Hi, I'm seeing a frequent KVM boot hang using qemu-kvm 1.0+noroms-0ubuntu14.7 since kernel 3.8.y. This report is for guest kernel 3.8.6, but the issue did also occur with kernel 3.8.2. I know this qemu-kvm version is a bit dated, but contacting Ubuntu people on IRC wasn't successfull. The qemu-kvm command line is quite a whopper (as used by virt-manager): /usr/bin/kvm -S -M pc-1.0 -cpu core2duo,+lahf_lm,+rdtscp,+pdpe1gb,+aes,+popcnt,+sse4.2,+sse4.1,+dca,+xtpr,+cx16,+tm2,+est,+vmx,+ds_cpl,+pbe,+tm,+ht,+ss,+acpi,+ds -enable-kvm -m 2048 -smp 2,sockets=2,cores=1,threads=1 -name hcl-kvm-01 -uuid 09a71c4f-ea29-145e-d6ac-e22b8550aaca -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/hcl-kvm-01.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot order=dcn,menu=on -drive file=/var/lib/libvirt/isolib/asg-9.080-10.1-hei12.iso,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive file=/var/lib/libvirt/images/hcl-kvm-01.img,if=none,id=drive-virtio-disk0,format=raw -device virtio-blk-pci,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id=virtio-disk0 -netdev tap,fd=17,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:d0:56:01,bus=pci.0,addr=0x3 -netdev tap,fd=19,id=hostnet1 -device virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:d0:56:02,bus=pci.0,addr=0x5 -netdev tap,fd=20,id=hostnet2 -device virtio-net-pci,netdev=hostnet2,id=net2,mac=52:54:00:d0:56:03,bus=pci.0,addr=0x6 -netdev tap,fd=21,id=hostnet3 -device virtio-net-pci,netdev=hostnet3,id=net3,mac=52:54:00:d0:56:04,bus=pci.0,addr=0x7 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev file,id=charserial1,path=/tmp/v9.1-ttyS0.log -device isa-serial,chardev=charserial1,id=serial1 -chardev file,id=charserial2,path=/tmp/hcl-kvm-01-console.log -device isa-serial,chardev=charserial2,id=serial2 -usb -vnc 127.0.0.1:0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 Most of the time the guest is stuck at: smpboot: Booting Node 0, Processors #1 OK Enabling DEBUG in arch/x86/kernel/smpboot.c and adding some additional debug lines I see then: ... [ 0.027205] smpboot: CPU0: Intel(R) Core(TM)2 Duo CPU T7700 @ 2.40GHz (fam: 06, model: 0f, stepping: 0b) [ 0.032000] Performance Events: unsupported p6 CPU model 15 no PMU driver, software events only. [ 0.032322] NMI watchdog: disabled (cpu0): hardware events not enabled [ 0.034997] smpboot: ++++++++++++++++++++=_---CPU UP 1 [ 0.036024] SMP alternatives: lockdep: fixing up alternatives [ 0.038078] CPU 1 irqstacks, hard=f5c74000 soft=f5c76000 [ 0.040006] smpboot: Booting Node 0, Processors #1 OK [ 0.041897] smpboot: Setting warm reset code and vector. [ 0.044030] smpboot: 1. [ 0.044898] smpboot: 2. [ 0.045777] smpboot: 3. [ 0.046665] smpboot: Asserting INIT [ 0.048019] smpboot: Waiting for send to finish... [ 0.060113] smpboot: Deasserting INIT [ 0.061488] smpboot: Waiting for send to finish... [ 0.063228] smpboot: #startup loops: 2 [ 0.064005] smpboot: Sending STARTUP #1 [ 0.065378] smpboot: After apic_write The 2 vCPU guest is running at 200% CPU time then. The full output from 'dmesg' is available here [1]. It is quite noisy, because lockdep is enabled, as well es several other locking-related checks. The partial output from running 'trace-cmd' is here [2]. And if not being stuck in the smpboot it is stuck in the ata_piix initialization most of the time: ... [ 0.272000] ata_eh_release: ENTER [ 0.272000] ata_eh_release: EXIT [ 0.272000] ata_msleep: about to msleep(150) Full output from 'dmesg' is here [3]. Again quite noisy, as I have enabled libata debugging, also added some debug lines. I can see that the first case mentioned is stuck in smpboot.c:wakeup_secondary_cpu_via_init(): udelay(300); and the 2nd case is stuck in ata_msleep(150). If I specify 'no-kvmclock' at boot the problem is gone. Also I found this link here [4], which describes a problem similar to the one I see. But this case is from 2010. I need further advise on how to debug this any further. Any help appreciated. /Holger [1] http://pastebin.com/yNSuSaWX [2] http://pastebin.com/qEdC217c [3] http://pastebin.com/hxrjEY7M [4] http://www.spinics.net/lists/kvm/msg42654.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
