commit c81b4f896f2768a34d6e65e5f3e588515b10f631
author Song Shan Gong <gongss@linux.vnet.ibm.com> Tue Jan 19 02:55:00 2016 +0100
committer Cornelia Huck <cornelia.huck@de.ibm.com> Wed Jan 27 15:34:47 2016 +0100
tree aa5013c5420be6aa91db3e1489a2dc68e5cff91b
parent f70202be535b5601fd02c725dc1d74f3bfc5039c

s390x: fix generation of event information crw

Only one channel report word (crw) may be pending if there is
event-information pending.

This patch introduces a bool-type field 'sei_pending' for the
channel subsystem, which indicates whether there are pending events.
It is set when event information is made pending and the crw
generated, and cleared after the guest has collected all pending
event information. A crw is not generated if this flag had already
been set.

Signed-off-by: Song Shan Gong <gongss@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/css.c

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 343c352..533357a 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -49,6 +49,7 @@
 
 typedef struct ChannelSubSys {
     QTAILQ_HEAD(, CrwContainer) pending_crws;
+    bool sei_pending;
     bool do_crw_mchk;
     bool crws_lost;
     uint8_t max_cssid;
@@ -1359,7 +1360,15 @@
 
 void css_generate_css_crws(uint8_t cssid)
 {
-    css_queue_crw(CRW_RSC_CSS, 0, 0, cssid);
+    if (!channel_subsys->sei_pending) {
+        css_queue_crw(CRW_RSC_CSS, 0, 0, cssid);
+    }
+    channel_subsys->sei_pending = true;
+}
+
+void css_clear_sei_pending(void)
+{
+    channel_subsys->sei_pending = false;
 }
 
 int css_enable_mcsse(void)
@@ -1509,6 +1518,7 @@
 {
     channel_subsys = g_malloc0(sizeof(*channel_subsys));
     QTAILQ_INIT(&channel_subsys->pending_crws);
+    channel_subsys->sei_pending = false;
     channel_subsys->do_crw_mchk = true;
     channel_subsys->crws_lost = false;
     channel_subsys->chnmon_active = false;
@@ -1561,6 +1571,7 @@
         QTAILQ_REMOVE(&channel_subsys->pending_crws, crw_cont, sibling);
         g_free(crw_cont);
     }
+    channel_subsys->sei_pending = false;
     channel_subsys->do_crw_mchk = true;
     channel_subsys->crws_lost = false;
 

hw/s390x/css.h

diff --git a/hw/s390x/css.h b/hw/s390x/css.h
index a09bb1f..a47937d 100644
--- a/hw/s390x/css.h
+++ b/hw/s390x/css.h
@@ -103,6 +103,7 @@
                            int hotplugged, int add);
 void css_generate_chp_crws(uint8_t cssid, uint8_t chpid);
 void css_generate_css_crws(uint8_t cssid);
+void css_clear_sei_pending(void);
 void css_adapter_interrupt(uint8_t isc);
 
 #define CSS_IO_ADAPTER_VIRTIO 1