Bug 723870

Plan: backport this ...
http://www.kraxel.org/cgit/qemu/log/?h=migration.2
... once merged upstream

Reproduced this issue with qemu-kvm-0.12.1.2-2.183.el6:
Steps:
1. boot a guest with ehci assigned 
2. start listening 
3. do migration
4. repeat step 1-3 with usb storage assigned
Actual Result:
after step 3 and 4, guest can finish migration
CLI:
/usr/libexec/qemu-kvm -M rhel6.2.0 -enable-kvm ...  -usb -device usb-tablet,id=input1 -device usb-ehci,id=ehci
(qemu) migrate -d tcp:xxxx:8000
(qemu) info migrate
Migration status: active
transferred ram: 828444 kbytes
remaining ram: 3498176 kbytes
total ram: 4325768 kbytes
(qemu) handle_dev_input: stop

(qemu) info migrate
Migration status: completed

/usr/libexec/qemu-kvm -M rhel6.2.0 -enable-kvm ...  -usb -device usb-tablet,id=input1,port=1 -drive file=/tmp/mount-point/image/usb-storage.qcow2,if=none,id=drive-usb-0-0,media=disk,format=qcow2,cache=none,werror=stop,rerror=stop -device usb-storage,drive=drive-usb-0-0,id=usb-0-0,removable=on,bus=usb.0,port=2
(qemu) migrate -d tcp:10.66.11.212:8000
(qemu) info migrate
Migration status: active
transferred ram: 185772 kbytes
remaining ram: 4141776 kbytes
total ram: 4325768 kbytes
(qemu) handle_dev_input: stop
(qemu) info migrate
Migration status: completed


Verified this issue with same steps with qemu-kvm-0.12.1.2-2.184.el6 
Actual Result:
after step 3,4, migration is both blocked.
For ehci:
(qemu) migrate -d tcp:xxxx:8000
state blocked by non-migratable device '0000:00:05.0/ehci'
For usb storage:
(qemu) migrate -d tcp:xxxx:8000
state blocked by non-migratable device '2.1/usb-storage'



-----conclusion:
Based on above, this issue has been fixed.

I tested usb-host here, found that it allows migration, but caused qemu exited with savevm errors, shall usb-host migration be blocked too?
(qemu) red_dispatcher_loadvm_commands:
handle_dev_input: loadvm_commands
Unknown savevm section or instance '2/usb-hub' 0
load of migration failed


Source CLI:
(qemu) info usbhost
husb: using sys file-system with /dev/bus/usb
  Bus 8, Addr 2, Port 1, Speed 12 Mb/s
    Hub: USB device 0557:7000
  Bus 8, Addr 3, Port 1.1, Speed 1.5 Mb/s
    Class 00: USB device 0557:2213, CS-1734A V4.2.411
(qemu) info usbhost
  Bus 8, Addr 2, Port 1, Speed 12 Mb/s
    Hub: USB device 0557:7000
  Bus 8, Addr 3, Port 1.1, Speed 1.5 Mb/s
    Class 00: USB device 0557:2213, CS-1734A V4.2.411
  Bus 1, Addr 2, Port 5, Speed 480 Mb/s  <--------------------
    Class 00: USB device 0781:5567, Cruzer Blade
(qemu) device_add usb-host,bus=usb.0,hostbus=1,hostport=5
husb: open device 1.2
husb: config #1 need -1
husb: 1 interfaces claimed for configuration 1
husb: grabbed usb device 1.2
(qemu) husb: config #1 need 1
husb: 1 interfaces claimed for configuration 1
husb: config #1 need 1
husb: 1 interfaces claimed for configuration 1
husb: config #1 need 1
husb: 1 interfaces claimed for configuration 1
(qemu) migrate -d tcp:xxxx:8000
(qemu) info migrate
Migration status: active
transferred ram: 891004 kbytes
remaining ram: 3438084 kbytes
total ram: 4325768 kbytes
(qemu) handle_dev_input: stop

(qemu) info migrate
Migration status: completed

Destination CLI:
/usr/libexec/qemu-kvm -M rhel6.2.0 -enable-kvm -m 4096 -smp 4,sockets=1,cores=4,threads=1 -name RHEL6.1_32 -uuid `uuidgen` -rtc base=utc,clock=host,driftfix=slew -boot dc -drive file=/tmp/mount-point/RHEL6.1-32-copy.qcow2,if=none,id=drive-virtio-0-0,media=disk,format=qcow2,cache=none,werror=stop,rerror=stop -device virtio-blk-pci,drive=drive-virtio-0-0,id=virt0-0-0,bootindex=1 -netdev tap,id=hostnet1,vhost=on -device virtio-net-pci,netdev=hostnet1,id=net1,mac=64:31:50:41:e1:c3 -usb -device usb-tablet,id=input1,port=1 -spice port=9000,disable-ticketing -vga qxl -global qxl-vga.vram_size=67108864 -monitor stdio -balloon none -device usb-host,bus=usb.0,hostbus=1,hostport=5 -incoming tcp:0:8000
(qemu) red_dispatcher_loadvm_commands:
handle_dev_input: loadvm_commands
Unknown savevm section or instance '2/usb-hub' 0
load of migration failed

There is a device tree mismatch between source and destination, there is a usb hub @ src which isn't there at dst, thats why dst doesn't know how to handle the section for the hub.  Try adding "port=2" to the usb-host monitor command and command line to prevent qemu from automagically adding usb hubs.

