdev->qtable);
+	vfio_ap_mdev_reset_queues(matrix_mdev);
 	vfio_ap_mdev_unlink_fr_queues(matrix_mdev);
 	list_del(&matrix_mdev->node);
 	mutex_unlock(&matrix_dev->mdevs_lock);
@@ -918,6 +935,47 @@ static void vfio_ap_mdev_link_adapter(struct ap_matrix_mdev *matrix_mdev,
 				       AP_MKQID(apid, apqi));
 }
 
+static int reset_queues_for_apids(struct ap_matrix_mdev *matrix_mdev,
+				  unsigned long *apm_reset)
+{
+	struct vfio_ap_queue *q, *tmpq;
+	struct list_head qlist;
+	unsigned long apid, apqi;
+	int apqn, ret = 0;
+
+	if (bitmap_empty(apm_reset, AP_DEVICES))
+		return 0;
+
+	INIT_LIST_HEAD(&qlist);
+
+	for_each_set_bit_inv(apid, apm_reset, AP_DEVICES) {
+		for_each_set_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm,
+				     AP_DOMAINS) {
+			/*
+			 * If the domain is not in the host's AP configuration,
+			 * then resetting it will fail with response code 01
+			 * (APQN not valid).
+			 */
+			if (!test_bit_inv(apqi,
+					  (unsigned long *)matrix_dev->info.aqm))
+				continue;
+
+			apqn = AP_MKQID(apid, apqi);
+			q = vfio_ap_mdev_get_queue(matrix_mdev, apqn);
+
+			if (q)
+				list_add_tail(&q->reset_qnode, &qlist);
+		}
+	}
+
+	ret = vfio_ap_mdev_reset_qlist(&qlist);
+
+	list_for_each_entry_safe(q, tmpq, &qlist, reset_qnode)
+		list_del(&q->reset_qnode);
+
+	return ret;
+}
+
 /**
  * assign_adapter_store - parses the APID from @buf and sets the
  * corresponding bit in the mediated matrix device's APM
@@ -958,6 +1016,7 @@ static ssize_t assign_adapter_store(struct device *dev,
 {
 	int ret;
 	unsigned long apid;
+	DECLARE_BITMAP(apm_filtered, AP_DEVICES);
 	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&ap_perms_mutex);
@@ -987,8 +1046,10 @@ static ssize_t assign_adapter_store(struct device *dev,
 
 	vfio_ap_mdev_link_adapter(matrix_mdev, apid);
 
-	if (vfio_ap_mdev_filter_matrix(matrix_mdev))
+	if (vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered)) {
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+		reset_queues_for_apids(matrix_mdev, apm_filtered);
+	}
 
 	ret = count;
 done:
@@ -1019,11 +1080,12 @@ static struct vfio_ap_queue
  *				 adapter was assigned.
  * @matrix_mdev: the matrix mediated device to which the adapter was assigned.
  * @apid: the APID of the unassigned adapter.
- * @qtable: table for storing queues associated with unassigned adapter.
+ * @qlist: list for storing queues associated with unassigned adapter that
+ *	   need to be reset.
  */
 static void vfio_ap_mdev_unlink_adapter(struct ap_matrix_mdev *matrix_mdev,
 					unsigned long apid,
-					struct ap_queue_table *qtable)
+					struct list_head *qlist)
 {
 	unsigned long apqi;
 	struct vfio_ap_queue *q;
@@ -1031,11 +1093,10 @@ static void vfio_ap_mdev_unlink_adapter(struct ap_matrix_mdev *matrix_mdev,
 	for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
 		q = vfio_ap_unlink_apqn_fr_mdev(matrix_mdev, apid, apqi);
 
-		if (q && qtable) {
+		if (q && qlist) {
 			if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm) &&
 			    test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm))
-				hash_add(qtable->queues, &q->mdev_qnode,
-					 q->apqn);
+				list_add_tail(&q->reset_qnode, qlist);
 		}
 	}
 }
@@ -1043,26 +1104,23 @@ 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)
 {
-	int loop_cursor;
-	struct vfio_ap_queue *q;
-	struct ap_queue_table *qtable = kzalloc(sizeof(*qtable), GFP_KERNEL);
+	struct vfio_ap_queue *q, *tmpq;
+	struct list_head qlist;
 
