Test is wrong and the backend can never updated. It could have led to
a QEMU crash but since the firmware deactivates flash access if a valid
layout is not detected, it went unnoticed.

Reported-by: Coverity CID 1465223
Fixes: 35dde5766211 ("ppc/pnv: Add a PNOR model")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 hw/ppc/pnv_pnor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/ppc/pnv_pnor.c b/hw/ppc/pnv_pnor.c
index 5ef1cf2afbe1..83ecccca28df 100644
--- a/hw/ppc/pnv_pnor.c
+++ b/hw/ppc/pnv_pnor.c
@@ -36,7 +36,7 @@ static void pnv_pnor_update(PnvPnor *s, int offset, int size)
     int offset_end;
     int ret;
 
-    if (s->blk) {
+    if (!s->blk || !blk_is_writable(s->blk)) {
         return;
     }
 
-- 
2.31.1