[vfio-users] sr-iov support on main boards

[Taiidan at gmx.com]

On 07/24/2017 03:35 AM, Torbjorn Jansson wrote:

> Hello.
>
> i'm considering upgrading my linux box that i use for virtualization 
> (i5-3470, Z77 mb).
> at the moment i have a successfully working setup where i pass thru a 
> gtx970 to a windows vm.
> i also have an aging 4 port network card, see below:
> ------
> 04:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit 
> Ethernet Controller (Copper) (rev 06)
> 04:00.1 Ethernet controller: Intel Corporation 82571EB Gigabit 
> Ethernet Controller (Copper) (rev 06)
> 05:00.0 Ethernet controller: Intel Corporation 82571EB Gigabit 
> Ethernet Controller (Copper) (rev 06)
> 05:00.1 Ethernet controller: Intel Corporation 82571EB Gigabit 
> Ethernet Controller (Copper) (rev 06)
> ------
>
> i was thinking of replacing this card since i at the moment can't 
> assign this in a good way, my only option now is to assign all 4 ports 
> to same vm which doesn't really help.
>
> so, i was thinking of getting a x99 based mb, a xeon e5 v4 cpu and a 
> I350-T2 network card that supports sr-iov.
A consumer board will probably not support it.
> question is, how do i know that the main board also have the necessary 
> bits for sr-iov support?
> as i understand it, the bios have to do something too to make it work.
You would have to ask the OEM.
> main boards i was considering was MSI X99A gaming 7 and also ASUS 
> X99-E WS.
> the msi board have a nice block diagram that says how things is 
> connected and manual looks abit better
Consumer boards probably won't support SR-IOV, ARI, ACS etc anything you 
need to do real virtualization besides just HVM they probably won't have 
and the vendor won't care :[ sad as gaming in a VM is common these days.
> my thinking was that maybe a workstation mb have higher probability of 
> better support for more advanced features like this.
> but this might be an incorrect assumption.
Yes it would, but as always you need to make sure.
> any advice would be welcomed.
If you want to do this for cheap I would pick up a used server from a 
few generations ago off ebay that supports it from one of the major 
vendors such as dell/hpe, there are many forums that will help you with 
this.