Re: [PATCH 1/1] Set TARGET_PAGE_BITS to be 10 instead of 8 bits

[Dr. David Alan Gilbert]

* Peter Maydell (peter.maydell@linaro.org) wrote:
> On Sun, 11 Apr 2021 at 16:15, Richard Henderson
> <richard.henderson@linaro.org> wrote:
> >
> > On 4/10/21 10:24 AM, Michael Rolnik wrote:
> > > Please review.
> >
> >
> > The first 256b is i/o, the next 768b are ram.  But having changed the page
> > size, it should mean that the first 1k are now treated as i/o.
> >
> > We do have a path by which instructions in i/o pages can be executed.  This
> > happens on some ARM board setups during cold boot.  But we do not save those
> > translations, so they run much much slower than it should.
> >
> > But perhaps in the case of AVR, "much much slower" really isn't visible?
> >
> > In general, I think changing the page size is wrong.  I also assume that
> > migration is largely irrelevant to this target.
> 
> Migration is irrelevant, but every target benefits from snapshot
> save-and-restore, and I think that uses the same codepaths ?

Yes it does.

My main problem for wanting this fixed is that I really wanted to add an
assert to stop us tripping over the page size/migration bits clash.

Dave

> -- PMM
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK