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 #include <asm/pgtable.h> 25 26 static struct gnttab_vm_area { 27 struct vm_struct *area; 28 pte_t **ptes; 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 arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames) 95 { 96 area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL); 97 if (area->ptes == NULL) 98 return -ENOMEM; 99 100 area->area = alloc_vm_area(PAGE_SIZE * nr_frames, area->ptes); 101 if (area->area == NULL) { 102 kfree(area->ptes); 103 return -ENOMEM; 104 } 105 106 return 0; 107 } 108 109 static void arch_gnttab_vfree(struct gnttab_vm_area *area) 110 { 111 free_vm_area(area->area); 112 kfree(area->ptes); 113 } 114 115 int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status) 116 { 117 int ret; 118 119 if (!xen_pv_domain()) 120 return 0; 121 122 ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared); 123 if (ret < 0) 124 return ret; 125 126 /* 127 * Always allocate the space for the status frames in case 128 * we're migrated to a host with V2 support. 129 */ 130 ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status); 131 if (ret < 0) 132 goto err; 133 134 return 0; 135 err: 136 arch_gnttab_vfree(&gnttab_shared_vm_area); 137 return -ENOMEM; 138 } 139 140 #ifdef CONFIG_XEN_PVH 141 #include <xen/events.h> 142 #include <xen/xen-ops.h> 143 static int __init xen_pvh_gnttab_setup(void) 144 { 145 if (!xen_pvh_domain()) 146 return -ENODEV; 147 148 xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); 149 150 return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, 151 &xen_auto_xlat_grant_frames.vaddr, 152 xen_auto_xlat_grant_frames.count); 153 } 154 /* Call it _before_ __gnttab_init as we need to initialize the 155 * xen_auto_xlat_grant_frames first. */ 156 core_initcall(xen_pvh_gnttab_setup); 157 #endif 158