[PATCH v20 17/20] s390/vfio-ap: handle config changed and scan complete notification

[Tony Krowiak]

This patch implements two new AP driver callbacks:

void (*on_config_changed)(struct ap_config_info *new_config_info,
                  struct ap_config_info *old_config_info);

void (*on_scan_complete)(struct ap_config_info *new_config_info,
                 struct ap_config_info *old_config_info);

The on_config_changed callback is invoked at the start of the AP bus scan
function when it determines that the host AP configuration information
has changed since the previous scan.

The vfio_ap device driver registers a callback function for this callback
that performs the following operations:

1. Unplugs the adapters, domains and control domains removed from the
host's AP configuration from the guests to which they are
assigned in a single operation.

2. Stores bitmaps identifying the adapters, domains and control domains
added to the host's AP configuration with the structure representing
the mediated device. When the vfio_ap device driver's probe callback is
subsequently invoked, the probe function will recognize that the
queue is being probed due to a change in the host's AP configuration
and the plugging of the queue into the guest will be bypassed.

The on_scan_complete callback is invoked after the ap bus scan is
completed if the host AP configuration data has changed. The vfio_ap
device driver registers a callback function for this callback that hot
plugs each queue and control domain added to the AP configuration for each
guest using them in a single hot plug operation.

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxx>
Reviewed-by: Jason J. Herne <jjherne@xxxxxxxxxxxxx>
---
 drivers/s390/crypto/vfio_ap_drv.c     |   2 +
 drivers/s390/crypto/vfio_ap_ops.c     | 341 +++++++++++++++++++++++++-
 drivers/s390/crypto/vfio_ap_private.h |  12 +
 3 files changed, 350 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c
index 2572fb0f0f54..f43cfeabd2cc 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -47,6 +47,8 @@ static struct ap_driver vfio_ap_drv = {
 	.probe = vfio_ap_mdev_probe_queue,
 	.remove = vfio_ap_mdev_remove_queue,
 	.in_use = vfio_ap_mdev_resource_in_use,
+	.on_config_changed = vfio_ap_on_cfg_changed,
+	.on_scan_complete = vfio_ap_on_scan_complete,
 	.ids = ap_queue_ids,
 };
 
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 41fc2072a77b..f6ad61f324a6 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -641,16 +641,11 @@ static bool vfio_ap_mdev_filter_cdoms(struct ap_matrix_mdev *matrix_mdev)
 static bool vfio_ap_mdev_filter_matrix(unsigned long *apm, unsigned long *aqm,
 				       struct ap_matrix_mdev *matrix_mdev)
 {
-	int ret;
 	unsigned long apid, apqi, apqn;
 	DECLARE_BITMAP(prev_shadow_apm, AP_DEVICES);
 	DECLARE_BITMAP(prev_shadow_aqm, AP_DOMAINS);
 	struct vfio_ap_queue *q;
 
-	ret = ap_qci(&matrix_dev->info);
-	if (ret)
-		return false;
-
 	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);
@@ -1975,3 +1970,339 @@ int vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm)
 
