Re: [PATCHv5 11/19] x86/mm: Implement vma_keyid()

[Dave Hansen <dave.hansen@intel.com>]

> --- a/arch/x86/mm/mktme.c
> +++ b/arch/x86/mm/mktme.c
> @@ -1,3 +1,4 @@
> +#include <linux/mm.h>
>  #include <asm/mktme.h>
>  
>  phys_addr_t mktme_keyid_mask;
> @@ -37,3 +38,14 @@ struct page_ext_operations page_mktme_ops = {
>  	.need = need_page_mktme,
>  	.init = init_page_mktme,
>  };
> +
> +int vma_keyid(struct vm_area_struct *vma)
> +{
> +	pgprotval_t prot;
> +
> +	if (!mktme_enabled())
> +		return 0;
> +
> +	prot = pgprot_val(vma->vm_page_prot);
> +	return (prot & mktme_keyid_mask) >> mktme_keyid_shift;
> +}

I'm a bit surprised this isn't inlined.  Not that function calls are
expensive, but we *could* entirely avoid them using the normal pattern of:

// In the header:
static inline vma_keyid(...)
{
	if (!mktme_enabled())
		return 0;

	return __vma_keyid(...); // <- the .c file version
}