Re: [PATCH 12/12] hw/xen: add support for Xen primary console in emulated mode

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 24/10/2023 16:37, David Woodhouse wrote:
> On Tue, 2023-10-24 at 15:20 +0100, Paul Durrant wrote:
> > On 16/10/2023 16:19, David Woodhouse wrote:
> > > From: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > >
> > > The primary console is special because the toolstack maps a page at a
> > > fixed GFN and also allocates the guest-side event channel. Add support
> > > for that in emulated mode, so that we can have a primary console.
> > >
> > > Add a *very* rudimentary stub of foriegnmem ops for emulated mode, which
> > > supports literally nothing except a single-page mapping of the console
> > > page. This might as well have been a hack in the xen_console driver, but
> > > this way at least the special-casing is kept within the Xen emulation
> > > code, and it gives us a hook for a more complete implementation if/when
> > > we ever do need one.
> > Why can't you map the console page via the grant table like the xenstore
> > page?
> I suppose we could, but I didn't really want the generic xen-console
> device code having any more of a special case for 'Xen emulation' than
> it does already by having to call xen_primary_console_create().
But doesn't is save you the whole foreignmem thing? You can use the 
grant table for primary and secondary consoles.
  Paul