From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Re: [vt-d][xen4-rc6] Hangs on startup Date: Mon, 22 Mar 2010 18:05:43 -0400 Message-ID: <20100322220543.GB1073@phenom.dumpdata.com> References: <20100317201446.GA7785@phenom.dumpdata.com> <20100318141909.GA14445@phenom.dumpdata.com> <20100322195010.GB32073@phenom.dumpdata.com> <8115AF16522A3D4383C1FF753036713F9B3AAA31@cosmail01.lsi.com> <20100322205428.GA428@phenom.dumpdata.com> <8115AF16522A3D4383C1FF753036713F9B3AAA7D@cosmail01.lsi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <8115AF16522A3D4383C1FF753036713F9B3AAA7D@cosmail01.lsi.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: "Nadolski, Ed" Cc: =?utf-8?B?xYF1a2FzeiBPbGXFmw==?= , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Mon, Mar 22, 2010 at 04:11:34PM -0600, Nadolski, Ed wrote: > > -----Original Message----- > > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > > Sent: Monday, March 22, 2010 2:54 PM > > To: Nadolski, Ed > > Cc: =C5=81ukasz Ole=C5=9B; xen-devel@lists.xensource.com > > Subject: Re: [Xen-devel] Re: [vt-d][xen4-rc6] Hangs on startup > >=20 > > On Mon, Mar 22, 2010 at 03:06:48PM -0600, Nadolski, Ed wrote: > > > > > > > > > > -----Original Message----- > > > > > > > PCI back is to be used _only_ with PV guests - you on the other > > > > hand are running an HVM guest. > > > > > > > > Per the earlier statement, I would recommend you use the 'pciback= ' > > > > instead of 'pci-stub' or just not compile pciback in and see what > > > > happens. Keep in mind: PCI back module is only needed when you wa= nt > > to > > > > do PV PCI passthrough, which is not what you are doing. > > > > > > I'm confused - does that mean pci-stub must be used for device > > assignment to an HVM guest? The VTdHowTo isn't clear on that. > >=20 > > Not per say. > >=20 > > xen-pciback can be used for both PV and HVM. >=20 > OK then what is the difference between pciback and xen-pciback? I thou= ght they were just a re-name, but there must be more than that if one sup= ports HVM and the other doesn't. That is is. Just a rename. >=20 >=20 > > pci-stub can only be used for HVM guests. >=20 > OK, but then why would I ever want to use pci-stub, if xen-pciback alre= ady does both? Uhh.. you probably wouldn't. But the pci-stub code has been in existence in the Linux kernel for some time.. >=20 >=20 >=20 > > But there seems to be a bug somewhere that when the PCI device is > > assigned to pci-stub, pciback tries to seize it and can't find it and > > somehow is stuck in a spin-lock. That shouldn't be happening. > >=20 > > Right now I am trying to figure out if we remove from Lukasza system > > pciback and only use pci-stub whether he still gets those MFN lookup > > errors with his QLogic card. Those are, I believe, a seperate issue > > from the pciback spinlock failure. >=20 > Yes, those sound like two different things. >=20 > I too am seeing problems with a Qlogic card in an HVM. It looks like m= y card's BIOS makes an INT1A call (FIND PCI DEVICE function) that fails w= hen the HVM is booting, and the code hangs forever. I would think this would work as the Bochs BIOS is actually being used with real hardware. Is it possible that some data-structure that Bochs BIOS has for the PCI enumeration is not up-to-date with the hvmloader sets up?=20 What about the BDF numbers? Any chance of trying to make them 1-to-1 (so what you see in Dom0 is what you would see in DomU)? Maybe there is an option in QEMU to do that? What about passing in the PCI device _after_ the OS has booted. You can do that by using 'pci-attach' (or something) flags. That will mean no BIOS initialization, but the qla2xxx driver might be OK with that. > But AFAICT it looks like Lukasz's latest trace hasn't gotten to the poi= nt where it tries to load the PCI option ROM from the card. I would be i= nterested to see if his card sees that error or not, once the MFN is reso= lved. >=20 > Has anyone used these Qlogic cards successfully under VT-d in a Xen HVM= ? I don't know of any reason why they should not work. I'm assuming (ho= ping) that they are virtualization-friendly enough to work under VT-d. I think you and Lukasz are the first ones.