On 09/07/15 21:42, Julien Grall wrote:
> Many PV drivers contain the idiom:
>
> pfn = page_to_mfn(...) /* Or similar */
> gnttab_grant_foreign_access_ref
>
> Replace it by a new helper. Note that when Linux is using a different
> page granularity than Xen, the helper only gives access to the first 4KB
> grant.
>
> This is useful where drivers are allocating a full Linux page for each
> grant.
>
> Also include xen/interface/grant_table.h rather than xen/grant_table.h in
> asm/page.h for x86 to fix a compilation issue [1]. Only the former is
> useful in order to get the structure definition.
>
> [1] Interpendency between asm/page.h and xen/grant_table.h which result
> to page_mfn not being defined when necessary.
[...]
> --- a/include/xen/grant_table.h
> +++ b/include/xen/grant_table.h
> @@ -131,6 +131,15 @@ void gnttab_cancel_free_callback(struct
> gnttab_free_callback *callback);
> void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
> unsigned long frame, int readonly);
>
> +/* Give access to the first 4K of the page */
> +static inline void gnttab_page_grant_foreign_access_ref(
> + grant_ref_t ref, domid_t domid,
> + struct page *page, int readonly)
> +{
> + gnttab_grant_foreign_access_ref(ref, domid, page_to_mfn(page),
Obviously this would use the new xen_page_to_gfn() macro here.
Otherwise,
Reviewed-by: David Vrabel <david.vra...@citrix.com>
David
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