-	hash_init(qtable->queues);
-	vfio_ap_mdev_unlink_adapter(matrix_mdev, apid, qtable);
+	INIT_LIST_HEAD(&qlist);
+	vfio_ap_mdev_unlink_adapter(matrix_mdev, apid, &qlist);
 
 	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);
+	vfio_ap_mdev_reset_qlist(&qlist);
 
-	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
+	list_for_each_entry_safe(q, tmpq, &qlist, reset_qnode) {
 		vfio_ap_unlink_mdev_fr_queue(q);
-		hash_del(&q->mdev_qnode);
+		list_del(&q->reset_qnode);
 	}
-
-	kfree(qtable);
 }
 
 /**
@@ -1163,6 +1221,7 @@ static ssize_t assign_domain_store(struct device *dev,
 {
 	int ret;
 	unsigned long apqi;
+	DECLARE_BITMAP(apm_filtered, AP_DEVICES);
 	struct ap_matrix_mdev *matrix_mdev = dev_get_drvdata(dev);
 
 	mutex_lock(&ap_perms_mutex);
@@ -1192,8 +1251,10 @@ static ssize_t assign_domain_store(struct device *dev,
 
 	vfio_ap_mdev_link_domain(matrix_mdev, apqi);
 
-	if (vfio_ap_mdev_filter_matrix(matrix_mdev))
+	if (vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered)) {
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+		reset_queues_for_apids(matrix_mdev, apm_filtered);
+	}
 
 	ret = count;
 done:
@@ -1206,7 +1267,7 @@ static DEVICE_ATTR_WO(assign_domain);
 
 static void vfio_ap_mdev_unlink_domain(struct ap_matrix_mdev *matrix_mdev,
 				       unsigned long apqi,
-				       struct ap_queue_table *qtable)
+				       struct list_head *qlist)
 {
 	unsigned long apid;
 	struct vfio_ap_queue *q;
@@ -1214,11 +1275,10 @@ static void vfio_ap_mdev_unlink_domain(struct ap_matrix_mdev *matrix_mdev,
 	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
 		q = vfio_ap_unlink_apqn_fr_mdev(matrix_mdev, apid, apqi);
 
-		if (q && qtable) {
+		if (q && qlist) {
 			if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm) &&
 			    test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm))
-				hash_add(qtable->queues, &q->mdev_qnode,
-					 q->apqn);
+				list_add_tail(&q->reset_qnode, qlist);
 		}
 	}
 }
@@ -1226,26 +1286,23 @@ 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)
 {
-	int loop_cursor;
-	struct vfio_ap_queue *q;
-	struct ap_queue_table *qtable = kzalloc(sizeof(*qtable), GFP_KERNEL);
+	struct vfio_ap_queue *q, *tmpq;
+	struct list_head qlist;
 
-	hash_init(qtable->queues);
-	vfio_ap_mdev_unlink_domain(matrix_mdev, apqi, qtable);
+	INIT_LIST_HEAD(&qlist);
+	vfio_ap_mdev_unlink_domain(matrix_mdev, apqi, &qlist);
 
 	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);
+	vfio_ap_mdev_reset_qlist(&qlist);
 
-	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
+	list_for_each_entry_safe(q, tmpq, &qlist, reset_qnode) {
 		vfio_ap_unlink_mdev_fr_queue(q);
-		hash_del(&q->mdev_qnode);
+		list_del(&q->reset_qnode);
 	}
-
-	kfree(qtable);
 }
 
 /**
@@ -1600,7 +1657,7 @@ static void vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev)
 		get_update_locks_for_kvm(kvm);
 
 		kvm_arch_crypto_clear_masks(kvm);
-		vfio_ap_mdev_reset_queues(&matrix_mdev->qtable);
+		vfio_ap_mdev_reset_queues(matrix_mdev);
 		kvm_put_kvm(kvm);
 		matrix_mdev->kvm = NULL;
 
