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