 	return ret;
 }
+
+/**
+ * vfio_ap_mdev_hot_unplug_cfg - hot unplug the adapters, domains and control
+ *				 domains that have been removed from the host's
+ *				 AP configuration from a guest.
+ *
+ * @matrix_mdev: an ap_matrix_mdev object attached to a KVM guest.
+ * @aprem: the adapters that have been removed from the host's AP configuration
+ * @aqrem: the domains that have been removed from the host's AP configuration
+ * @cdrem: the control domains that have been removed from the host's AP
+ *	   configuration.
+ */
+static void vfio_ap_mdev_hot_unplug_cfg(struct ap_matrix_mdev *matrix_mdev,
+					unsigned long *aprem,
+					unsigned long *aqrem,
+					unsigned long *cdrem)
+{
+	int do_hotplug = 0;
+
+	if (!bitmap_empty(aprem, AP_DEVICES)) {
+		do_hotplug |= bitmap_andnot(matrix_mdev->shadow_apcb.apm,
+					    matrix_mdev->shadow_apcb.apm,
+					    aprem, AP_DEVICES);
+	}
+
+	if (!bitmap_empty(aqrem, AP_DOMAINS)) {
+		do_hotplug |= bitmap_andnot(matrix_mdev->shadow_apcb.aqm,
+					    matrix_mdev->shadow_apcb.aqm,
+					    aqrem, AP_DEVICES);
+	}
+
+	if (!bitmap_empty(cdrem, AP_DOMAINS))
+		do_hotplug |= bitmap_andnot(matrix_mdev->shadow_apcb.adm,
+					    matrix_mdev->shadow_apcb.adm,
+					    cdrem, AP_DOMAINS);
+
+	if (do_hotplug)
+		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+}
+
+/**
+ * vfio_ap_mdev_cfg_remove - determines which guests are using the adapters,
+ *			     domains and control domains that have been removed
+ *			     from the host AP configuration and unplugs them
+ *			     from those guests.
+ *
+ * @ap_remove:	bitmap specifying which adapters have been removed from the host
+ *		config.
+ * @aq_remove:	bitmap specifying which domains have been removed from the host
+ *		config.
+ * @cd_remove:	bitmap specifying which control domains have been removed from
+ *		the host config.
+ */
+static void vfio_ap_mdev_cfg_remove(unsigned long *ap_remove,
+				    unsigned long *aq_remove,
+				    unsigned long *cd_remove)
+{
+	struct ap_matrix_mdev *matrix_mdev;
+	DECLARE_BITMAP(aprem, AP_DEVICES);
+	DECLARE_BITMAP(aqrem, AP_DOMAINS);
+	DECLARE_BITMAP(cdrem, AP_DOMAINS);
+	int do_remove = 0;
+
+	list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
+		mutex_lock(&matrix_mdev->kvm->lock);
+		mutex_lock(&matrix_dev->mdevs_lock);
+
+		do_remove |= bitmap_and(aprem, ap_remove,
+					  matrix_mdev->matrix.apm,
+					  AP_DEVICES);
+		do_remove |= bitmap_and(aqrem, aq_remove,
+					  matrix_mdev->matrix.aqm,
+					  AP_DOMAINS);
+		do_remove |= bitmap_andnot(cdrem, cd_remove,
+					     matrix_mdev->matrix.adm,
+					     AP_DOMAINS);
+
+		if (do_remove)
+			vfio_ap_mdev_hot_unplug_cfg(matrix_mdev, aprem, aqrem,
+						    cdrem);
+
+		mutex_unlock(&matrix_dev->mdevs_lock);
+		mutex_unlock(&matrix_mdev->kvm->lock);
+	}
+}
+
+/**
+ * vfio_ap_mdev_on_cfg_remove - responds to the removal of adapters, domains and
+ *				control domains from the host AP configuration
+ *				by unplugging them from the guests that are
+ *				using them.
+ * @cur_config_info: the current host AP configuration information
+ * @prev_config_info: the previous host AP configuration information
+ */
+static void vfio_ap_mdev_on_cfg_remove(struct ap_config_info *cur_config_info,
+				       struct ap_config_info *prev_config_info)
+{
+	int do_remove;
+	DECLARE_BITMAP(aprem, AP_DEVICES);
+	DECLARE_BITMAP(aqrem, AP_DOMAINS);
+	DECLARE_BITMAP(cdrem, AP_DOMAINS);
+
+	do_remove = bitmap_andnot(aprem,
+				  (unsigned long *)prev_config_info->apm,
+				  (unsigned long *)cur_config_info->apm,
+				  AP_DEVICES);
+	do_remove |= bitmap_andnot(aqrem,
+				   (unsigned long *)prev_config_info->aqm,
+				   (unsigned long *)cur_config_info->aqm,
+				   AP_DEVICES);
+	do_remove |= bitmap_andnot(cdrem,
