From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751633AbbJJMYb (ORCPT ); Sat, 10 Oct 2015 08:24:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57372 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751055AbbJJMYa (ORCPT ); Sat, 10 Oct 2015 08:24:30 -0400 Date: Sat, 10 Oct 2015 20:24:24 +0800 From: Baoquan He To: Joerg Roedel Cc: iommu@lists.linux-foundation.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 06/10] iommu/amd: Add functions copy_command_buffer/copy_event_buffer Message-ID: <20151010122424.GA31787@dhcp-16-116.nay.redhat.com> References: <1443076656-31776-1-git-send-email-bhe@redhat.com> <1443076656-31776-7-git-send-email-bhe@redhat.com> <20150929160439.GN3036@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150929160439.GN3036@8bytes.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joerg, On 09/29/15 at 06:04pm, Joerg Roedel wrote: > On Thu, Sep 24, 2015 at 02:37:32PM +0800, Baoquan He wrote: > > Copy command buffer and event buffer from the old to kdump kernel. > > > > Still there are 2 problems: > > 1) Not very sure if this is necessary. If do not copy the old command buffer, and > > only set the newly allocated command buffer, is there anything wrong? > > No, there is no need to copy command and event buffers. Just make sure > they get re-initialized and flush all iommu caches after setting the new > device table. Thanks for your reviewing. I did a lot of tests. Seems that it doesn't matter with copy or without a copy. And it's also OK even completely ignore the command buffer and event log handling here. Thanks Baoquan