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>
---
v8: Define HAS_MEM_ACCESS/PAGING/SHARING in config/x86_*.mk
    and wrap required parts in mem_event into ifdefs accordingly.

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 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>
Acked-by: Tim Deegan <tim@xen.org>
xen: Relocate p2m_access_t into common and swap the order

We swap the order of the enum of types n ... rwx, as to have rwx at 0, which is
the default setting when mem_access is not in use. This has performance benefits for
non-memaccess paths, as now comparison is to 0 when checking if memaccess is in use,
which is often faster.

We fix one location in nested_hap where the order of the enum made a difference.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Acked-by: Tim Deegan <tim@xen.org>
xen: Relocate p2m_mem_access_resume to mem_access common

Relocate p2m_mem_access_resume to common and abstract the new
p2m_mem_event_emulate_check into the p2m layer to.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v9: Pass the vcpu instead of the domain to emulate_check
    and a small cosmetic fix.
v8: Abstract p2m_mem_event_emulate_check.
v6: Keep the comment describing the function.
v5: Style fix.
xen: Relocate set_access_required domctl into common

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Acked-by: Tim Deegan <tim@xen.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
v9: Wrap domctl into ifdef check for HAS_MEM_ACCESS.
v8: Remove superfluous paranthesis in macro get_hostp2m.
xen: Relocate mem_event_op domctl and access_op memop into common.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
v9: Rename abstracted function to p2m_setup_introspection.
v8: Move the new enable_msr_exit_interception test into the p2m layer.
v6: Grouping style fix of #includes in common/memory.c.
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>
Acked-by: Tim Deegan <tim@xen.org>
---
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>
Acked-by: Tim Deegan <tim@xen.org>
---
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>
Acked-by: Tim Deegan <tim@xen.org>
---
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 necessary changes for page table construction routines to pass
the default access information. We store the p2m_access_t info in a
Radix tree as the PTE lacks enough software programmable bits.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v10: - Typo fix and drop reshuffling things that no longer need
      shuffling.
v8: - Drop lock inputs as common mem_access_check is postponed.
    - Resurrect the radix tree with an extra boolean access_in_use flag
      to indicate if the tree is empty to avoid lookups.
v7: - Remove radix tree init/destroy and move p2m_access_t store to page_info.
    - Add p2m_gpfn_lock/unlock functions.
    - Add bool_t lock input to p2m_lookup and apply_p2m_changes so the caller
      can specify if locking should be performed. This is needed in order to
      support mem_access_check from common.
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>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Julien Grall <julien.grall@linaro.org>
---
v8: Determine level_shift in p2m_shatter_page instead of passing as argument.
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. A custom boolean, access_in_use,
specifies if the tree is in use to avoid unecessary lookups on an empty tree.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
---
v10: - Remove ASSERT from MEMACCESS case.
    - Flush the tlb in the MEMACCESS case as we progress.
    - Typos and style fixes.
v8: - Revert to arch specific p2m_mem_access_check.
    - Retire dabt_dfsc enum and use FSC_FLT defines.
    - Revert to Radix tree approach and use access_in_use flag to
      indicate if the tree is in use or not to avoid uneccessary lookups.
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.
    - Add p2m_get_entry/set_entry compat functions which are required by
      the common mem_access_check function.
    - 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: Temporarily disable mem_access for hypervisor access

The guestcopy helpers use the MMU to verify that the given guest has read/write
access to a given page during hypercalls. As we may have custom mem_access
permissions set on these pages, we temporarily disable them to allow Xen to
finish the hypercalls. This is permissible as mem_access events are only
reported for events when the guest directly accesses protected memory on x86
as well.

Signed-off-by: Tamas K Lengyel <tklengyel@sec.in.tum.de>
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>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
v9: - Minor comment fix for describing s1ptw.
v8: - Revert to arch specific p2m_mem_access_check.
    - Retire iabt_fsc enum and use FSC_FLT instead.
    - Complete the struct definition of hsr_iabt.
v7: - Use the new common mem_access_check.
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>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Julien Grall <julien.grall@linaro.org>
---
v8: All MEM_* flags have been converted to HAS_* and moved into config/*.mk

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.