On Thu, Nov 06, 2008 at 05:38:16PM +0000, Fischer, Anna 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? > > A VF appears to the Linux OS as a standard (full, additional) PCI > device. The driver is associated in the same way as for a normal PCI > device. Ideally, you would use SR-IOV devices on a virtualized system, > for example, using Xen. A VF can then be assigned to a guest domain as > a full PCI device. It's that "second" part that I'm worried about. How is that going to happen? Do you have any patches that show this kind of "assignment"? > > Will all drivers that want to bind to a "VF" device need to be > > rewritten? > > Currently, any vendor providing a SR-IOV device needs to provide a PF > driver and a VF driver that runs on their hardware. Are there any such drivers available yet? > A VF driver does not necessarily need to know much about SR-IOV but > just run on the presented PCI device. You might want to have a > communication channel between PF and VF driver though, for various > reasons, if such a channel is not provided in hardware. Agreed, but what does that channel look like in Linux? I have some ideas of what I think it should look like, but if people already have code, I'd love to see that as well. > > > I have so far only seen Yu Zhao's "7-patch" set. I've not yet looked > > > at his subsequently tendered "15-patch" set so I don't know what has > > > changed. The hardware/firmware implementation for any given SR-IOV > > > compatible device, will determine the extent of differences required > > > between a PF driver and a VF driver. > > > > Yeah, that's what I'm worried/curious about. Without seeing the code > > for such a driver, how can we properly evaluate if this infrastructure > > is the correct one and the proper way to do all of this? > > Yu's API allows a PF driver to register with the Linux PCI code and > use it to activate VFs and allocate their resources. The PF driver > needs to be modified to work with that API. While you can argue about > how that API is supposed to look like, it is clear that such an API is > required in some form. I totally agree, I'm arguing about what that API looks like :) I want to see some code... 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
