Re: [PATCH v2 1/2] virtio-vga: fix virtio-vga bar ordering

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Apr 22, 2020 at 11:54:54PM +0200, Anthoine Bourgeois wrote:
> With virtio-vga, pci bar are reordered. Bar #2 is used for compatibility
> with stdvga. By default, bar #2 is used by virtio modern io bar.
> This bar is the last one introduce in the virtio pci bar layout and it's
> crushed by the virtio-vga reordering. So virtio-vga and
> modern-pio-notify are incompatible because virtio-vga failed to
> initialize with this option.
> 
> This fix sets the modern io bar to the bar #5 to avoid conflict.
> 
> Signed-off-by: Anthoine Bourgeois <anthoine.bourgeois@gmail.com>

Gerd, would you say it's required for 5.0?

> ---
>  hw/display/virtio-vga.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/display/virtio-vga.c b/hw/display/virtio-vga.c
> index 2b4c2aa126..95757a6619 100644
> --- a/hw/display/virtio-vga.c
> +++ b/hw/display/virtio-vga.c
> @@ -114,6 +114,7 @@ static void virtio_vga_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>       */
>      vpci_dev->modern_mem_bar_idx = 2;
>      vpci_dev->msix_bar_idx = 4;
> +    vpci_dev->modern_io_bar_idx = 5;
>  
>      if (!(vpci_dev->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)) {
>          /*
> -- 
> 2.20.1