diff options
Diffstat (limited to 'include/xen/grant_table.h')
| -rw-r--r-- | include/xen/grant_table.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 4478f4b4aae2..05b5b08c2afc 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -45,8 +45,10 @@ #include <asm/xen/hypervisor.h> #include <xen/features.h> +#include <xen/page.h> #include <linux/mm_types.h> #include <linux/page-flags.h> +#include <linux/kernel.h> #define GNTTAB_RESERVED_XENSTORE 1 @@ -224,4 +226,44 @@ static inline struct xen_page_foreign *xen_page_foreign(struct page *page) #endif } +/* Split Linux page in chunk of the size of the grant and call fn + * + * Parameters of fn: + * gfn: guest frame number + * offset: offset in the grant + * len: length of the data in the grant. + * data: internal information + */ +typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset, + unsigned int len, void *data); + +void gnttab_foreach_grant_in_range(struct page *page, + unsigned int offset, + unsigned int len, + xen_grant_fn_t fn, + void *data); + +/* Helper to get to call fn only on the first "grant chunk" */ +static inline void gnttab_for_one_grant(struct page *page, unsigned int offset, + unsigned len, xen_grant_fn_t fn, + void *data) +{ + /* The first request is limited to the size of one grant */ + len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK), + len); + + gnttab_foreach_grant_in_range(page, offset, len, fn, data); +} + +/* Get the number of grant in a specified region + * + * start: Offset from the beginning of the first page + * len: total length of data (can cross multiple page) + */ +static inline unsigned int gnttab_count_grant(unsigned int start, + unsigned int len) +{ + return XEN_PFN_UP(xen_offset_in_page(start) + len); +} + #endif /* __ASM_GNTTAB_H__ */ |