From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Young Subject: Re: [PATCH v9 0/10] iommu/vt-d: Fix intel vt-d faults in kdump kernel Date: Thu, 7 May 2015 21:25:36 +0800 Message-ID: <20150507132536.GA4559@localhost.localdomain> 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> <20150506081617.GB20611@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20150506081617.GB20611-zLv9SwRftAIdnm+yROfE0A@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: 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 05/06/15 at 10:16am, Joerg Roedel wrote: > 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. Ok, thanks for explanation. so it explains sometimes kdump kernel boot ok with faults, sometimes it hangs instead. Dave