linux/include/xen/grant_table.h
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   1/******************************************************************************
   2 * grant_table.h
   3 *
   4 * Two sets of functionality:
   5 * 1. Granting foreign access to our memory reservation.
   6 * 2. Accessing others' memory reservations via grant references.
   7 * (i.e., mechanisms for both sender and recipient of grant references)
   8 *
   9 * Copyright (c) 2004-2005, K A Fraser
  10 * Copyright (c) 2005, Christopher Clark
  11 *
  12 * This program is free software; you can redistribute it and/or
  13 * modify it under the terms of the GNU General Public License version 2
  14 * as published by the Free Software Foundation; or, when distributed
  15 * separately from the Linux kernel or incorporated into other
  16 * software packages, subject to the following license:
  17 *
  18 * Permission is hereby granted, free of charge, to any person obtaining a copy
  19 * of this source file (the "Software"), to deal in the Software without
  20 * restriction, including without limitation the rights to use, copy, modify,
  21 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  22 * and to permit persons to whom the Software is furnished to do so, subject to
  23 * the following conditions:
  24 *
  25 * The above copyright notice and this permission notice shall be included in
  26 * all copies or substantial portions of the Software.
  27 *
  28 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  29 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  30 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  31 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  32 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  33 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  34 * IN THE SOFTWARE.
  35 */
  36
  37#ifndef __ASM_GNTTAB_H__
  38#define __ASM_GNTTAB_H__
  39
  40#include <asm/page.h>
  41
  42#include <xen/interface/xen.h>
  43#include <xen/interface/grant_table.h>
  44
  45#include <asm/xen/hypervisor.h>
  46
  47#include <xen/features.h>
  48#include <xen/page.h>
  49#include <linux/mm_types.h>
  50#include <linux/page-flags.h>
  51#include <linux/kernel.h>
  52
  53#define GNTTAB_RESERVED_XENSTORE 1
  54
  55/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
  56#define NR_GRANT_FRAMES 4
  57
  58struct gnttab_free_callback {
  59        struct gnttab_free_callback *next;
  60        void (*fn)(void *);
  61        void *arg;
  62        u16 count;
  63};
  64
  65struct gntab_unmap_queue_data;
  66
  67typedef void (*gnttab_unmap_refs_done)(int result, struct gntab_unmap_queue_data *data);
  68
  69struct gntab_unmap_queue_data
  70{
  71        struct delayed_work     gnttab_work;
  72        void *data;
  73        gnttab_unmap_refs_done  done;
  74        struct gnttab_unmap_grant_ref *unmap_ops;
  75        struct gnttab_unmap_grant_ref *kunmap_ops;
  76        struct page **pages;
  77        unsigned int count;
  78        unsigned int age;
  79};
  80
  81int gnttab_init(void);
  82int gnttab_suspend(void);
  83int gnttab_resume(void);
  84
  85int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
  86                                int readonly);
  87
  88/*
  89 * End access through the given grant reference, iff the grant entry is no
  90 * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
  91 * use.
  92 */
  93int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
  94
  95/*
  96 * Eventually end access through the given grant reference, and once that
  97 * access has been ended, free the given page too.  Access will be ended
  98 * immediately iff the grant entry is not in use, otherwise it will happen
  99 * some time later.  page may be 0, in which case no freeing will occur.
 100 */
 101void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
 102                               unsigned long page);
 103
 104int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
 105
 106unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
 107unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
 108
 109int gnttab_query_foreign_access(grant_ref_t ref);
 110
 111/*
 112 * operations on reserved batches of grant references
 113 */
 114int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
 115
 116void gnttab_free_grant_reference(grant_ref_t ref);
 117
 118void gnttab_free_grant_references(grant_ref_t head);
 119
 120int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
 121
 122int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
 123
 124void gnttab_release_grant_reference(grant_ref_t *private_head,
 125                                    grant_ref_t release);
 126
 127void gnttab_request_free_callback(struct gnttab_free_callback *callback,
 128                                  void (*fn)(void *), void *arg, u16 count);
 129void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
 130
 131void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 132                                     unsigned long frame, int readonly);
 133
 134/* Give access to the first 4K of the page */
 135static inline void gnttab_page_grant_foreign_access_ref_one(
 136        grant_ref_t ref, domid_t domid,
 137        struct page *page, int readonly)
 138{
 139        gnttab_grant_foreign_access_ref(ref, domid, xen_page_to_gfn(page),
 140                                        readonly);
 141}
 142
 143void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
 144                                       unsigned long pfn);
 145
 146static inline void
 147gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,
 148                  uint32_t flags, grant_ref_t ref, domid_t domid)
 149{
 150        if (flags & GNTMAP_contains_pte)
 151                map->host_addr = addr;
 152        else if (xen_feature(XENFEAT_auto_translated_physmap))
 153                map->host_addr = __pa(addr);
 154        else
 155                map->host_addr = addr;
