Re: [Xen-devel] [V3 PATCH 4/9] x86/hvm: pkeys, add functions to get pkeys value from PTE

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 07/12/15 09:16, Huaitong Han wrote:
> This patch adds functions to get pkeys value from PTE.
> 
> Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>
> ---
>  xen/include/asm-x86/guest_pt.h    |  7 +++++++
>  xen/include/asm-x86/page.h        |  5 +++++
>  xen/include/asm-x86/x86_64/page.h | 12 ++++++++++++
>  3 files changed, 24 insertions(+)
> 
> diff --git a/xen/include/asm-x86/guest_pt.h b/xen/include/asm-x86/guest_pt.h
> index 3447973..6b0af70 100644
> --- a/xen/include/asm-x86/guest_pt.h
> +++ b/xen/include/asm-x86/guest_pt.h
> @@ -154,6 +154,13 @@ static inline u32 guest_l4e_get_flags(guest_l4e_t gl4e)
>  { return l4e_get_flags(gl4e); }
>  #endif
>  
> +static inline u32 guest_l1e_get_pkeys(guest_l1e_t gl1e)
> +{ return l1e_get_pkeys(gl1e); }
> +static inline u32 guest_l2e_get_pkeys(guest_l2e_t gl2e)
> +{ return l2e_get_pkeys(gl2e); }
> +static inline u32 guest_l3e_get_pkeys(guest_l3e_t gl3e)
> +{ return l3e_get_pkeys(gl3e); }
> +
>  static inline guest_l1e_t guest_l1e_from_gfn(gfn_t gfn, u32 flags)
>  { return l1e_from_pfn(gfn_x(gfn), flags); }
>  static inline guest_l2e_t guest_l2e_from_gfn(gfn_t gfn, u32 flags)
> diff --git a/xen/include/asm-x86/page.h b/xen/include/asm-x86/page.h
> index a095a93..93a0db0 100644
> --- a/xen/include/asm-x86/page.h
> +++ b/xen/include/asm-x86/page.h
> @@ -93,6 +93,11 @@
>  #define l3e_get_flags(x)           (get_pte_flags((x).l3))
>  #define l4e_get_flags(x)           (get_pte_flags((x).l4))
>  
> +/* Get pte pkeys (unsigned int). */
> +#define l1e_get_pkeys(x)           (get_pte_pkeys((x).l1))
> +#define l2e_get_pkeys(x)           (get_pte_pkeys((x).l2))
> +#define l3e_get_pkeys(x)           (get_pte_pkeys((x).l3))
> +
>  /* Construct an empty pte. */
>  #define l1e_empty()                ((l1_pgentry_t) { 0 })
>  #define l2e_empty()                ((l2_pgentry_t) { 0 })
> diff --git a/xen/include/asm-x86/x86_64/page.h 
> b/xen/include/asm-x86/x86_64/page.h
> index 19ab4d0..3ca489a 100644
> --- a/xen/include/asm-x86/x86_64/page.h
> +++ b/xen/include/asm-x86/x86_64/page.h
> @@ -134,6 +134,18 @@ typedef l4_pgentry_t root_pgentry_t;
>  #define get_pte_flags(x) (((int)((x) >> 40) & ~0xFFF) | ((int)(x) & 0xFFF))
>  #define put_pte_flags(x) (((intpte_t)((x) & ~0xFFF) << 40) | ((x) & 0xFFF))
>  
> +/*
> + * Protection keys define a new 4-bit protection key field
> + * (PKEY) in bits 62:59 of leaf entries of the page tables.
> + * This corresponds to bit 22:19 of a 24-bit flags.
> + *
> + * Notice: Bit 22 is used by _PAGE_GNTTAB which is visible to PV guests,
> + * so Protection keys must be disabled on PV guests.
> + */
> +#define _PAGE_PKEY_BITS  (0x780000)   /* Protection Keys, 22:19 */
> +
> +#define get_pte_pkeys(x) (MASK_EXTR(get_pte_flags(x), _PAGE_PKEY_BITS))

Sorry if I'm getting nit-picky here, but any given pte will only have a
single pkey, right?  Would it be better if these were "get_pte_pkey()"
(i.e., singular)?

 -George


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