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
  49 static struct gnttab_vm_area {
  50         struct vm_struct *area;
  51         pte_t **ptes;
  52 } gnttab_shared_vm_area, gnttab_status_vm_area;
  53
  54 int 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
  76 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
  77                            unsigned long max_nr_gframes,
  78                            grant_status_t **__shared)
  79 {
  80         grant_status_t *shared = *__shared;
  81         unsigned long addr;
  82         unsigned long i;
  83
  84         if (shared == NULL)
  85                 *__shared = shared = gnttab_status_vm_area.area->addr;
  86
  87         addr = (unsigned long)shared;
  88
  89         for (i = 0; i < nr_gframes; i++) {
  90                 set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
  91                            mfn_pte(frames[i], PAGE_KERNEL));
  92                 addr += PAGE_SIZE;
  93         }
  94
  95         return 0;
  96 }
  97
  98 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
  99 {
 100         pte_t **ptes;
 101         unsigned long addr;
 102         unsigned long i;
 103
 104         if (shared == gnttab_status_vm_area.area->addr)
 105                 ptes = gnttab_status_vm_area.ptes;
 106         else
 107                 ptes = gnttab_shared_vm_area.ptes;
 108
 109         addr = (unsigned long)shared;
 110
 111         for (i = 0; i < nr_gframes; i++) {
 112                 set_pte_at(&init_mm, addr, ptes[i], __pte(0));
 113                 addr += PAGE_SIZE;
 114         }
 115 }
 116
 117 static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
 118 {
 119         area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
 120         if (area->ptes == NULL)
 121                 return -ENOMEM;
 122
 123         area->area = alloc_vm_area(PAGE_SIZE * nr_frames, area->ptes);
 124         if (area->area == NULL) {
 125                 kfree(area->ptes);
 126                 return -ENOMEM;
 127         }
 128
 129         return 0;
 130 }
 131
 132 static void arch_gnttab_vfree(struct gnttab_vm_area *area)
 133 {
 134         free_vm_area(area->area);
 135         kfree(area->ptes);
 136 }
 137
 138 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
 139 {
 140         int ret;
 141
 142         if (!xen_pv_domain())
 143                 return 0;
 144
 145         ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
 146         if (ret < 0)
 147                 return ret;
 148
 149         /*
 150          * Always allocate the space for the status frames in case
 151          * we're migrated to a host with V2 support.
 152          */
 153         ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
 154         if (ret < 0)
 155                 goto err;
 156
 157         return 0;
 158 err:
 159         arch_gnttab_vfree(&gnttab_shared_vm_area);
 160         return -ENOMEM;
 161 }
 162
 163 #ifdef CONFIG_XEN_PVH
 164 #include <xen/events.h>
 165 #include <xen/xen-ops.h>
 166 static int __init xen_pvh_gnttab_setup(void)
 167 {
 168         if (!xen_pvh_domain())
 169                 return -ENODEV;
 170
 171         xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames();
 172
 173         return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn,
 174                                              &xen_auto_xlat_grant_frames.vaddr,
 175                                              xen_auto_xlat_grant_frames.count);
 176 }
 177 /* Call it _before_ __gnttab_init as we need to initialize the
 178  * xen_auto_xlat_grant_frames first. */
 179 core_initcall(xen_pvh_gnttab_setup);
 180 #endif