LXR linux/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/slab.h>
  40#include <linux/vmalloc.h>
  41
  42#include <xen/interface/xen.h>
  43#include <xen/page.h>
  44#include <xen/grant_table.h>
  45#include <xen/xen.h>
  46
  47#include <asm/pgtable.h>
  48
  49static struct gnttab_vm_area {
  50        struct vm_struct *area;
  51        pte_t **ptes;
  52} gnttab_shared_vm_area;
  53
  54int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
  55                           unsigned long max_nr_gframes,
  56                           void **__shared)
  57{
  58        void *shared = *__shared;
  59        unsigned long addr;
  60        unsigned long i;
  61
  62        if (shared == NULL)
  63                *__shared = shared = gnttab_shared_vm_area.area->addr;
  64
  65        addr = (unsigned long)shared;
  66
  67        for (i = 0; i < nr_gframes; i++) {
  68                set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
  69                           mfn_pte(frames[i], PAGE_KERNEL));
  70                addr += PAGE_SIZE;
  71        }
  72
  73        return 0;
  74}
  75
  76void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
  77{
  78        unsigned long addr;
  79        unsigned long i;
  80
  81        addr = (unsigned long)shared;
  82
  83        for (i = 0; i < nr_gframes; i++) {
  84                set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
  85                           __pte(0));
  86                addr += PAGE_SIZE;
  87        }
  88}
  89
  90static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
  91{
  92        area->ptes = kmalloc(sizeof(pte_t *) * nr_frames, GFP_KERNEL);
  93        if (area->ptes == NULL)
  94                return -ENOMEM;
  95
  96        area->area = alloc_vm_area(PAGE_SIZE * nr_frames, area->ptes);
  97        if (area->area == NULL) {
  98                kfree(area->ptes);
  99                return -ENOMEM;
 100        }
 101
 102        return 0;
 103}
 104
 105int arch_gnttab_init(unsigned long nr_shared)
 106{
 107        if (!xen_pv_domain())
 108                return 0;
 109
 110        return arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
 111}
 112
 113#ifdef CONFIG_XEN_PVH
 114#include <xen/balloon.h>
 115#include <xen/events.h>
 116#include <linux/slab.h>
 117static int __init xlated_setup_gnttab_pages(void)
 118{
 119        struct page **pages;
 120        xen_pfn_t *pfns;
 121        void *vaddr;
 122        int rc;
 123        unsigned int i;
 124        unsigned long nr_grant_frames = gnttab_max_grant_frames();
 125
 126        BUG_ON(nr_grant_frames == 0);
 127        pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL);
 128        if (!pages)
 129                return -ENOMEM;
 130
 131        pfns = kcalloc(nr_grant_frames, sizeof(pfns[0]), GFP_KERNEL);
 132        if (!pfns) {
 133                kfree(pages);
 134                return -ENOMEM;
 135        }
 136        rc = alloc_xenballooned_pages(nr_grant_frames, pages, 0 /* lowmem */);
 137        if (rc) {
 138                pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__,
 139                        nr_grant_frames, rc);
 140                kfree(pages);
 141                kfree(pfns);
 142                return rc;
 143        }
 144        for (i = 0; i < nr_grant_frames; i++)
 145                pfns[i] = page_to_pfn(pages[i]);
 146
 147        vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL);
 148        if (!vaddr) {
 149                pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__,
 150                        nr_grant_frames, rc);
 151                free_xenballooned_pages(nr_grant_frames, pages);
 152                kfree(pages);
 153                kfree(pfns);
 154                return -ENOMEM;
 155        }
 156        kfree(pages);
 157
 158        xen_auto_xlat_grant_frames.pfn = pfns;
 159        xen_auto_xlat_grant_frames.count = nr_grant_frames;
 160        xen_auto_xlat_grant_frames.vaddr = vaddr;
 161
 162        return 0;
 163}
 164
 165static int __init xen_pvh_gnttab_setup(void)
 166{
 167        if (!xen_pvh_domain())
 168                return -ENODEV;
 169
 170        return xlated_setup_gnttab_pages();
 171}
 172/* Call it _before_ __gnttab_init as we need to initialize the
 173 * xen_auto_xlat_grant_frames first. */
 174core_initcall(xen_pvh_gnttab_setup);
 175#endif
 176