s390x/css: Add a callback for when subchannel gets disabled

We need a possibility to run code when a subchannel gets disabled.
This patch adds the necessary infrastructure.
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>

hw/s390x/css.c

@@ -588,6 +588,7 @@ int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
 {
     SCSW *s = &sch->curr_status.scsw;
     PMCW *p = &sch->curr_status.pmcw;
+    uint16_t oldflags;
     int ret;
     SCHIB schib;
 
@@ -610,6 +611,7 @@ int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
     copy_schib_from_guest(&schib, orig_schib);
     /* Only update the program-modifiable fields. */
     p->intparm = schib.pmcw.intparm;
+    oldflags = p->flags;
     p->flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
                   PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |
                   PMCW_FLAGS_MASK_MP);
@@ -625,6 +627,12 @@ int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
             (PMCW_CHARS_MASK_MBFC | PMCW_CHARS_MASK_CSENSE);
     sch->curr_status.mba = schib.mba;
 
+    /* Has the channel been disabled? */
+    if (sch->disable_cb && (oldflags & PMCW_FLAGS_MASK_ENA) != 0
+        && (p->flags & PMCW_FLAGS_MASK_ENA) == 0) {
+        sch->disable_cb(sch);
+    }
+
     ret = 0;
 
 out:
@@ -1498,6 +1506,10 @@ void css_reset_sch(SubchDev *sch)
 {
     PMCW *p = &sch->curr_status.pmcw;
 
+    if ((p->flags & PMCW_FLAGS_MASK_ENA) != 0 && sch->disable_cb) {
+        sch->disable_cb(sch);
+    }
+
     p->intparm = 0;
     p->flags &= ~(PMCW_FLAGS_MASK_ISC | PMCW_FLAGS_MASK_ENA |
                   PMCW_FLAGS_MASK_LM | PMCW_FLAGS_MASK_MME |

hw/s390x/css.h

@@ -81,6 +81,7 @@ struct SubchDev {
     uint8_t ccw_no_data_cnt;
     /* transport-provided data: */
     int (*ccw_cb) (SubchDev *, CCW1);
+    void (*disable_cb)(SubchDev *);
     SenseId id;
     void *driver_data;
 };