Re: [RFC PATCH] x86/split_lock: Disable SLD if an unaware (out-of-tree) module enables VMX

From: Peter Zijlstra
Date: Mon Apr 06 2020 - 10:34:34 EST


On Mon, Apr 06, 2020 at 04:04:04PM +0200, Peter Zijlstra wrote:
> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> index 65c2ecd730c5..0bd5ea46f1d2 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -274,6 +274,11 @@ typedef struct pgprot { pgprotval_t pgprot; } pgprot_t;
>
> typedef struct { pgdval_t pgd; } pgd_t;
>

This lost:

#define pgprot_nx pgprot_nx

> +static inline pgprot_t pgprot_nx(pgprot_t prot)
> +{
> + return __pgprot(pgprot_val(prot) | _PAGE_NX);
> +}
> +
> #ifdef CONFIG_X86_PAE
>
> /*

> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index e2e2bef07dd2..ee66c1f8b141 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -490,6 +490,10 @@ static inline int arch_unmap_one(struct mm_struct *mm,
> #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
> #endif
>
> +#ifndef pgprot_nx
> +#define pgprot_nx(prot) (prot)
> +#endif
> +
> #ifndef pgprot_noncached
> #define pgprot_noncached(prot) (prot)
> #endif