From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: raw disks no longer work in latest kvm (kvm-88 was fine) Date: Sun, 23 May 2010 17:18:02 +0300 Message-ID: <4BF9391A.1080302@redhat.com> References: <4B92BF97.4040001@nagafix.co.uk> <4B92C90B.4030807@msgid.tls.msk.ru> <4B932829.8090503@nagafix.co.uk> <4B9372B6.3050408@msgid.tls.msk.ru> <20100307100022.GA23201@infradead.org> <4B93A624.8010707@nagafix.co.uk> <4B93AF8A.3070805@nagafix.co.uk> <4B93C2F9.7030904@msgid.tls.msk.ru> <4B93DE3F.4090103@nagafix.co.uk> <4B93DFF0.5050905@redhat.com> <20100307172151.GA24859@infradead.org> <4B93E29E.6090609@redhat.com> <4B93E9EE.6020701@nagafix.co.uk> <4B93F4A4.9050003@redhat.com> <4B93F96E.30508@nagafix.co.uk> <4B93FA18.2090808@redhat.com> <4B93FAD8.9010207@nagafix.co.uk> <4B93FBC1.3000209@redhat.com> <4B93FD94.7060508@nagafix.co.uk> <4B93FFEE.4080007@redhat.com> <4B9B6008.4090902@nagafix.co.uk> <4BBE51F4.6070904@nagafix.co.uk> <4BF7B589.1070808@nagafix.co.uk> <4BF7BD33.2090700@msgid.tls. msk.ru> <4BF7C172.2000508@nagafix.co.uk> <4BF8ED0C.2070004@nagafix.co.uk> <4BF91844.8030903@redhat.com> <4BF936BB.5000401@nagafix.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Michael Tokarev , Christoph Hellwig , kvm@vger.kernel.org To: Antoine Martin Return-path: Received: from mx1.redhat.com ([209.132.183.28]:49257 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754654Ab0EWOSM (ORCPT ); Sun, 23 May 2010 10:18:12 -0400 In-Reply-To: <4BF936BB.5000401@nagafix.co.uk> Sender: kvm-owner@vger.kernel.org List-ID: On 05/23/2010 05:07 PM, Antoine Martin wrote: > On 05/23/2010 06:57 PM, Avi Kivity wrote: >> On 05/23/2010 11:53 AM, Antoine Martin wrote: >>> I'm not: 64-bit host and 64-bit guest. >>> Just to be sure, I've tested that patch and still no joy: >>> /dev/vdc: read failed after 0 of 512 at 0: Input/output error >>> /dev/vdc: read failed after 0 of 512 at 0: Input/output error >>> /dev/vdc: read failed after 0 of 2048 at 0: Input/output error >>> pread is still broken on this big raw disk. >>> >> >> Can you summarize your environment and reproducer again? The thread >> is so long it is difficult to understand exactly what you are testing. >> > Sure thing: > > Description of the problem: > A guest tries to mount a large raw partition (1.5TB /dev/sda9 in my > case), this fails with pread enabled, works with it disabled. Did you mean: preadv? > > What has been tested: > Host has had 2.6.31.x and now 2.6.34 - with no improvement. > Guest has had numerous kernel versions and patches applied for testing > (from 2.6.31.x to 2.6.34) - none made any difference. (although the > recent patch stopped the large partition from getting corrupted by the > merged requests bug.. yay!) > It was once thought that glibc needed to be rebuilt against newer > kernel headers, done that too, and rebuilt qemu-kvm afterwards. (was > 2.6.28 then 2.6.31 and now 2.6.33) > > What has been reported: straces, kernel error messages as above. > Here is the qemu command line (sanitized - removed the virtual disks > which work fine and network config): > qemu -clock dynticks -m 256 -L ./ -kernel ./bzImage-2.6.34-aio -append > "root=/dev/vda" -nographic -drive file=/dev/sda9,if=virtio,cache=none > > Let me know if you need any other details. I can also arrange ssh > access to the system if needed. And: 64-bit host kernel, 64-bit host userspace, yes? Does aio=native help? How about if=ide? -- error compiling committee.c: too many arguments to function