From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59160) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4JOM-0005JT-ED for qemu-devel@nongnu.org; Tue, 08 Nov 2016 22:17:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c4JOJ-0005Hm-8v for qemu-devel@nongnu.org; Tue, 08 Nov 2016 22:17:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53384) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c4JOJ-0005Hd-3Z for qemu-devel@nongnu.org; Tue, 08 Nov 2016 22:17:35 -0500 Date: Wed, 9 Nov 2016 11:17:29 +0800 From: Dave Young Message-ID: <20161109031729.GA3675@dhcp-128-65.nay.redhat.com> References: <20161109030146.GA3802@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161109030146.GA3802@dhcp-128-65.nay.redhat.com> Subject: Re: [Qemu-devel] virsh dump (qemu guest memory dump?): KASLR enabled linux guest support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: wency@cn.fujitsu.com Cc: lersek@redhat.com, anderson@redhat.com, qemu-devel@nongnu.org, bhe@redhat.com Drop qiaonuohan, seems the mail address is wrong.. On 11/09/16 at 11:01am, Dave Young wrote: > Hi, > > Latest linux kernel enabled kaslr to randomiz phys/virt memory > addresses, we had some effort to support kexec/kdump so that crash > utility can still works in case crashed kernel has kaslr enabled. > > But according to Dave Anderson virsh dump does not work, quoted messages > from Dave below: > > """ > with virsh dump, there's no way of even knowing that KASLR > has randomized the kernel __START_KERNEL_map region, because there is no > virtual address information -- e.g., like "SYMBOL(_stext)" in the kdump > vmcoreinfo data to compare against the vmlinux file symbol value. > Unless virsh dump can export some basic virtual memory data, which > they say it can't, I don't see how KASLR can ever be supported. > """ > > I assume virsh dump is using qemu guest memory dump facility so it > should be first addressed in qemu. Thus post this query to qemu devel > list. If this is not correct please let me know. > > Could you qemu dump people make it work? Or we can not support virt dump > as long as KASLR being enabled. Latest Fedora kernel has enabled it in x86_64. > > Thanks > Dave