Re: [PATCH v2 09/39] x86/ibt,paravirt: Sprinkle ENDBR

[Kees Cook]

On Thu, Feb 24, 2022 at 03:51:47PM +0100, Peter Zijlstra wrote:
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---
>  arch/x86/entry/entry_64.S                 |    1 +
>  arch/x86/include/asm/paravirt.h           |    1 +
>  arch/x86/include/asm/qspinlock_paravirt.h |    3 +++
>  arch/x86/kernel/kvm.c                     |    3 ++-
>  arch/x86/kernel/paravirt.c                |    2 ++
>  5 files changed, 9 insertions(+), 1 deletion(-)
> 
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -635,6 +635,7 @@ SYM_INNER_LABEL(restore_regs_and_return_
>  
>  SYM_INNER_LABEL_ALIGN(native_iret, SYM_L_GLOBAL)
>  	UNWIND_HINT_IRET_REGS
> +	ENDBR // paravirt_iret

If this is also setting the stage for finer grain CFI schemes, should
these macros instead be something more generically named? Like,
INDIRECT_ENTRY, or so? I imagine that'd avoid future churn, but maybe
I'm pre-optimizing... Regardless:

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook