From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39672) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4NZZ-000837-Lo for qemu-devel@nongnu.org; Wed, 09 Nov 2016 02:45:33 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c4NZV-0005HB-MD for qemu-devel@nongnu.org; Wed, 09 Nov 2016 02:45:29 -0500 Received: from [59.151.112.132] (port=63745 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c4NZV-0005GT-99 for qemu-devel@nongnu.org; Wed, 09 Nov 2016 02:45:25 -0500 References: <20161109030146.GA3802@dhcp-128-65.nay.redhat.com> <20161109031729.GA3675@dhcp-128-65.nay.redhat.com> <962ee966-641a-2f74-3e26-7c7967fa8f7e@cn.fujitsu.com> <20161109050248.GA4431@dhcp-128-65.nay.redhat.com> From: Wen Congyang Message-ID: Date: Wed, 9 Nov 2016 15:42:49 +0800 MIME-Version: 1.0 In-Reply-To: <20161109050248.GA4431@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 , anderson@redhat.com Cc: lersek@redhat.com, qemu-devel@nongnu.org, bhe@redhat.com On 11/09/2016 01:02 PM, Dave Young wrote: > On 11/09/16 at 11:58am, Wen Congyang wrote: >> 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. > > Do they need different fixes? Dave, I guess you mean --memory-only, but > could you clarify and confirm it? > >> >> I think I should study kaslr first... > > Thanks for taking care of it. Can you give me the patch for kexec/kdump. I want to know what I need to do for dump-guest-memory. Thanks Wen Congyang > >> >> 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 >>> >>> >>> >> >> >> > > > . >