Re: [PATCH] libxl: ignore run_hotplug_scripts setting when backend_domid!=0

["Roger Pau Monné" <roger.pau@citrix.com>]

On 04/07/13 14:40, George Dunlap wrote:
> On 04/07/13 12:39, Roger Pau Monné wrote:
>> On 04/07/13 12:42, George Dunlap wrote:
>>> On Tue, Apr 9, 2013 at 9:49 AM, Marek Marczykowski
>>> <marmarek@invisiblethingslab.com> wrote:
>>>> Instead of forcing the user to change run_hotplug_scripts setting
>>>> globally, just ignore it for backends outside of dom0.
>>>>
>>>> Signed-off-by: Marek Marczykowski <marmarek@invisiblethingslab.com>
>>> This seems like a good idea -- Roger / Ian, any thoughts?
>> We already have this behaviour in libxl (see
>> libxl_device.c:device_hotplug):
>>
>> /*
>>   * If device is attached from a driver domain don't try to execute
>>   * hotplug scripts
>>   */
>> if (aodev->dev->backend_domid != LIBXL_TOOLSTACK_DOMID)
>>      goto out;
>>
>> This was introduced by commit 05bfd984dfe7014f1f5ea1133608b9bab589c120
> 
> But you still get an error on domain creation if you actually set a
> non-dom0 backend and run_hotplug_scripts is set; so you can't actually
> run in "mixed mode" anyway.  This patch should, I think, enable you to
> have libxl run the scripts in dom0, but udev run them in domu.

Not for block devices that run in driver domains, but that might be true
for network devices (I have not checked in libxl if the flow of network
devices will error at some point if backend != 0).

For block devices you just need to follow
http://wiki.xen.org/wiki/Storage_driver_domains, there's no need to
perform any kind of obscure tricks to get it running.