spapr: Move RMA memory region registration code

PPC970 does not support VRMA (virtual RMA) so real memory required
for SLOF to execute must be allocated by the KVM_ALLOCATE_RMA ioctl.
Later this memory is used as a part of the guest RAM area.
The RMA allocating code also registers a memory region for this piece
of RAM.

We are going to simplify memory regions layout: RMA memory region
will be a subregion in the RAM memory region, both starting from zero.
This way we will not have to take care of start address alignment for
the piece of RAM next to the RMA.

This moves memory region business closer to the RAM memory region
creation/allocation code.

As this is a mechanical patch, no change in behaviour is expected.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
[agraf: fix compilation on non-kvm systems]
Signed-off-by: Alexander Graf <agraf@suse.de>
spapr: Enable use of huge pages

0b183fc87 "memory: move mem_path handling to
memory_region_allocate_system_memory" disabled -mempath use for all
machines that do not use memory_region_allocate_system_memory() to
register RAM. Since SPAPR uses memory_region_init_ram(), the huge pages
support was disabled for it.

This replaces memory_region_init_ram()+vmstate_register_ram_global() with
memory_region_allocate_system_memory() to get huge pages back.

This changes RAM size from (ram_limit - rma_alloc_size) to ram_limit as
the previous patch moved RMA memory region allocation after RAM allocation
and therefore this change does not have immediate effect but simplifies
the code.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>
sPAPR/IOMMU: Fix TCE entry permission

The permission of TCE entry should exclude physical base address.
Otherwise, unmapping TCE entry can be interpreted to mapping TCE
entry wrongly for VFIO devices.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>