Re: [Xen-API] PCI passthrough - XCP vs XenServer

[Dave Scott <Dave.Scott@xxxxxxxxxxxxx>]

Hi Phil,

There's a difference between what /should/ work in the code, versus what a 
particular commercial support organization is prepared to help you with. The 
code for XCP and XenServer is the same. Generally in the XenServer/XCP code PCI 
pass through should work, although so far it's only commercially supported in 
special cases. 

I expect PCI pass through to become more and more common in future. It's 
especially important for "Windsor": our planned disaggregated architecture for 
XenServer. Therefore I expect the code will become more and more polished and 
reliable over time-- this is where your feedback could be really useful!

My advice is to give it a go, and report back to the list on what works (and 
what doesn't). To request a device passthrough, you'll need to add an 
"other-config" "pci" key via the CLI, naming the bus, device and function you 
want to passthrough. Try something like:

xe vm-param-set uuid=... other-config:pci=0/0000:bus:dev.fun,1/0000:bus:dev.fun2

Be careful to always pass through all functions of multi-function devices (some 
hardware doesn't like it when the functions are separated) and beware the code 
paths are different for HVM and PV. I would recommend installing a modern Linux 
distro as HVM (easiest done in XenServer by using the "other install media" 
template), and use that. For reference, I often use Ubuntu 12.04 but anything 
modern should be ok. 

Use the most recent version of the XenServer code that you can. Conveniently an 
update was released last week -- I recommend grabbing 6.2 from xenserver.org.

What kind of DVB-T tuners have you got? I was considering something similar 
myself with one of mine.

Cheers,
-- 
Dave Scott
XenServer System Architect

On Jun 30, 2013, at 8:42 AM, "Phill Edwards" <philledwards@xxxxxxxxx> wrote:

> I've been running the free version of Citrix XenServer for a while and
> I now want to set up some PCI devices with PCI passthrough. I don't
> believe this is possible on Citrix XenServer other than for video
> cards which I'm not interested in (my PCI devices are DVB-T TV tuner
> cards).
> 
> So I then started looking at XCP but I've found it difficult
> understanding whether this may be possible in XCP or not. My confusion
> is now further compounded by the fact that when you now go to download
> XCP from http://www.xenproject.org/downloads/xen-cloud-platform-archives.html
> it advises you to download the recently open sourced XenServer
> instead. That of course will get me nowhere if PCI passthrough isn't
> well supported on XenServer.
> 
> So if I download and install XCP amd I likely to make make much
> progress on this or am I pushing stuff uphill?
> 
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