Beside that it probably makes sense to block usb-host too.  Most likely migration will succeed but the device will not work as expected.

(In reply to comment #8)

> Beside that it probably makes sense to block usb-host too.  Most likely
> migration will succeed but the device will not work as expected.

So, do you suggest to open a new bug to track this?

I think we can just continue to use this one,
it is the same issue after all, just a forgotton device.

> There is a device tree mismatch between source and destination, there is a usb
> hub @ src which isn't there at dst, thats why dst doesn't know how to handle
> the section for the hub.  Try adding "port=2" to the usb-host monitor command
> and command line to prevent qemu from automagically adding usb hubs.
> 
Yes, after adding "port=2" to the usb-host monitor command and command line,
dst guests won't exit when migration finished.

1.reproduce on qemu-kvm-0.12.1.2-2.172.el6.x86_64

reproduce usb device migrate steps:
(1)./usr/libexec/qemu-kvm -m 2G -smp 4 -M rhel6.1.0  -drive file=/home/ple-pf/rhel61.qcow2,if=none,id=drive-ide0-0-0,format=qcow2,cache=none,aio=native -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device e1000,netdev=hostnet0,id=net0,mac=52:56:00:94:a3:20 -uuid 9e6f04cf-2ad7-45aa-9333-2d2ee26570c6 -balloon virtio -usb -device usb-tablet,id=input1 -device usb-ehci,id=ehci -monitor stdio -spice id=on,disable-ticketing,port=5911 -vga qxl

(qemu) info usb
  Device 0.2, Port 1, Speed 12 Mb/s, Product QEMU USB Tablet

(2)./usr/libexec/qemu-kvm -m 2G -smp 4 -M rhel6.1.0  -drive file=/home/ple-pf/rhel61.qcow2,if=none,id=drive-ide0-0-0,format=qcow2,cache=none,aio=native -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device e1000,netdev=hostnet0,id=net0,mac=52:56:00:94:a3:20 -uuid 9e6f04cf-2ad7-45aa-9333-2d2ee26570c6 -balloon virtio -usb -device usb-tablet,id=input1 -device usb-ehci,id=ehci -monitor stdio -spice id=on,disable-ticketing,port=5912 -vga qxl -incoming tcp:0:5555

(3).migrate -d tcp:10.66.104.52:5555
(4).(qemu) info migrate
Migration status: completed
(qemu) info usb
  Device 0.2, Port 1, Speed 12 Mb/s, Product QEMU USB Tablet

2.reproduce usb-host allow migration
(1).repeat above 1,2 steps
(2).(qemu) info usbhost
husb: using sys file-system with /dev/bus/usb
  Bus 2, Addr 2, Port 2, Speed 480 Mb/s
    Hub: USB device 0424:2514
  Bus 3, Addr 2, Port 2, Speed 12 Mb/s
    Class 00: USB device 0624:0248, USB Composite Device-0
(qemu) spice_server_add_interface: SPICE_INTERFACE_TABLET

(qemu) device_add usb-host,bus=usb.0,hostbus=3,hostport=2
husb: open device 3.2
husb: config #1 need -1
husb: 2 interfaces claimed for configuration 1
husb: grabbed usb device 3.2
(qemu) husb: config #1 need 1
husb: 2 interfaces claimed for configuration 1
husb: config #1 need 1
husb: 2 interfaces claimed for configuration 1
husb: config #1 need 1
husb: 2 interfaces claimed for configuration 1

(3).(qemu) migrate -d tcp:10.66.104.52:5555
(qemu) info migrate
Migration status: active
transferred ram: 1744748 kbytes
remaining ram: 484452 kbytes
total ram: 2228680 kbytes
(qemu) handle_dev_input: stop
spice_server_migrate_switch: 

(qemu) info migrate
Migration status: completed

(4).dst monitor receive message
(qemu) red_dispatcher_loadvm_commands: 
handle_dev_input: loadvm_commands
Unknown savevm section or instance '2/usb-hub' 0
load of migration failed


3.verify on qemu-kvm-0.12.1.2-2.195.el6.x86_64
  verify steps is the same with above

(1) verify usb device migrate 
result:
(qemu) migrate -d tcp:10.66.104.52:5555
state blocked by non-migratable device '0000:00:05.0/ehci'

(2)verify usb-host allow migration
result:
(qemu) info usbhost
husb: using sys file-system with /dev/bus/usb
  Bus 2, Addr 2, Port 2, Speed 480 Mb/s
    Hub: USB device 0424:2514
  Bus 3, Addr 2, Port 2, Speed 12 Mb/s
    Class 00: USB device 0624:0248, USB Composite Device-0

(qemu) device_add usb-host,bus=usb.0,hostbus=3,hostport=2
husb: open device 3.2
husb: config #1 need -1
husb: 2 interfaces claimed for configuration 1
husb: grabbed usb device 3.2
(qemu) husb: config #1 need 1
husb: 2 interfaces claimed for configuration 1
husb: config #1 need 1
husb: 2 interfaces claimed for configuration 1
husb: config #1 need 1
husb: 2 interfaces claimed for configuration 1

(qemu) migrate -d tcp:10.66.104.52:5555
state blocked by non-migratable device '0000:00:05.0/ehci'

base on above verify result, this bug has been fixed.

Moving to ON_QA because Errata Tool did not do it

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2011-1531.html