xen: Relocate and refactor mem_access_check into common.

The p2m_mem_access_check function thus far hasn't really done 'checking',
was used only to automatically promote the special-case mem_access rights
and to allocate the mem_access message. In this patch we abstract the
violation check into a common mem_access_check function and change its
return value to int. Return with rc < 0 means the fault wasn't triggered
by mem_access permissions, rc == 0 means vcpu is paused, rc > 0 means
mem_access permissions had been automatically promoted and the vcpu is
not paused.

As part of this patch, we relocate the x86/mm/mm-locks.h header into asm
as to be able to create a generic inlined p2m_gpfn_lock/unlock wrapper
that each arch can define based on its locking scheme.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
x86/p2m: Typo fix for spelling ambiguous

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
x86/p2m: Fix conversion macro of p2m_access to XENMEM_access

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

Add p2m_access_t to struct page_info and add necessary changes for
page table construction routines to pass the default access information.
We store the p2m_access_t info in page_info as the PTE lacks enough
software programmable bits.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v7: - Remove radix tree init/destroy and move p2m_access_t store to page_info.
    - Add p2m_gpfn_lock/unlock functions.
v6: - Move mem_event header include to first patch that needs it.
v5: - #include grouping style-fix.
v4: - Move p2m_get_hostp2m definition here.
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.

We use this in xenaccess as to avoid the user attempting to set page
permissions on pages which don't exist for the domain, as a non-arch specific
sanity check.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
xen/arm: Add p2m_set_permission and p2m_shatter_page helpers.

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>
---
v7: - Removed p2m_shatter_page and p2m_set_permission into separate
      patch.
    - Replace Radix tree settings store with extended struct page_info *
      approach. This way the trap handlers can use the MMU directly to
      locate the permission store instead of having to do a tree-lookup.
    - Typo fixes.
v6: - Add helper function p2m_shatter_page.
    - Only allocate 4k pages when mem_access is in use.
    - If no setting was found in radix tree but PTE exists,
      return rwx as permission.
    - Move the inclusion of various headers into this patch.
    - Make npfec a const.
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>
---
v6: - Make npfec a const.
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

Define the ARM specific test_and_set_bit functions and switch
to use maximum gpfn as the limit to setting permissions. Also,
move HAS_MEM_ACCESS definition into config.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v6: - Just use xc_domain_maximum_gpfn to get max_gpfn.
v5: - Use the new information returned by getdomaininfo, max_gpfn, to
      set access permissions. On ARM this will include the potential
      memory hole as well which the hypervisor just loops over.
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.