On 24/10/2023 16:49, David Woodhouse wrote:
On Tue, 2023-10-24 at 16:39 +0100, Paul Durrant wrote:
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.
Yes. And I could leave the existing foreignmem thing just for the case
of primary console under true Xen. It's probably not that awful a
special case, in the end.
Then again, I was surprised I didn't *already* have a foreignmem ops
for the emulated case, and we're probably going to want to continue
fleshing it out later, so I don't really mind adding it.
True. We'll need it for some of the other more fun protocols like vkbd
or fb. Still, I think it'd be nicer to align the xenstore and primary
console code to look similar and punt the work until then :-)
Paul