+				   (unsigned long *)prev_config_info->adm,
+				   (unsigned long *)cur_config_info->adm,
+				   AP_DEVICES);
+
+	if (do_remove)
+		vfio_ap_mdev_cfg_remove(aprem, aqrem, cdrem);
+}
+
+/**
+ * vfio_ap_filter_apid_by_qtype: filter APIDs from an AP mask for adapters that
+ *				 are older than AP type 10 (CEX4).
+ * @apm: a bitmap of the APIDs to examine
+ * @aqm: a bitmap of the APQIs of the queues to query for the AP type.
+ */
+static void vfio_ap_filter_apid_by_qtype(unsigned long *apm, unsigned long *aqm)
+{
+	bool apid_cleared;
+	struct ap_queue_status status;
+	unsigned long apid, apqi, info;
+	int qtype, qtype_mask = 0xff000000;
+
+	for_each_set_bit_inv(apid, apm, AP_DEVICES) {
+		apid_cleared = false;
+
+		for_each_set_bit_inv(apqi, aqm, AP_DOMAINS) {
+			status = ap_test_queue(AP_MKQID(apid, apqi), 1, &info);
+			switch (status.response_code) {
+			/*
+			 * According to the architecture in each case
+			 * below, the queue's info should be filled.
+			 */
+			case AP_RESPONSE_NORMAL:
+			case AP_RESPONSE_RESET_IN_PROGRESS:
+			case AP_RESPONSE_DECONFIGURED:
+			case AP_RESPONSE_CHECKSTOPPED:
+			case AP_RESPONSE_BUSY:
+				qtype = info & qtype_mask;
+
+				/*
+				 * The vfio_ap device driver only
+				 * supports CEX4 and newer adapters, so
+				 * remove the APID if the adapter is
+				 * older than a CEX4.
+				 */
+				if (qtype < AP_DEVICE_TYPE_CEX4) {
+					clear_bit_inv(apid, apm);
+					apid_cleared = true;
+				}
+
+				break;
+
+			default:
+				/*
+				 * If we don't know the adapter type,
+				 * clear its APID since it can't be
+				 * determined whether the vfio_ap
+				 * device driver supports it.
+				 */
+				clear_bit_inv(apid, apm);
+				apid_cleared = true;
+				break;
+			}
+
+			/*
+			 * If we've already cleared the APID from the apm, there
+			 * is no need to continue examining the remainin AP
+			 * queues to determine the type of the adapter.
+			 */
+			if (apid_cleared)
+				continue;
+		}
+	}
+}
+
+/**
+ * vfio_ap_mdev_cfg_add - store bitmaps specifying the adapters, domains and
+ *			  control domains that have been added to the host's
+ *			  AP configuration for each matrix mdev to which they
+ *			  are assigned.
+ *
+ * @apm_add: a bitmap specifying the adapters that have been added to the AP
+ *	     configuration.
+ * @aqm_add: a bitmap specifying the domains that have been added to the AP
+ *	     configuration.
+ * @adm_add: a bitmap specifying the control domains that have been added to the
+ *	     AP configuration.
+ */
+static void vfio_ap_mdev_cfg_add(unsigned long *apm_add, unsigned long *aqm_add,
+				 unsigned long *adm_add)
+{
+	struct ap_matrix_mdev *matrix_mdev;
+
+	if (list_empty(&matrix_dev->mdev_list))
+		return;
+
+	vfio_ap_filter_apid_by_qtype(apm_add, aqm_add);
+
+	list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
+		bitmap_and(matrix_mdev->apm_add,
+			   matrix_mdev->matrix.apm, apm_add, AP_DEVICES);
+		bitmap_and(matrix_mdev->aqm_add,
+			   matrix_mdev->matrix.aqm, aqm_add, AP_DOMAINS);
+		bitmap_and(matrix_mdev->adm_add,
+			   matrix_mdev->matrix.adm, adm_add, AP_DEVICES);
+	}
+}
+
+/**
+ * vfio_ap_mdev_on_cfg_add - responds to the addition of adapters, domains and
+ *			     control domains to the host AP configuration
+ *			     by updating the bitmaps that specify what adapters,
+ *			     domains and control domains have been added so they
+ *			     can be hot plugged into the guest when the AP bus
+ *			     scan completes (see vfio_ap_on_scan_complete
+ *			     function).
+ * @cur_config_info: the current AP configuration information
+ * @prev_config_info: the previous AP configuration information
+ */
+static void vfio_ap_mdev_on_cfg_add(struct ap_config_info *cur_config_info,
