Re: [PATCH 0/4] x86: decode Xen/KVM emulate prefixes

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, May 12, 2022 at 01:56:47PM +0000, Maximilian Heyne wrote:
> This is a backport of a patch series for 5.4.x.
> 
> The patch series allows the x86 decoder to decode the Xen and KVM emulate
> prefixes.
> 
> In particular this solves the following issue that appeared when commit
> db6c6a0df840 ("objtool: Fix noreturn detection for ignored functions") was
> backported to 5.4.69:
> 
>   arch/x86/xen/enlighten_pv.o: warning: objtool: xen_cpuid()+0x25: can't find jump dest instruction at .text+0x9c
> 
> Also now that this decoding is possible, also backport the commit which prevents
> kprobes on probing such prefixed instructions. This was also part of the
> original series.
> 
> The series applied mostly cleanly on 5.4.192 except for a contextual problem in
> the 3rd patch ("x86: xen: insn: Decode Xen and KVM emulate-prefix signature").
> 
> Masami Hiramatsu (4):
>   x86/asm: Allow to pass macros to __ASM_FORM()
>   x86: xen: kvm: Gather the definition of emulate prefixes
>   x86: xen: insn: Decode Xen and KVM emulate-prefix signature
>   x86: kprobes: Prohibit probing on instruction which has emulate prefix
> 
>  arch/x86/include/asm/asm.h                  |  8 +++--
>  arch/x86/include/asm/emulate_prefix.h       | 14 +++++++++
>  arch/x86/include/asm/insn.h                 |  6 ++++
>  arch/x86/include/asm/xen/interface.h        | 11 +++----
>  arch/x86/kernel/kprobes/core.c              |  4 +++
>  arch/x86/kvm/x86.c                          |  4 ++-
>  arch/x86/lib/insn.c                         | 34 +++++++++++++++++++++
>  tools/arch/x86/include/asm/emulate_prefix.h | 14 +++++++++
>  tools/arch/x86/include/asm/insn.h           |  6 ++++
>  tools/arch/x86/lib/insn.c                   | 34 +++++++++++++++++++++
>  tools/objtool/sync-check.sh                 |  3 +-
>  tools/perf/check-headers.sh                 |  3 +-
>  12 files changed, 128 insertions(+), 13 deletions(-)
>  create mode 100644 arch/x86/include/asm/emulate_prefix.h
>  create mode 100644 tools/arch/x86/include/asm/emulate_prefix.h
> 
> 
> base-commit: 1d72b776f6dc973211f5d153453cf8955fb3d70a
> -- 
> 2.32.0
> 
> 
> 
> 
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> 

All now queued up, thanks.

greg k-h