From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: virtio-blk-pci chokes on some PCI slots Date: Tue, 16 Jun 2009 14:31:27 -0300 Message-ID: <20090616173127.GB4397@amt.cnet> References: <87fxe0t9am.fsf@pike.pond.sub.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, hch@lst.de To: Markus Armbruster Return-path: Received: from mx2.redhat.com ([66.187.237.31]:45274 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751043AbZFPRcM (ORCPT ); Tue, 16 Jun 2009 13:32:12 -0400 Content-Disposition: inline In-Reply-To: <87fxe0t9am.fsf@pike.pond.sub.org> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Jun 16, 2009 at 06:47:45PM +0200, Markus Armbruster wrote: > I'm working on make PCI slots configurable in QEMU. While testing the > feature for virtio-blk-pci, I ran into a task hang with Fedora kernel > 2.6.27.5-117.fc10. Marcelo tested it with a newer kernel, and will > follow up with details. > > Instead of the full QEMU patch I'm working on, the appended little hack > suffices to reproduce the problem. > > $ QEMU_VIRTIO_BLK=9 qemu foo.qcow2 -drive file=bar.img,if=virtio -serial stdio > [...] > Loading virtio_pci module > ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 11 > virtio-pci 0000:00:04.0: PCI INT A -> Link[LNKD] -> GSI 11 (level, low) -> IRQ 11 > virtio-pci 0000:00:09.0: can't derive routing for PCI INT A > virtio-pci 0000:00:09.0: PCI INT A: no GSI - using IRQ 11 > Loading virtio_blk module > vda: > [tick-tock-tick-tock...] > <3>INFO: task modprobe:491 blocked for more than 120 seconds. > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > modprobe D c04303f1 0 491 1 > c6baeae8 00000082 c6baea80 c04303f1 c6bae000 c087667c c0879c00 c0879c00 > c0879c00 c6b659b0 c6b65c24 c1108c00 00000000 c1108c00 83a43d86 00000002 > c781aaa8 c6baead0 c04418d0 c6b65c24 00004d88 c781aaa8 00004d88 c6baeb3c > Call Trace: > [] ? irq_exit+0x5f/0x83 > [] ? getnstimeofday+0x3c/0xc9 > [] ? ktime_get_ts+0x4a/0x4e > [] io_schedule+0x52/0x8a > [] sync_page+0x46/0x4c > [] __wait_on_bit_lock+0x34/0x5e > [] ? sync_page+0x0/0x4c > [] __lock_page+0x78/0x81 > [] ? wake_bit_function+0x0/0x43 > [] lock_page+0x2c/0x2f > [] read_cache_page_async+0xa4/0xfb > [] ? blkdev_readpage+0x0/0x11 > [] read_cache_page+0xc/0x3c > [] read_dev_sector+0x34/0x6a > [] ? efi_partition+0x0/0x676 > [] read_lba+0x69/0xc6 > [] ? efi_partition+0x84/0x676 > [] ? efi_partition+0x0/0x676 > [] efi_partition+0xa3/0x676 > [] ? vprintk+0x2c8/0x2f3 > [] ? iget5_locked+0x33/0x114 > [] ? snprintf+0x15/0x17 > [] ? efi_partition+0x0/0x676 > [] rescan_partitions+0x106/0x242 > [] ? need_resched+0x18/0x22 > [] ? _cond_resched+0x8/0x32 > [] do_open+0x1ff/0x290 > [] __blkdev_get+0x71/0x7c > [] blkdev_get+0xd/0xf > [] register_disk+0xf0/0x141 > [] add_disk+0x34/0x89 > [] ? exact_match+0x0/0xb > [] ? exact_lock+0x0/0x11 > [] virtblk_probe+0x275/0x2a8 [virtio_blk] > [] virtio_dev_probe+0x89/0xb3 > [] driver_probe_device+0xa0/0x136 > [] __driver_attach+0x3a/0x59 > [] bus_for_each_dev+0x3b/0x63 > [] driver_attach+0x14/0x16 > [] ? __driver_attach+0x0/0x59 > [] bus_add_driver+0x9d/0x1ba > [] driver_register+0x81/0xe1 > [] ? register_blkdev+0xc8/0xdc > [] register_virtio_driver+0x1f/0x21 > [] init+0x22/0x24 [virtio_blk] > [] _stext+0x3d/0x115 > [] ? init+0x0/0x24 [virtio_blk] > [] sys_init_module+0x87/0x178 > [] syscall_call+0x7/0xb > ======================= > > Some slots work, e.g. 5, some don't, e.g. 6. > > What's going on here? > > > diff --git a/hw/pc.c b/hw/pc.c > index 143b697..15c44ac 100644 > --- a/hw/pc.c > +++ b/hw/pc.c > @@ -1146,7 +1146,8 @@ static void pc_init1(ram_addr_t ram_size, > int unit_id = 0; > > while ((index = drive_get_index(IF_VIRTIO, 0, unit_id)) != -1) { > - pci_create_simple(pci_bus, -1, "virtio-blk-pci"); > + char *devfn = getenv("QEMU_VIRTIO_BLK"); > + pci_create_simple(pci_bus, devfn ? atoi(devfn) * 8: -1, "virtio-blk-pci"); > unit_id++; > } > } no softlockup with 2.6.29-06638-g17db0a0, but not very friendly either (note the backing device has no partitions in my case, perhaps that makes a difference). virtio-pci 0000:00:04.0: PCI INT A -> Link[LNKD] -> GSI 10 (level, low) -> IRQ 10 virtio-pci 0000:00:09.0: can't derive routing for PCI INT A virtio-pci 0000:00:09.0: PCI INT A: no GSI - using IRQ 11 Starting udev: Wait timeout. Will continue in the background.[FAILED] [root@guest ~]# dmesg | grep vda vda:<6>EXT3 FS on dm-0, internal journal [root@guest ~]# mount /dev/vda /mnt Hangs there forever.