From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from g1t5425.austin.hp.com ([15.216.225.55]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YsLlA-0007M1-O9 for kexec@lists.infradead.org; Wed, 13 May 2015 01:46:57 +0000 Message-ID: <5552ACB9.5050309@hp.com> Date: Wed, 13 May 2015 09:45:29 +0800 From: "Li, ZhenHua" MIME-Version: 1.0 Subject: Re: [PATCH v11 02/10] iommu/vt-d: Items required for kdump References: <1431337974-545-1-git-send-email-zhen-hual@hp.com> <1431337974-545-3-git-send-email-zhen-hual@hp.com> <20150512081723.GC4561@localhost.localdomain> In-Reply-To: <20150512081723.GC4561@localhost.localdomain> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Dave Young Cc: alex.williamson@redhat.com, indou.takao@jp.fujitsu.com, bhe@redhat.com, tom.vaden@hp.com, rwright@hp.com, linux-pci@vger.kernel.org, joro@8bytes.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, lisa.mitchell@hp.com, jerry.hoemann@hp.com, iommu@lists.linux-foundation.org, "Li, ZhenHua" , ddutile@redhat.com, doug.hatch@hp.com, ishii.hironobu@jp.fujitsu.com, bhelgaas@google.com, billsumnerlinux@gmail.com, li.zhang6@hp.com, dwmw2@infradead.org, vgoyal@redhat.com On 05/12/2015 04:17 PM, Dave Young wrote: > On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote: >> Add context entry functions needed for kdump. >> +/* >> + * Fix Crashdump failure caused by leftover DMA through a hardware IOMMU >> + * >> + * Fixes the crashdump kernel to deal with an active iommu and legacy >> + * DMA from the (old) panicked kernel in a manner similar to how legacy >> + * DMA is handled when no hardware iommu was in use by the old kernel -- >> + * allow the legacy DMA to continue into its current buffers. >> + * >> + * In the crashdump kernel, this code: >> + * 1. skips disabling the IOMMU's translating. >> + * 2. Do not re-enable IOMMU's translating. >> + * 3. In kdump kernel, use the old root entry table. >> + * 4. Allocate pages for new context entry, copy data from old context entries >> + * in the old kernel to the new ones. >> + * >> + * In other kinds of kernel, for example, a kernel started by kexec, >> + * do the same thing as crashdump kernel. >> + */ >> + >> + > > Above comments should come along with the code changes instead of putting it > in this patch. > > BTW, there's one more blank line at the end.. Code change is in 00/10, the cover letter. And the blank does not matter, I checked the patch with scripts/checkpatch.pl, no warnings, no errors. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec