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

[Grygorii Strashko <grygorii_strashko@epam.com>]

Hi All,

I'm planning to send v3 - so would be appreciated for any other comments.

On 19.11.25 21:30, Grygorii Strashko wrote:
> 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(-)
> 

-- 
Best regards,
-grygorii