Xen_os.XenSourceSome more Xen-specific that is neither part of scheduling nor startup info, and not tied to xenstore either.
Allow a local xen domain to read/write memory exported ("granted") from foreign domains. Safe memory sharing is a building block of all xen inter-domain communication protocols such as those for virtual network and disk devices.
Foreign domains will explicitly "grant" us access to certain memory regions such as disk buffers. These regions are uniquely identified by the pair of (foreign domain id, integer reference) which is passed to us over some existing channel (typically via xenstore keys or via structures in previously-shared memory region).
In xen-4.2 and later, the domain builder will allocate one of the reserved grant table entries and use it to pre-authorise the console backend domain.