Four day week.

[VIRT-344 # ARMv8.5-MemTag, Memory Tagging Extension ]

Lots of work here.

Noticed that our TBI handling is wrong for system mode, such that the FAR_ELx register gets the wrong contents. Noticed that SVE isn't handling TBI at all, much less being prepared for MTE. Noticed that even AdvSIMD would not quite produce the correct results for LD*/ST* (multiple structures).

Rearranging the actual MTE check from the ground up. Found an odd case with DC_ZVA that threw a wrench into that planning.

[VIRT-327 # Richard's upstream QEMU work ]

Honor more HCR_EL2 trap bits. HPPA patch queue flushed. Patch review for ppc "hardfloat" patch. Patch review for memory_region_allocate_system_memory.

r~