From: Baoquan He Subject: Re: [PATCH v5 5/8] iommu/amd: copy old trans table from old kernel Date: Wed, 28 Sep 2016 21:01:36 +0800 Message-ID: <20160928130136.GA9185@x1.redhat.com> References: <1473951806-25511-1-git-send-email-bhe@redhat.com> <1473951806-25511-6-git-send-email-bhe@redhat.com> <20160920124031.GD3541@8bytes.org> <20160928013702.GH14155@x1.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160928013702.GH14155-ejN7fcUYdH/by3iVrkZq2A@public.gmane.org> 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: Joerg Roedel Cc: kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vincent.Wan-5C7GfCeVMHo@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On 09/28/16 at 09:37am, Baoquan He wrote: > Hi Joerg, > > On 09/20/16 at 02:40pm, Joerg Roedel wrote: > > > + if ( !is_pre_enabled) { > > > + for_each_iommu(iommu) > > > + early_enable_iommu(iommu); > > > + } else { > > > + if (copy_dev_tables()) { > > > + pr_err("Failed to copy DEV table from previous kernel.\n"); > > > + /* > > > + * If failed to copy dev tables from old kernel, continue to proceed > > > + * as it does in normal kernel. > > > + */ > > > + for_each_iommu(iommu) { > > > + clear_translation_pre_enabled(iommu); > > > + early_enable_iommu(iommu); > > > + } > > > + } else { > > > + pr_info("Copied DEV table from previous kernel.\n"); > > > + for_each_iommu(iommu) { > > > + iommu_feature_disable(iommu, CONTROL_CMDBUF_EN); > > > + iommu_feature_disable(iommu, CONTROL_EVT_LOG_EN); > > > > Could you move that into new helpers (iommu_disable_command_buffer...)? > > Did you mean wraping iommu_feature_disable(iommu, CONTROL_CMDBUF_EN) into a > helper function like iommu_disable_command_buffer(), and wraping > iommu_feature_disable(iommu, CONTROL_EVT_LOG_EN) into > iommu_disable_event_buffer()? > > I retest with not disabling command buffer and event log here, it works > on amd iommu v1 and v2 systems. So if I understand your comment > correctly, there's no need to add "iommu_feature_disable(iommu, > CONTROL_CMDBUF_EN)" and "iommu_feature_disable(iommu, > CONTROL_EVT_LOG_EN)" here. I remember I added them here because more > IO_PAGE_FAULT messages are printed without them. But now it seems not to > related to them. So I will remove above two lines of code. Oh, sorry, please ignore this. It will print many lines of below message if do not disable cmd buffer and event log here. [ 0.455642] AMD-Vi: Completion-Wait loop timed out