[Qemu-devel] [RFC PATCH] spapr: Provide an error message when migration fails due to htab_shift mismatch

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

Include an error message when migration fails due to mismatch in
htab_shift values at source and target. This should provide a bit more
verbose message in addition to the current migration failure message
that reads like:

qemu-system-ppc64: error while loading state for instance 0x0 of device 'spapr/htab'

After this patch, the failure message will look like this:

qemu-system-ppc64: htab_shift mismatch: source 29 target 24
qemu-system-ppc64: error while loading state for instance 0x0 of device 'spapr/htab'

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
Applies against spapr-next branch of David Gibson's tree.

 hw/ppc/spapr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index dfd808f..2dcab34 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1471,6 +1471,8 @@ static int htab_load(QEMUFile *f, void *opaque, int version_id)
     if (section_hdr) {
         /* First section, just the hash shift */
         if (spapr->htab_shift != section_hdr) {
+            error_report("htab_shift mismatch: source %d target %d",
+                         section_hdr, spapr->htab_shift);
             return -EINVAL;
         }
         return 0;
-- 
2.1.0