Re: [PULL 01/30] migration: Fix migration crash when target psize larger than host

[Juan Quintela]

Michael Tokarev <mjt@tls.msk.ru> wrote:
> 07.02.2023 03:56, Juan Quintela wrote:
>> From: Peter Xu <peterx@redhat.com>
>> Commit d9e474ea56 overlooked the case where the target psize is even
>> larger
>> than the host psize.  One example is Alpha has 8K page size and migration
>> will start to crash the source QEMU when running Alpha migration on x86.
>> Fix it by detecting that case and set host start/end just to cover
>> the
>> single page to be migrated.
>
> FWIW, commit in question, which is d9e474ea56, has been applied after the
> last released version to date, which is 7.2.0.  So I guess this change is
> not applicable to -stable.

I think it should.

This is a bug that can happen when your host page is smaller than the
guest size.

And has been that way for a long time.
Once told that, people don't migrate alpha guests a lot, but it can also
happens with funny combinations of large pages.

Peter Xu knows more about this.

Later, Juan.