From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753487AbbANO6j (ORCPT ); Wed, 14 Jan 2015 09:58:39 -0500 Received: from smtp.citrix.com ([66.165.176.89]:8739 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753057AbbANO6i (ORCPT ); Wed, 14 Jan 2015 09:58:38 -0500 X-IronPort-AV: E=Sophos;i="5.07,756,1413244800"; d="scan'208";a="215970190" Message-ID: <54B68419.9010503@citrix.com> Date: Wed, 14 Jan 2015 14:58:33 +0000 From: David Vrabel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.2.0 MIME-Version: 1.0 To: Sander Eikelenboom , Jiang Liu , Konrad Rzeszutek Wilk CC: , Subject: Re: 3.19-rc4: Xen pci-passthrough regression, bisected to commit cffe0a2b5a34c95a4dadc9ec7132690a5b0f6687 "x86, irq: Keep balance of IOAPIC pin reference count" References: <74756708.20150114151521@eikelenboom.it> In-Reply-To: <74756708.20150114151521@eikelenboom.it> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/01/15 14:15, Sander Eikelenboom wrote: > Hi Gerry / David / Konrad, > > Some more testing uncovered another issue under Xen, this time with PCI-passthrough. What device? In particular what interrupts is it using? > I have bisected it to the following commit: > cffe0a2b5a34c95a4dadc9ec7132690a5b0f6687 "x86, irq: Keep balance of IOAPIC pin reference count" > > It causes these symptoms: > > - On Intel > - Running on Xen with pci devices seized on host boot with xen-pciback.hide= parameter > - Running a HVM guest with PCI passthrough of two devices (NIC + wireless NIC) > - While the driver loads fine, the device isn't working properly, looking in /proc/interrupts in the guest > shows that it doesn't receive any interrupts. > - Reverting this particular commit (in the dom0 kernel only) makes the device receive interrupts and work properly again. > > - On AMD (more subtle symptom) > - Running on Xen with pci devices seized on host boot with xen-pciback.hide= parameter > - Running a HVM guest with PCI passthrough of one devices (videograbber) > - While the driver loads fine and the device looks like it's working, the videostream isn't stable and it skips or repeats frames. > - Reverting this particular commit (in the dom0 kernel only) makes the device work properly again with a stable videostream. > > -- > Sander >