From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36771) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UfUjg-0005vx-ED for qemu-devel@nongnu.org; Thu, 23 May 2013 08:35:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UfUjb-0000l4-JW for qemu-devel@nongnu.org; Thu, 23 May 2013 08:35:12 -0400 Received: from smtp.citrix.com ([66.165.176.89]:50491) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UfUjb-0000kL-CT for qemu-devel@nongnu.org; Thu, 23 May 2013 08:35:07 -0400 Date: Thu, 23 May 2013 13:34:54 +0100 From: Stefano Stabellini In-Reply-To: <33183CC9F5247A488A2544077AF190206C8FCB9B@szxeml538-mbx.china.huawei.com> Message-ID: References: <33183CC9F5247A488A2544077AF190206C8FCB9B@szxeml538-mbx.china.huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Subject: Re: [Qemu-devel] use O_DIRECT to open disk images for IDE failed under xen-4.1.2 and qemu upstream List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Gonglei (Arei)" Cc: Hanweidong , Luonengjun , "qemu-devel@nongnu.org" , Wangzhenguo , "xen-devel@lists.xen.org" , "Huangweidong (Hardware)" On Thu, 23 May 2013, Gonglei (Arei) wrote: > Hi, all > > I use O_DIRECT to open disk images for IDE, but I'm failed. After debug, I get the below logs: > [2013-05-22 23:25:46] ide: CMD=c8 > [2013-05-22 23:25:46] bmdma: readb 0x00 : 0x08 > [2013-05-22 23:25:46] bmdma: writeb 0x00 : 0x09 > [2013-05-22 23:25:46] bmdma_cmd_writeb: 0x00000009 > [2013-05-22 23:25:46] bmdma: readb 0x02 : 0x01 > [2013-05-22 23:25:46] bmdma: readb 0x02 : 0x01 > [2013-05-22 23:25:46] bmdma: readb 0x02 : 0x01 > [2013-05-22 23:25:46] bmdma: readb 0x02 : 0x01 > [2013-05-22 23:25:46] bmdma: readb 0x02 : 0x01 > [2013-05-22 23:25:46] bmdma: readb 0x02 : 0x01 > [2013-05-22 23:26:39] bmdma: writeb 0x00 : 0x08 > [2013-05-22 23:26:39] bmdma_cmd_writeb: 0x00000008 > [2013-05-22 23:26:56] ====== offset:0 buf:0x7ff100f21c00 count:512 aio_offset:0 > [2013-05-22 23:31:30] ====== offset:0 buf:0x7ff100f21c00 count:512 aio_offset:0 > [2013-05-22 23:31:30] ====== handle_aiocb_rw_linear errno: -14 > [2013-05-22 23:31:30] ====== paio_complete errno=14 > [2013-05-22 23:31:30] ====== ide_dma_error!!! > [2013-05-22 23:31:30] ide: read status addr=0x3f6 val=41 > > QEMU command line : > qemu-system-i386 -xen-domid 837 -chardev socket,id=libxl-cmd,path=/var/run/xen/qmp-libxl-837,server,nowait -mon chardev=libxl-cmd,mode=control -name suse11 -vnc 0.0.0.0:1 -serial pty -boot order=c -usb -usbdevice tablet -smp 2,maxcpus=2 -device rtl8139,id=nic0,netdev=net0,mac=00:16:3e:13:d3:72 -netdev type=tap,id=net0,ifname=tap837.0,downscript=no -M xenfv -m 2040 -drive file=/mnt/sdd/image/suse.image,if=ide,index=0,media=disk,format=raw,cache=none > > errno 14 shows Bad Address. And I find QEMU_AIO_MISALIGNED flag bit is not set through debug. > > /* > * If O_DIRECT is used the buffer needs to be aligned on a sector > * boundary. Check if this is the case or tell the low-level > * driver that it needs to copy the buffer. > */ > if ((bs->open_flags & BDRV_O_NOCACHE)) { > if (!bdrv_qiov_is_aligned(bs, qiov)) { //if the address is aligned-512, will no meet the conditions > type |= QEMU_AIO_MISALIGNED; > #ifdef CONFIG_LINUX_AIO > } else if (s->use_aio) { > return laio_submit(bs, s->aio_ctx, s->fd, sector_num, qiov, > nb_sectors, cb, opaque, type); > #endif > > Next process: > static ssize_t handle_aiocb_rw(struct qemu_paiocb *aiocb) > { > ssize_t nbytes; > char *buf; > > if (!(aiocb->aio_type & QEMU_AIO_MISALIGNED)) { > /* > * If there is just a single buffer, and it is properly aligned > * we can just use plain pread/pwrite without any problems. > */ > if (aiocb->aio_niov == 1) > return handle_aiocb_rw_linear(aiocb, aiocb->aio_iov->iov_base); //this way, and reports errno 14 next > > Anyone have a good method to resolve this bug? Thanks! I know that this is not the answer you are looking for but why do you want to use O_DIRECT with IDE? It should be perfectly safe to use write-back.