Re: [Qemu-devel] address order of virtio-mmio devices

[Peter Maydell]

On 29 January 2015 at 19:09, Richard W.M. Jones <address@hidden> wrote:
> On Thu, Jan 29, 2015 at 07:29:09PM +0100, Laszlo Ersek wrote:
>> On 01/29/15 19:15, Peter Maydell wrote:
>> > Note that you can't rely on device ordering anyway. Guests
>> > should be using UUIDs or similar to ensure they mount the
>> > right filesystems in the right places, because the kernel
>> > makes no guarantee that it will enumerate devices in the
>> > device tree in any particular order.
>>
>> Understood. Then we'll probably have to address this in libguestfs.
>
> That's pretty much impossible.  If we can't fix qemu, then libguestfs
> will need to add the drives in reverse order on the command line (for
> this case virtio-blk && -M virt).

This is still wrong, because the kernel doesn't guarantee the
device ordering. It could break tomorrow with a new kernel version.

> I should note that we're only trying to use virtio-blk because
> virtio-scsi is broken ...  Laszlo: is there a public bug for that?

I don't think the kernel guarantees device order for *anything*.

-- PMM