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; 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 void 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 90 static 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 } 104 105 int 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> 117 static 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 } 164 165 static 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. */ 174 core_initcall(xen_pvh_gnttab_setup); 175 #endif 176