Re: [Qemu-devel] [BUG] ahci -device ide-hd|ide-cd select a bus already in use

[Fabio Fantoni]

Il 03/12/2013 11:32, Markus Armbruster ha scritto:
> Fabio Fantoni <address@hidden> writes:
>
> > I started to test/implement q35 cipset on xen hvm domUs.
> > I found that ide disks and cdrom don't works with q35 using old qemu
> > parameters without -device, this is not a blocking problem.
> > I tried with new qemu parameters and ahci and the disk works.
> > When I tried to add more that one ahci disk/cdrom devices qemu gave
> > this error:
> > > qemu-system-i386: -device ide-cd,drive=drive-sata-disk1,id=sata1:
> > > Can't create IDE unit 1, bus supports only 1 units
> > > qemu-system-i386: -device ide-cd,drive=drive-sata-disk1,id=sata1:
> > > Device initialization failed.
> > > qemu-system-i386: -device ide-cd,drive=drive-sata-disk1,id=sata1:
> > > Device 'ide-cd' could not be initialized
> > I used qemu 1.6.1 for the test and searching online I found the same
> > problem was reported also on fedora, ubuntu and red hat bugtrackers.
> > Looking for the solution on qemu-devel and git I found this patch:
> > http://git.qemu.org/?p=qemu.git;a=commit;h=0ee20e665840d8a887c145b368ee121cb86a028e
> > It is applied on qemu 1.6 but it seems it doesn't solve the problem of
> > the selection of full bus but it only show an error when it happens.
> > Xen with old qemu parameters use index instead of bus and unit but it
> > seems missing if I try to use it on -device.
> > I also read docs/qdev-device-use.txt but it doesn't mention index with
> > new -device ide-hd|ide-cd parameters and I found nothing about if=none
> > or any ahci disks informations, I think that this document needs to be
> > updated/improved.
> >
> > Thanks for any reply.
> You didn't tell us your complete command line.  Your error messages
> suggest you try to add more than one device to the same IDE bus, like
> this:
>
>      $ qemu -nodefaults -S -display none -monitor stdio -M q35 -drive 
> if=none,id=drive0,file=test.qcow2 -drive if=none,id=drive1 -device 
> ide-hd,drive=drive0 -device ide-cd,drive=drive1
>      QEMU 1.7.50 monitor - type 'help' for more information
>      (qemu) upstream-qemu: -device ide-cd,drive=drive1: Can't create IDE unit 
> 1, bus supports only 1 units
>      upstream-qemu: -device ide-cd,drive=drive1: Device initialization failed.
>      upstream-qemu: -device ide-cd,drive=drive1: Device 'ide-cd' could not be 
> initialized

Sorry, these are qemu parameters of my domU:

libxl: debug: libxl_dm.c:1327:libxl__spawn_local_dm: Spawning 
device-model /usr/lib/xen/bin/qemu-system-i386 with arguments:
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
/usr/lib/xen/bin/qemu-system-i386
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -xen-domid
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   9
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -chardev
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
socket,id=libxl-cmd,path=/var/run/xen/qmp-libxl-9,server,nowait
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -mon
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
chardev=libxl-cmd,mode=control
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -nodefaults
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -name
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   W7-q35
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -vnc
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 0.0.0.0:0,to=99
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -k
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   it
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -device
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   VGA
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -boot
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   order=d
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -smp
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   2,maxcpus=2
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -device
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
rtl8139,id=nic0,netdev=net0,mac=00:16:3e:3b:27:20
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -netdev
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
type=tap,id=net0,ifname=vif9.0-emu,script=no,downscript=no
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -machine
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   q35,accel=xen
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -device
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   xen-platform
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -device
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: i82801b11-bridge
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -drive
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
file=/mnt/vm/disks/W7-q35.disk1.xm,if=none,id=drive-sata-disk0,format=raw,cache=writeback
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -device
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
ide-drive,drive=drive-sata-disk0,id=sata0
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -drive
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
file=/mnt/vm/iso/ubcd.iso,if=none,id=drive-sata-disk1,format=raw,cache=writeback
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -device
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm: 
ide-cd,drive=drive-sata-disk1,id=sata1
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   -m
libxl: debug: libxl_dm.c:1329:libxl__spawn_local_dm:   2032

Probably I can try to use libxl variable used for index on bus instead.

> Old IDE provides buses ide.0 and ide.1, and each bus can have up to two
> units, master and slave.
>
> AHCI provides buses ide.0 .. ide.6, but each bus can have only one unit.

Default ahci controller of q35 machine is named always ide or can change?
If I use bus in new -device parameters on xen I must be sure to use very 
stable parameter also on long term.

Thanks for any reply.

> -device is stupid: it picks the first bus it finds, and then the first
> free unit.  Good enough for two devices with IDE, but only one with
> AHCI.
>
> Use explicit bus and unit parameters.  Except you can omit unit=0 with
> AHCI, because it's the only permissible unit anyway:
>
>      $ qemu -nodefaults -S -display none -monitor stdio -M q35 -drive 
> if=none,id=drive0,file=test.qcow2 -drive if=none,id=drive1 -device 
> ide-hd,drive=drive0,bus=ide.0 -device ide-cd,drive=drive1,bus=ide.1