[XEN][PATCH v2 0/4] x86: pvh: allow to disable 32-bit (COMPAT) interface support

[Grygorii Strashko <grygorii_strashko@epam.com>]

From: Grygorii Strashko <grygorii_strashko@epam.com>

Hi

This series introduces possibility to disable 32-bit (COMPAT) interface support
in the following case:
      - Only PVH domains are used
      - Guests (OS) are started by using direct Direct Kernel Boot
      - Guests (OS) are 64-bit and Guest early boot code, which is running not
        in 64-bit mode, does not access Xen interfaces
        (hypercalls, shared_info, ..)

If above criterias are met the COMPAT HVM interface become unreachable and can be disabled.
Coverage reports analyze and adding guard (debug) exceptions in hvm_hypercall/hvm_do_multicall_call
and hvm_latch_shinfo_size() confirm that COMPAT HVM interface is unused for safety use-case.

Changes in v2 described in each patch:
- patch "x86: constify has_32bit_shinfo() if !CONFIG_COMPAT" squashed in patch 2.

v1:
 https://patchwork.kernel.org/project/xen-devel/cover/20251111175413.3540690-1-grygorii_strashko@epam.com/

Grygorii Strashko (4):
  x86: hvm: dm: factor out compat code under ifdefs
  x86: hvm: compat: introduce is_hcall_compat() helper
  x86: hvm: factor out COMPAT code under ifdefs
  x86: pvh: allow to disable 32-bit interface support

 xen/arch/x86/hvm/Kconfig          | 19 ++++++++++++++++++-
 xen/arch/x86/hvm/dm.c             |  2 ++
 xen/arch/x86/hvm/hvm.c            | 24 ++++++++++++++++++++----
 xen/arch/x86/hvm/hypercall.c      | 22 +++++++++++++++++-----
 xen/arch/x86/hypercall.c          |  6 +-----
 xen/arch/x86/include/asm/domain.h |  9 +++++++--
 xen/common/kernel.c               |  2 +-
 xen/include/hypercall-defs.c      |  9 +++++++--
 xen/include/xen/sched.h           |  9 +++++++++
 9 files changed, 82 insertions(+), 20 deletions(-)

-- 
2.34.1