Re: basic support for (software concept) "pci domains" in the MI pci code

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Aug 24, 2009 at 12:54:37PM +0200, Christoph Egger wrote:
> On Monday 24 August 2009 11:58:46 Manuel Bouyer wrote:
> > On Mon, Aug 24, 2009 at 11:47:59AM +0200, Christoph Egger wrote:
> > > In newer Xen versions, PCI passthrough works this way:
> > >
> > > xm help  enlists these commands:
> > >
> > >  pci-attach           Insert a new pass-through pci device.
> > >  pci-detach           Remove a domain's pass-through pci device.
> > >  pci-list                  List pass-through pci devices for a domain.
> > >  pci-list-assignable-devices   List all the assignable pci devices
> > >
> > >
> > > 1. Enlist all PCI devices you may assign a domU
> > >
> > > # xm pci-list-assignable-devices
> > > 0000:02:00.0
> > > 0000:02:00.1
> > >
> > > 2. Assign these two devices to the first domU
> > >
> > > # xm pci-attach 1 0000:02:00.0
> > > # xm pci-attach 1 0000:02:00.1
> > >
> > > 3. List devices assigned to first domU
> > >
> > > # xm pci-list 1
> > > VSlt domain bus  slot func
> > > 0x06 0x0000 0x02 0x00 0x0
> > > 0x07 0x0000 0x02 0x00 0x1
> > >
> > > "VSlt" is the "virtual slot"
> >
> > I can't see wht this can't work with NetBSD now, as this uses the same
> > infos as Xen 3.1. domain is hardwired to 0, and we can get bus, slot and
> > func from the kernel though pcictl. The patch I added to xentools3 just
> > needs to be ported to xentools33. As I don't speak python I can't easily do
> > it myself ...
> 
> There are machines with multiple PCI host controllers.
> Let's take the PCI topology on your alpha as an example:
> 
> tsc0 at mainbus0: 21272 Core Logic Chipset, Cchip rev 0
> tsc0: 4 Dchips, 1 memory bus of 32 bytes
> tsc0: arrays present: 1024MB (split), 0MB, 0MB, 0MB, Dchip 0 rev 1
> tsp0 at tsc0
> pci0 at tsp0 bus 0
> tsp1 at tsc0
> pci1 at tsp1 bus 0
> 
> With PCI domains hardwired to 0, xm pci-list-assignable-devices can print
> 
> 0000:00:00.0
> 0000:00:00.0

Or
0000:00:00.0
0000:01:00.0

as you can use the autoconfig index as bus number.

Also I'm not sure we can have the same bus number twice on x86 these
days, because the BIOS needs the bus number to be unique AFAIK.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--