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: slightly re-arrange 32-bit handling in dom0_construct_pv() 2: don't maintain compat M2P when !PV32 3: don't override INVALID_M2P_ENTRY with SHARED_M2P_ENTRY Jan
