Implements the driver callback invoked by the AP bus when the host
AP configuration has changed. Since this callback is invoked prior to
unbinding a device from its device driver, the vfio_ap driver will
respond by unplugging the AP adapters, domains and control domains
removed from the host's AP configuration from the guests using them.

Signed-off-by: Tony Krowiak <akrow...@linux.ibm.com>
---
 drivers/s390/crypto/vfio_ap_drv.c     |   5 +-
 drivers/s390/crypto/vfio_ap_ops.c     | 148 +++++++++++++++++++++++---
 drivers/s390/crypto/vfio_ap_private.h |   7 +-
 3 files changed, 146 insertions(+), 14 deletions(-)

diff --git a/drivers/s390/crypto/vfio_ap_drv.c 
b/drivers/s390/crypto/vfio_ap_drv.c
index 86fc83701e05..f0f83c1b8983 100644
--- a/drivers/s390/crypto/vfio_ap_drv.c
+++ b/drivers/s390/crypto/vfio_ap_drv.c
@@ -113,9 +113,11 @@ static int vfio_ap_matrix_dev_create(void)
 
        /* Fill in config info via PQAP(QCI), if available */
        if (test_facility(12)) {
-               ret = ap_qci(&matrix_dev->info);
+               ret = ap_qci(&matrix_dev->config_info);
                if (ret)
                        goto matrix_alloc_err;
+               memcpy(&matrix_dev->config_info_prev, &matrix_dev->config_info,
+                      sizeof(struct ap_config_info));
        }
 
        mutex_init(&matrix_dev->lock);
@@ -175,6 +177,7 @@ static int __init vfio_ap_init(void)
        vfio_ap_drv.remove = vfio_ap_queue_dev_remove;
        vfio_ap_drv.in_use = vfio_ap_mdev_resource_in_use;
        vfio_ap_drv.ids = ap_queue_ids;
+       vfio_ap_drv.on_config_changed = vfio_ap_on_cfg_changed;
 
        ret = ap_driver_register(&vfio_ap_drv, THIS_MODULE, VFIO_AP_DRV_NAME);
        if (ret) {
diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
b/drivers/s390/crypto/vfio_ap_ops.c
index 3df050eae112..e3c4b2d73072 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -347,8 +347,9 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct 
mdev_device *mdev)
        }
 
        matrix_mdev->mdev = mdev;
-       vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->matrix);
-       vfio_ap_matrix_init(&matrix_dev->info, &matrix_mdev->shadow_apcb);
+       vfio_ap_matrix_init(&matrix_dev->config_info, &matrix_mdev->matrix);
+       vfio_ap_matrix_init(&matrix_dev->config_info,
+                           &matrix_mdev->shadow_apcb);
        hash_init(matrix_mdev->qtable);
        mdev_set_drvdata(mdev, matrix_mdev);
        matrix_mdev->pqap_hook.hook = handle_pqap;
@@ -527,8 +528,8 @@ static int vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev 
*matrix_mdev,
                 * If the APID is not assigned to the host AP configuration,
                 * we can not assign it to the guest's AP configuration
                 */
-               if (!test_bit_inv(apid,
-                                 (unsigned long *)matrix_dev->info.apm)) {
+               if (!test_bit_inv(apid, (unsigned long *)
+                                 matrix_dev->config_info.apm)) {
                        clear_bit_inv(apid, shadow_apcb->apm);
                        continue;
                }
@@ -541,7 +542,7 @@ static int vfio_ap_mdev_filter_matrix(struct ap_matrix_mdev 
*matrix_mdev,
                         * guest's AP configuration
                         */
                        if (!test_bit_inv(apqi, (unsigned long *)
-                                         matrix_dev->info.aqm)) {
+                                         matrix_dev->config_info.aqm)) {
                                clear_bit_inv(apqi, shadow_apcb->aqm);
                                continue;
                        }
@@ -595,7 +596,7 @@ static bool vfio_ap_mdev_config_shadow_apcb(struct 
ap_matrix_mdev *matrix_mdev)
        int napm, naqm;
        struct ap_matrix shadow_apcb;
 
