Re: [Qemu-devel] [Xen-devel] [PATCHv3] QEMU(upstream): Disable xen's use of O_DIRECT by default as it results in crashes.

[George Dunlap]

On 20/03/13 10:24, Stefano Stabellini wrote:
> That is true. My guess is that nobody really migrates HVM guests without
> PV drivers installed (it's not even possible on XenServer but xl let you
> do that if you want to). When the PV drivers initialize at boot time,
> the IDE disk is closed. Therefore we wouldn't have this problem.
>
> Maybe we should prevent HVM guest migration without PV drivers with xl
> too. Ian, what do you think?

We should be able to make it safe if we just make sure that qemu does a 
metadata sync / FS sync when we ask qemu to write the save file.

 -George