Re: [PATCH v3 2/3] xen/igd: don't register rom bar twice

[Tomita Moeko <tomitamoeko@xxxxxxxxx>]

On 2026-07-10 02:35, Chuck Zmudzinski wrote:
> This also fixes a failed assertion in pci [1] for Qemu
> version 10 and higher when passing through an Intel
> IGD with an option ROM to the guest.
> 
> [1] f6fc01c ("hw/pci: Assert a bar is not registered multiple times")
> 
> Fixes: 881213f ("xen, gfx passthrough: retrieve VGA BIOS to work")

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> Signed-off-by: Chuck Zmudzinski <brchuckz@xxxxxxx>
> ---
> Changes in v2:
>   - get 'pcibus_t romsize' instead of 'PCIIORegion region'
>   - move definition of romsize to the top of the function
>     and make it constant
>   - add stable to Cc list
> 
> Changes in v3:
>   - fix Cc address for qemu-stable
> 
>  hw/xen/xen_pt.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
> index 474606e..8b30b61 100644
> --- a/hw/xen/xen_pt.c
> +++ b/hw/xen/xen_pt.c
> @@ -459,6 +459,7 @@ static int xen_pt_register_regions(XenPCIPassthroughState 
> *s, uint16_t *cmd)
>  {
>      int i = 0;
>      XenHostPCIDevice *d = &s->real_device;
> +    const pcibus_t romsize = s->dev.io_regions[PCI_ROM_SLOT].size;
>  
>      /* Register PIO/MMIO BARs */
>      for (i = 0; i < PCI_ROM_SLOT; i++) {
> @@ -495,7 +496,7 @@ static int xen_pt_register_regions(XenPCIPassthroughState 
> *s, uint16_t *cmd)
>      }
>  
>      /* Register expansion ROM address */
> -    if (d->rom.base_addr && d->rom.size) {
> +    if (!romsize && d->rom.base_addr && d->rom.size) {
>          uint32_t bar_data = 0;
>  
>          /* Re-set BAR reported by OS, otherwise ROM can't be read. */