 156
 157        map->flags = flags;
 158        map->ref = ref;
 159        map->dom = domid;
 160}
 161
 162static inline void
 163gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, phys_addr_t addr,
 164                    uint32_t flags, grant_handle_t handle)
 165{
 166        if (flags & GNTMAP_contains_pte)
 167                unmap->host_addr = addr;
 168        else if (xen_feature(XENFEAT_auto_translated_physmap))
 169                unmap->host_addr = __pa(addr);
 170        else
 171                unmap->host_addr = addr;
 172
 173        unmap->handle = handle;
 174        unmap->dev_bus_addr = 0;
 175}
 176
 177int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
 178int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
 179                           unsigned long max_nr_gframes,
 180                           void **__shared);
 181int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
 182                           unsigned long max_nr_gframes,
 183                           grant_status_t **__shared);
 184void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
 185
 186struct grant_frames {
 187        xen_pfn_t *pfn;
 188        unsigned int count;
 189        void *vaddr;
 190};
 191extern struct grant_frames xen_auto_xlat_grant_frames;
 192unsigned int gnttab_max_grant_frames(void);
 193int gnttab_setup_auto_xlat_frames(phys_addr_t addr);
 194void gnttab_free_auto_xlat_frames(void);
 195
 196#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
 197
 198int gnttab_alloc_pages(int nr_pages, struct page **pages);
 199void gnttab_free_pages(int nr_pages, struct page **pages);
 200
 201#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
 202struct gnttab_dma_alloc_args {
 203        /* Device for which DMA memory will be/was allocated. */
 204        struct device *dev;
 205        /* If set then DMA buffer is coherent and write-combine otherwise. */
 206        bool coherent;
 207
 208        int nr_pages;
 209        struct page **pages;
 210        xen_pfn_t *frames;
 211        void *vaddr;
 212        dma_addr_t dev_bus_addr;
 213};
 214
 215int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args *args);
 216int gnttab_dma_free_pages(struct gnttab_dma_alloc_args *args);
 217#endif
 218
 219int gnttab_pages_set_private(int nr_pages, struct page **pages);
 220void gnttab_pages_clear_private(int nr_pages, struct page **pages);
 221
 222int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 223                    struct gnttab_map_grant_ref *kmap_ops,
 224                    struct page **pages, unsigned int count);
 225int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 226                      struct gnttab_unmap_grant_ref *kunmap_ops,
 227                      struct page **pages, unsigned int count);
 228void gnttab_unmap_refs_async(struct gntab_unmap_queue_data* item);
 229int gnttab_unmap_refs_sync(struct gntab_unmap_queue_data *item);
 230
 231
 232/* Perform a batch of grant map/copy operations. Retry every batch slot
 233 * for which the hypervisor returns GNTST_eagain. This is typically due
 234 * to paged out target frames.
 235 *
 236 * Will retry for 1, 2, ... 255 ms, i.e. 256 times during 32 seconds.
 237 *
 238 * Return value in each iand every status field of the batch guaranteed
 239 * to not be GNTST_eagain.
 240 */
 241void gnttab_batch_map(struct gnttab_map_grant_ref *batch, unsigned count);
 242void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count);
 243
 244
 245struct xen_page_foreign {
 246        domid_t domid;
 247        grant_ref_t gref;
 248};
 249
 250static inline struct xen_page_foreign *xen_page_foreign(struct page *page)
 251{
 252        if (!PageForeign(page))
 253                return NULL;
 254#if BITS_PER_LONG < 64
 255        return (struct xen_page_foreign *)page->private;
 256#else
 257        BUILD_BUG_ON(sizeof(struct xen_page_foreign) > BITS_PER_LONG);
 258        return (struct xen_page_foreign *)&page->private;
 259#endif
 260}
 261
 262/* Split Linux page in chunk of the size of the grant and call fn
 263 *
 264 * Parameters of fn:
 265 *      gfn: guest frame number
 266 *      offset: offset in the grant
 267 *      len: length of the data in the grant.
 268 *      data: internal information
 269 */
 270typedef void (*xen_grant_fn_t)(unsigned long gfn, unsigned int offset,
 271                               unsigned int len, void *data);
 272
 273void gnttab_foreach_grant_in_range(struct page *page,
 274                                   unsigned int offset,
 275                                   unsigned int len,
 276                                   xen_grant_fn_t fn,
 277                                   void *data);
 278
 279/* Helper to get to call fn only on the first "grant chunk" */
 280static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
 281                                        unsigned len, xen_grant_fn_t fn,
 282                                        void *data)
 283{
 284        /* The first request is limited to the size of one grant */
 285        len = min_t(unsigned int, XEN_PAGE_SIZE - (offset & ~XEN_PAGE_MASK),
 286                    len);
 287
 288        gnttab_foreach_grant_in_range(page, offset, len, fn, data);
 289}
 290
 291/* Get @nr_grefs grants from an array of page and call fn for each grant */
 292void gnttab_foreach_grant(struct page **pages,
 293                          unsigned int nr_grefs,
 294                          xen_grant_fn_t fn,
 295                          void *data);
 296
 297/* Get the number of grant in a specified region
 298 *
 299 * start: Offset from the beginning of the first page
 300 * len: total length of data (can cross multiple page)
 301 */
 302static inline unsigned int gnttab_count_grant(unsigned int start,
 303                                              unsigned int len)
 304{
 305        return XEN_PFN_UP(xen_offset_in_page(start) + len);
 306}
 307
 308#endif /* __ASM_GNTTAB_H__ */
 309