arch/x86/xen/grant-table.c

   1 /******************************************************************************
   2  * grant_table.c
   3  * x86 specific part
   4  *
   5  * Granting foreign access to our memory reservation.
   6  *
   7  * Copyright (c) 2005-2006, Christopher Clark
   8  * Copyright (c) 2004-2005, K A Fraser
   9  * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
  10  *                    VA Linux Systems Japan. Split out x86 specific part.
  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 #include <linux/sched.h>
  38 #include <linux/mm.h>
  39 #include <linux/vmalloc.h>
  40
  41 #include <xen/interface/xen.h>
  42 #include <xen/page.h>
  43 #include <xen/grant_table.h>
  44
  45 #include <asm/pgtable.h>
  46
  47 static int map_pte_fn(pte_t *pte, struct page *pmd_page,
  48                       unsigned long addr, void *data)
  49 {
  50         unsigned long **frames = (unsigned long **)data;
  51
  52         set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
  53         (*frames)++;
  54         return 0;
  55 }
  56
  57 static int unmap_pte_fn(pte_t *pte, struct page *pmd_page,
  58                         unsigned long addr, void *data)
  59 {
  60
  61         set_pte_at(&init_mm, addr, pte, __pte(0));
  62         return 0;
  63 }
  64
  65 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
  66                            unsigned long max_nr_gframes,
  67                            struct grant_entry **__shared)
  68 {
  69         int rc;
  70         struct grant_entry *shared = *__shared;
  71
  72         if (shared == NULL) {
  73                 struct vm_struct *area =
  74                         xen_alloc_vm_area(PAGE_SIZE * max_nr_gframes);
  75                 BUG_ON(area == NULL);
  76                 shared = area->addr;
  77                 *__shared = shared;
  78         }
  79
  80         rc = apply_to_page_range(&init_mm, (unsigned long)shared,
  81                                  PAGE_SIZE * nr_gframes,
  82                                  map_pte_fn, &frames);
  83         return rc;
  84 }
  85
  86 void arch_gnttab_unmap_shared(struct grant_entry *shared,
  87                               unsigned long nr_gframes)
  88 {
  89         apply_to_page_range(&init_mm, (unsigned long)shared,
  90                             PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL);
  91 }