[Xen-devel] [PATCH 0/2] x86: Add a hvmop for setting the #VE suppress bit

[Adrian Pop <apop@xxxxxxxxxxxxxxx>]

As the code stands right now, after DomU has enabled #VE using
HVMOP_altp2m_vcpu_enable_notify, all its pages have the #VE suppress bit
cleared, generating #VEs for any EPT violation.  There is currently no
way to change the value of the #VE suppress bit for a page from a
domain; it can only be done in Xen internally using ept_set_entry().

Following the discussion from
https://lists.xen.org/archives/html/xen-devel/2017-03/msg01312.html this
patch introduces a new hvmop to set this bit and thus have control over
which pages generate #VE and which VM-Exit.

I'm not sure whether it's best to define p2m_set_suppress_ve() in
mem_access.c since this file contains common functions for x86 (vmx &
svm) and the function is Intel-specific.

changes in v2:
- check if #VE has been enabled on the target domain (Tamas K Lengyel)
- check if the cpu has the #VE feature
- make the suppress_ve argument boolean (Jan Beulich)
- initialize only local variables that need initializing (Jan Beulich)
- use fewer local variables (Jan Beulich)
- fix indentation (Jan Beulich)
- remove unnecessary braces (Jan Beulich)
- use gfn_lock() instead of p2m_lock() in the non-altp2m case (Jan
  Beulich)
- allow only privileged domains to use this hvmop
- merge patch #2 and patch #3 (Jan Beulich)

Adrian Pop (1):
  x86/altp2m: Add a hvmop for setting the suppress #VE bit

Vlad Ioan Topan (1):
  x86/mm: Change default value for suppress #VE in set_mem_access()

 tools/libxc/include/xenctrl.h   |  2 ++
 tools/libxc/xc_altp2m.c         | 24 ++++++++++++++++++
 xen/arch/x86/hvm/hvm.c          | 14 +++++++++++
 xen/arch/x86/mm/mem_access.c    | 55 +++++++++++++++++++++++++++++++++++++++--
 xen/include/public/hvm/hvm_op.h | 15 +++++++++++
 xen/include/xen/mem_access.h    |  3 +++
 6 files changed, 111 insertions(+), 2 deletions(-)

-- 
2.13.0


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