From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH v9 0/10] iommu/vt-d: Fix intel vt-d faults in kdump kernel Date: Wed, 6 May 2015 10:16:17 +0200 Message-ID: <20150506081617.GB20611@8bytes.org> References: <1426743388-26908-1-git-send-email-zhen-hual@hp.com> <20150403084031.GF22579@dhcp-128-53.nay.redhat.com> <20150504110551.GD15736@8bytes.org> <20150505060931.GB31063@dhcp-128-4.nay.redhat.com> <20150505152343.GP15736@8bytes.org> <20150506014649.GA14065@dhcp-128-4.nay.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: <20150506014649.GA14065-0VdLhd/A9PlTxLCkMk2GaBcY2uh10dtjAL8bYrjMMd8@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: Dave Young Cc: bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, tom.vaden-VXdhtT5mjnY@public.gmane.org, rwright-VXdhtT5mjnY@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lisa.mitchell-VXdhtT5mjnY@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, "Li, Zhen-Hua" , doug.hatch-VXdhtT5mjnY@public.gmane.org, ishii.hironobu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, billsumnerlinux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, li.zhang6-VXdhtT5mjnY@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Wed, May 06, 2015 at 09:46:49AM +0800, Dave Young wrote: > For the original problem, the key issue is dmar faults cause kdump kernel > hang so that vmcore can not be saved. I do not know the reason why it hangs > I think it is acceptable if kdump kernel boot ok with some dma errors.. It hangs because some devices can't handle the DMAR faults and the kdump kernel can't initialize them and will hang itself. For that it doesn't matter whether the fault was caused by a read or write request. Joerg