RE: [Xen-devel] RE: PCI devices remap from dom0 to domU with pv-ops kernel

["Lin, Ray" <Ray.Lin@xxxxxxx>]

Thanks. I'll look into it.


-Ray 

-----Original Message-----
From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@xxxxxxxxxx] 
Sent: Thursday, October 14, 2010 10:49 AM
To: Lin, Ray
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx; bruce.edge@xxxxxxxxx
Subject: Re: [Xen-devel] RE: PCI devices remap from dom0 to domU with pv-ops 
kernel

On Thu, Oct 14, 2010 at 11:26:03AM -0600, Lin, Ray wrote:
> 
> Konrad,
> 
>   We choose "Virtual" and the dom0/domU show like this. It doesn't remap to 
> what we want. You mentioned about "write your own plugin that would do 
> remapping per your desire". Could you elaborate it a bit ? Thanks.

Sure. Look in drivers/xen/pciback. There are four files of interest:

vpci.c
slot.c
passthrough.c
controller.c

By default, the vpci.c is selected, where in the domU the devices start from 
00:00.0. The passthrough is obvious. 

The slot.c is where we have only two bus and all the devices are stuck under 
the slots.
So a maximum of 64 devices, and the device function is ignored:

This is what it would show up (I think, you might want to double-check this):
00:01.0:0c04: 11f8:8032 (rev 08)
00:02.0:0c04: 11f8:8032 (rev 08)
00:03.0:0c04: 11f8:8032 (rev 08)
00:04.0:0c04: 11f8:8032 (rev 08)

The controller, is "PCI "Controller" Backend - virtualize PCI bus topology 
based on PCI  controllers.  Devices under the same PCI controller are exposed 
on the  same virtual domain:bus.  Within a bus, device slots are virtualized  
to compact the bus. " (from controller.c)

I think based on what you said earlier, you just want to use the "slot" backend:
CONFIG_XEN_PCIDEV_BACKEND_SLOT=y
> 
> Dom0:
> kaan-18:~# lspci -n | grep 11f8
> 07:00.0 0c04: 11f8:8032 (rev 08)
> 07:00.1 0c04: 11f8:8032 (rev 08)
> 07:00.2 0c04: 11f8:8032 (rev 08)
> 07:00.3 0c04: 11f8:8032 (rev 08)
> 
> DomU:
> kaan-18-dpm:~# lspci -n
> 00:00.0 0c04: 11f8:8032 (rev 08)
> 00:00.1 0c04: 11f8:8032 (rev 08)
> 00:00.2 0c04: 11f8:8032 (rev 08)
> 00:00.3 0c04: 11f8:8032 (rev 08)
> 
> 
> -Ray
> 
> -----Original Message-----
> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@xxxxxxxxxx]
> Sent: Wednesday, October 13, 2010 11:52 AM
> To: Lin, Ray
> Cc: bruce.edge@xxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: PCI devices remap from dom0 to domU with pv-ops kernel
> 
> On Wed, Oct 13, 2010 at 10:49:12AM -0600, Lin, Ray wrote:
> > 
> > Konrad,
> > 
> >     We try to remap the pci devices from dom0 to domU by assigning 
> > the pci in the domU configuration file. Such as
> > 
> >     pci="['01:00.0@11', '01:00.1@10', '04:00.0@13', '04:00.1@12']"
> > 
> > In hvm kernel, the domU would see the pci devices remapped like 
> > this,
> > 
> >     dom0 pci device 01:00.0   => domU pci device 00:11.0
> >     dom0 pci device 01:00.1  =>  domU pci device 00:10.0
> >     dom0 pci device 04:00.0  =>  domU pci device 00:13.0
> >     dom0 pci device 04:00.1  =>  domU pci device 00:12.0
> > 
> >  But pv-ops kernel seems ignore the remapping. Is there any way (kernel 
> > configuration setting ??) to make it work ?
> 
> Not completly.
> 
> When you compile your Xen PCI backend, you should see an option whether you 
> want Virtual PCI, Passthrough or some other type. By default it will pick the 
> Virtual one so that it just enumerates from zero the PCI devices. You could 
> write your own plugin that would do remaping per your desire.
> > 
> > Thanks,
> > Ray
> > 
> > 
> 
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