1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES. 3 * 4 */ 5 #ifndef __IO_PAGETABLE_H 6 #define __IO_PAGETABLE_H 7 8 #include <linux/interval_tree.h> 9 #include <linux/kref.h> 10 #include <linux/mutex.h> 11 #include <linux/xarray.h> 12 13 #include "iommufd_private.h" 14 15 struct iommu_domain; 16 17 /* 18 * Each io_pagetable is composed of intervals of areas which cover regions of 19 * the iova that are backed by something. iova not covered by areas is not 20 * populated in the page table. Each area is fully populated with pages. 21 * 22 * iovas are in byte units, but must be iopt->iova_alignment aligned. 23 * 24 * pages can be NULL, this means some other thread is still working on setting 25 * up or tearing down the area. When observed under the write side of the 26 * domain_rwsem a NULL pages must mean the area is still being setup and no 27 * domains are filled. 28 * 29 * storage_domain points at an arbitrary iommu_domain that is holding the PFNs 30 * for this area. It is locked by the pages->mutex. This simplifies the locking 31 * as the pages code can rely on the storage_domain without having to get the 32 * iopt->domains_rwsem. 33 * 34 * The io_pagetable::iova_rwsem protects node 35 * The iopt_pages::mutex protects pages_node 36 * iopt and iommu_prot are immutable 37 * The pages::mutex protects num_accesses 38 */ 39 struct iopt_area { 40 struct interval_tree_node node; 41 struct interval_tree_node pages_node; 42 struct io_pagetable *iopt; 43 struct iopt_pages *pages; 44 struct iommu_domain *storage_domain; 45 /* How many bytes into the first page the area starts */ 46 unsigned int page_offset; 47 /* IOMMU_READ, IOMMU_WRITE, etc */ 48 int iommu_prot; 49 bool prevent_access : 1; 50 unsigned int num_accesses; 51 }; 52 53 struct iopt_allowed { 54 struct interval_tree_node node; 55 }; 56 57 struct iopt_reserved { 58 struct interval_tree_node node; 59 void *owner; 60 }; 61 62 int iopt_area_fill_domains(struct iopt_area *area, struct iopt_pages *pages); 63 void iopt_area_unfill_domains(struct iopt_area *area, struct iopt_pages *pages); 64 65 int iopt_area_fill_domain(struct iopt_area *area, struct iommu_domain *domain); 66 void iopt_area_unfill_domain(struct iopt_area *area, struct iopt_pages *pages, 67 struct iommu_domain *domain); 68 void iopt_area_unmap_domain(struct iopt_area *area, 69 struct iommu_domain *domain); 70 iopt_area_index(struct iopt_area * area)71 static inline unsigned long iopt_area_index(struct iopt_area *area) 72 { 73 return area->pages_node.start; 74 } 75 iopt_area_last_index(struct iopt_area * area)76 static inline unsigned long iopt_area_last_index(struct iopt_area *area) 77 { 78 return area->pages_node.last; 79 } 80 iopt_area_iova(struct iopt_area * area)81 static inline unsigned long iopt_area_iova(struct iopt_area *area) 82 { 83 return area->node.start; 84 } 85 iopt_area_last_iova(struct iopt_area * area)86 static inline unsigned long iopt_area_last_iova(struct iopt_area *area) 87 { 88 return area->node.last; 89 } 90 iopt_area_length(struct iopt_area * area)91 static inline size_t iopt_area_length(struct iopt_area *area) 92 { 93 return (area->node.last - area->node.start) + 1; 94 } 95 96 /* 97 * Number of bytes from the start of the iopt_pages that the iova begins. 98 * iopt_area_start_byte() / PAGE_SIZE encodes the starting page index 99 * iopt_area_start_byte() % PAGE_SIZE encodes the offset within that page 100 */ iopt_area_start_byte(struct iopt_area * area,unsigned long iova)101 static inline unsigned long iopt_area_start_byte(struct iopt_area *area, 102 unsigned long iova) 103 { 104 if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) 105 WARN_ON(iova < iopt_area_iova(area) || 106 iova > iopt_area_last_iova(area)); 107 return (iova - iopt_area_iova(area)) + area->page_offset + 108 iopt_area_index(area) * PAGE_SIZE; 109 } 110 iopt_area_iova_to_index(struct iopt_area * area,unsigned long iova)111 static inline unsigned long iopt_area_iova_to_index(struct iopt_area *area, 112 unsigned long iova) 113 { 114 return iopt_area_start_byte(area, iova) / PAGE_SIZE; 115 } 116 117 #define __make_iopt_iter(name) \ 118 static inline struct iopt_##name *iopt_##name##_iter_first( \ 119 struct io_pagetable *iopt, unsigned long start, \ 120 unsigned long last) \ 121 { \ 122 struct interval_tree_node *node; \ 123 \ 124 lockdep_assert_held(&iopt->iova_rwsem); \ 125 node = interval_tree_iter_first(&iopt->name##_itree, start, \ 126 last); \ 127 if (!node) \ 128 return NULL; \ 129 return container_of(node, struct iopt_##name, node); \ 130 } \ 131 static inline struct iopt_##name *iopt_##name##_iter_next( \ 132 struct iopt_##name *last_node, unsigned long start, \ 133 unsigned long last) \ 134 { \ 135 struct interval_tree_node *node; \ 136 \ 137 node = interval_tree_iter_next(&last_node->node, start, last); \ 138 if (!node) \ 139 return NULL; \ 140 return container_of(node, struct iopt_##name, node); \ 141 } 142 143 __make_iopt_iter(area) 144 __make_iopt_iter(allowed) 145 __make_iopt_iter(reserved) 146 147 struct iopt_area_contig_iter { 148 unsigned long cur_iova; 149 unsigned long last_iova; 150 struct iopt_area *area; 151 }; 152 struct iopt_area *iopt_area_contig_init(struct iopt_area_contig_iter *iter, 153 struct io_pagetable *iopt, 154 unsigned long iova, 155 unsigned long last_iova); 156 struct iopt_area *iopt_area_contig_next(struct iopt_area_contig_iter *iter); 157 iopt_area_contig_done(struct iopt_area_contig_iter * iter)158 static inline bool iopt_area_contig_done(struct iopt_area_contig_iter *iter) 159 { 160 return iter->area && iter->last_iova <= iopt_area_last_iova(iter->area); 161 } 162 163 /* 164 * Iterate over a contiguous list of areas that span the iova,last_iova range. 165 * The caller must check iopt_area_contig_done() after the loop to see if 166 * contiguous areas existed. 167 */ 168 #define iopt_for_each_contig_area(iter, area, iopt, iova, last_iova) \ 169 for (area = iopt_area_contig_init(iter, iopt, iova, last_iova); area; \ 170 area = iopt_area_contig_next(iter)) 171 172 enum { 173 IOPT_PAGES_ACCOUNT_NONE = 0, 174 IOPT_PAGES_ACCOUNT_USER = 1, 175 IOPT_PAGES_ACCOUNT_MM = 2, 176 }; 177 178 /* 179 * This holds a pinned page list for multiple areas of IO address space. The 180 * pages always originate from a linear chunk of userspace VA. Multiple 181 * io_pagetable's, through their iopt_area's, can share a single iopt_pages 182 * which avoids multi-pinning and double accounting of page consumption. 183 * 184 * indexes in this structure are measured in PAGE_SIZE units, are 0 based from 185 * the start of the uptr and extend to npages. pages are pinned dynamically 186 * according to the intervals in the access_itree and domains_itree, npinned 187 * records the current number of pages pinned. 188 */ 189 struct iopt_pages { 190 struct kref kref; 191 struct mutex mutex; 192 size_t npages; 193 size_t npinned; 194 size_t last_npinned; 195 struct task_struct *source_task; 196 struct mm_struct *source_mm; 197 struct user_struct *source_user; 198 void __user *uptr; 199 bool writable:1; 200 u8 account_mode; 201 202 struct xarray pinned_pfns; 203 /* Of iopt_pages_access::node */ 204 struct rb_root_cached access_itree; 205 /* Of iopt_area::pages_node */ 206 struct rb_root_cached domains_itree; 207 }; 208 209 struct iopt_pages *iopt_alloc_pages(void __user *uptr, unsigned long length, 210 bool writable); 211 void iopt_release_pages(struct kref *kref); iopt_put_pages(struct iopt_pages * pages)212 static inline void iopt_put_pages(struct iopt_pages *pages) 213 { 214 kref_put(&pages->kref, iopt_release_pages); 215 } 216 217 void iopt_pages_fill_from_xarray(struct iopt_pages *pages, unsigned long start, 218 unsigned long last, struct page **out_pages); 219 int iopt_pages_fill_xarray(struct iopt_pages *pages, unsigned long start, 220 unsigned long last, struct page **out_pages); 221 void iopt_pages_unfill_xarray(struct iopt_pages *pages, unsigned long start, 222 unsigned long last); 223 224 int iopt_area_add_access(struct iopt_area *area, unsigned long start, 225 unsigned long last, struct page **out_pages, 226 unsigned int flags); 227 void iopt_area_remove_access(struct iopt_area *area, unsigned long start, 228 unsigned long last); 229 int iopt_pages_rw_access(struct iopt_pages *pages, unsigned long start_byte, 230 void *data, unsigned long length, unsigned int flags); 231 232 /* 233 * Each interval represents an active iopt_access_pages(), it acts as an 234 * interval lock that keeps the PFNs pinned and stored in the xarray. 235 */ 236 struct iopt_pages_access { 237 struct interval_tree_node node; 238 unsigned int users; 239 }; 240 241 #endif 242