Re: Configuration vs. compat hints [was Re: [Qemu-devel] [PATCHv3 03/13] qemu: add routines to manage PCI capabilities]

[Anthony Liguori]

Avi Kivity wrote:
> On 06/14/2009 12:50 PM, Michael S. Tsirkin wrote:
> > On Fri, Jun 12, 2009 at 05:48:23PM +0100, Mark McLoughlin wrote:
> >   
> > > However, in order to retain compat for that SCSI device (e.g. ensuring
> > > the PCI address doesn't change as other devices are added an removed),
> > > we're back to the same problem ... either:
> > >
> > >    1) Use '-drive file=foo.img,if=scsi,pci_addr=foo'; in order to 
> > > figure
> > >       out what address to use, libvirt would need to query qemu for 
> > > what
> > >       address was originally allocated to device or it would do all the
> > >       PCI address allocation itself ...
> > >      
> >
> > This last option makes sense to me: in a real world the user has
> > control over where he places the device on the bus, so why
> > not with qemu?
> >    
>
> Yes, the user build the machine using the command line and monitor 
> (or, in 2017, the machine configuration file),

Considering pbrook just posted a machine config for arm, I think it 
would be rather sad if pc wasn't converted to it by 2017...

> then turns on the power.  Command line options are the parts lying 
> around when we start.
>
> btw, -drive needs to be separated:
>
>   -controller type=lsi1234,pci_addr=foobar,name=blah
>   -drive file=foo.img,controller=blah,index=0
>   -drive file=bar.img,controller=blah,index=1
>
> Drives to not have pci addresses.

Drivers don't have indexes and buses but we specify it on the -drive 
line.  -drive is convenient syntax.  It stops being convenient when you 
force it to be two options.

Regards,

Anthony Liguori