From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Michael Rolnik <mrolnik@gmail.com>,
Richard Henderson <richard.henderson@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>,
Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH 1/1] Set TARGET_PAGE_BITS to be 10 instead of 8 bits
Date: Tue, 27 Apr 2021 18:52:06 +0100 [thread overview]
Message-ID: <YIhPRprgFqNahPRp@work-vm> (raw)
In-Reply-To: <CAFEAcA-ccgKHzgxvK_Wb8hD4ce=KYu2NbZ-3UGhaW447JTVgAg@mail.gmail.com>
* 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
prev parent reply other threads:[~2021-04-27 17:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-20 22:09 [PATCH 0/1] Set AVR TARGET_PAGE_BITS to be 10 instead of 8 Michael Rolnik
2021-03-20 22:09 ` [PATCH 1/1] Set TARGET_PAGE_BITS to be 10 instead of 8 bits Michael Rolnik
2021-03-23 12:46 ` Dr. David Alan Gilbert
2021-03-23 20:11 ` Michael Rolnik
2021-03-23 20:28 ` Michael Rolnik
2021-04-10 17:24 ` Michael Rolnik
2021-04-11 15:12 ` Richard Henderson
2021-04-12 9:07 ` Peter Maydell
2021-04-27 17:52 ` Dr. David Alan Gilbert [this message]
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