Re: [PATCH] xenbus: Add support for xenbus backend in stub domain

[Daniel De Graaf <dgdegra@tycho.nsa.gov>]

On 01/12/2012 03:59 AM, Jan Beulich wrote:
>>>> On 11.01.12 at 18:22, Daniel De Graaf <dgdegra@tycho.nsa.gov> wrote:
>> This adds two ioctls to the /dev/xen/xenbus_backend device allowing the
>> xenbus backend to be started after the kernel has booted. This is
>> intended to allow dom0 to start another domain to run xenstore.
>>
>> IOCTL_XENBUS_BACKEND_REMOTE_SETUP requires that the xenstore domain be
>> started; the domain ID is passed as the ioctl argument. This sets up a
>> listening event channel and grant reference to xenbus, but does not
>> start using this interface. It returns the local event channel port.
> 
> Any chance to get at least the setup part matched with the
> legacy Linux implementation (defining IOCTL_XENBUS_ALLOC)?
> 
> Jan

>From what I can tell, the legacy ioctl cannot restore watches because the
return value must be used to set up xenstore communication before they can
be used.

Or were you just asking if IOCTL_XENBUS_BACKEND_REMOTE_SETUP's parameter
can be changed to xenbus_alloc_t?  That structure could be populated in the
same way as the legacy implementation, but it wouldn't give any more
information than the current ioctl does.

> 
>> IOCTL_XENBUS_BACKEND_REMOTE_COMMIT causes the kernel to begin using the
>> event channel set up in the previous ioctl, reregistering all watches
>> and deallocating the previous xenstored event channel.
>>
>> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
>> ---
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