From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41884) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XztRC-0000mW-Ex for qemu-devel@nongnu.org; Sat, 13 Dec 2014 15:37:23 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XztR3-000438-Cl for qemu-devel@nongnu.org; Sat, 13 Dec 2014 15:37:14 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:35880 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XztR3-00042l-1u for qemu-devel@nongnu.org; Sat, 13 Dec 2014 15:37:05 -0500 Message-ID: <548CA35D.4050804@kamp.de> Date: Sat, 13 Dec 2014 21:36:45 +0100 From: Peter Lieven MIME-Version: 1.0 References: <548B605B.6030002@kamp.de> <1418422905.1095.189.camel@bling.home> In-Reply-To: <1418422905.1095.189.camel@bling.home> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] vfio-pci issues with multiple devices on the same root port List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: "qemu-devel@nongnu.org" Am 12.12.2014 um 23:21 schrieb Alex Williamson: > On Fri, 2014-12-12 at 22:38 +0100, Peter Lieven wrote: >> Hi, >> >> we have a Cisco UCS infrastructure where we have fnic Fibre-Channel Adapters that we expose to guests. The UCS >> infrastruture allows to create virtual HBAs that can be exposed to a host so its possible to have quite a lot of them. >> >> We ran into a strange issue when we started having more than one vServer with a FibreChannel Adapter passed >> thru with vfio-pci. >> >> When a hypervisor shuts down it the kernel sees the following error: >> >> pcieport 0000:00:07.0: AER: Uncorrected (Non-Fatal) error received: id=0038 >> pcieport 0000:00:07.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, id=0038(Receiver ID) >> pcieport 0000:00:07.0: device [8086:340e] error status/mask=00200000/00100000 >> pcieport 0000:00:07.0: [21] Unknown Error Bit (First) >> pcieport 0000:00:07.0: broadcast error_detected message >> pcieport 0000:00:07.0: AER: Device recovery failed >> >> Bit 21 seems to be ACS Violation. And 0000:00:07.0 is the PCIE Root Port on that System. >> >> This wouldn't be a big problem, altough I would like to find out what the ACS Violation causes. >> >> The real problem is that all other vfio-pci cards on that root port get notified of this error and the connected vServers are suspended >> with RUN_STATE_INTERNAL_ERROR. >> >> Any ideas to work around this other than hacking qemu to not register an error handler or modifying vfio_err_notifier_handler >> to not suspend the vServer? > You could set bit 21 in the AER uncorrected error mask register to avoid > the root port signaling the error. Is bit 21 already clear in the > severity register to make this non-fatal? Can you give me a hint where I find those registers and how I mangle them? At least the syslog output states non-fatal. I am not that familiar with PCI internals, I am more the Block Layer guy. > >> Is it correct that all children of a root port are notified? Should qemu distinguish between fatal and non-fatal errors when >> suspending a vServer? > Yes, each child is notified. QEMU only gets an eventfd signal, which is > supposed to occur only for fatal errors. I don't quite understand why > this apparently non-fatal error is getting through. The kernel-side > VFIO code is where filtering of fatal vs non-fatal should occur. I will look at that. Has there been any bugfix since 3.13 ? Peter