Changing boot flags

You might want to change boot flags for a domU, for example to boot up into
kmdb (-kd). Currently this is slightly awkward (we will soon have a much
better, stable, interface for this). First generate the configuration:

virsh dumpxml domain1 >domain1.xml

Now, below the <bootloader> line, add an additional line such as:

  <bootloader_args>--args="-kdv"</bootloader_args>

Finally re-import the configuration:

virsh define domain1.xml

Now you can reboot your domU and it should pick up the flags. You can also
specify an Install kernel if you're hacking on kernel stuff, for example:

  <bootloader_args>--kernel=/platform/i86xpv/Install.myglom/amd64/unix --ramdisk=/platform/i86pc/amd64/boot_archive --args="-kdv"</bootloader_args>

Booting in 32-bit mode

Solaris will boot 64-bit by default on capable hardware. To have it boot 32-bit, we can follow the process above, specifying a 32-bit kernel and ramdisk:

<bootloader_args>--kernel=/platform/i86xpv/kernel/unix --ramdisk=/platform/i86pc/boot_archive</bootloader_args>