+				    struct ap_config_info *prev_config_info)
+{
+	bool do_add;
+	DECLARE_BITMAP(apm_add, AP_DEVICES);
+	DECLARE_BITMAP(aqm_add, AP_DOMAINS);
+	DECLARE_BITMAP(adm_add, AP_DOMAINS);
+
+	do_add = bitmap_andnot(apm_add,
+			       (unsigned long *)cur_config_info->apm,
+			       (unsigned long *)prev_config_info->apm,
+			       AP_DEVICES);
+	do_add |= bitmap_andnot(aqm_add,
+				(unsigned long *)cur_config_info->aqm,
+				(unsigned long *)prev_config_info->aqm,
+				AP_DOMAINS);
+	do_add |= bitmap_andnot(adm_add,
+				(unsigned long *)cur_config_info->adm,
+				(unsigned long *)prev_config_info->adm,
+				AP_DOMAINS);
+
+	if (do_add)
+		vfio_ap_mdev_cfg_add(apm_add, aqm_add, adm_add);
+}
+
+/**
+ * vfio_ap_on_cfg_changed - handles notification of changes to the host AP
+ *			    configuration.
+ *
+ * @cur_cfg_info: the current host AP configuration
+ * @prev_cfg_info: the previous host AP configuration
+ */
+void vfio_ap_on_cfg_changed(struct ap_config_info *cur_cfg_info,
+			    struct ap_config_info *prev_cfg_info)
+{
+	if (!cur_cfg_info || !prev_cfg_info)
+		return;
+
+	mutex_lock(&matrix_dev->guests_lock);
+
+	vfio_ap_mdev_on_cfg_remove(cur_cfg_info, prev_cfg_info);
+	vfio_ap_mdev_on_cfg_add(cur_cfg_info, prev_cfg_info);
+	memcpy(&matrix_dev->info, cur_cfg_info, sizeof(*cur_cfg_info));
+
+	mutex_unlock(&matrix_dev->guests_lock);
+}
+
+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);
+
+	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);
+
+	if (bitmap_intersects(matrix_mdev->matrix.adm, matrix_mdev->adm_add,
+			      AP_DOMAINS))
+		do_hotplug |= vfio_ap_mdev_filter_cdoms(matrix_mdev);
+
+	if (do_hotplug)
+		vfio_ap_mdev_update_guest_apcb(matrix_mdev);
+
+	mutex_unlock(&matrix_dev->mdevs_lock);
+	mutex_unlock(&matrix_mdev->kvm->lock);
+}
+
+void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
+			      struct ap_config_info *old_config_info)
+{
+	struct ap_matrix_mdev *matrix_mdev;
+
+	mutex_lock(&matrix_dev->guests_lock);
+
+	list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
+		if (bitmap_empty(matrix_mdev->apm_add, AP_DEVICES) &&
+		    bitmap_empty(matrix_mdev->aqm_add, AP_DOMAINS) &&
+		    bitmap_empty(matrix_mdev->adm_add, AP_DOMAINS))
+			continue;
+
+		vfio_ap_mdev_hot_plug_cfg(matrix_mdev);
+		bitmap_clear(matrix_mdev->apm_add, 0, AP_DEVICES);
+		bitmap_clear(matrix_mdev->aqm_add, 0, AP_DOMAINS);
+		bitmap_clear(matrix_mdev->adm_add, 0, AP_DOMAINS);
+	}
+
+	mutex_unlock(&matrix_dev->guests_lock);
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index e19a3e38fb32..7a3525c861e8 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -105,6 +105,10 @@ struct ap_queue_table {
  *		PQAP(AQIC) instruction.
  * @mdev:	the mediated device
  * @qtable:	table of queues (struct vfio_ap_queue) assigned to the mdev
+ * @apm_add:	bitmap of APIDs added to the host's AP configuration
+ * @aqm_add:	bitmap of APQIs added to the host's AP configuration
+ * @adm_add:	bitmap of control domain numbers added to the host's AP
+ *		configuration
  */
 struct ap_matrix_mdev {
 	struct vfio_device vdev;
@@ -116,6 +120,9 @@ struct ap_matrix_mdev {
 	crypto_hook pqap_hook;
 	struct mdev_device *mdev;
 	struct ap_queue_table qtable;
+	DECLARE_BITMAP(apm_add, AP_DEVICES);
+	DECLARE_BITMAP(aqm_add, AP_DOMAINS);
+	DECLARE_BITMAP(adm_add, AP_DOMAINS);
 };
 
 /**
@@ -146,4 +153,9 @@ void vfio_ap_mdev_remove_queue(struct ap_device *queue);
 
 int vfio_ap_mdev_resource_in_use(unsigned long *apm, unsigned long *aqm);
 
+void vfio_ap_on_cfg_changed(struct ap_config_info *new_config_info,
+			    struct ap_config_info *old_config_info);
+void vfio_ap_on_scan_complete(struct ap_config_info *new_config_info,
+			      struct ap_config_info *old_config_info);
+
 #endif /* _VFIO_AP_PRIVATE_H_ */
-- 
2.35.3