From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36638) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4K4k-00054C-6a for qemu-devel@nongnu.org; Tue, 08 Nov 2016 23:01:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c4K4h-0000sn-5R for qemu-devel@nongnu.org; Tue, 08 Nov 2016 23:01:26 -0500 Received: from [59.151.112.132] (port=58476 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4K4g-0000rI-OO for qemu-devel@nongnu.org; Tue, 08 Nov 2016 23:01:23 -0500 References: <20161109030146.GA3802@dhcp-128-65.nay.redhat.com> <20161109031729.GA3675@dhcp-128-65.nay.redhat.com> From: Wen Congyang Message-ID: <962ee966-641a-2f74-3e26-7c7967fa8f7e@cn.fujitsu.com> Date: Wed, 9 Nov 2016 11:58:33 +0800 MIME-Version: 1.0 In-Reply-To: <20161109031729.GA3675@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit 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: Dave Young Cc: lersek@redhat.com, anderson@redhat.com, qemu-devel@nongnu.org, bhe@redhat.com On 11/09/2016 11:17 AM, Dave Young wrote: > 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. IIRC, 'virsh dump --memory-only' uses dump-guest-memory, and 'virsh dump' uses migration to dump. I think I should study kaslr first... Thanks Wen Congyang >> >> 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 > > >