p2m_add_page() is simply a rename from guest_physmap_add_entry().
p2m_remove_page() then is its counterpart, despite rendering
guest_physmap_remove_page(). This way callers can use suitable pairs of
functions (previously violated by hvm/grant_table.c).
Obviously this needs some clarification. While we're here, I find this a bit confusing; I tend to use the present tense for the way the code is before the patch, and the imperative for what the patch does; so Id' say:
Rename guest_physmap_add_entry() to p2m_add_page; make guest_physmap_remove_page a wrapper with p2m_remove_page. That way callers can use suitable pairs...
Other than that looks good.