[PATCH 6/6] KVM: arm64: Simplify PAGE_S2_MEMATTR

[Will Deacon]

On Mon, Jan 19, 2026 at 10:56:51AM +0000, Marc Zyngier wrote:
> Restore PAGE_S2_MEMATTR() to its former glory, keeping the use of
> FWB as an implementation detail.
> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/include/asm/pgtable-prot.h | 4 ++--
>  arch/arm64/kvm/hyp/pgtable.c          | 6 ++----
>  2 files changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
> index 161e8660edddc..d27e8872fe3c8 100644
> --- a/arch/arm64/include/asm/pgtable-prot.h
> +++ b/arch/arm64/include/asm/pgtable-prot.h
> @@ -109,10 +109,10 @@ static inline bool __pure lpa2_is_enabled(void)
>  #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL_EXEC)
>  #define PAGE_KERNEL_EXEC_CONT	__pgprot(_PAGE_KERNEL_EXEC_CONT)
>  
> -#define PAGE_S2_MEMATTR(attr, has_fwb)					\
> +#define PAGE_S2_MEMATTR(attr)						\
>  	({								\
>  		u64 __val;						\
> -		if (has_fwb)						\
> +		if (cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))		\
>  			__val = PTE_S2_MEMATTR(MT_S2_FWB_ ## attr);	\
>  		else							\
>  			__val = PTE_S2_MEMATTR(MT_S2_ ## attr);		\
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index 3c2f7967fdc03..34c9afa442932 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -660,11 +660,9 @@ void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
>  	({								\
>  		kvm_pte_t __attr;					\
>  		if((pgt)->flags & KVM_PGTABLE_S2_AS_S1)			\
> -			__attr = PAGE_S2_MEMATTR(AS_S1,			\
> -						 stage2_has_fwb());	\
> +			__attr = PAGE_S2_MEMATTR(AS_S1);		\
>  		else							\
> -			__attr = PAGE_S2_MEMATTR(attr,			\
> -						 stage2_has_fwb());	\
> +			__attr = PAGE_S2_MEMATTR(attr);			\
>  									\


tbh, I'd probably just kill stage2_has_fwb() entirely and use the cap
everywhere...

Up to you.

Will