1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2020 Google LLC 4 * Author: Quentin Perret <qperret@google.com> 5 */ 6 7 #include <linux/kvm_host.h> 8 #include <asm/kvm_hyp.h> 9 #include <asm/kvm_mmu.h> 10 #include <asm/kvm_pgtable.h> 11 #include <asm/kvm_pkvm.h> 12 13 #include <nvhe/early_alloc.h> 14 #include <nvhe/fixed_config.h> 15 #include <nvhe/gfp.h> 16 #include <nvhe/memory.h> 17 #include <nvhe/mem_protect.h> 18 #include <nvhe/mm.h> 19 #include <nvhe/pkvm.h> 20 #include <nvhe/trap_handler.h> 21 22 unsigned long hyp_nr_cpus; 23 24 #define hyp_percpu_size ((unsigned long)__per_cpu_end - \ 25 (unsigned long)__per_cpu_start) 26 27 static void *vmemmap_base; 28 static void *vm_table_base; 29 static void *hyp_pgt_base; 30 static void *host_s2_pgt_base; 31 static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops; 32 static struct hyp_pool hpool; 33 34 static int divide_memory_pool(void *virt, unsigned long size) 35 { 36 unsigned long nr_pages; 37 38 hyp_early_alloc_init(virt, size); 39 40 nr_pages = hyp_vmemmap_pages(sizeof(struct hyp_page)); 41 vmemmap_base = hyp_early_alloc_contig(nr_pages); 42 if (!vmemmap_base) 43 return -ENOMEM; 44 45 nr_pages = hyp_vm_table_pages(); 46 vm_table_base = hyp_early_alloc_contig(nr_pages); 47 if (!vm_table_base) 48 return -ENOMEM; 49 50 nr_pages = hyp_s1_pgtable_pages(); 51 hyp_pgt_base = hyp_early_alloc_contig(nr_pages); 52 if (!hyp_pgt_base) 53 return -ENOMEM; 54 55 nr_pages = host_s2_pgtable_pages(); 56 host_s2_pgt_base = hyp_early_alloc_contig(nr_pages); 57 if (!host_s2_pgt_base) 58 return -ENOMEM; 59 60 return 0; 61 } 62 63 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, 64 unsigned long *per_cpu_base, 65 u32 hyp_va_bits) 66 { 67 void *start, *end, *virt = hyp_phys_to_virt(phys); 68 unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT; 69 enum kvm_pgtable_prot prot; 70 int ret, i; 71 72 /* Recreate the hyp page-table using the early page allocator */ 73 hyp_early_alloc_init(hyp_pgt_base, pgt_size); 74 ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits, 75 &hyp_early_alloc_mm_ops); 76 if (ret) 77 return ret; 78 79 ret = hyp_create_idmap(hyp_va_bits); 80 if (ret) 81 return ret; 82 83 ret = hyp_map_vectors(); 84 if (ret) 85 return ret; 86 87 ret = hyp_back_vmemmap(hyp_virt_to_phys(vmemmap_base)); 88 if (ret) 89 return ret; 90 91 ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC); 92 if (ret) 93 return ret; 94 95 ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO); 96 if (ret) 97 return ret; 98 99 ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP); 100 if (ret) 101 return ret; 102 103 ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP); 104 if (ret) 105 return ret; 106 107 for (i = 0; i < hyp_nr_cpus; i++) { 108 struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i); 109 unsigned long hyp_addr; 110 111 start = (void *)kern_hyp_va(per_cpu_base[i]); 112 end = start + PAGE_ALIGN(hyp_percpu_size); 113 ret = pkvm_create_mappings(start, end, PAGE_HYP); 114 if (ret) 115 return ret; 116 117 /* 118 * Allocate a contiguous HYP private VA range for the stack 119 * and guard page. The allocation is also aligned based on 120 * the order of its size. 121 */ 122 ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr); 123 if (ret) 124 return ret; 125 126 /* 127 * Since the stack grows downwards, map the stack to the page 128 * at the higher address and leave the lower guard page 129 * unbacked. 130 * 131 * Any valid stack address now has the PAGE_SHIFT bit as 1 132 * and addresses corresponding to the guard page have the 133 * PAGE_SHIFT bit as 0 - this is used for overflow detection. 134 */ 135 hyp_spin_lock(&pkvm_pgd_lock); 136 ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE, 137 PAGE_SIZE, params->stack_pa, PAGE_HYP); 138 hyp_spin_unlock(&pkvm_pgd_lock); 139 if (ret) 140 return ret; 141 142 /* Update stack_hyp_va to end of the stack's private VA range */ 143 params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE); 144 } 145 146 /* 147 * Map the host sections RO in the hypervisor, but transfer the 148 * ownership from the host to the hypervisor itself to make sure they 149 * can't be donated or shared with another entity. 150 * 151 * The ownership transition requires matching changes in the host 152 * stage-2. This will be done later (see finalize_host_mappings()) once 153 * the hyp_vmemmap is addressable. 