From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lu Baolu Subject: Re: [RFC PATCH] iommu/vt-d: Fix IOMMU field not populated on device hot re-plug Date: Tue, 8 Oct 2019 10:27:57 +0800 Message-ID: <0131be21-0ae3-ac1e-6ee3-c256e3d2a38f@linux.intel.com> References: <20190822142922.31526-1-janusz.krzysztofik@linux.intel.com> <52fbfac9-c879-4b45-dd74-fafe62c2432b@linux.intel.com> <2674326.ZPvzKFr69O@jkrzyszt-desk.ger.corp.intel.com> <7739498.9tyZrNxj5X@jkrzyszt-desk.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <7739498.9tyZrNxj5X-RCb3PieevP79BXuAQUXR0fooFf0ArEBIu+b9c/7xato@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Janusz Krzysztofik Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, =?UTF-8?Q?Micha=c5=82_Wajdeczko?= , David Woodhouse , intel-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org List-Id: intel-gfx@lists.freedesktop.org Hi, On 10/1/19 11:01 PM, Janusz Krzysztofik wrote: > Hi Baolu, > > On Tuesday, September 3, 2019 9:41:23 AM CEST Janusz Krzysztofik wrote: >> Hi Baolu, >> >> On Tuesday, September 3, 2019 3:29:40 AM CEST Lu Baolu wrote: >>> Hi Janusz, >>> >>> On 9/2/19 4:37 PM, Janusz Krzysztofik wrote: >>>>> I am not saying that keeping data is not acceptable. I just want to >>>>> check whether there are any other solutions. >>>> Then reverting 458b7c8e0dde and applying this patch still resolves the >> issue >>>> for me. No errors appear when mappings are unmapped on device close after >> the >>>> device has been removed, and domain info preserved on device removal is >>>> successfully reused on device re-plug. >>> >>> This patch doesn't look good to me although I agree that keeping data is >>> acceptable. > > Any progress with that? Which mailing list should I watch for updates?\ We had a holiday last week. I will go ahead with reproducing it locally. Feel free to let me know if you have any new proposal. Best regards, Baolu > > Thanks, > Janusz > >>> It updates dev->archdata.iommu, but leaves the hardware >>> context/pasid table unchanged. This might cause problems somewhere. >>> >>>> >>>> Is there anything else I can do to help? >>> >>> Can you please tell me how to reproduce the problem? >> >> The most simple way to reproduce the issue, assuming there are no non-Intel >> graphics adapters installed, is to run the following shell commands: >> >> #!/bin/sh >> # load i915 module >> modprobe i915 >> # open an i915 device and keep it open in background >> cat /dev/dri/card0 >/dev/null & >> sleep 2 >> # simulate device unplug >> echo 1 >/sys/class/drm/card0/device/remove >> # make the background process close the device on exit >> kill $! >> >> Thanks, >> Janusz >> >> >>> Keeping the per >>> device domain info while device is unplugged is a bit dangerous because >>> info->dev might be a wild pointer. We need to work out a clean fix. >>> >>>> >>>> Thanks, >>>> Janusz >>>> >>> >>> Best regards, >>> Baolu >>> >> >> >> >> >> > > > > >