Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752977Ab2EUS6y (ORCPT ); Mon, 21 May 2012 14:58:54 -0400 Received: from mail-vc0-f174.google.com ([209.85.220.174]:37733 "EHLO mail-vc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752144Ab2EUS6w (ORCPT ); Mon, 21 May 2012 14:58:52 -0400 MIME-Version: 1.0 In-Reply-To: <4FB35C48.30708@cn.fujitsu.com> References: <4FB35C48.30708@cn.fujitsu.com> Date: Mon, 21 May 2012 11:58:51 -0700 Message-ID: Subject: Re: [PATCH v2 0/5] Export offsets of VMCS fields as note information for kdump From: Eric Northup To: zhangyanfei Cc: Avi Kivity , mtosatti@redhat.com, ebiederm@xmission.com, luto@mit.edu, Joerg Roedel , dzickus@redhat.com, paul.gortmaker@windriver.com, ludwig.nussel@suse.de, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kexec@lists.infradead.org, Greg KH Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1511 Lines: 31 On Wed, May 16, 2012 at 12:50 AM, zhangyanfei wrote: > > This patch set exports offsets of VMCS fields as note information for > kdump. We call it VMCSINFO. The purpose of VMCSINFO is to retrieve > runtime state of guest machine image, such as registers, in host > machine's crash dump as VMCS format. The problem is that VMCS internal > is hidden by Intel in its specification. So, we slove this problem > by reverse engineering implemented in this patch set. The VMCSINFO > is exported via sysfs to kexec-tools just like VMCOREINFO. Perhaps I'm wrong, but this solution seems much, much more dynamic than it needs to be. The VMCS offsets aren't going to change between different boots on the same CPU, unless perhaps the microcode has been updated. So you can have the VMCS offset dumping be a manually-loaded module. Build a database mapping from (CPUID, microcode revision) -> (VMCSINFO). There's no need for anything beyond the (CPUID, microcode revision) to be put in the kdump, since your offline processing of a kdump can then look up the rest. It means you don't have to interact with the vmx module at all, and no extra modules or code have to be loaded on the millions of Linux machines that won't need the functionality. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/