Re: [Qemu-devel] [RFC PATCH 3/3] s390x/css: add hint for devno missmatch

[Halil Pasic]

This one has to be fixed up to 's390x: vmstatify config migration for
virtio-ccw' provided we want to achieve the same as 's390x/css: catch
section mismatch on load' does.

Signed-off-by: Halil Pasic <address@hidden>
---

This is on tom of 's390x: vmstatify config migration for virtio-ccw'
which ain't on top of 's390x/css: catch section mismatch on load' but on
top of master.  I kind of have a circular dependency here. This is why
the series is RFC. 

Wanted to provide an usage example. Faked 'Re: ' so patchew does not
try to apply this on top of current master.
---
 hw/s390x/css.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 348129e1b2..de277d6a3d 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -134,6 +134,10 @@ static const VMStateDescription vmstate_sense_id = {
 static int subch_dev_post_load(void *opaque, int version_id);
 static void subch_dev_pre_save(void *opaque);
 
+const char err_hint_devno[] = "Devno mismatch, tried to load wrong section!"
+    " Likely reason: some sequences of plug and unplug  can break"
+    " migration for machine versions prior to  2.7 (known design flaw).";
+
 const VMStateDescription vmstate_subch_dev = {
     .name = "s390_subch_dev",
     .version_id = 1,
@@ -144,7 +148,7 @@ const VMStateDescription vmstate_subch_dev = {
         VMSTATE_UINT8_EQUAL(cssid, SubchDev),
         VMSTATE_UINT8_EQUAL(ssid, SubchDev),
         VMSTATE_UINT16(migrated_schid, SubchDev),
-        VMSTATE_UINT16(devno, SubchDev),
+        VMSTATE_UINT16_EQUAL_HINT(devno, SubchDev, err_hint_devno),
         VMSTATE_BOOL(thinint_active, SubchDev),
         VMSTATE_STRUCT(curr_status, SubchDev, 0, vmstate_schib, SCHIB),
         VMSTATE_UINT8_ARRAY(sense_data, SubchDev, 32),
-- 
2.11.2