diff options
Diffstat (limited to 'include/xen/grant_table.h')
| -rw-r--r-- | include/xen/grant_table.h | 61 |
1 files changed, 47 insertions, 14 deletions
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index 9bc5bc07d4d3..e279be353e3f 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -50,7 +50,12 @@ #include <linux/page-flags.h> #include <linux/kernel.h> -#define GNTTAB_RESERVED_XENSTORE 1 +/* + * Technically there's no reliably invalid grant reference or grant handle, + * so pick the value that is the most unlikely one to be observed valid. + */ +#define INVALID_GRANT_REF ((grant_ref_t)-1) +#define INVALID_GRANT_HANDLE ((grant_handle_t)-1) /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */ #define NR_GRANT_FRAMES 4 @@ -90,33 +95,46 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, * longer in use. Return 1 if the grant entry was freed, 0 if it is still in * use. */ -int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly); +int gnttab_end_foreign_access_ref(grant_ref_t ref); /* * Eventually end access through the given grant reference, and once that * access has been ended, free the given page too. Access will be ended * immediately iff the grant entry is not in use, otherwise it will happen - * some time later. page may be 0, in which case no freeing will occur. + * some time later. page may be NULL, in which case no freeing will occur. + * Note that the granted page might still be accessed (read or write) by the + * other side after gnttab_end_foreign_access() returns, so even if page was + * specified as NULL it is not allowed to just reuse the page for other + * purposes immediately. gnttab_end_foreign_access() will take an additional + * reference to the granted page in this case, which is dropped only after + * the grant is no longer in use. + * This requires that multi page allocations for areas subject to + * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing + * via free_pages_exact()) in order to avoid high order pages. */ -void gnttab_end_foreign_access(grant_ref_t ref, int readonly, - unsigned long page); - -int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn); - -unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref); -unsigned long gnttab_end_foreign_transfer(grant_ref_t ref); +void gnttab_end_foreign_access(grant_ref_t ref, struct page *page); -int gnttab_query_foreign_access(grant_ref_t ref); +/* + * End access through the given grant reference, iff the grant entry is + * no longer in use. In case of success ending foreign access, the + * grant reference is deallocated. + * Return 1 if the grant entry was freed, 0 if it is still in use. + */ +int gnttab_try_end_foreign_access(grant_ref_t ref); /* * operations on reserved batches of grant references */ int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head); +int gnttab_alloc_grant_reference_seq(unsigned int count, grant_ref_t *first); + void gnttab_free_grant_reference(grant_ref_t ref); void gnttab_free_grant_references(grant_ref_t head); +void gnttab_free_grant_reference_seq(grant_ref_t head, unsigned int count); + int gnttab_empty_grant_references(const grant_ref_t *pprivate_head); int gnttab_claim_grant_reference(grant_ref_t *pprivate_head); @@ -140,9 +158,6 @@ static inline void gnttab_page_grant_foreign_access_ref_one( readonly); } -void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid, - unsigned long pfn); - static inline void gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr, uint32_t flags, grant_ref_t ref, domid_t domid) @@ -157,6 +172,7 @@ gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr, map->flags = flags; map->ref = ref; map->dom = domid; + map->status = 1; /* arbitrary positive value */ } static inline void @@ -198,6 +214,23 @@ void gnttab_free_auto_xlat_frames(void); int gnttab_alloc_pages(int nr_pages, struct page **pages); void gnttab_free_pages(int nr_pages, struct page **pages); +struct gnttab_page_cache { + spinlock_t lock; +#ifdef CONFIG_XEN_UNPOPULATED_ALLOC + struct page *pages; +#else + struct list_head pages; +#endif + unsigned int num_pages; +}; + +void gnttab_page_cache_init(struct gnttab_page_cache *cache); +int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page); +void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page, + unsigned int num); +void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, + unsigned int num); + #ifdef CONFIG_XEN_GRANT_DMA_ALLOC struct gnttab_dma_alloc_args { /* Device for which DMA memory will be/was allocated. */ |