Re: virtio-vga: PCI Express Root Port reduces VGA/VESA modes

[Kevin Locke]

On Tue, 2022-05-31 at 16:04 -0600, Kevin Locke wrote:
> This works well.  However, if I understand correctly, it does not
> follow the QEMU PCI Express Guidelines[1] which recommend only placing
> legacy PCI devices on the Root Complex.  If virtio-vga is attached to
> a PCI Express Root Port as recommended:
> 
> qemu-system-x86_64 \
>       -no-user-config \
>       -nodefaults \
>       -machine pc-q35-7.0,accel=kvm \
>       -m 2G \
>       -cdrom "$iso" \
>       -device pcie-root-port,id=root_port1,bus=pcie.0 \
>       -device virtio-vga,bus=root_port1
> 
> The guest is only able to use a reduced set of VGA/VESA modes.

Quick follow-up:  The problem is not specific to virtio-vga.  I just
confirmed that the symptoms are the same with `-device qxl-vga` and
`-device vga`.

Thanks again,
Kevin