* Michael Rolnik (mrol...@gmail.com) wrote: > ok. I will try to fix it. Thanks, if you can that would be great.
Dave > Regards, > Michael Rolnik > > On Thu, Mar 18, 2021 at 11:55 AM Dr. David Alan Gilbert <dgilb...@redhat.com> > wrote: > > > * Michael Rolnik (mrol...@gmail.com) wrote: > > > Hi Dave. > > > > > > What is the smallest supported page size? > > > > Currently 512 I think; in migration/ram.c we have: > > > > #define RAM_SAVE_FLAG_FULL 0x01 /* Obsolete, not used anymore */ > > #define RAM_SAVE_FLAG_ZERO 0x02 > > #define RAM_SAVE_FLAG_MEM_SIZE 0x04 > > #define RAM_SAVE_FLAG_PAGE 0x08 > > #define RAM_SAVE_FLAG_EOS 0x10 > > #define RAM_SAVE_FLAG_CONTINUE 0x20 > > #define RAM_SAVE_FLAG_XBZRLE 0x40 > > /* 0x80 is reserved in migration.h start with 0x100 next */ > > #define RAM_SAVE_FLAG_COMPRESS_PAGE 0x100 > > > > so we're already using the 0x100 (256) flag. > > > > I spotted this yesterday because a patch tried to use the 0x200 flag. > > > > Dave > > > > > > On Wed, Mar 17, 2021 at 10:14 PM Dr. David Alan Gilbert < > > dgilb...@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 / dgilb...@redhat.com / Manchester, UK > > > > > > > > > > > > > > -- > > > Best Regards, > > > Michael Rolnik > > -- > > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > > > > > > -- > Best Regards, > Michael Rolnik -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
