pflash: fix cpr

During normal migration, new QEMU creates and initializes memory regions,
then loads the preserved contents of the region from vmstate.

During CPR, memory regions are preserved in place, then the realize
method initializes the regions contents, losing the old contents.  To
fix, skip the re-init during CPR.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Message-ID: <1741380954-341079-3-git-send-email-steven.sistare@oracle.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>

hw/block/block.c

@@ -12,6 +12,7 @@
 #include "system/blockdev.h"
 #include "system/block-backend.h"
 #include "hw/block/block.h"
+#include "migration/cpr.h"
 #include "qapi/error.h"
 #include "qapi/qapi-types-block.h"
 
@@ -66,6 +67,10 @@ bool blk_check_size_and_read_all(BlockBackend *blk, DeviceState *dev,
     int ret;
     g_autofree char *dev_id = NULL;
 
+    if (cpr_is_incoming()) {
+        return true;
+    }
+
     blk_len = blk_getlength(blk);
     if (blk_len < 0) {
         error_setg_errno(errp, -blk_len,