Re: [PATCH RFC v2 8/9] x86/fpu/apx: Enable APX state support

From: Sohil Mehta
Date: Mon Apr 14 2025 - 11:41:46 EST


On 3/20/2025 4:42 PM, Chang S. Bae wrote:
> With securing APX against conflicting MPX, it is now ready to be enabled.
> Include APX in the enabled xfeature set.
>
> Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
> ---
> arch/x86/include/asm/fpu/xstate.h | 3 ++-
> arch/x86/kernel/fpu/xstate.c | 3 ++-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>

Reviewed-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>

> diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
> index 7f39fe7980c5..b308a76afbb7 100644
> --- a/arch/x86/include/asm/fpu/xstate.h
> +++ b/arch/x86/include/asm/fpu/xstate.h
> @@ -32,7 +32,8 @@
> XFEATURE_MASK_PKRU | \
> XFEATURE_MASK_BNDREGS | \
> XFEATURE_MASK_BNDCSR | \
> - XFEATURE_MASK_XTILE)
> + XFEATURE_MASK_XTILE | \
> + XFEATURE_MASK_APX)
>
> /*
> * Features which are restored when returning to user space.
> diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
> index 0d68d5c4bc48..a5e3954dc834 100644
> --- a/arch/x86/kernel/fpu/xstate.c
> +++ b/arch/x86/kernel/fpu/xstate.c
> @@ -371,7 +371,8 @@ static __init void os_xrstor_booting(struct xregs_state *xstate)
> XFEATURE_MASK_BNDCSR | \
> XFEATURE_MASK_PASID | \
> XFEATURE_MASK_CET_USER | \
> - XFEATURE_MASK_XTILE)
> + XFEATURE_MASK_XTILE | \
> + XFEATURE_MASK_APX)
>
> /*
> * setup the xstate image representing the init state