Re: [Qemu-devel] [PATCH v2] arm: change vendor ID for virtio-mmio

[Peter Maydell]

On 30 July 2015 at 09:04, Michael S. Tsirkin <address@hidden> wrote:
> On Thu, Jul 30, 2015 at 09:23:20AM +0800, Shannon Zhao wrote:
>>
>> Why do we drop the previous way using "QEMUXXXX"? Something I missed?
>
> So that guests that bind to this interface will work fine with non QEMU
> implementations of virtio-mmio.

I don't understand this sentence. If there are pre-existing
non-QEMU virtio-mmio implementations, then they're using
LNRO0005, and we should use it too. If there are going to
be implementations of virtio-mmio in future, then they will
use whatever identifier we pick here. Either way, we get
interoperability. I don't see any difference between our
saying "the ID for virtio-mmio is QEMU0005" and saying
"the ID for virtio-mmio is 1AF4103F".

(The latter seems unnecessarily opaque to me, to be honest.
At least an ID string QEMUxxxx gives you a clue where to
look for who owns the thing.)

Note also that strictly you don't mean "non-QEMU implementations
of virtio-mmio", you mean "non-QEMU implementations of the
ACPI tables". The hardware implementation of virtio-mmio
doesn't care at all about the ACPI ID. (In fact the most
plausible other-implementation would be UEFI using its
own (hard-coded) ACPI tables on top of a QEMU vexpress-a15
model or something similar.)

-- PMM