diff --git a/hw/ppc/pnv_pnor.c b/hw/ppc/pnv_pnor.c
index 0e86ae2fea..b061106d1c 100644
--- a/hw/ppc/pnv_pnor.c
+++ b/hw/ppc/pnv_pnor.c
@@ -111,7 +111,7 @@ static void pnv_pnor_realize(DeviceState *dev, Error **errp)
 }
 
 static Property pnv_pnor_properties[] = {
-    DEFINE_PROP_UINT32("size", PnvPnor, size, 128 << 20),
+    DEFINE_PROP_INT64("size", PnvPnor, size, 128 << 20),
     DEFINE_PROP_DRIVE("drive", PnvPnor, blk),
     DEFINE_PROP_END_OF_LIST(),
 };
diff --git a/include/hw/ppc/pnv_pnor.h b/include/hw/ppc/pnv_pnor.h
index c3dd28643c..4f96abdfb4 100644
--- a/include/hw/ppc/pnv_pnor.h
+++ b/include/hw/ppc/pnv_pnor.h
@@ -23,7 +23,7 @@ typedef struct PnvPnor {
     BlockBackend   *blk;
 
     uint8_t        *storage;
-    uint32_t       size;
+    int64_t        size;
     MemoryRegion   mmio;
 } PnvPnor;