Hi On Thu, Apr 13, 2017 at 1:17 AM Marc-André Lureau < marcandre.lur...@gmail.com> wrote:
> Hi > > On Thu, Apr 13, 2017 at 1:03 AM Ben Warren <b...@skyportsystems.com> wrote: > > On Apr 12, 2017, at 1:47 PM, Marc-André Lureau <marcandre.lur...@gmail.com> > wrote: > > Hi > > On Thu, Apr 13, 2017 at 12:25 AM Ben Warren <b...@skyportsystems.com> > wrote: > > On Apr 12, 2017, at 1:22 PM, Marc-André Lureau <marcandre.lur...@gmail.com> > wrote: > > Hi > > On Thu, Apr 13, 2017 at 12:17 AM Ben Warren <b...@skyportsystems.com> > wrote: > > On Apr 12, 2017, at 1:06 PM, Marc-André Lureau <marcandre.lur...@gmail.com> > wrote: > > +Device Usage: > +------------- > + > +The device has one property, which may be only be set using the command > line: > + > + guid - sets the value of the GUID. A special value "auto" instructs > + QEMU to generate a new random GUID. > + > +For example: > + > + QEMU -device vmgenid,guid="324e6eaf-d1d1-4bf6-bf41-b9bb6c91fb87" > + QEMU -device vmgenid,guid=auto > > > The default will keep uuid to null, should it be documented? Wouldn't it > make sense to default to auto? > > There is no default - you have to supply a value. It’s up to whatever > software is managing VM lifecycle to decide what value to pass in. Always > setting to ‘auto’ will cause a lot of churn within Windows that may or may > not be acceptable to your use case. > > > Why would you have a vmgenid device if it's always null? Does that please > some windows use-cases as well? > > > I don’t get what you mean by this. What device is always null? Either > the device is instantiated or it isn’t. If not there, Windows will not > find a device and I don’t know how derived objects (Invocation ID, etc.) > are handled. > > > If you start a VM without specifying guid argument, you'll always have a > genid null uuid, event after a migration (this could have been handled by > qemu without requiring management layer, no?). I don't understand why auto > would create more churn than what the management layer would do by setting > new uuid for each VM started. Could you explain? > > Looks like there’s a bug. GUID should be a mandatory parameter. > > > Not necessarily a bug, if the guid can be changed when starting a "new" > VM, which I think should work. > > However, I didn't manage to get your driver noticing the acpi event. I > tried to migrate/save & restore, and no vmgenid_notify kernel messages came > out, nor notices got incremented. How did you test it? > > Actually I was using an old bios, now I can change the guid and the guest notices the change. { "execute": "qom-set", "arguments": { "path": "/machine/peripheral-anon/device[1]", "property": "guid", "value": "..." } } works, the guest noticed the change and the new value can be read. I don't know what else would be required (except a better API) to allow QMP to modify it. thanks -- Marc-André Lureau