xen: Relocate mem_access and mem_event into common.

In preparation to add support for ARM LPAE mem_event, relocate mem_access,
mem_event and auxiliary functions into common Xen code.
This patch makes no functional changes to the X86 side, for ARM mem_event
and mem_access functions are just defined as placeholder stubs, and are
actually enabled later in the series.

Edits that are only header path adjustments:
   xen/arch/x86/domctl.c
   xen/arch/x86/mm/hap/nested_ept.c
   xen/arch/x86/mm/hap/nested_hap.c
   xen/arch/x86/mm/mem_paging.c
   xen/arch/x86/mm/mem_sharing.c
   xen/arch/x86/mm/p2m-pod.c
   xen/arch/x86/mm/p2m-pt.c
   xen/arch/x86/mm/p2m.c
   xen/arch/x86/x86_64/compat/mm.c
   xen/arch/x86/x86_64/mm.c

Makefile adjustments for new/removed code:
   xen/common/Makefile
   xen/arch/x86/mm/Makefile

Relocated prepare_ring_for_helper and destroy_ring_for_helper functions:
   xen/include/xen/mm.h
   xen/common/memory.c
   xen/include/asm-x86/hvm/hvm.h
   xen/arch/x86/hvm/hvm.c

Code movement of mem_event and mem_access:
    xen/arch/x86/mm/mem_access.c -> xen/common/mem_access.c
    xen/arch/x86/mm/mem_event.c -> xen/common/mem_event.c
    xen/include/asm-x86/mem_access.h -> xen/include/xen/mem_access.h
    xen/include/asm-x86/mem_event.h -> xen/include/xen/mem_event.h

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Acked-by: Tim Deegan <tim@xen.org>
---
v5: Make <xen/mem-event.h> include <xen/sched.h> by default.
    Style fix with grouping of #includes.

v4: Make <xen/mem_access.h> include <public/memory.h> by default.

v3: Replace asm/domain.h with xen/sched.h in mem_event.c to better
    accomodate for the new code location.
    Replace #ifdef CONFIG_X86 wrappers with HAS_MEM_ACCESS flags.

v2: Update MAINTAINERS.
    More descriptive commit message to aid in the review process.
xen: Relocate p2m_mem_access_resume to mem_access common

The p2m_mem_access resume function is not p2m specific and could be shared across ARM/x86.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: Style fix.
xen: Relocate struct npfec definition into common

Nested page fault exception code definitions can be reused on ARM as well.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Acked-by: Jan Beulich <jbeulich@suse.com>
xen: Relocate mem_event_op domctl and access_op memop into common.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: Move memop compat into common as well.
    Position domctl in switch relative to the domctl #.
v4: Don't remove memop handling from x86_64/compat and style fixes.
xen/mem_event: Clean out superfluous white-spaces

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Acked-by: Tim Deegan <tim@xen.org>
---
v2: Clean the mem_event header as well.
xen/mem_event: Relax error condition on debug builds

A faulty tool stack can brick a debug hypervisor. Unpleasant while dev/test.

Suggested-by: Andres Lagar Cavilla <andres@lagarcavilla.org>
Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: Make printout greppable.
v4: Add domain_id to the printout.
v3: Switch to gdprintk and print the vCPU id as well.
xen/mem_event: Abstract architecture specific sanity checks

Move architecture specific sanity checks into its own function
which is called when enabling mem_event.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: Style fix.
v4: Style fix.
v2: Move sanity check function into architecture specific p2m.h
xen/mem_access: Abstract architecture specific sanity check

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: Style fix.
v4: Style fix.
v2: Move sanity check function into architecture specific p2m.h
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>
---
v5: #include grouping style-fix.
v4: move p2m_get_hostp2m definition here.
xen/arm: Add set access required domctl

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
xen/arm: Implement domain_get_maximum_gpfn

The function domain_get_maximum_gpfn is returning the maximum gpfn ever
mapped in the guest. We can use d->arch.p2m.max_mapped_gfn for this purpose.

Suggested-by: Julien Grall <julien.grall@linaro.org>
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.
As the LPAE PTE's lack enough available software programmable bits,
we store the permissions in a Radix tree, where the key is the pfn
of a 4k page. Only settings other than p2m_access_rwx are saved
in the Radix tree.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: - Move p2m_set_entry's logic into apply_one_level via
      a new p2m_op, MEMACCESS.
v4: - Add p2m_mem_access_radix_set function to be called
      when inserting new PTE's and when updating existing entries.
    - Switch p2m_mem_access_check to return bool_t.
    - Use new struct npfec to pass violation info.
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>
---
v4: - Don't mark instruction fetch violation as read violation.
    - Use new struct npfec to pass violation info.
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: 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>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
---
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>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
tools/tests: Enable xen-access on ARM

On ARM the guest memory doesn't start from 0 and has multiple banks
of memory, thus we adjust the setting/unsetting routines accordingly.
We also define the ARM specific test_and_set_bit function.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v5: - Use tot_pages instead of max_pages as to avoid hitting
      the limit domain_max_gpfn reports.
v4: - Take into account multiple guest ram banks on ARM.
    - Move HAS_MEM_ACCESS definition into config/*.mk and only compile
      xen-access when it is defined.
    - Pass CONFIG_X86/CONFIG_ARM flags during compilation in xen-access
      Makefile.