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(sizeof(pte_t *) * nr_frames, 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/balloon.h> 165 #include <xen/events.h> 166 #include <linux/slab.h> 167 static int __init xlated_setup_gnttab_pages(void) 168 { 169 struct page **pages; 170 xen_pfn_t *pfns; 171 int rc; 172 unsigned int i; 173 unsigned long nr_grant_frames = gnttab_max_grant_frames(); 174 175 BUG_ON(nr_grant_frames == 0); 176 pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL); 177 if (!pages) 178 return -ENOMEM; 179 180 pfns = kcalloc(nr_grant_frames, sizeof(pfns[0]), GFP_KERNEL); 181 if (!pfns) { 182 kfree(pages); 183 return -ENOMEM; 184 } 185 rc = alloc_xenballooned_pages(nr_grant_frames, pages, 0 /* lowmem */); 186 if (rc) { 187 pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__, 188 nr_grant_frames, rc); 189 kfree(pages); 190 kfree(pfns); 191 return rc; 192 } 193 for (i = 0; i < nr_grant_frames; i++) 194 pfns[i] = page_to_pfn(pages[i]); 195 196 rc = arch_gnttab_map_shared(pfns, nr_grant_frames, nr_grant_frames, 197 &xen_auto_xlat_grant_frames.vaddr); 198 199 if (rc) { 200 pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__, 201 nr_grant_frames, rc); 202 free_xenballooned_pages(nr_grant_frames, pages); 203 kfree(pages); 204 kfree(pfns); 205 return rc; 206 } 207 kfree(pages); 208 209 xen_auto_xlat_grant_frames.pfn = pfns; 210 xen_auto_xlat_grant_frames.count = nr_grant_frames; 211 212 return 0; 213 } 214 215 static int __init xen_pvh_gnttab_setup(void) 216 { 217 if (!xen_pvh_domain()) 218 return -ENODEV; 219 220 return xlated_setup_gnttab_pages(); 221 } 222 /* Call it _before_ __gnttab_init as we need to initialize the 223 * xen_auto_xlat_grant_frames first. */ 224 core_initcall(xen_pvh_gnttab_setup); 225 #endif 226