include/xen/gnttab.h

   1 /******************************************************************************
   2  * gnttab.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/hypervisor.h>
  41 #include <asm/maddr.h> /* maddr_t */
  42 #include <linux/mm.h>
  43 #include <linux/delay.h>
  44 #include <xen/interface/grant_table.h>
  45 #include <xen/features.h>
  46
  47 #define GRANT_INVALID_REF       0
  48
  49 struct gnttab_free_callback {
  50         struct gnttab_free_callback *next;
  51         void (*fn)(void *);
  52         void *arg;
  53         u16 count;
  54         u8 queued;
  55 };
  56
  57 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
  58                                 int flags);
  59
  60 /*
  61  * End access through the given grant reference, iff the grant entry is no
  62  * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
  63  * use.
  64  */
  65 int gnttab_end_foreign_access_ref(grant_ref_t ref);
  66
  67 /*
  68  * Eventually end access through the given grant reference, and once that
  69  * access has been ended, free the given page too.  Access will be ended
  70  * immediately iff the grant entry is not in use, otherwise it will happen
  71  * some time later.  page may be 0, in which case no freeing will occur.
  72  */
  73 void gnttab_end_foreign_access(grant_ref_t ref, unsigned long page);
  74
  75 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
  76
  77 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
  78 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
  79
  80 int gnttab_query_foreign_access(grant_ref_t ref);
  81
  82 /*
  83  * operations on reserved batches of grant references
  84  */
  85 int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
  86
  87 void gnttab_free_grant_reference(grant_ref_t ref);
  88
  89 void gnttab_free_grant_references(grant_ref_t head);
  90
  91 int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
  92
  93 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
  94
  95 void gnttab_release_grant_reference(grant_ref_t *private_head,
  96                                     grant_ref_t release);
  97
  98 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
  99                                   void (*fn)(void *), void *arg, u16 count);
 100 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
 101
 102 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
 103                                      unsigned long frame, int flags);
 104
 105 void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
 106                                        unsigned long pfn);
 107
 108 int gnttab_copy_grant_page(grant_ref_t ref, struct page **pagep);
 109 #if defined(CONFIG_XEN_BACKEND) || defined(CONFIG_XEN_BACKEND_MODULE)
 110 void __gnttab_dma_map_page(struct page *page);
 111 #else
 112 #define __gnttab_dma_map_page __gnttab_dma_unmap_page
 113 #endif
 114 static inline void __gnttab_dma_unmap_page(struct page *page)
 115 {
 116 }
 117
 118 void gnttab_reset_grant_page(struct page *page);
 119
 120 #ifndef CONFIG_XEN
 121 int gnttab_resume(void);
 122 #endif
 123
 124 void *arch_gnttab_alloc_shared(unsigned long *frames);
 125
 126 static inline void
 127 gnttab_set_map_op(struct gnttab_map_grant_ref *map, maddr_t addr,
 128                   uint32_t flags, grant_ref_t ref, domid_t domid)
 129 {
 130         if (flags & GNTMAP_contains_pte)
 131                 map->host_addr = addr;
 132         else if (xen_feature(XENFEAT_auto_translated_physmap))
 133                 map->host_addr = __pa(addr);
 134         else
 135                 map->host_addr = addr;
 136
 137         map->flags = flags;
 138         map->ref = ref;
 139         map->dom = domid;
 140 }
 141
 142 static inline void
 143 gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, maddr_t addr,
 144                     uint32_t flags, grant_handle_t handle)
 145 {
 146         if (flags & GNTMAP_contains_pte)
 147                 unmap->host_addr = addr;
 148         else if (xen_feature(XENFEAT_auto_translated_physmap))
 149                 unmap->host_addr = __pa(addr);
 150         else
 151                 unmap->host_addr = addr;
 152
 153         unmap->handle = handle;
 154         unmap->dev_bus_addr = 0;
 155 }
 156
 157 static inline void
 158 gnttab_set_replace_op(struct gnttab_unmap_and_replace *unmap, maddr_t addr,
 159                       maddr_t new_addr, grant_handle_t handle)
 160 {
 161         if (xen_feature(XENFEAT_auto_translated_physmap)) {
 162                 unmap->host_addr = __pa(addr);
 163                 unmap->new_addr = __pa(new_addr);
 164         } else {
 165                 unmap->host_addr = addr;
 166                 unmap->new_addr = new_addr;
 167         }
 168
 169         unmap->handle = handle;
 170 }
 171
 172 #define gnttab_check_GNTST_eagain_while(__HCop, __HCarg_p)                      \
 173 {                                                                               \
 174         u8 __hc_delay = 1;                                                      \
 175         int __ret;                                                              \
 176         while (unlikely((__HCarg_p)->status == GNTST_eagain && __hc_delay)) {   \
 177                 msleep(__hc_delay++);                                           \
 178                 __ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);      \
 179                 BUG_ON(__ret);                                                  \
 180         }                                                                       \
 181         if (__hc_delay == 0) {                                                  \
 182                 pr_err("%s: %s gnt busy\n", __func__, current->comm);           \
 183                 (__HCarg_p)->status = GNTST_bad_page;                           \
 184         }                                                                       \
 185         if ((__HCarg_p)->status != GNTST_okay)                                  \
 186                 pr_err("%s: %s gnt status %x\n",                                \
 187                         __func__, current->comm, (__HCarg_p)->status);          \
 188 }
 189
 190 #define gnttab_check_GNTST_eagain_do_while(__HCop, __HCarg_p)                   \
 191 {                                                                               \
 192         u8 __hc_delay = 1;                                                      \
 193         int __ret;                                                              \
 194         do {                                                                    \
 195                 __ret = HYPERVISOR_grant_table_op(__HCop, (__HCarg_p), 1);      \
 196                 BUG_ON(__ret);                                                  \
 197                 if ((__HCarg_p)->status == GNTST_eagain)                        \
 198                         msleep(__hc_delay++);                                   \
 199         } while ((__HCarg_p)->status == GNTST_eagain && __hc_delay);            \
 200         if (__hc_delay == 0) {                                                  \
 201                 pr_err("%s: %s gnt busy\n", __func__, current->comm);           \
 202                 (__HCarg_p)->status = GNTST_bad_page;                           \
 203         }                                                                       \
 204         if ((__HCarg_p)->status != GNTST_okay)                                  \
 205                 pr_err("%s: %s gnt status %x\n",                                \
 206                         __func__, current->comm, (__HCarg_p)->status);          \
 207 }
 208
 209 #endif /* __ASM_GNTTAB_H__ */