Re: [RFC PATCH] vfio/pci-quirks: Exclude non-ioport BAR from ATI quirk

[Alex Williamson <alex.williamson@redhat.com>]

On Tue, 11 Mar 2025 00:58:33 +0100
Vasilis Liaskovitis <vliaskovitis@suse.com> wrote:

> The ATI BAR4 quirk is targeting an ioport BAR. Older devices may
> have a BAR4 which is not an ioport, causing a segfault here. Test
> the BAR type to skip these devices.
> 
> Similar to
> "8f419c5b: vfio/pci-quirks: Exclude non-ioport BAR from NVIDIA quirk"
> 
> Untested, as I don't have the card to test.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2856
> Signed-off-by: Vasilis Liaskovitis <vliaskovitis@suse.com>
> ---
>  hw/vfio/pci-quirks.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> index c53591fe2b..15598bbaf4 100644
> --- a/hw/vfio/pci-quirks.c
> +++ b/hw/vfio/pci-quirks.c
> @@ -403,7 +403,7 @@ static void vfio_probe_ati_bar4_quirk(VFIOPCIDevice *vdev, int nr)
>  
>      /* This windows doesn't seem to be used except by legacy VGA code */
>      if (!vfio_pci_is(vdev, PCI_VENDOR_ID_ATI, PCI_ANY_ID) ||
> -        !vdev->vga || nr != 4) {
> +        !vdev->vga || nr != 4 || !vdev->bars[4].ioport) {
>          return;
>      }
>  

We should probably predicate calls to vfio_bar_quirk_setup() on
VFIOBAR.size to avoid such segfaults, but agree this likely fixes the
reported issue as well.

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>