[Qemu-devel] Re: [PATCH 2/2] qdev: add command line option to set global defaults for properties.

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Nov 25, 2009 at 01:55:18PM +0100, Gerd Hoffmann wrote:
> On 11/24/09 15:11, Michael S. Tsirkin wrote:
>> On Tue, Nov 24, 2009 at 12:06:28PM +0100, Gerd Hoffmann wrote:
>>> This patch adds infrastructure and command line option for setting
>>> global defaults for device properties, i.e. you can for example use
>>>
>>>    -global virtio-blk-pci.vectors=0
>>>
>>> to turn off msi by default for all virtio block devices.  The config
>>> file syntax is:
>>>
>>> [global]
>>>    driver = "virtio-blk-pci"
>>>    property = "vectors"
>>>    value = "0"
>>
>> Where's this documented?
>
> config file syntax is git-style, the details are not (yet) documented.
>
> Easiest way to get one if you want to play with it is
>   "qemu <all-your-vm-options-here> -writeconfig <filename>".
>
> Note that not all command line options are covered.
>
> I've attached a sample to this mail.  Needs a few patches sent to the  
> list yesterday and today to actually work though.
>
>> How would one figure out the command lines you give in
>> the examples above?
>
> "info qtree" in monitor prints the device names and properties for all  
> devices used by the virtual machine.
>
> "info qdm" and '-device ?' list all devices known to qemu.

So maybe add "use -device ? to get list of all devices"
to help text?

[mst@tuck qemu]$ ~/qemu-git/bin/qemu-system-x86_64 -device ?
/home/mst/qemu-git/bin/qemu-system-x86_64: invalid option -- '-device'
[mst@tuck qemu]$ ~/qemu-git/bin/qemu-system-x86_64 --device ?
/home/mst/qemu-git/bin/qemu-system-x86_64: invalid option -- '-device'

>  The device  
> properties are not listed there though (one of the items on my todo 
> list).

Yes, and in fact each option should supply a help text
explaining what it is. This was not done this way upfront
and each day makes it harder to document as new options
are added without documentation.


> cheers,
>   Gerd