According to the PIIX3 datasheet, the reset control register is one byte in size.
Moreover, PIIX4 has it, so add it to PIIX3 as well.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 hw/isa/piix3.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/isa/piix3.c b/hw/isa/piix3.c
index b54ff1c948..c8c2dd6048 100644
--- a/hw/isa/piix3.c
+++ b/hw/isa/piix3.c
@@ -290,7 +290,11 @@ static uint64_t rcr_read(void *opaque, hwaddr addr, unsigned len)
 static const MemoryRegionOps rcr_ops = {
     .read = rcr_read,
     .write = rcr_write,
-    .endianness = DEVICE_LITTLE_ENDIAN
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 1,
+    },
 };
 
 static void pci_piix3_realize(PCIDevice *dev, Error **errp)
-- 
2.37.3

On 1/9/22 18:25, Bernhard Beschow wrote:
> According to the PIIX3 datasheet, the reset control register is one byte in size.
> Moreover, PIIX4 has it, so add it to PIIX3 as well.
> 
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
> ---
>   hw/isa/piix3.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>