[Xen-devel] [PATCH 0 of 7] Mem event ring setup interface update

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

Update the interface for setting up mem event rings (for sharing, mem access or
paging).

Remove the "shared page", which was a waste of a whole page for a single event
channel port value.

More importantly, both the shared page and the ring page were dom0 user-space
process pages mapped by the hypervisor. If the dom0 process does not clean up,
the hypervisor keeps posting events (and holding a map) to a page now belonging
to another process.

Solutions proposed:
- Pass the event channel port explicitly as part of the domctl payload.
- Reserve a pfn in the guest physmap for a each mem event ring. Set/retrieve
these pfns via hvm params. Ensure they are set during build and restore, and
retrieved during save. Ensure these pages don't leak and domains are left 
zombie.

In all cases mem events consumers in-tree (xenpaging and xen-access) have been
updated.

Updating the interface to deal with these problems requires
backwards-incompatible changes on both the helper<->libxc and
libxc<->hypervisor interfaces.

Take advantage of the interface update to plumb setting up of the sharing ring,
which was missing.

All patches touch x86/mm hypervisor bits. Patches 1, 3 and 5 are tools patches
as well.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

 tools/libxc/xc_mem_access.c         |  10 +++-
 tools/libxc/xc_mem_event.c          |  13 +++--
 tools/libxc/xc_mem_paging.c         |  10 +++-
 tools/libxc/xenctrl.h               |   6 +-
 tools/tests/xen-access/xen-access.c |  22 +--------
 tools/xenpaging/xenpaging.c         |  18 +------
 tools/xenpaging/xenpaging.h         |   2 +-
 xen/arch/x86/mm/mem_event.c         |  33 +-------------
 xen/include/public/domctl.h         |   4 +-
 xen/include/public/mem_event.h      |   4 -
 xen/include/xen/sched.h             |   2 -
 xen/arch/x86/hvm/hvm.c              |  48 ++++++++++++++++-----
 xen/include/asm-x86/hvm/hvm.h       |   7 +++
 tools/libxc/xc_domain_restore.c     |  42 ++++++++++++++++++
 tools/libxc/xc_domain_save.c        |  36 ++++++++++++++++
 tools/libxc/xc_hvm_build.c          |  21 ++++++--
 tools/libxc/xc_mem_access.c         |   6 +-
 tools/libxc/xc_mem_event.c          |   3 +-
 tools/libxc/xc_mem_paging.c         |   6 +-
 tools/libxc/xenctrl.h               |   8 +--
 tools/libxc/xg_save_restore.h       |   4 +
 tools/tests/xen-access/xen-access.c |  83 +++++++++++++++++-------------------
 tools/xenpaging/xenpaging.c         |  52 ++++++++++++++++------
 xen/arch/x86/mm/mem_event.c         |  50 ++++++++++------------
 xen/include/public/domctl.h         |   1 -
 xen/include/public/hvm/params.h     |   7 ++-
 xen/include/xen/sched.h             |   1 +
 xen/arch/x86/mm/mem_event.c         |  41 ++++++++++++++++++
 xen/include/public/domctl.h         |  20 ++++++++-
 xen/include/xen/sched.h             |   3 +
 tools/libxc/xc_memshr.c             |  25 +++++++++++
 tools/libxc/xenctrl.h               |   5 ++
 xen/arch/x86/mm/mem_event.c         |  11 ++++
 xen/common/domain.c                 |   3 +
 xen/include/asm-arm/mm.h            |   3 +-
 xen/include/asm-ia64/mm.h           |   3 +-
 xen/include/asm-x86/mm.h            |   2 +
 xen/arch/x86/mm/mem_event.c         |   6 +-
 38 files changed, 413 insertions(+), 208 deletions(-)

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