From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TNmpZ-00031j-8Q for kexec@lists.infradead.org; Mon, 15 Oct 2012 15:43:50 +0000 Message-ID: <507C2F18.8080904@redhat.com> Date: Mon, 15 Oct 2012 17:43:20 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [PATCH 0/3] x86: clear vmcss on all cpus when doing kdump if necessary References: <5077BB7B.4030203@cn.fujitsu.com> In-Reply-To: <5077BB7B.4030203@cn.fujitsu.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Zhang Yanfei Cc: x86@kernel.org, "kvm@vger.kernel.org" , linux-doc@vger.kernel.org, mtosatti@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org On 10/12/2012 08:40 AM, Zhang Yanfei wrote: > Currently, kdump just makes all the logical processors leave VMX operation by > executing VMXOFF instruction, so any VMCSs active on the logical processors may > be corrupted. But, sometimes, we need the VMCSs to debug guest images contained > in the host vmcore. To prevent the corruption, we should VMCLEAR the VMCSs before > executing the VMXOFF instruction. How have you verified that VMXOFF doesn't flush cached VMCSs already? > > The patch set provides an alternative way to clear VMCSs related to guests > on all cpus when host is doing kdump. > I'm not sure the sysctl is really necessary. The only reason to turn if off is if the corruption is so severe that the loaded vmcs list itself causes a crash. I think it should be rare enough that we can do it unconditionally. -- error compiling committee.c: too many arguments to function _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec