[Xen-devel] [PATCH 13/16] xen: Expect xenstore write to fail when restricted

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

From: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>

Saving the current state to xenstore may fail when running restricted
(in particular, after a migration). Therefore, don't report the error or
exit when running restricted.  Toolstacks that want to allow running
QEMU restricted should instead make use of QMP events to listen for
state changes.

CC: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Reviewed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
v6: New patch in this version of the series
---
 hw/xen/xen-common.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/xen/xen-common.c b/hw/xen/xen-common.c
index 454777c..6ec14c7 100644
--- a/hw/xen/xen-common.c
+++ b/hw/xen/xen-common.c
@@ -101,7 +101,12 @@ static void xenstore_record_dm_state(struct xs_handle *xs, 
const char *state)
     }
 
     snprintf(path, sizeof (path), "device-model/%u/state", xen_domid);
-    if (!xs_write(xs, XBT_NULL, path, state, strlen(state))) {
+    /*
+     * This call may fail when running restricted so don't make it fatal in
+     * that case. Toolstacks should instead use QMP to listen for state 
changes.
+     */
+    if (!xs_write(xs, XBT_NULL, path, state, strlen(state)) &&
+            !xen_domid_restrict) {
         error_report("error recording dm state");
         exit(1);
     }
-- 
2.1.4


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