-       vfio_ap_matrix_init(&matrix_dev->info, &shadow_apcb);
+       vfio_ap_matrix_init(&matrix_dev->config_info, &shadow_apcb);
        napm = bitmap_weight(matrix_mdev->matrix.apm, AP_DEVICES);
        naqm = bitmap_weight(matrix_mdev->matrix.aqm, AP_DOMAINS);
        /*
@@ -741,7 +742,7 @@ static bool vfio_ap_mdev_assign_apqis_4_apid(struct 
ap_matrix_mdev *matrix_mdev,
 
        for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
                if (!test_bit_inv(apqi,
-                                 (unsigned long *) matrix_dev->info.aqm))
+                                 (unsigned long *)matrix_dev->config_info.aqm))
                        clear_bit_inv(apqi, aqm);
 
                apqn = AP_MKQID(apid, apqi);
@@ -764,7 +765,7 @@ static bool vfio_ap_mdev_assign_guest_apid(struct 
ap_matrix_mdev *matrix_mdev,
        unsigned long apqi, apqn;
 
        if (!vfio_ap_mdev_has_crycb(matrix_mdev) ||
-           !test_bit_inv(apid, (unsigned long *)matrix_dev->info.apm))
+           !test_bit_inv(apid, (unsigned long *)matrix_dev->config_info.apm))
                return false;
 
        if (bitmap_empty(matrix_mdev->shadow_apcb.aqm, AP_DOMAINS))
@@ -931,8 +932,8 @@ static bool vfio_ap_mdev_assign_apids_4_apqi(struct 
ap_matrix_mdev *matrix_mdev,
        bitmap_copy(apm, matrix_mdev->matrix.apm, AP_DEVICES);
 
        for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, AP_DEVICES) {
-               if (!test_bit_inv(apid,
-                                 (unsigned long *) matrix_dev->info.apm))
+               if (!test_bit_inv(apid, (unsigned long *)
+                                 matrix_dev->config_info.apm))
                        clear_bit_inv(apqi, apm);
 
                apqn = AP_MKQID(apid, apqi);
@@ -955,7 +956,7 @@ static bool vfio_ap_mdev_assign_guest_apqi(struct 
ap_matrix_mdev *matrix_mdev,
        unsigned long apid, apqn;
 
        if (!vfio_ap_mdev_has_crycb(matrix_mdev) ||
-           !test_bit_inv(apqi, (unsigned long *)matrix_dev->info.aqm))
+           !test_bit_inv(apqi, (unsigned long *)matrix_dev->config_info.aqm))
                return false;
 
        if (bitmap_empty(matrix_mdev->shadow_apcb.apm, AP_DEVICES))
@@ -1702,7 +1703,7 @@ int vfio_ap_mdev_probe_queue(struct ap_queue *queue)
 void vfio_ap_mdev_remove_queue(struct ap_queue *queue)
 {
        struct vfio_ap_queue *q;
-       int apid, apqi;
+       unsigned long apid, apqi;
 
        mutex_lock(&matrix_dev->lock);
        q = dev_get_drvdata(&queue->ap_dev.device);
@@ -1729,3 +1730,126 @@ bool vfio_ap_mdev_resource_in_use(unsigned long *apm, 
unsigned long *aqm)
 
