From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Wang2 Subject: Re: [PATCH] msi: Avoid uninitialized msi descriptors Date: Thu, 12 Aug 2010 15:30:24 +0200 Message-ID: <201008121530.25037.wei.wang2@amd.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: Xen-devel , Dante Cinco List-Id: xen-devel@lists.xenproject.org Keir, I would suggest to backport this patch. I saw the same issue on both Xen-4.= 0.1=20 RC6 and xen-unstable. Actually, some MSI-X capable devices will also offer= =20 MSI capabilities. For such device, MSI will be enabled first by OS. When gu= est=20 driver (like Broadcom driver) detects multiple vcpus, it will disable MSI a= nd=20 enable MSI-X block for better cpu-interrupt affinity. In this case, the who= le=20 system crashes. But on UP system, only MSI block will be enabled, it migh= t=20 still work even without the fix. Thanks, Wei On Wednesday 11 August 2010 19:36:47 Keir Fraser wrote: > On 11/08/2010 18:09, "Dante Cinco" wrote: > > I'm glad that somebody who is familiar with MSI has resolved this > > problem although I haven't applied and verified the proposed patch yet > > on my system. I posted the Xen crash I experienced related to this > > issue on xen-devel a couple of weeks ago (see link below) but wasn't > > familiar enough with the MSI/MSI-X code to propose a solution other > > than to back out changelist 21778. > > Let me know when you confirm. I backported 21778 for 4.0.1, perhaps in too > much haste. If this is a good fix then I should backport it as well. > > Thanks, > Keir > > > http://old.nabble.com/Re:-(XEN)-RIP:-e008:-%3Cffff82c48015564b%3E---wri= te > >_msi_ msg%2B0x2b-0x150-p29301832.html > > > > Dante > > > > > > -----Original Message----- > > From: xen-devel-bounces@lists.xensource.com > > [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Wei Wang2 > > Sent: Wednesday, August 11, 2010 6:43 AM > > To: xen-devel@lists.xensource.com > > Subject: [Xen-devel] [PATCH] msi: Avoid uninitialized msi descriptors > > > > Hi, > > When __pci_enable_msix() returns early, output parameter (struct msi_de= sc > > **desc) will not be initialized. On my machine, a Broadcom BCM5709 > > nic has both MSI and MSIX capability blocks and when guest tries to > > enable msix interrupts but __pci_enable_msix() returns early for > > encountering a msi block, the whole system will crash for fatal page > > fault immediately. > > > > Thanks, > > Wei > > > > Signed-off-by: Wei Wang > > -- > > AMD GmbH, Germany > > Operating System Research Center > > > > Legal Information: > > Advanced Micro Devices GmbH > > Karl-Hammerschmidt-Str. 34 > > 85609 Dornach b. M=FCnchen > > > > Gesch=E4ftsf=FChrer: Andrew Bowd, Thomas M. McCoy, Giuliano Meroni > > Sitz: Dornach, Gemeinde Aschheim, Landkreis M=FCnchen Registergericht > > M=FCnchen, HRB Nr. 43632 > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xensource.com > > http://lists.xensource.com/xen-devel