[Qemu-devel] q35 migration broken

[Dr. David Alan Gilbert]

Hi,
  I'm seeing a breakage on q35 migration on head (and possibly older
but certainly head; it's also on a 2.5.0 world I've got with a bunch
of patches but I've not tried a clean 2.5.0 yet).

It looks like some type of interrupt screwup; with a virtio-net device
I get a:
  BUG: soft lockup - CPU#0 stuck for 22s!
  ...  virtnet_config_changed_work 

but if I swap that out for an e1000 I get:
  Disabling IRQ #22

  and various timeouts on e1000 and cdrom (scsi).
The guest kind of limps along with an existing terminal scrolling dmesg -w 
output.

This is an f23 guest on a rhel7.2-ish host; with the guest sitting an idle
(MATE) Gui.

i440fx works.

qemu     30823     1 15 14:51 ?        00:00:07 
/opt/qemu-head/bin/qemu-system-x86_64 -name f23-q35 -S -machine 
pc-q35-2.6,accel=kvm,usb=off,vmport=off -cpu SandyBridge -m 4096 -realtime 
mlock=off -smp 4,sockets=4,cores=1,threads=1 -uuid 
3cc93d9b-9b87-4472-847c-25cea2bfc51f -no-user-config -nodefaults -chardev 
socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-12-f23-q35/monitor.sock,server,nowait
 -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew 
-global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global 
ICH9-LPC.disable_s3=1 -global ICH9-LPC.disable_s4=1 -boot strict=on -device 
i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e -device 
pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 -device 
ich9-usb-ehci1,id=usb,bus=pcie.0,addr=0x1d.0x7 -device 
ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pcie.0,multifunction=on,addr=0x1d
 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pcie.0,addr=0x1d.0x1 
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pcie.0,addr=0x1d.0x2 
-device virtio-scsi-pci,id=scsi0,bus=pci.2,addr=0x3 -device 
virtio-serial-pci,id=virtio-serial0,bus=pci.2,addr=0x4 -drive 
file=/home/vms/f23-q35.qcow2,format=qcow2,if=none,id=drive-virtio-disk0,cache=none
 -device 
virtio-blk-pci,scsi=off,bus=pci.2,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1
 -drive if=none,id=drive-scsi0-0-0-0,readonly=on -device 
scsi-cd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0
 -netdev tap,fd=25,id=hostnet0 -device 
e1000,netdev=hostnet0,id=net0,mac=52:54:00:98:12:7d,bus=pci.2,addr=0x1 -chardev 
pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev 
socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/domain-12-f23-q35/org.qemu.guest_agent.0,server,nowait
 -device 
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0
 -chardev spicevmc,id=charchannel1,name=vdagent -device 
virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0
 -device usb-tablet,id=input0 -spice 
port=5900,addr=127.0.0.1,disable-ticketing,seamless-migration=on -device 
qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,bus=pcie.0,addr=0x1
 -device intel-hda,id=sound0,bus=pci.2,addr=0x2 -device 
hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev 
spicevmc,id=charredir0,name=usbredir -device 
usb-redir,chardev=charredir0,id=redir0 -chardev 
spicevmc,id=charredir1,name=usbredir -device 
usb-redir,chardev=charredir1,id=redir1 -incoming defer -device 
virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x6 -msg timestamp=on

(Attaching libvirt xml that generated that lot).

Dave
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK

f23-q35.xml
Description: Text Data