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 <d...@amazon.co.uk> > > > > > > > > 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.
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