@@ -1736,15 +1793,33 @@ static void vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q)
 	}
 }
 
-static int vfio_ap_mdev_reset_queues(struct ap_queue_table *qtable)
+static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev)
 {
 	int ret = 0, loop_cursor;
 	struct vfio_ap_queue *q;
 
-	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode)
+	hash_for_each(matrix_mdev->qtable.queues, loop_cursor, q, mdev_qnode)
 		vfio_ap_mdev_reset_queue(q);
 
-	hash_for_each(qtable->queues, loop_cursor, q, mdev_qnode) {
+	hash_for_each(matrix_mdev->qtable.queues, loop_cursor, q, mdev_qnode) {
+		flush_work(&q->reset_work);
+
+		if (q->reset_status.response_code)
+			ret = -EIO;
+	}
+
+	return ret;
+}
+
+static int vfio_ap_mdev_reset_qlist(struct list_head *qlist)
+{
+	int ret = 0;
+	struct vfio_ap_queue *q;
+
+	list_for_each_entry(q, qlist, reset_qnode)
+		vfio_ap_mdev_reset_queue(q);
+
+	list_for_each_entry(q, qlist, reset_qnode) {
 		flush_work(&q->reset_work);
 
 		if (q->reset_status.response_code)
@@ -1930,7 +2005,7 @@ static ssize_t vfio_ap_mdev_ioctl(struct vfio_device *vdev,
 		ret = vfio_ap_mdev_get_device_info(arg);
 		break;
 	case VFIO_DEVICE_RESET:
-		ret = vfio_ap_mdev_reset_queues(&matrix_mdev->qtable);
+		ret = vfio_ap_mdev_reset_queues(matrix_mdev);
 		break;
 	case VFIO_DEVICE_GET_IRQ_INFO:
 			ret = vfio_ap_get_irq_info(arg);
@@ -2062,6 +2137,7 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
 {
 	int ret;
 	struct vfio_ap_queue *q;
+	DECLARE_BITMAP(apm_filtered, AP_DEVICES);
 	struct ap_matrix_mdev *matrix_mdev;
 
 	ret = sysfs_create_group(&apdev->device.kobj, &vfio_queue_attr_group);
@@ -2094,15 +2170,17 @@ int vfio_ap_mdev_probe_queue(struct ap_device *apdev)
 		    !bitmap_empty(matrix_mdev->aqm_add, AP_DOMAINS))
 			goto done;
 
-		if (vfio_ap_mdev_filter_matrix(matrix_mdev))
+		if (vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered)) {
 			vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+			reset_queues_for_apids(matrix_mdev, apm_filtered);
+		}
 	}
 
 done:
 	dev_set_drvdata(&apdev->device, q);
 	release_update_locks_for_mdev(matrix_mdev);
 
-	return 0;
+	return ret;
 
 err_remove_group:
 	sysfs_remove_group(&apdev->device.kobj, &vfio_queue_attr_group);
@@ -2446,6 +2524,7 @@ void vfio_ap_on_cfg_changed(struct ap_config_info *cur_cfg_info,
 
 static void vfio_ap_mdev_hot_plug_cfg(struct ap_matrix_mdev *matrix_mdev)
 {
+	DECLARE_BITMAP(apm_filtered, AP_DEVICES);
 	bool filter_domains, filter_adapters, filter_cdoms, do_hotplug = false;
 
 	mutex_lock(&matrix_mdev->kvm->lock);
@@ -2459,7 +2538,7 @@ static void vfio_ap_mdev_hot_plug_cfg(struct ap_matrix_mdev *matrix_mdev)
 					 matrix_mdev->adm_add, AP_DOMAINS);
 
 	if (filter_adapters || filter_domains)
-		do_hotplug = vfio_ap_mdev_filter_matrix(matrix_mdev);
+		do_hotplug = vfio_ap_mdev_filter_matrix(matrix_mdev, apm_filtered);
 
 	if (filter_cdoms)
 		do_hotplug |= vfio_ap_mdev_filter_cdoms(matrix_mdev);
@@ -2467,6 +2546,8 @@ static void vfio_ap_mdev_hot_plug_cfg(struct ap_matrix_mdev *matrix_mdev)
 	if (do_hotplug)
 		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
 
