1 // SPDX-License-Identifier: GPL-2.0 OR MIT 2 /****************************************************************************** 3 * grant_table.c 4 * x86 specific part 5 * 6 * Granting foreign access to our memory reservation. 7 * 8 * Copyright (c) 2005-2006, Christopher Clark 9 * Copyright (c) 2004-2005, K A Fraser 10 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp> 11 * VA Linux Systems Japan. Split out x86 specific part. 12 */ 13 14 #include <linux/sched.h> 15 #include <linux/mm.h> 16 #include <linux/slab.h> 17 #include <linux/vmalloc.h> 18 19 #include <xen/interface/xen.h> 20 #include <xen/page.h> 21 #include <xen/grant_table.h> 22 #include <xen/xen.h> 23 24 25 static struct gnttab_vm_area { 26 struct vm_struct *area; 27 pte_t **ptes; 28 int idx; 29 } gnttab_shared_vm_area, gnttab_status_vm_area; 30 31 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, 32 unsigned long max_nr_gframes, 33 void **__shared) 34 { 35 void *shared = *__shared; 36 unsigned long addr; 37 unsigned long i; 38 39 if (shared == NULL) 40 *__shared = shared = gnttab_shared_vm_area.area->addr; 41 42 addr = (unsigned long)shared; 43 44 for (i = 0; i < nr_gframes; i++) { 45 set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i], 46 mfn_pte(frames[i], PAGE_KERNEL)); 47 addr += PAGE_SIZE; 48 } 49 50 return 0; 51 } 52 53 int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, 54 unsigned long max_nr_gframes, 55 grant_status_t **__shared) 56 { 57 grant_status_t *shared = *__shared; 58 unsigned long addr; 59 unsigned long i; 60 61 if (shared == NULL) 62 *__shared = shared = gnttab_status_vm_area.area->addr; 63 64 addr = (unsigned long)shared; 65 66 for (i = 0; i < nr_gframes; i++) { 67 set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i], 68 mfn_pte(frames[i], PAGE_KERNEL)); 69 addr += PAGE_SIZE; 70 } 71 72 return 0; 73 } 74 75 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes) 76 { 77 pte_t **ptes; 78 unsigned long addr; 79 unsigned long i; 80 81 if (shared == gnttab_status_vm_area.area->addr) 82 ptes = gnttab_status_vm_area.ptes; 83 else 84 ptes = gnttab_shared_vm_area.ptes; 85 86 addr = (unsigned long)shared; 87 88 for (i = 0; i < nr_gframes; i++) { 89 set_pte_at(&init_mm, addr, ptes[i], __pte(0)); 90 addr += PAGE_SIZE; 91 } 92 } 93 94 static int gnttab_apply(pte_t *pte, unsigned long addr, void *data) 95 { 96 struct gnttab_vm_area *area = data; 97 98 area->ptes[area->idx++] = pte; 99 return 0; 100 } 101 102 static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames) 103 { 104 area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL); 105 if (area->ptes == NULL) 106 return -ENOMEM; 107 area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP); 108 if (!area->area) 109 goto out_free_ptes; 110 if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr, 111 PAGE_SIZE * nr_frames, gnttab_apply, area)) 112 goto out_free_vm_area; 113 return 0; 114 out_free_vm_area: 115 free_vm_area(area->area); 116 out_free_ptes: 117 kfree(area->ptes); 118 return -ENOMEM; 119 } 120 121 static void arch_gnttab_vfree(struct gnttab_vm_area *area) 122 { 123 free_vm_area(area->area); 124 kfree(area->ptes); 125 } 126 127 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status) 128 { 129 int ret; 130 131 if (!xen_pv_domain()) 132 return 0; 133 134 ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared); 135 if (ret < 0) 136 return ret; 137 138 /* 139 * Always allocate the space for the status frames in case 140 * we're migrated to a host with V2 support. 141 */ 142 ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status); 143 if (ret < 0) 144 goto err; 145 146 return 0; 147 err: 148 arch_gnttab_vfree(&gnttab_shared_vm_area); 149 return -ENOMEM; 150 } 151 152 #ifdef CONFIG_XEN_PVH 153 #include <xen/events.h> 154 #include <xen/xen-ops.h> 155 static int __init xen_pvh_gnttab_setup(void) 156 { 157 if (!xen_pvh_domain()) 158 return -ENODEV; 159 160 xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); 161 162 return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, 163 &xen_auto_xlat_grant_frames.vaddr, 164 xen_auto_xlat_grant_frames.count); 165 } 166 /* Call it _before_ __gnttab_init as we need to initialize the 167 * xen_auto_xlat_grant_frames first. */ 168 core_initcall(xen_pvh_gnttab_setup); 169 #endif 170