Re: [PATCH for-4.19? 1/2] xen/x86: account for max guest gfn and number of foreign mappings in the p2m

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

On Mon, May 06, 2024 at 04:55:45PM +0200, Jan Beulich wrote:
> On 06.05.2024 16:32, Roger Pau Monné wrote:
> > On Mon, May 06, 2024 at 12:07:33PM +0200, Jan Beulich wrote:
> >> On 30.04.2024 18:58, Roger Pau Monne wrote:
> >  My initial intention was to do it
> > in p2m_entry_modify() so that nr_foreign and max_gfn where set in the
> > same function, but that requires passing yet another parameter to the
> > function.
> 
> I was indeed implying that would have been the reason for you to not have
> put it there.
> 
> What you don't answer though is the question of how you determined that
> none of the other ->set_entry() invocations would need to have similar
> code added. There are quite a few of them, after all.

Aside from the mem_sharing copying/forking usages, the rest of the
uses of ->set_entry() looked like changes over existing entries, and
strictly not adding new entries.  I might be wrong however, I see that
some of the altp2m usages could also end up populating altp2m entries
(not that the teardown will work with altp2m-s anyway).

Thanks, Roger.