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Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function |
Date: |
Tue, 7 Aug 2018 16:12:15 +0100 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
* Peter Maydell (address@hidden) wrote:
> On 7 August 2018 at 16:05, Juan Quintela <address@hidden> wrote:
> > Peter Maydell <address@hidden> wrote:
> >> So it's better to use a needed-always subsection, which will give
> >> the desired behaviour:
> >> * new QEMU -> new QEMU: state is always migrated
> >> * old QEMU -> new QEMU: migration doesn't fail, and guest
> >> will work assuming it didn't care about this corner of the
> >> device's functionality (the device will end up with state
> >> as it was at reset, or possibly special-cased via
> >> pre_load/post_load hooks for the "section not present" case)
> >
> > we break by definiton new QEMU -M <old machine type> into old QEMU.
>
> Is that supposed to work? I always thought that we never
> supported migration back to an older QEMU version like that.
Downstream we do a lot of hard work to keep that working for versioned
machine types; using subsections makes this a lot easier and if it's
done right in the first place then it works upstream as well.
> In any case, for all the devices here the machine types are
> not versioned.
Right.
Dave
> thanks
> -- PMM
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Juan Quintela, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Juan Quintela, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Juan Quintela, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Juan Quintela, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/07
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function,
Dr. David Alan Gilbert <=
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Juan Quintela, 2018/08/08
- Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Peter Maydell, 2018/08/08
Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Dr. David Alan Gilbert, 2018/08/07
Re: [Qemu-devel] [PATCH] migration: Correctly handle subsections with no 'needed' function, Dr. David Alan Gilbert, 2018/08/07