xen/arm: p2m type definitions and changes

Define p2m_access_t in ARM and add necessary changes for page table
construction routines to pass the default access information. Also,
define the Radix tree that will hold access permission settings as
the PTE's don't have enough software programmable bits available.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
xen/arm: Add set access required domctl

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
xen/arm: Data abort exception (R/W) mem_events.

This patch enables to store, set, check and deliver LPAE R/W mem_events.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v3: - Add new function for updating the PTE entries, p2m_set_entry.
    - Use the new struct npfec to pass violation information.
    - Implement n2rwx, rx2rw and listener required routines.

v2: - Patch been split to ease the review process.
    - Add definitions of data abort data fetch status codes (enum dabt_dfsc)
      and only call p2m_mem_access_check for traps caused by permission violations.
    - Only call p2m_write_pte in p2m_lookup if the PTE permission actually changed.
    - Properly save settings in the Radix tree and pause the VCPU with
      mem_event_vcpu_pause.
xen/arm: Instruction prefetch abort (X) mem_event handling

Add missing structure definition for iabt and update the trap handling
mechanism to only inject the exception if the mem_access checker
decides to do so.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v2: Add definition for instruction abort instruction fetch status codes (enum iabt_ifsc)
       and only call p2m_mem_access_check for traps triggered for permission violations.
xen/arm: Shatter large pages when using mem_acces

When using mem_acccess+mem_event, the coarsest granularity is required
in the pagetables, therefore we shatter each large page (1GB/2MB) as we
apply the permission changes.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
xen/arm: Enable the compilation of mem_access and mem_event on ARM.

This patch sets up the infrastructure to support mem_access and mem_event
on ARM and turns on compilation. We define the required XSM functions.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v3: Wrap mem_event related functions in XSM into #ifdef HAS_MEM_ACCESS
       blocks.
    Update XSM hooks in flask to properly wire it up on ARM.

v2: Add CONFIG_MEM_PAGING and CONFIG_MEM_SHARING definitions and
       use them instead of CONFIG_X86.
    Split domctl copy-back and p2m type definitions into separate
       patches and move this patch to the end of the series.
tools/libxc: Allocate magic page for mem access on ARM

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Reviewed-by: Julien Grall <julien.grall@linaro.org>
tools/tests: Enable xen-access on ARM

On ARM the guest memory doesn't start from 0, thus we include the
required headers and define GUEST_RAM_BASE_PFN in both architecture
to be passed to mem_access as the starting pfn.
We also define the ARM specific test_and_set_bit function.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>