        return in_use;
 }
+
+/**
+ * vfio_ap_mdev_unassign_apids
+ *
+ * @matrix_mdev: The matrix mediated device
+ *
+ * @aqm: A bitmap with 256 bits. Each bit in the map represents an APID from 0
+ *      to 255 (with the leftmost bit corresponding to APID 0).
+ *
+ * Unassigns each APID specified in @aqm that is assigned to the shadow CRYCB
+ * of @matrix_mdev. Returns true if at least one APID is unassigned; otherwise,
+ * returns false.
+ */
+bool vfio_ap_mdev_unassign_apids(struct ap_matrix_mdev *matrix_mdev,
+                                unsigned long *apm_unassign)
+{
+       unsigned long apid;
+       bool unassigned = false;
+
+       /*
+        * If the matrix mdev is not in use by a KVM guest, return indicating
+        * that no APIDs have been unassigned.
+        */
+       if (!vfio_ap_mdev_has_crycb(matrix_mdev))
+               return false;
+
+       for_each_set_bit_inv(apid, apm_unassign, AP_DEVICES) {
+               unassigned |= vfio_ap_mdev_unassign_guest_apid(matrix_mdev,
+                                                              apid);
+       }
+
+       return unassigned;
+}
+
+/**
+ * vfio_ap_mdev_unassign_apqis
+ *
+ * @matrix_mdev: The matrix mediated device
+ *
+ * @aqm: A bitmap with 256 bits. Each bit in the map represents an APQI from 0
+ *      to 255 (with the leftmost bit corresponding to APQI 0).
+ *
+ * Unassigns each APQI specified in @aqm that is assigned to the shadow CRYCB
+ * of @matrix_mdev. Returns true if at least one APQI is unassigned; otherwise,
+ * returns false.
+ */
+bool vfio_ap_mdev_unassign_apqis(struct ap_matrix_mdev *matrix_mdev,
+                                unsigned long *aqm_unassign)
+{
+       unsigned long apqi;
+       bool unassigned = false;
+
+       /*
+        * If the matrix mdev is not in use by a KVM guest, return indicating
+        * that no APQIs have been unassigned.
+        */
+       if (!vfio_ap_mdev_has_crycb(matrix_mdev))
+               return false;
+
+       for_each_set_bit_inv(apqi, aqm_unassign, AP_DOMAINS) {
+               unassigned |= vfio_ap_mdev_unassign_guest_apqi(matrix_mdev,
+                                                              apqi);
+       }
+
+       return unassigned;
+}
+
+void vfio_ap_on_cfg_changed(struct ap_config_info *new_config_info,
+                           struct ap_config_info *old_config_info)
+{
+       bool unassigned;
+       int ap_remove, aq_remove;
+       struct ap_matrix_mdev *matrix_mdev;
+       DECLARE_BITMAP(apm_unassign, AP_DEVICES);
+       DECLARE_BITMAP(aqm_unassign, AP_DOMAINS);
+
+       unsigned long *cur_apm, *cur_aqm, *prev_apm, *prev_aqm;
+
+       if (matrix_dev->flags & AP_MATRIX_CFG_CHG) {
+               WARN_ONCE(1, "AP host configuration change already reported");
+               return;
+       }
+
+       memcpy(&matrix_dev->config_info, new_config_info,
+              sizeof(struct ap_config_info));
+       memcpy(&matrix_dev->config_info_prev, old_config_info,
+              sizeof(struct ap_config_info));
+
+       cur_apm = (unsigned long *)matrix_dev->config_info.apm;
+       cur_aqm = (unsigned long *)matrix_dev->config_info.aqm;
+       prev_apm = (unsigned long *)matrix_dev->config_info_prev.apm;
+       prev_aqm = (unsigned long *)matrix_dev->config_info_prev.aqm;
+
+       ap_remove = bitmap_andnot(apm_unassign, prev_apm, cur_apm, AP_DEVICES);
+       aq_remove = bitmap_andnot(aqm_unassign, prev_aqm, cur_aqm, AP_DOMAINS);
+
+       mutex_lock(&matrix_dev->lock);
+       matrix_dev->flags |= AP_MATRIX_CFG_CHG;
+
+       list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) {
+               if (!vfio_ap_mdev_has_crycb(matrix_mdev))
+                       continue;
+
+               unassigned = false;
+
+               if (ap_remove)
+                       if (bitmap_intersects(matrix_mdev->shadow_apcb.apm,
+                                             apm_unassign, AP_DEVICES))
+                               if (vfio_ap_mdev_unassign_apids(matrix_mdev,
+                                                               apm_unassign))
+                                       unassigned = true;
+               if (aq_remove)
+                       if (bitmap_intersects(matrix_mdev->shadow_apcb.aqm,
+                                             aqm_unassign, AP_DOMAINS))
+                               if (vfio_ap_mdev_unassign_apqis(matrix_mdev,
+                                                               aqm_unassign))
+                                       unassigned = true;
+
+               if (unassigned)
+                       vfio_ap_mdev_commit_shadow_apcb(matrix_mdev);
+       }
+       mutex_unlock(&matrix_dev->lock);
+}
diff --git a/drivers/s390/crypto/vfio_ap_private.h 
b/drivers/s390/crypto/vfio_ap_private.h
index 055bce6d45db..fc8629e28ad3 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -40,10 +40,13 @@
 struct ap_matrix_dev {
        struct device device;
        atomic_t available_instances;
-       struct ap_config_info info;
+       struct ap_config_info config_info;
+       struct ap_config_info config_info_prev;
        struct list_head mdev_list;
        struct mutex lock;
        struct ap_driver  *vfio_ap_drv;
+       #define AP_MATRIX_CFG_CHG (1UL << 0)
+       unsigned long flags;
 };
 
 extern struct ap_matrix_dev *matrix_dev;
@@ -108,5 +111,7 @@ int vfio_ap_mdev_probe_queue(struct ap_queue *queue);
 void vfio_ap_mdev_remove_queue(struct ap_queue *queue);
 
 bool 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);
 
 #endif /* _VFIO_AP_PRIVATE_H_ */
-- 
2.21.1

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