usb disk image and device pass-through treated differently

[Jamin W. Collins]

It seems that an image dump from a USB device and passing through the actual device are treated differently by KVM. For instance, if I pass through a physical USB thumb drive I can select it from the virtual machine's boot menu. However, if I take an image dump of the very same thumb drive and then add it to the VM as a USB storage device, it does not appear as an option from the virtual machine's boot menu.

I would expect for the two to be functionally identical.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: kvm 1:84+dfsg-0ubuntu16+1.0+noroms+0ubuntu13
ProcVersionSignature: Ubuntu 3.2.0-26.41-generic 3.2.19
Uname: Linux 3.2.0-26-generic x86_64
ApportVersion: 2.0.1-0ubuntu8
Architecture: amd64
Date: Mon Jul 2 08:17:43 2012
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
KvmCmdLine: Error: command ['ps', '-C', 'kvm', '-F'] failed with exit code 1: UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
MachineType: LENOVO 2436CTO
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-26-generic root=/dev/mapper/ssd-root ro vga=792 splash crashkernel=384M-2G:64M,2G-:128M quiet splash vt.handoff=7
SourcePackage: qemu-kvm
UdevDb: Error: [Errno 2] No such file or directory
UpgradeStatus: Upgraded to precise on 2012-04-27 (65 days ago)
dmi.bios.date: 05/25/2012
dmi.bios.vendor: LENOVO
dmi.bios.version: G5ET29WW (1.07 )
dmi.board.asset.tag: Not Available
dmi.board.name: 2436CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG5ET29WW(1.07):bd05/25/2012:svnLENOVO:pn2436CTO:pvrThinkPadW530:rvnLENOVO:rn2436CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2436CTO
dmi.product.version: ThinkPad W530
dmi.sys.vendor: LENOVO

[Serge Hallyn (serge-hallyn)]

Thanks for reporting this bug.

Can you show

1. the url for the usb image you created (or the iso assuming you used usb-creator-gtk)
2. the exact command you used to create the usb stick dump
3. the exact kvm command line which you used in both cases

I'll try to reproduce.

[Jamin W. Collins (jcollins)]

ISO image used to create the USB stick (via usb-creator-gtk): ubuntu-12.04-alternate-amd64.iso

Command used to create the disk image of the USB stick: sudo dd if=/dev/sdc of=usb-sandisk.img

kvm command lines (based on virt-manager):

USB device pass-through (able to select USB boot from menu):
/usr/bin/kvm -M pc-1.0 -enable-kvm -m 4096 -smp 2,sockets=2,cores=1,threads=1 -name usb-test -rtc base=utc -no-shutdown -boot order=c,menu=on -drive file=usb-test-hd.img,if=none,id=drive-virtio-disk0,format=raw -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0 -usb -device usb-host,hostbus=3,hostaddr=2,id=hostdev0

USB disk image (no USB boot option in menu)
/usr/bin/kvm -M pc-1.0 -enable-kvm -m 4096 -smp 2,sockets=2,cores=1,threads=1 -name usb-test -rtc base=utc -no-shutdown -boot order=c,menu=on -drive file=usb-test-hd.img,if=none,id=drive-virtio-disk0,format=raw -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0 -usb -drive file=/home/jcollins/usb-sandisk.img,if=none,id=drive-usb-disk0,format=raw -device usb-storage,drive=drive-usb-disk0,id=usb-disk0

[Serge Hallyn (serge-hallyn)]

Confirmed with precise. It works with upstream qemu git head. I have not yet tested quantal. The exact arguments I used with the dd'd usb image file (for the sake of brevity) were:

-m 1024 -boot order=c,menu=on -hda /home/serge/x.img -usb -usbdevice disk:format=raw:/home/serge/usb-sandisk.img -vnc :2 -monitor stdio --enable-kvm

[Serge Hallyn (serge-hallyn)]

works in quantal's qemu-kvm. will look for a commit to cherrypick to fix in precise.

[Serge Hallyn (serge-hallyn)]

I wonder if it could be due to commit cf8ce30d03339861a46c31aa44c11279c282f2b0.

[Serge Hallyn (serge-hallyn)]

No, that didn't help. The fix is probably around that area though. Will have to look more closely.

[Serge Hallyn (serge-hallyn)]

Looks like the fix came in somewhere between 65bb3a5c11b00671c1067ee27ea364b6d7e6e2ac and 0cc6a0f19e3de830eaa898ad31c0bc607470b8cb.

[Serge Hallyn (serge-hallyn)]

No, I wasn't passing '-L /usr/share/qemu'. 65bb3a5c11b is actually good.

[Serge Hallyn (serge-hallyn)]

It appears to be a race condition. When I hand-compile the precise-updates qemu-kvm tree on quantal

 ./configure --target-list=x86_64-softmmu && make -j3

and run

 cd x86_64-softmmu
 ./qemu-system-x86_64 -m 1024 -boot order=c,menu=on -hda /home/serge/x.img -usb -usbdevice disk:format=raw:/home/serge/usb-sandisk.img -vnc :2 -monitor stdio --enable-kvm -L /usr/share/qemu

then it does not show up in the boot menu. But when I strace it:

 cd x86_64-softmmu
 strace -f -o/tmp/qqq ./qemu-system-x86_64 -m 1024 -boot order=c,menu=on -hda /home/serge/x.img -usb -usbdevice disk:format=raw:/home/serge/usb-sandisk.img -vnc :2 -monitor stdio --enable-kvm -L /usr/share/qemu

it does.

[Serge Hallyn (serge-hallyn)]

Correction - in addition to the timing issue, the newer seabios is also required.

That could be due to seabios commit 2762de0867345d059ab70690f98144921f8e151b: usb: fix boot paths.

[Serge Hallyn (serge-hallyn)]

cherrypicking the 'usb: fix boot paths' commit does not make it work even with strace, so more would be needed.

[Steve Langasek (vorlon)]

The Precise Pangolin has reached end of life, so this bug will not be fixed for that release