On Thu, Nov 06, 2008 at 03:54:06PM -0800, Chris Wright wrote: > * Greg KH (greg@xxxxxxxxx) wrote: > > On Thu, Nov 06, 2008 at 10:47:41AM -0700, Matthew Wilcox wrote: > > > 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. > > > > Hm, I would like to see that code before we can properly evaluate this > > interface. Especially as they are all tightly tied together. > > > > > 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. > > > > I'd love to hear those ideas. > > First there's the question of how to represent the VF on the host. > Ideally (IMO) this would show up as a normal interface so that normal tools > can configure the interface. This is not exactly how the first round of > patches were designed. > > Second there's the question of reserving the BDF on the host such that > we don't have two drivers (one in the host and one in a guest) trying to > drive the same device (an issue that shows up for device assignment as > well as VF assignment). > > Third there's the question of whether the VF can be used in the host at > all. > > Fourth there's the question of whether the VF and PF drivers are the > same or separate. > > The typical usecase is assigning the VF to the guest directly, so > there's only enough functionality in the host side to allocate a VF, > configure it, and assign it (and propagate AER). This is with separate > PF and VF driver. > > As Anthony mentioned, we are interested in allowing the host to use the > VF. This could be useful for containers as well as dedicating a VF (a > set of device resources) to a guest w/out passing it through. All of this looks great. So, with all of these questions, how does the current code pertain to these issues? It seems like we have a long way to go... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
