Re: of AVR target page size

[Michael Rolnik]

Hi Dave.

What is the smallest supported page size?

On Wed, Mar 17, 2021 at 10:14 PM Dr. David Alan Gilbert <dgilbert@redhat.com> wrote:

Hi Michael,
  I noticed your AVR code defines:

  #define TARGET_PAGE_BITS 8

and has an explanation of why.

Note however that's not going to work with the current live
migration/snapshotting code, since you're a couple of bits smaller
than the smallest page size we had so far, and for many years
the RAM migration code has stolen the bottom few bits of the address
as a flag field, and has already used 0x100 up; see migration/ram.c
RAM_SAVE_FLAG_*    - and it's actually tricky to change it, because if
you change it then it'll break migration compatibility with existing
qemu's.

Hmm.

Dave

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

--

Best Regards,
Michael Rolnik