RE: [Xen-devel] 82576 VF passthrough

["Rose, Gregory V" <gregory.v.rose@xxxxxxxxx>]

I've only ever used HVMs.  I can't say whether VF passthrough to a PV guest works or not but I can't think of any reason it wouldn't.  Can you pass other devices through to this PV guest?  If so then a VF should work also.  Generally any guest that you can a physical device through will also work with a VF device.

 

Next thing to consider is whether your BIOS supports SR-IOV.  There are a lot of machines that have the necessary HW to support SR-IOV but the BIOS does not properly detect SR-IOV capable devices and program the upstream switches and bridges properly to make sure the I/O aperture is large enough to accommodate the extra VF devices when they are enabled by the driver.  There are very few BIOS vendors shipping SR-IOV capable BIOS at the moment.  If your machine does not have the right BIOS then there is a work around in the Xen 3.4 release that you can use.  Or at least I think it's still there.

 

pci=assign-mmio=0000:01

 

Try adding that to your kernel command line but substitute the domain/bus of your device.  For instance if your Kawela is on bus 4 then you would change the command to pci=assign-mmio=0000:04.

 

Hope that helps.

 

- Greg

 

---

From: Satish Chowdhury [mailto:satish.chowdhury@xxxxxxxxxxxxxxxxxx]
Sent: Thursday, September 24, 2009 10:32 PM
To: Rose, Gregory V
Cc: Simon Horman; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] 82576 VF passthrough

Hi Greg,
I am using Vt-d machine. Sorry for the confusion.
My Hardware is HP  dc7800p Chipset: Q35, with Intel Core 2 Duo E8400 processor. NIC Card  is 82576 E1G42ET (dual port RJ-45 copper).

Is VF passthrough can be done only to HVM guest? Is VF passthrough to paravirtal guest is supported?

Regards,
-Satish

On Fri, Sep 25, 2009 at 10:36 AM, Rose, Gregory V <gregory.v.rose@xxxxxxxxx> wrote:

>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of
>Simon Horman
>Sent: Wednesday, September 23, 2009 4:25 PM
>To: Satish Chowdhury
>Cc: xen-devel@xxxxxxxxxxxxxxxxxxx

>Subject: Re: [Xen-devel] 82576 VF passthrough
>

>On Thu, Sep 24, 2009 at 12:26:25AM +0530, Satish Chowdhury wrote:
>> Hi,
>>
>> I am trying to setup 82576 VF passthrough to pv domU non
>Vt-d machine

You can't run SR-IOV VF devices in VM guests on a non Vt-d machine.  VT-d is required for VF passthrough to a guest.

- Greg
LAD
Intel Corp.

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