xen: Relocate the definition of 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. This allows
us to memset the permission store to 0, without having to specify rwx as the default
permission when memaccess is not in use. This also has performance benefits for
non-memaccess paths, as now comparison is to 0 when checking if memaccess is in use,
which is usually 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>
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.
    - 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>
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.
    - 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: 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>
---
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>
---
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.