xen/grant: Add helper gnttab_page_grant_foreign_access_ref_one

Many PV drivers contain the idiom:

pfn = page_to_gfn(...) /* 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] Interdependency between asm/page.h and xen/grant_table.h which result
to page_mfn not being defined when necessary.

Signed-off-by: Julien Grall <julien.grall@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit is contained in:
Julien Grall 2015-06-19 18:05:06 +01:00 committed by David Vrabel
parent 008c320a96
commit 3922f32c1e

View File

@ -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_one(
grant_ref_t ref, domid_t domid,
struct page *page, int readonly)
{
gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
readonly);
}
void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
unsigned long pfn);