+	reset_queues_for_apids(matrix_mdev, apm_filtered);
+
 	mutex_unlock(&matrix_dev->mdevs_lock);
 	mutex_unlock(&matrix_mdev->kvm->lock);
 }
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 88aff8b81f2f..20eac8b0f0b9 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -83,10 +83,10 @@ struct ap_matrix {
 };
 
 /**
- * struct ap_queue_table - a table of queue objects.
- *
- * @queues: a hashtable of queues (struct vfio_ap_queue).
- */
+  * struct ap_queue_table - a table of queue objects.
+  *
+  * @queues: a hashtable of queues (struct vfio_ap_queue).
+  */
 struct ap_queue_table {
 	DECLARE_HASHTABLE(queues, 8);
 };
@@ -133,6 +133,8 @@ struct ap_matrix_mdev {
  * @apqn: the APQN of the AP queue device
  * @saved_isc: the guest ISC registered with the GIB interface
  * @mdev_qnode: allows the vfio_ap_queue struct to be added to a hashtable
+ * @reset_qnode: allows the vfio_ap_queue struct to be added to a list of queues
+ *		 that need to be reset
  * @reset_status: the status from the last reset of the queue
  * @reset_work: work to wait for queue reset to complete
  */
@@ -143,6 +145,7 @@ struct vfio_ap_queue {
 #define VFIO_AP_ISC_INVALID 0xff
 	unsigned char saved_isc;
 	struct hlist_node mdev_qnode;
+	struct list_head reset_qnode;
 	struct ap_queue_status reset_status;
 	struct work_struct reset_work;
 };
-- 
2.43.0

[PATCH v2 5/6] s390/vfio-ap: reset queues associated with adapter for queue unbound from driver

[Tony Krowiak]

When a queue is unbound from the vfio_ap device driver, if that queue is
assigned to a guest's AP configuration, its associated adapter is removed
because queues are defined to a guest via a matrix of adapters and
domains; so, it is not possible to remove a single queue.

If an adapter is removed from the guest's AP configuration, all associated
queues must be reset to prevent leaking crypto data should any of them be
assigned to a different guest or device driver. The one caveat is that if
the queue is being removed because the adapter or domain has been removed
from the host's AP configuration, then an attempt to reset the queue will
fail with response code 01, AP-queue number not valid; so resetting these
queues should be skipped.
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Fixes: 09d31ff78793 ("s390/vfio-ap: hot plug/unplug of AP devices when probed/removed")
Cc: <stable@vger.kernel.org>
---
 drivers/s390/crypto/vfio_ap_ops.c | 78 ++++++++++++++++---------------
 1 file changed, 41 insertions(+), 37 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 11f8f0bcc7ed..e014108067dc 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -935,45 +935,45 @@ static void vfio_ap_mdev_link_adapter(struct ap_matrix_mdev *matrix_mdev,
 				       AP_MKQID(apid, apqi));
 }
 
+static void collect_queues_to_reset(struct ap_matrix_mdev *matrix_mdev,
+				    unsigned long apid,
+				    struct list_head *qlist)
+{
+	struct vfio_ap_queue *q;
+	unsigned long  apqi;
+
+	for_each_set_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm, AP_DOMAINS) {
+		q = vfio_ap_mdev_get_queue(matrix_mdev, AP_MKQID(apid, apqi));
+		if (q)
+			list_add_tail(&q->reset_qnode, qlist);
+	}
+}
+
+static void reset_queues_for_apid(struct ap_matrix_mdev *matrix_mdev,
+				  unsigned long apid)
+{
+	struct list_head qlist;
+
+	INIT_LIST_HEAD(&qlist);
+	collect_queues_to_reset(matrix_mdev, apid, &qlist);
+	vfio_ap_mdev_reset_qlist(&qlist);
+}
+
 static int reset_queues_for_apids(struct ap_matrix_mdev *matrix_mdev,
 				  unsigned long *apm_reset)
 {
-	struct vfio_ap_queue *q, *tmpq;
 	struct list_head qlist;
-	unsigned long apid, apqi;
-	int apqn, ret = 0;
+	unsigned long apid;
 
