[Xen-devel] [PATCH RFC v2 0/4] Add mem_access support for PV domains

[Aravindh Puthiyaparambil <aravindp@xxxxxxxxx>]

This patch series adds mem_access support for PV domains. To do this the PV
domain domain has to be run with shadow paging. A p2m implementation for
mem_access has been added to track the access permissions. Since special ring
pages are not created for PV domains, this is done as part of enabling
mem_access.This page is freed when mem_access is disabled or when the domain
is destroyed.

When mem_access is enabled for a PV domain, shadow paging is turned on and all
the shadows are dropped. In the resulting pagefaults, the entries are created
with the default access permissions. On future pagefaults, if there is a 
violation,
a mem_event is sent to the mem_access listener who will then resolve it.

The access permissions for individual pages are stored in the shadow_flags field
in the page_info structure. To get the access permissions for individual pages,
this field is referenced. To set the access permission of individual pages, the 
new
permission is set in the shadow_flags and the shadow for the gmfn is dropped. 
On the
resulting fault, the new PTE entry will be created with the new permission. A
new API has been added to set the default access permissions for PV domains.

Patches are based on top of commit f9cff088.

Signed-off-by: Aravindh Puthiyaparambil <aravindp@xxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

  x86/mm: Shadow and p2m changes for PV mem_access
  x86/mem_access: mem_access and mem_event changes to support PV domains
  tools/libxc: Add APIs for PV mem_access
  tool/xen-access: Add support for PV domains

 tools/libxc/xc_mem_access.c          |  42 ++++++
 tools/libxc/xc_mem_event.c           |  23 +++-
 tools/libxc/xc_private.h             |   9 ++
 tools/libxc/xenctrl.h                |  28 +++-
 tools/tests/xen-access/xen-access.c  | 104 +++++++++------
 xen/arch/x86/domain.c                |  12 ++
 xen/arch/x86/mm/Makefile             |   2 +-
 xen/arch/x86/mm/mem_access.c         | 244 ++++++++++++++++++++++++++++++++++-
 xen/arch/x86/mm/mem_event.c          |  62 +++++++--
 xen/arch/x86/mm/p2m-ma.c             | 148 +++++++++++++++++++++
 xen/arch/x86/mm/p2m.c                |  52 +++++---
 xen/arch/x86/mm/paging.c             |   7 +
 xen/arch/x86/mm/shadow/common.c      |  75 ++++++++++-
 xen/arch/x86/mm/shadow/multi.c       | 101 ++++++++++++++-
 xen/arch/x86/mm/shadow/private.h     |   7 +
 xen/arch/x86/srat.c                  |   1 +
 xen/arch/x86/usercopy.c              |  12 ++
 xen/common/page_alloc.c              |   3 +
 xen/drivers/video/vesa.c             |   1 +
 xen/include/asm-x86/domain.h         |   9 ++
 xen/include/asm-x86/mem_access.h     |   3 +
 xen/include/asm-x86/mm.h             |   1 -
 xen/include/asm-x86/p2m.h            |  17 +++
 xen/include/asm-x86/paging.h         |   1 +
 xen/include/asm-x86/shadow.h         |  15 +++
 xen/include/asm-x86/x86_64/uaccess.h |   7 +
 xen/include/public/memory.h          |   3 +
 27 files changed, 899 insertions(+), 90 deletions(-)
 create mode 100644 xen/arch/x86/mm/p2m-ma.c

-- 
1.9.1


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