[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] (Another) 1.4.1 -> 1.5.0 migration failure

From: mdroth
Subject: Re: [Qemu-devel] (Another) 1.4.1 -> 1.5.0 migration failure
Date: Tue, 21 May 2013 17:07:33 -0500
User-agent: Mutt/1.5.21 (2010-09-15)

On Tue, May 21, 2013 at 10:16:48PM +0100, Peter Maydell wrote:
> On 21 May 2013 21:43, mdroth <address@hidden> wrote:
> > Makes sense, but apparently version IDs for incoming device state are
> > not allowed to exceed the destination's version, so we can't bump it
> > beyond the value in 1.5 without breaking migration from 1.5+ -> 1.5
> We care about backwards migration? That sounds like a pain.

As a best effort at least, hence subsections and whatnot, but not
always. This case for instance...

> > So I think our only option for version ID is to lock in the 1.5 value,
> > which seems to be 1936 (hopefully that's consistent across builds...).
> Yeah, I'm not convinced that's going to be consistent across builds,
> compilers, 64 vs 32 bit, etc etc etc. That's why I suggested a really
> high number.

Yah, it's more important to ensure old->new. Playing guessing games
about struct sizes to try to maintain new->old is likely to conflict
with that, so I guess we don't have much choice here. I'll send a patch
out shortly.

> thanks
> -- PMM

reply via email to

[Prev in Thread] Current Thread [Next in Thread]