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

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

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

I don't see how 'xm pci-attach 0000:00:00.0' works w/o PCI domains.

Christoph