Re: [Qemu-devel] [patch 2/2] qemu: PCI device, disk and host network hot-add / hot-remove

[Daniel P. Berrange]

On Sun, Feb 08, 2009 at 03:28:45PM -0200, Marcelo Tosatti wrote:
> On Sun, Feb 08, 2009 at 12:08:34PM +0200, Avi Kivity wrote:
> > Marcelo Tosatti wrote:
> >> Add monitor command to hot-add PCI devices (nic and storage).
> >>     Syntax is:
> >>     pci_add pci_addr=[[<domain>:]<bus>:]<slot> nic|storage params
> >>     It returns the domain, bus and slot for the newly added device on 
> >> success
> >
> > Instead of returning something, how about
> >
> >  pci_add pci_addr=...,name=blah
> >
> > and then
> >
> >  pci_del blah
> >
> > 'info pci' could also output the name so that it could be associated  
> > with the bus address.
> 
> Sure that can be done. Like an alias. So you identify <domain,bus,slot>
> with a name. I can see it simplifies direct management of hotplug on the
> monitor.

Also bear in mind that we need the ability to hot unplug devices which
were specified on the command line argv. For these we currently have
neither the pci <domain,bus,slot>, nor are given any 'name'. Markus
has previously suggested allowing <domain,bus,slot> to be specified on
the cli which would let us manually assign & use that info for unplug.

A device type specific unique naming would be useful too though. In
changeset r6220,  Mark McLoughlin provided the ability to give every
single NIC a unique name. I'd like to be able to use that name for
unplug. 

For disks, meanwhile we generally know the logic bus,unit,index info as
provided to -drive / pci_add disk, which can be used to unplug.

So, I'd suggest that pci_del allow either a <domain,bus,slot> or some
form of unique name, or device type specific unique identifier. Ideally
so we can still just as easily use unplug for devices added on the cli,
as for those added via the monitor.

Daniel
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