From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57199) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4J9C-0001vu-CB for qemu-devel@nongnu.org; Tue, 08 Nov 2016 22:01:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c4J98-0000w1-EK for qemu-devel@nongnu.org; Tue, 08 Nov 2016 22:01:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55140) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c4J98-0000vY-8Y for qemu-devel@nongnu.org; Tue, 08 Nov 2016 22:01:54 -0500 Date: Wed, 9 Nov 2016 11:01:46 +0800 From: Dave Young Message-ID: <20161109030146.GA3802@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [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, qiaonuohan@cn.fujitsu.com Cc: lersek@redhat.com, anderson@redhat.com, qemu-devel@nongnu.org, bhe@redhat.com 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