linux/arch/x86/xen/grant-table.c
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   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
  47static 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
  57static 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
  65int 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
  86void 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}
  92