From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43659) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WKQPi-0004He-Jk for Qemu-devel@nongnu.org; Mon, 03 Mar 2014 05:48:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WKQPb-0005cV-AF for Qemu-devel@nongnu.org; Mon, 03 Mar 2014 05:48:02 -0500 Received: from mail-pd0-f178.google.com ([209.85.192.178]:64103) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WKQPb-0005cO-3k for Qemu-devel@nongnu.org; Mon, 03 Mar 2014 05:47:55 -0500 Received: by mail-pd0-f178.google.com with SMTP id x10so3566721pdj.37 for ; Mon, 03 Mar 2014 02:47:54 -0800 (PST) Message-ID: <53145DD4.4040101@ozlabs.ru> Date: Mon, 03 Mar 2014 21:47:48 +1100 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <6777CD901FD53644B082307CD745FB8326AC9348@SACEXCMBX02-PRD.hq.netapp.com> <530AC892.2080109@ozlabs.ru> <5311D2DD.4090904@ozlabs.ru> <531251CB.10102@redhat.com> <5313E1AD.5050409@ozlabs.ru> <53143E50.5060205@redhat.com> In-Reply-To: <53143E50.5060205@redhat.com> Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] e1000 memory corruption in guest OS List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , "Hoyer, David" , "Qemu-devel@nongnu.org" Cc: "Moyer, Keith" , "Best, Tish" On 03/03/2014 07:33 PM, Paolo Bonzini wrote: > Il 03/03/2014 02:58, Alexey Kardashevskiy ha scritto: >> On 03/02/2014 08:31 AM, Paolo Bonzini wrote: >>> Il 01/03/2014 13:30, Alexey Kardashevskiy ha scritto: >>>>>> >>>>>> Corrupted DMA buffer is 0x e00000 -- 0x7f15c313f000. >>>>>> The e1000 packet is at 0x12ffac2 -- 0x7f15c313eac2. >>>>>> >>>>>> (0x7f15c313f000 - 0x7f15c313eac2) = 0x53e which is less than 0x5aa and >>>>>> (0x5aa - 0x53e) = 0x6c bytes get corrupted. >>>>>> >>>>>> I see here buffer overrun from e1000 and I suspect that your patch just >>>>>> hides this problem. What did I miss? >>>> >>>> Ping, anyone? >>> >>> You missed that this is a Xen-specific problem. Xen maps things a page at >>> a time, so address_space_map/unmap/rw can operate only on a small part of >>> the requested [address, address+length) range. >> >> Sorry, I am not following you here. Does KVM map things not page-aligned? > > Look in exec.c for xen_enabled(). Xen's implementation of > address_space_map/unmap is completely different. Honestly cannot see much difference in the current QEMU... > >>> So there is no overrun in e1000. The patch is incomplete, because it fixes >>> only address_space_rw, but the problem is indeed in exec.c. >> >> So you know what the problem is? We have a bunch of bugreports against >> e1000 breaking things... > > This one had been reported and fixed already. Any hint? :) Could not spot any related to overrun except: a0ae17a 8 months ago Andrew Jones e1000: cleanup process_tx_desc but commit message says "complaints are false positives"... -- Alexey