Re: [libvirt] [Qemu-devel] [Qemu PATCH v2] add a boot option to do strict boot

On Wed, Jan 09, 2013 at 12:36:52PM -0500, Laine Stump wrote: > On 01/09/2013 10:52 AM, Amos Kong wrote: >> On Wed, Jan 09, 2013 at 08:14:07AM -0700, Eric Blake wrote: >>> On 01/09/2013 01:39 AM, Amos Kong wrote: >>>> Current seabios will try to boot from selected devices first, >>>> if they are all failed, seabios will also try to boot from >>>> un-selected devices. >>>> >>>> We need to make it configurable. I already posted a seabios >>>> patch to add a new device type to halt booting. Qemu can add >>>> "HALT" at the end of bootindex string, then seabios will halt >>>> booting after trying to boot from selected devices. >>>> >>>> This option only effects when boot priority is changed by >>>> bootindex options, the old style(-boot order=..) will still >>>> try to boot from un-selected devices. >>>> >>>> v2: add HALT entry in get_boot_devices_list() >>>> define boot_strict to bool >>>> >>>> Signed-off-by: Amos Kong <akong(a)redhat.com&gt; >>>> --- >>> Libvirt will need to expose an attribute that lets the user control >>> whether to use this new option; how do we probe via QMP whether the new >>> -boot strict=on command-line option is available? >> Old style to adjust boot priority by order parameter: >> -boot order=n,strict=on (BAD, unselected devices will be tried) >> >> New style to adjust boot priority by bootindex: >> -device virtio-net-pci,...,bootindex=1 -boot strict=on (OK) >> >> We only want strict option to support new style. >> >> (those two styles are implemented in two different way insider >> seabios, the latest simple patch only changed the bootindex way) > Just a note about this: as far as I can tell virt-manager currently only > uses the "old style" of specifying boot order; it needs to be enhanced > to recognize the presence of bootindex=n ordering, and behave > accordingly. Looking from the outside, that looks to be not completely > trivial, as the old style of ordering only allows specifying "hard disk" > as a single line in the priority order, but the new style has each disk > specified separately. Not only that, but *which* of the disks is tried > first under the old order may change depending on whether or not a > bootmenu is requested (in one case it picks unit=0 on the controller, in > the other case, it orders the disks alphabetically by target dev name) Hmm, well libvirt should be using bootindex=n on the QEMU command line regardless of what applications put in the XML. ie if the application uses the old style XML, libvirt should translate that into bootindex=n for them.