[libvirt] XML support for arbitrary command line arguments

[Harsh Bora]

On 09/22/2010 01:12 AM, Venkateswararao Jujjuri (JV) wrote:
> On 9/21/2010 10:02 AM, Daniel P. Berrange wrote:
>> On Mon, Sep 20, 2010 at 04:07:32PM -0700, Venkateswararao Jujjuri 
>> (JV) wrote:
>>> On 9/14/2010 9:34 AM, Venkateswararao Jujjuri (JV) wrote:
>>>> On 9/14/2010 2:43 AM, Daniel P. Berrange wrote:
>>>>> On Tue, Sep 14, 2010 at 11:03:04AM +0530, Harsh Bora wrote:
>>>>>> As QEMU provides support for accessing such shared directory with 
>>>>>> the
>>>>>> help of 9p server, and therefore need to be passed additional
>>>>>> commandline argument while starting, I wanted to test it using 
>>>>>> XML and
>>>>>> libvirt.
>>>>>
>>>>>> So, if the idea looks good to everyone, we can have something like:
>>>>>>
>>>>>> <shareddir fstype=local path='/folder/to/share' 
>>>>>> mount_tag='unique_tag'
>>>>>> security_model='as_applicable'>
>>>>
>>>> fstype may not be 'local' all the time. So in the XML description, 
>>>> I would
>>>> propose something like
>>>> fstype='filesystem type' or something like that. For now only QEMU
>>>> supports local.
>>>> This keyword represents all local filesystems like ext3/ext4 etc.
>>>>>
>>>>> We already have an XML syntax defined for filesystems using
>>>>> the<filesystem>  element. I've proposed an impl for QEMU using
>>>>> p9fs before, but we didn't apply it yet.
>>>>>
>>>>> http://www.redhat.com/archives/libvir-list/2010-July/msg00458.html
>>>
>>>
>>> Taking a closer look at the Danial's patch above, it covers almost 
>>> all our
>>> needs.
>>> Except that the fstype and security models are hard coded.
>>
>> fstype is hardcoded to local only in so much as there aren't
>> any other options in QEMU for fstype. If QEMU adds other
>> fstype options, we'll extend<filesystem type='XXXX'>  to
>> cover them. Currently type='bind' in the XML maps to fstype=local
>> in QEMU.
>
Daniel,
I am not able to find 'bind' in the list of possible values that 
<filesystem type='XXX'> supports.
I am checking in docs/schemas/domain.rng, it does only have file, block, 
mount, template.
Are you talking about something else?

-Harsh
> local is the only option now. But we expect it to have more options 
> sooner if
> not later. It will be great if there is a way we can make it a 
> tag/variable in this attempt.
> If you think it is better to deal with it later..sure we can live with 
> that. :)
>
>>
>>>
>>> +    virBufferAddLit(&opt, "local,security_model=mapped");
>>>
>>> Any reason why it was not taken yet?
>>
>> I wanted to decide on best setting for security model. I think it
>> might be better to make it use passthrough by default, since that
>> gives better interoperability for users with matching host/guest
>> IDs.
>
> Sure passthrough is the most compatible option. Can you please explain
> what do you mean by "best setting"? you mean the tag name?
> Can we introduce new tags for security_mode and fstype(instead of 
> overloading type=bind)?
>
> Thanks,
> JV
>
>>
>> Daniel
>
>