Re: Xen support for PCI-SIG I/O Virtualization

[Greg Law <glaw@solarflare.com>]

Masroor Vettuparambil wrote:
> Hi,
>  
> what is the current support of Xen for PCI-SIG IOV SR/MR spec?
> I have a PCIe device which supports multiple virtual functions(VF), and 
> want to enable direct assignment of each of these VFs to different domUs.
> So is it possible to assign a PCIe virtual channel/function to domU 
> directly?

Have you seen the work we did recently to allow smart NIC's to be 
accessed directly from the guest?  Essentially your "accelerated" driver 
is a plugin to netfront (which knows how to send/receive packets with 
safe direct access hardware to the NIC), and a plugin for netback which 
deals with the privileged part of programming the NIC (e.g. creating 
virtual devices and handing them out to the guests as appropriate). 
Among other things, this architecture means you can support migrating to 
machines with no smart hardware, or a different smart NIC.

Let me know if you want to know more.

As far as programming the IOMMU goes, I've seen various patches flying 
around so I know work has been done here, but I don't know any more than 
that.

Cheers,

Greg
-- 
Greg Law                                              +44 1223 518 040