From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: xen-unstable warn_on in msi.c:636 Date: Mon, 1 Aug 2011 14:16:01 +0100 Message-ID: <4E36A711.3060007@citrix.com> References: <4E32D1C20200007800073CFD@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4E32D1C20200007800073CFD@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: George Dunlap , Olaf Hering , Yunhong Jiang , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 29/07/11 15:29, Jan Beulich wrote: >>>> On 30.06.11 at 15:31, George Dunlap wrote: >> On Thu, Jun 30, 2011 at 1:17 PM, Jan Beulich wrote: >>>>>> On 30.06.11 at 14:03, George Dunlap wrote: >>>> Olaf / Jan / all, what do you think of the attached patch, which >>>> teaches the MSI code how to deal with 0 pbas? >>> No, definitely not an option. They simply must not be zero. The >>> problem just is that the BARs for virtual functions all read as zero >>> (and the real value must be calculated from information from the >>> PF's config space). >> But at the moment it IS zero, and this "real value" is simply not >> being calculated. >> >> I realize this needs to be fixed the Right Way eventually, but at the >> moment anyone who uses SRIOV will have a bunch of scary warnings which >> they can't do anything about except ignore; and it's never a good idea >> to condition people to ignore this kind of warning. >> >> If the current situation is safe enough that fixing it is a low >> priority, then it's safe enough to remove the warnings for the time >> being. If it's not safe enough to remove the warnings, then it's not >> safe enough to leave and a fix needs to be a priority. > Attached a patch that eliminates the warnings for me (tested on a single > system only so far). It ought to apply cleanly to current tip of -unstable. > > Jan Tested on 2 Citrix SR-IOV boxes: 1) Dell R710 with igb, ixgbe and sfc virtual functions 2) Netscalar with 320 individual ixgbe virtual functions across 40 VMs I tested against our Xen-4.1.1, but the patch applied cleanly. There seems no adverse affect on VF functionality. -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com