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 /* 58 * This function is used to map shared frames to store grant status. It is 59 * different from map_pte_fn above, the frames type here is uint64_t. 60 */ 61 static int map_pte_fn_status(pte_t *pte, struct page *pmd_page, 62 unsigned long addr, void *data) 63 { 64 uint64_t **frames = (uint64_t **)data; 65 66 set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL)); 67 (*frames)++; 68 return 0; 69 } 70 71 static int unmap_pte_fn(pte_t *pte, struct page *pmd_page, 72 unsigned long addr, void *data) 73 { 74 75 set_pte_at(&init_mm, addr, pte, __pte(0)); 76 return 0; 77 } 78 79 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, 80 unsigned long max_nr_gframes, 81 void **__shared) 82 { 83 int rc; 84 void *shared = *__shared; 85 86 if (shared == NULL) { 87 struct vm_struct *area = 88 alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL); 89 BUG_ON(area == NULL); 90 shared = area->addr; 91 *__shared = shared; 92 } 93 94 rc = apply_to_page_range(&init_mm, (unsigned long)shared, 95 PAGE_SIZE * nr_gframes, 96 map_pte_fn, &frames); 97 return rc; 98 } 99 100 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, 101 unsigned long max_nr_gframes, 102 grant_status_t **__shared) 103 { 104 int rc; 105 grant_status_t *shared = *__shared; 106 107 if (shared == NULL) { 108 /* No need to pass in PTE as we are going to do it 109 * in apply_to_page_range anyhow. */ 110 struct vm_struct *area = 111 alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL); 112 BUG_ON(area == NULL); 113 shared = area->addr; 114 *__shared = shared; 115 } 116 117 rc = apply_to_page_range(&init_mm, (unsigned long)shared, 118 PAGE_SIZE * nr_gframes, 119 map_pte_fn_status, &frames); 120 return rc; 121 } 122 123 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes) 124 { 125 apply_to_page_range(&init_mm, (unsigned long)shared, 126 PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL); 127 } 128 #ifdef CONFIG_XEN_PVH 129 #include <xen/balloon.h> 130 #include <xen/events.h> 131 #include <xen/xen.h> 132 #include <linux/slab.h> 133 static int __init xlated_setup_gnttab_pages(void) 134 { 135 struct page **pages; 136 xen_pfn_t *pfns; 137 int rc; 138 unsigned int i; 139 unsigned long nr_grant_frames = gnttab_max_grant_frames(); 140 141 BUG_ON(nr_grant_frames == 0); 142 pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL); 143 if (!pages) 144 return -ENOMEM; 145 146 pfns = kcalloc(nr_grant_frames, sizeof(pfns[0]), GFP_KERNEL); 147 if (!pfns) { 148 kfree(pages); 149 return -ENOMEM; 150 } 151 rc = alloc_xenballooned_pages(nr_grant_frames, pages, 0 /* lowmem */); 152 if (rc) { 153 pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__, 154 nr_grant_frames, rc); 155 kfree(pages); 156 kfree(pfns); 157 return rc; 158 } 159 for (i = 0; i < nr_grant_frames; i++) 160 pfns[i] = page_to_pfn(pages[i]); 161 162 rc = arch_gnttab_map_shared(pfns, nr_grant_frames, nr_grant_frames, 163 &xen_auto_xlat_grant_frames.vaddr); 164 165 if (rc) { 166 pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__, 167 nr_grant_frames, rc); 168 free_xenballooned_pages(nr_grant_frames, pages); 169 kfree(pages); 170 kfree(pfns); 171 return rc; 172 } 173 kfree(pages); 174 175 xen_auto_xlat_grant_frames.pfn = pfns; 176 xen_auto_xlat_grant_frames.count = nr_grant_frames; 177 178 return 0; 179 } 180 181 static int __init xen_pvh_gnttab_setup(void) 182 { 183 if (!xen_pvh_domain()) 184 return -ENODEV; 185 186 return xlated_setup_gnttab_pages(); 187 } 188 /* Call it _before_ __gnttab_init as we need to initialize the 189 * xen_auto_xlat_grant_frames first. */ 190 core_initcall(xen_pvh_gnttab_setup); 191 #endif 192