154 */ 155 prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED); 156 ret = pkvm_create_mappings(&kvm_vgic_global_state, 157 &kvm_vgic_global_state + 1, prot); 158 if (ret) 159 return ret; 160 161 return 0; 162 } 163 164 static void update_nvhe_init_params(void) 165 { 166 struct kvm_nvhe_init_params *params; 167 unsigned long i; 168 169 for (i = 0; i < hyp_nr_cpus; i++) { 170 params = per_cpu_ptr(&kvm_init_params, i); 171 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd); 172 dcache_clean_inval_poc((unsigned long)params, 173 (unsigned long)params + sizeof(*params)); 174 } 175 } 176 177 static void *hyp_zalloc_hyp_page(void *arg) 178 { 179 return hyp_alloc_pages(&hpool, 0); 180 } 181 182 static void hpool_get_page(void *addr) 183 { 184 hyp_get_page(&hpool, addr); 185 } 186 187 static void hpool_put_page(void *addr) 188 { 189 hyp_put_page(&hpool, addr); 190 } 191 192 static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx, 193 enum kvm_pgtable_walk_flags visit) 194 { 195 enum kvm_pgtable_prot prot; 196 enum pkvm_page_state state; 197 phys_addr_t phys; 198 199 if (!kvm_pte_valid(ctx->old)) 200 return 0; 201 202 if (ctx->level != (KVM_PGTABLE_MAX_LEVELS - 1)) 203 return -EINVAL; 204 205 phys = kvm_pte_to_phys(ctx->old); 206 if (!addr_is_memory(phys)) 207 return -EINVAL; 208 209 /* 210 * Adjust the host stage-2 mappings to match the ownership attributes 211 * configured in the hypervisor stage-1. 212 */ 213 state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(ctx->old)); 214 switch (state) { 215 case PKVM_PAGE_OWNED: 216 return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP); 217 case PKVM_PAGE_SHARED_OWNED: 218 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED); 219 break; 220 case PKVM_PAGE_SHARED_BORROWED: 221 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED); 222 break; 223 default: 224 return -EINVAL; 225 } 226 227 return host_stage2_idmap_locked(phys, PAGE_SIZE, prot); 228 } 229 230 static int fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx *ctx, 231 enum kvm_pgtable_walk_flags visit) 232 { 233 /* 234 * Fix-up the refcount for the page-table pages as the early allocator 235 * was unable to access the hyp_vmemmap and so the buddy allocator has 236 * initialised the refcount to '1'. 237 */ 238 if (kvm_pte_valid(ctx->old)) 239 ctx->mm_ops->get_page(ctx->ptep); 240 241 return 0; 242 } 243 244 static int fix_host_ownership(void) 245 { 246 struct kvm_pgtable_walker walker = { 247 .cb = fix_host_ownership_walker, 248 .flags = KVM_PGTABLE_WALK_LEAF, 249 }; 250 int i, ret; 251 252 for (i = 0; i < hyp_memblock_nr; i++) { 253 struct memblock_region *reg = &hyp_memory[i]; 254 u64 start = (u64)hyp_phys_to_virt(reg->base); 255 256 ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker); 257 if (ret) 258 return ret; 259 } 260 261 return 0; 262 } 263 264 static int fix_hyp_pgtable_refcnt(void) 265 { 266 struct kvm_pgtable_walker walker = { 267 .cb = fix_hyp_pgtable_refcnt_walker, 268 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, 269 .arg = pkvm_pgtable.mm_ops, 270 }; 271 272 return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits), 273 &walker); 274 } 275 276 void __noreturn __pkvm_init_finalise(void) 277 { 278 struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data); 279 struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt; 280 unsigned long nr_pages, reserved_pages, pfn; 281 int ret; 282 283 /* Now that the vmemmap is backed, install the full-fledged allocator */ 284 pfn = hyp_virt_to_pfn(hyp_pgt_base); 285 nr_pages = hyp_s1_pgtable_pages(); 286 reserved_pages = hyp_early_alloc_nr_used_pages(); 287 ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages); 288 if (ret) 289 goto out; 290 291 ret = kvm_host_prepare_stage2(host_s2_pgt_base); 292 if (ret) 293 goto out; 294 295 pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) { 296 .zalloc_page = hyp_zalloc_hyp_page, 297 .phys_to_virt = hyp_phys_to_virt, 298 .virt_to_phys = hyp_virt_to_phys, 299 .get_page = hpool_get_page, 300 .put_page = hpool_put_page, 301 .page_count = hyp_page_count, 302 }; 303 pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops; 304 305 ret = fix_host_ownership(); 306 if (ret) 307 goto out; 308 309 ret = fix_hyp_pgtable_refcnt(); 310 if (ret) 311 goto out; 312 313 ret = hyp_create_pcpu_fixmap(); 314 if (ret) 315 goto out; 316 317 pkvm_hyp_vm_table_init(vm_table_base); 318 out: 319 /* 320 * We tail-called to here from handle___pkvm_init() and will not return, 321 * so make sure to propagate the return value to the host. 322 */ 323 cpu_reg(host_ctxt, 1) = ret; 324 325 __host_enter(host_ctxt); 326 } 327 328 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus, 329 unsigned long *per_cpu_base, u32 hyp_va_bits) 330 { 331 struct kvm_nvhe_init_params *params; 332 void *virt = hyp_phys_to_virt(phys); 333 void (*fn)(phys_addr_t params_pa, void *finalize_fn_va); 334 int ret; 335 336 BUG_ON(kvm_check_pvm_sysreg_table()); 337 338 if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size)) 339 return -EINVAL; 340 341 hyp_spin_lock_init(&pkvm_pgd_lock); 342 hyp_nr_cpus = nr_cpus; 343 344 ret = divide_memory_pool(virt, size); 345 if (ret) 346 return ret; 347 348 ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits); 349 if (ret) 350 return ret; 351 352 update_nvhe_init_params(); 353 354 /* Jump in the idmap page to switch to the new page-tables */ 355 params = this_cpu_ptr(&kvm_init_params); 356 fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd); 357 fn(__hyp_pa(params), __pkvm_init_finalise); 358 359 unreachable(); 360 } 361