[PATCH v2 0/5] x86: M2P maintenance adjustments (step 1)

[Jan Beulich <jbeulich@xxxxxxxx>]

As pointed out by Andrew, maintaining the compat M2P when !PV32
(or when "pv=no-32" was given) is a pointless waste of memory. Do
away with this, with a possible plan to subsequently use the
compat instance instead of the native one in shim mode with a
32-bit guest (requiring more intrusive rework, in particular to
delay setting up the M2P until the bitness of the client domain
is known).

1: convert set_gpfn_from_mfn() to a function
2: don't maintain compat M2P when !PV32
3: don't override INVALID_M2P_ENTRY with SHARED_M2P_ENTRY
4: PV: also check kernel endianness when building Dom0
5: simplify is_guest_l2_slot()

Jan