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Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are
From: |
Rusty Russell |
Subject: |
Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?) |
Date: |
Tue, 11 Dec 2012 10:24:45 +1030 |
User-agent: |
Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) |
Anthony Liguori <address@hidden> writes:
> Rusty Russell <address@hidden> writes:
>
>> "Michael S. Tsirkin" <address@hidden> writes:
>>
>> No, because I don't understand it. Is it true for the case of
>> virtio_blk, which has outstanding requests?
>>
>>>> Currently we dump a massive structure; it's inelegant at the very
>>>> least.
>
> Inelegant is a kind word..
>
> There's a couple things to consider though which is why this code hasn't
> changed so far.
>
> 1) We're writing native endian values to the wire. This is seriously
> broken. Just imagine trying to migrate from qemu-system-i386 on an
> big endian box to a little endian box.
>
> 2) Fixing (1) either means (a) breaking migration across the board
> gracefully or (b) breaking migration on [big|little] endian hosts in
> an extremely ungraceful way.
>
> 3) We send a ton of crap over the wire that is unnecessary, but we need
> to maintain it.
>
> I wrote up a patch series to try to improve the situation that I'll send
> out. I haven't gotten around to testing it with an older version of
> QEMU yet.
>
> I went for 2.b and choose to break big endian hosts.
Since we only actually want to save the descriptor head, I was planning
on a new format version. That will fix both...
Look forward to your patch,
Rusty.
- [Qemu-devel] vmstate conversion for virtio?, Rusty Russell, 2012/12/03
- Re: [Qemu-devel] vmstate conversion for virtio?, Michael S. Tsirkin, 2012/12/04
- Re: [Qemu-devel] vmstate conversion for virtio?, Juan Quintela, 2012/12/04
- Re: [Qemu-devel] vmstate conversion for virtio?, Rusty Russell, 2012/12/04
- [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?), Michael S. Tsirkin, 2012/12/05
- Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?), Rusty Russell, 2012/12/06
- Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?), Michael S. Tsirkin, 2012/12/06
- Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?), Rusty Russell, 2012/12/06
- Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?), Anthony Liguori, 2012/12/10
- Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?),
Rusty Russell <=
- Re: [Qemu-devel] [PATCH] virtio: verify that all outstanding buffers are flushed (was Re: vmstate conversion for virtio?), Michael S. Tsirkin, 2012/12/10