hw/pci: Replace -1 with UINT32_MAX for romsize

romsize is an uint32_t variable. Specifying -1 as an uint32_t value is
obscure way to denote UINT32_MAX.

Worse, if int is wider than 32-bit, it will change the behavior of a
construct like the following:
romsize = -1;
if (romsize != -1) {
    ...
}

When -1 is assigned to romsize, -1 will be implicitly casted into
uint32_t, resulting in UINT32_MAX. On contrary, when evaluating
romsize != -1, romsize will be casted into int, and it will be a
comparison of UINT32_MAX and -1, and result in false.

Replace -1 with UINT32_MAX for statements involving the variable to
clarify the intent and prevent potential breakage.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20240627-reuse-v10-10-7ca0b8ed3d9f@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/hw/xen/xen_pt_load_rom.c b/hw/xen/xen_pt_load_rom.c
index 03422a8..6bc64ac 100644
--- a/hw/xen/xen_pt_load_rom.c
+++ b/hw/xen/xen_pt_load_rom.c
@@ -53,7 +53,7 @@ void *pci_assign_dev_load_option_rom(PCIDevice *dev,
     }
     fseek(fp, 0, SEEK_SET);
 
-    if (dev->romsize != -1) {
+    if (dev->romsize != UINT_MAX) {
         if (st.st_size > dev->romsize) {
             error_report("ROM BAR \"%s\" (%ld bytes) is too large for ROM size %u",
                          rom_file, (long) st.st_size, dev->romsize);