Re: [XEN PATCH] x86/hvm: make stdvga support optional

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Sep 16, 2024 at 09:37:16AM +0300, Sergiy Kibrik wrote:
> 12.09.24 12:14, Roger Pau Monné:
> > Shouldn't Xen report an error if a user attempts to create a domain
> > with X86_EMU_VGA set in emulation_flags, but stdvga has been built
> > time disabled?
> 
> I'm afraid this can accidentally render the system unbootable, because it
> looks like toolstack always sets X86_EMU_VGA flag.

Not for PV or PVH guests.  It won't render the system unbootable, it
would just leave it unable to create HVM guests.  dom0 however, and PV
or PVH guests don't use the X86_EMU_VGA flag.

As pointed out by Jan, we need slightly better integration with the
toolstack.  IMO if we want to pursue this route we need a way for Xen
to advertise which X86_EMU_* are supported at least.

Thanks, Roger.