Linux Virtualization - Nov 2016 - SR-PCIM support in Xen

Hi All,

Is there any support for software mailbox communication between PF and VF driver
in Xen ?

As per the following link:
http://www-archive.xenproject.org/files/xensummitboston08/Xen-SR-IOV.pdf
It says that for software based virtual mailbox we require SR-PCIM support.

So for this purpose is SR-PCIM implemented as part of Xen ?
Or is there any other method that Xen provides for communication between PF
& VF ?

Thanks & regards,
Bharat