 	if (bitmap_empty(apm_reset, AP_DEVICES))
 		return 0;
 
 	INIT_LIST_HEAD(&qlist);
 
-	for_each_set_bit_inv(apid, apm_reset, AP_DEVICES) {
-		for_each_set_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm,
-				     AP_DOMAINS) {
-			/*
-			 * If the domain is not in the host's AP configuration,
-			 * then resetting it will fail with response code 01
-			 * (APQN not valid).
-			 */
-			if (!test_bit_inv(apqi,
-					  (unsigned long *)matrix_dev->info.aqm))
-				continue;
-
-			apqn = AP_MKQID(apid, apqi);
-			q = vfio_ap_mdev_get_queue(matrix_mdev, apqn);
-
-			if (q)
-				list_add_tail(&q->reset_qnode, &qlist);
-		}
-	}
+	for_each_set_bit_inv(apid, apm_reset, AP_DEVICES)
+		collect_queues_to_reset(matrix_mdev, apid, &qlist);
 
-	ret = vfio_ap_mdev_reset_qlist(&qlist);
-
-	list_for_each_entry_safe(q, tmpq, &qlist, reset_qnode)
-		list_del(&q->reset_qnode);
-
-	return ret;
+	return vfio_ap_mdev_reset_qlist(&qlist);
 }
 
 /**
@@ -2199,24 +2199,28 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
 	matrix_mdev = q->matrix_mdev;
 
 	if (matrix_mdev) {
-		vfio_ap_unlink_queue_fr_mdev(q);
-
-		apid = AP_QID_CARD(q->apqn);
-		apqi = AP_QID_QUEUE(q->apqn);
-
-		/*
-		 * If the queue is assigned to the guest's APCB, then remove
-		 * the adapter's APID from the APCB and hot it into the guest.
-		 */
+		/* If the queue is assigned to the guest's AP configuration */
 		if (test_bit_inv(apid, matrix_mdev->shadow_apcb.apm) &&
 		    test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm)) {
+			/*
+			 * Since the queues are defined via a matrix of adapters
+			 * and domains, it is not possible to hot unplug a
+			 * single queue; so, let's unplug the adapter.
+			 */
 			clear_bit_inv(apid, matrix_mdev->shadow_apcb.apm);
 			vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+			reset_queues_for_apid(matrix_mdev, apid);
+			goto done;
 		}
 	}
 
 	vfio_ap_mdev_reset_queue(q);
 	flush_work(&q->reset_work);
+
+done:
+	if (matrix_mdev)
+		vfio_ap_unlink_queue_fr_mdev(q);
+
 	dev_set_drvdata(&apdev->device, NULL);
 	kfree(q);
 	release_update_locks_for_mdev(matrix_mdev);
-- 
2.43.0

[PATCH v2 6/6] s390/vfio-ap: do not reset queue removed from host config

[Tony Krowiak]

When a queue is unbound from the vfio_ap device driver, it is reset to
ensure its crypto data is not leaked when it is bound to another device
driver. If the queue is unbound due to the fact that the adapter or domain
was removed from the host's AP configuration, then attempting to reset it
will fail with response code 01 (APID not valid) getting returned from the
reset command. Let's ensure that the queue is assigned to the host's
configuration before resetting it.

Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Fixes: eeb386aeb5b7 ("s390/vfio-ap: handle config changed and scan complete notification")
Cc: <stable@vger.kernel.org>
---
 drivers/s390/crypto/vfio_ap_ops.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index e014108067dc..84decb0d5c97 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -2197,6 +2197,8 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
 	q = dev_get_drvdata(&apdev->device);
 	get_update_locks_for_queue(q);
 	matrix_mdev = q->matrix_mdev;
+	apid = AP_QID_CARD(q->apqn);
+	apqi = AP_QID_QUEUE(q->apqn);
 
 	if (matrix_mdev) {
 		/* If the queue is assigned to the guest's AP configuration */
@@ -2214,8 +2216,16 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
 		}
 	}
 
-	vfio_ap_mdev_reset_queue(q);
-	flush_work(&q->reset_work);
+	/*
+	 * If the queue is not in the host's AP configuration, then resetting
+	 * it will fail with response code 01, (APQN not valid); so, let's make
+	 * sure it is in the host's config.
+	 */
+	if (test_bit_inv(apid, (unsigned long *)matrix_dev->info.apm) &&
+	    test_bit_inv(apqi, (unsigned long *)matrix_dev->info.aqm)) {
+		vfio_ap_mdev_reset_queue(q);
+		flush_work(&q->reset_work);
+	}
 
 done:
 	if (matrix_mdev)
-- 
2.43.0

Re: [PATCH v2 6/6] s390/vfio-ap: do not reset queue removed from host config

[Jason J. Herne]

On 12/12/23 4:25 PM, Tony Krowiak wrote:
> When a queue is unbound from the vfio_ap device driver, it is reset to
> ensure its crypto data is not leaked when it is bound to another device
> driver. If the queue is unbound due to the fact that the adapter or domain
> was removed from the host's AP configuration, then attempting to reset it
> will fail with response code 01 (APID not valid) getting returned from the
> reset command. Let's ensure that the queue is assigned to the host's
> configuration before resetting it.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Fixes: eeb386aeb5b7 ("s390/vfio-ap: handle config changed and scan complete notification")
> Cc: <stable@vger.kernel.org>
> ---
>   drivers/s390/crypto/vfio_ap_ops.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index e014108067dc..84decb0d5c97 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -2197,6 +2197,8 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
>   	q = dev_get_drvdata(&apdev->device);
>   	get_update_locks_for_queue(q);
>   	matrix_mdev = q->matrix_mdev;
> +	apid = AP_QID_CARD(q->apqn);
> +	apqi = AP_QID_QUEUE(q->apqn);
>   
>   	if (matrix_mdev) {
>   		/* If the queue is assigned to the guest's AP configuration */
> @@ -2214,8 +2216,16 @@ void vfio_ap_mdev_remove_queue(struct ap_device *apdev)
>   		}
>   	}
>   
> -	vfio_ap_mdev_reset_queue(q);
> -	flush_work(&q->reset_work);
> +	/*
> +	 * If the queue is not in the host's AP configuration, then resetting
> +	 * it will fail with response code 01, (APQN not valid); so, let's make
> +	 * sure it is in the host's config.
> +	 */
> +	if (test_bit_inv(apid, (unsigned long *)matrix_dev->info.apm) &&
> +	    test_bit_inv(apqi, (unsigned long *)matrix_dev->info.aqm)) {
> +		vfio_ap_mdev_reset_queue(q);
> +		flush_work(&q->reset_work);
> +	}
>   
>   done:
>   	if (matrix_mdev)

Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>

Re: [PATCH v2 6/6] s390/vfio-ap: do not reset queue removed from host config

[Halil Pasic]

On Tue, 12 Dec 2023 16:25:17 -0500
Tony Krowiak <akrowiak@linux.ibm.com> wrote:

> When a queue is unbound from the vfio_ap device driver, it is reset to
> ensure its crypto data is not leaked when it is bound to another device
> driver. If the queue is unbound due to the fact that the adapter or domain
> was removed from the host's AP configuration, then attempting to reset it
> will fail with response code 01 (APID not valid) getting returned from the
> reset command. Let's ensure that the queue is assigned to the host's
> configuration before resetting it.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>

Reviewed-by: Halil Pasic <pasic@linux.ibm.com>