[libvirt] [RFC PATCH] qemu: Shorten SCSI hostdev alias to avoid QEMU failure
The alias for hostdevs of type SCSI can be too long for QEMU if larger LUNs are encountered. Here's a real life example: <hostdev mode='subsystem' type='scsi' managed='no'> <source> <adapter name='scsi_host0'/> <address bus='0' target='19' unit='1088634913'/> </source> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </hostdev> this results in a too long drive id, resulting in QEMU yelling Property 'scsi-generic.drive' can't find value 'drive-hostdev-scsi_host0-0-19-1088634913' This commit changes the alias back to the default hostdev$(index) scheme. Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> --- Actually this is highlighting a larger issue. Apparently QEMU ids are limited to a length of 32 bytes. This means that SCSI based drives are also in danger to exceed this limit. We should consider to use a drive index for controller-attached disks for alias generation instead of the verbose drive-$bustype-$busaddress schema. src/qemu/qemu_command.c | 10 +--------- .../qemuxml2argv-hostdev-scsi-boot.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-lsi.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-readonly.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-virtio-scsi.args | 4 ++-- 5 files changed, 9 insertions(+), 17 deletions(-) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 879aed8..8c8bef2 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -818,16 +818,8 @@ qemuAssignDeviceHostdevAlias(virDomainDefPtr def, virDomainHostdevDefPtr hostdev } } - if (hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI) { - if (virAsprintf(&hostdev->info->alias, "hostdev-%s-%d-%d-%d", - hostdev->source.subsys.u.scsi.adapter, - hostdev->source.subsys.u.scsi.bus, - hostdev->source.subsys.u.scsi.target, - hostdev->source.subsys.u.scsi.unit) < 0) - return -1; - } else if (virAsprintf(&hostdev->info->alias, "hostdev%d", idx) < 0) { + if (virAsprintf(&hostdev->info->alias, "hostdev%d", idx) < 0) return -1; - } return 0; } diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-boot.args b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-boot.args index cd22672..ba1e6c6 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-boot.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-boot.args @@ -4,6 +4,6 @@ unix:/tmp/test-monitor,server,nowait -no-acpi \ -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x3 -usb \ -drive file=/dev/HostVG/QEMUGuest2,if=none,id=drive-ide0-0-0 \ -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \ --drive file=/dev/sg0,if=none,id=drive-hostdev-scsi_host0-0-0-0 \ --device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,drive=drive-hostdev-scsi_host0-0-0-0,id=hostdev-scsi_host0-0-0-0,bootindex=1 \ +-drive file=/dev/sg0,if=none,id=drive-hostdev0 \ +-device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,drive=drive-hostdev0,id=hostdev0,bootindex=1 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-lsi.args b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-lsi.args index 06f7938..2cbf9be 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-lsi.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-lsi.args @@ -4,6 +4,6 @@ unix:/tmp/test-monitor,server,nowait -no-acpi -boot c \ -device lsi,id=scsi0,bus=pci.0,addr=0x3 -usb \ -drive file=/dev/HostVG/QEMUGuest2,if=none,id=drive-ide0-0-0 \ -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \ --drive file=/dev/sg0,if=none,id=drive-hostdev-scsi_host0-0-0-0 \ --device scsi-generic,bus=scsi0.0,scsi-id=7,drive=drive-hostdev-scsi_host0-0-0-0,id=hostdev-scsi_host0-0-0-0 \ +-drive file=/dev/sg0,if=none,id=drive-hostdev0 \ +-device scsi-generic,bus=scsi0.0,scsi-id=7,drive=drive-hostdev0,id=hostdev0 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-readonly.args b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-readonly.args index ea2f7af..8c274a9 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-readonly.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-readonly.args @@ -4,6 +4,6 @@ unix:/tmp/test-monitor,server,nowait -no-acpi -boot c \ -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x3 -usb \ -drive file=/dev/HostVG/QEMUGuest2,if=none,id=drive-ide0-0-0 \ -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \ --drive file=/dev/sg0,if=none,id=drive-hostdev-scsi_host0-0-0-0,readonly=on \ --device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,drive=drive-hostdev-scsi_host0-0-0-0,id=hostdev-scsi_host0-0-0-0 \ +-drive file=/dev/sg0,if=none,id=drive-hostdev0,readonly=on \ +-device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,drive=drive-hostdev0,id=hostdev0 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 diff --git a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-virtio-scsi.args b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-virtio-scsi.args index b92afc7..a7d6789 100644 --- a/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-virtio-scsi.args +++ b/tests/qemuxml2argvdata/qemuxml2argv-hostdev-scsi-virtio-scsi.args @@ -4,6 +4,6 @@ unix:/tmp/test-monitor,server,nowait -no-acpi -boot c \ -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x3 -usb \ -drive file=/dev/HostVG/QEMUGuest2,if=none,id=drive-ide0-0-0 \ -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \ --drive file=/dev/sg0,if=none,id=drive-hostdev-scsi_host0-0-0-0 \ --device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,drive=drive-hostdev-scsi_host0-0-0-0,id=hostdev-scsi_host0-0-0-0 \ +-drive file=/dev/sg0,if=none,id=drive-hostdev0 \ +-device scsi-generic,bus=scsi0.0,channel=0,scsi-id=4,lun=8,drive=drive-hostdev0,id=hostdev0 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 -- 1.7.9.5
On Fri, Jul 12, 2013 at 05:13:56PM +0200, Viktor Mihajlovski wrote:
The alias for hostdevs of type SCSI can be too long for QEMU if larger LUNs are encountered. Here's a real life example:
<hostdev mode='subsystem' type='scsi' managed='no'> <source> <adapter name='scsi_host0'/> <address bus='0' target='19' unit='1088634913'/> </source> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </hostdev>
this results in a too long drive id, resulting in QEMU yelling
Property 'scsi-generic.drive' can't find value 'drive-hostdev-scsi_host0-0-19-1088634913'
This commit changes the alias back to the default hostdev$(index) scheme.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> ---
Actually this is highlighting a larger issue. Apparently QEMU ids are limited to a length of 32 bytes. This means that SCSI based drives are also in danger to exceed this limit. We should consider to use a drive index for controller-attached disks for alias generation instead of the verbose drive-$bustype-$busaddress schema.
Urgh that sucks. I had no idea QEMU would impose such an arbitrary length limitation for something like this.
src/qemu/qemu_command.c | 10 +--------- .../qemuxml2argv-hostdev-scsi-boot.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-lsi.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-readonly.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-virtio-scsi.args | 4 ++-- 5 files changed, 9 insertions(+), 17 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 879aed8..8c8bef2 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -818,16 +818,8 @@ qemuAssignDeviceHostdevAlias(virDomainDefPtr def, virDomainHostdevDefPtr hostdev } }
- if (hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI) { - if (virAsprintf(&hostdev->info->alias, "hostdev-%s-%d-%d-%d", - hostdev->source.subsys.u.scsi.adapter, - hostdev->source.subsys.u.scsi.bus, - hostdev->source.subsys.u.scsi.target, - hostdev->source.subsys.u.scsi.unit) < 0) - return -1; - } else if (virAsprintf(&hostdev->info->alias, "hostdev%d", idx) < 0) { + if (virAsprintf(&hostdev->info->alias, "hostdev%d", idx) < 0) return -1; - }
return 0; }
ACK There's no back compatibility issues, since we store the aliases for running guests in the state XML. Thus this will only affect newly launched guests Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
On 22.07.2013 11:58, Daniel P. Berrange wrote:
On Fri, Jul 12, 2013 at 05:13:56PM +0200, Viktor Mihajlovski wrote:
The alias for hostdevs of type SCSI can be too long for QEMU if larger LUNs are encountered. Here's a real life example:
<hostdev mode='subsystem' type='scsi' managed='no'> <source> <adapter name='scsi_host0'/> <address bus='0' target='19' unit='1088634913'/> </source> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </hostdev>
this results in a too long drive id, resulting in QEMU yelling
Property 'scsi-generic.drive' can't find value 'drive-hostdev-scsi_host0-0-19-1088634913'
This commit changes the alias back to the default hostdev$(index) scheme.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com> ---
Actually this is highlighting a larger issue. Apparently QEMU ids are limited to a length of 32 bytes. This means that SCSI based drives are also in danger to exceed this limit. We should consider to use a drive index for controller-attached disks for alias generation instead of the verbose drive-$bustype-$busaddress schema.
Urgh that sucks. I had no idea QEMU would impose such an arbitrary length limitation for something like this.
src/qemu/qemu_command.c | 10 +--------- .../qemuxml2argv-hostdev-scsi-boot.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-lsi.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-readonly.args | 4 ++-- .../qemuxml2argv-hostdev-scsi-virtio-scsi.args | 4 ++-- 5 files changed, 9 insertions(+), 17 deletions(-)
ACK
There's no back compatibility issues, since we store the aliases for running guests in the state XML. Thus this will only affect newly launched guests
Daniel
Pushed now. Michal
participants (3)
-
Daniel P. Berrange -
Michal Privoznik -
Viktor Mihajlovski