Re: [PATCH 0/16 v6] PCI: Linux kernel SR-IOV support

From: Matthew Wilcox
Date: Thu Nov 06 2008 - 12:48:17 EST


On Thu, Nov 06, 2008 at 08:49:19AM -0800, Greg KH wrote:
> On Thu, Nov 06, 2008 at 08:41:53AM -0800, H L wrote:
> > I have not modified any existing drivers, but instead I threw together
> > a bare-bones module enabling me to make a call to pci_iov_register()
> > and then poke at an SR-IOV adapter's /sys entries for which no driver
> > was loaded.
> >
> > It appears from my perusal thus far that drivers using these new
> > SR-IOV patches will require modification; i.e. the driver associated
> > with the Physical Function (PF) will be required to make the
> > pci_iov_register() call along with the requisite notify() function.
> > Essentially this suggests to me a model for the PF driver to perform
> > any "global actions" or setup on behalf of VFs before enabling them
> > after which VF drivers could be associated.
>
> Where would the VF drivers have to be associated? On the "pci_dev"
> level or on a higher one?
>
> Will all drivers that want to bind to a "VF" device need to be
> rewritten?

The current model being implemented by my colleagues has separate
drivers for the PF (aka native) and VF devices. I don't personally
believe this is the correct path, but I'm reserving judgement until I
see some code.

I don't think we really know what the One True Usage model is for VF
devices. Chris Wright has some ideas, I have some ideas and Yu Zhao has
some ideas. I bet there's other people who have other ideas too.

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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