Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751918AbYKFSEU (ORCPT ); Thu, 6 Nov 2008 13:04:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750842AbYKFSEG (ORCPT ); Thu, 6 Nov 2008 13:04:06 -0500 Received: from kroah.org ([198.145.64.141]:38381 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750827AbYKFSEE (ORCPT ); Thu, 6 Nov 2008 13:04:04 -0500 Date: Thu, 6 Nov 2008 10:03:54 -0800 From: Greg KH To: "Fischer, Anna" Cc: H L , "randy.dunlap@oracle.com" , "grundler@parisc-linux.org" , "Chiang, Alexander" , "matthew@wil.cx" , "linux-pci@vger.kernel.org" , "rdreier@cisco.com" , "linux-kernel@vger.kernel.org" , "jbarnes@virtuousgeek.org" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "mingo@elte.hu" Subject: Re: [PATCH 0/16 v6] PCI: Linux kernel SR-IOV support Message-ID: <20081106180354.GA17429@kroah.com> References: <20081106154351.GA30459@kroah.com> <894107.30288.qm@web45108.mail.sp1.yahoo.com> <20081106164919.GA4099@kroah.com> <0199E0D51A61344794750DC57738F58E5E26F996C4@GVW1118EXC.americas.hpqcorp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0199E0D51A61344794750DC57738F58E5E26F996C4@GVW1118EXC.americas.hpqcorp.net> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3339 Lines: 74 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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/