arch/arm64/kvm/hyp/nvhe/setup.c

   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/ffa.h>
  15 #include <nvhe/fixed_config.h>
  16 #include <nvhe/gfp.h>
  17 #include <nvhe/memory.h>
  18 #include <nvhe/mem_protect.h>
  19 #include <nvhe/mm.h>
  20 #include <nvhe/pkvm.h>
  21 #include <nvhe/trap_handler.h>
  22
  23 unsigned long hyp_nr_cpus;
  24
  25 #define hyp_percpu_size ((unsigned long)__per_cpu_end - \
  26                          (unsigned long)__per_cpu_start)
  27
  28 static void *vmemmap_base;
  29 static void *vm_table_base;
  30 static void *hyp_pgt_base;
  31 static void *host_s2_pgt_base;
  32 static void *ffa_proxy_pages;
  33 static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
  34 static struct hyp_pool hpool;
  35
  36 static int divide_memory_pool(void *virt, unsigned long size)
  37 {
  38         unsigned long nr_pages;
  39
  40         hyp_early_alloc_init(virt, size);
  41
  42         nr_pages = hyp_vmemmap_pages(sizeof(struct hyp_page));
  43         vmemmap_base = hyp_early_alloc_contig(nr_pages);
  44         if (!vmemmap_base)
  45                 return -ENOMEM;
  46
  47         nr_pages = hyp_vm_table_pages();
  48         vm_table_base = hyp_early_alloc_contig(nr_pages);
  49         if (!vm_table_base)
  50                 return -ENOMEM;
  51
  52         nr_pages = hyp_s1_pgtable_pages();
  53         hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
  54         if (!hyp_pgt_base)
  55                 return -ENOMEM;
  56
  57         nr_pages = host_s2_pgtable_pages();
  58         host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
  59         if (!host_s2_pgt_base)
  60                 return -ENOMEM;
  61
  62         nr_pages = hyp_ffa_proxy_pages();
  63         ffa_proxy_pages = hyp_early_alloc_contig(nr_pages);
  64         if (!ffa_proxy_pages)
  65                 return -ENOMEM;
  66
  67         return 0;
  68 }
  69
  70 static int pkvm_create_host_sve_mappings(void)
  71 {
  72         void *start, *end;
  73         int ret, i;
  74
  75         if (!system_supports_sve())
  76                 return 0;
  77
  78         for (i = 0; i < hyp_nr_cpus; i++) {
  79                 struct kvm_host_data *host_data = per_cpu_ptr(&kvm_host_data, i);
  80                 struct cpu_sve_state *sve_state = host_data->sve_state;
  81
  82                 start = kern_hyp_va(sve_state);
  83                 end = start + PAGE_ALIGN(pkvm_host_sve_state_size());
  84                 ret = pkvm_create_mappings(start, end, PAGE_HYP);
  85                 if (ret)
  86                         return ret;
  87         }
  88
  89         return 0;
  90 }
  91
  92 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
  93                                  unsigned long *per_cpu_base,
  94                                  u32 hyp_va_bits)
  95 {
  96         void *start, *end, *virt = hyp_phys_to_virt(phys);
  97         unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
  98         enum kvm_pgtable_prot prot;
  99         int ret, i;
 100
 101         /* Recreate the hyp page-table using the early page allocator */
 102         hyp_early_alloc_init(hyp_pgt_base, pgt_size);
 103         ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
 104                                    &hyp_early_alloc_mm_ops);
 105         if (ret)
 106                 return ret;
 107
 108         ret = hyp_create_idmap(hyp_va_bits);
 109         if (ret)
 110                 return ret;
 111
 112         ret = hyp_map_vectors();
 113         if (ret)
 114                 return ret;
 115
 116         ret = hyp_back_vmemmap(hyp_virt_to_phys(vmemmap_base));
 117         if (ret)
 118                 return ret;
 119
 120         ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
 121         if (ret)
 122                 return ret;
 123
 124         ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
 125         if (ret)
 126                 return ret;
 127
 128         ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
 129         if (ret)
 130                 return ret;
 131
 132         ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
 133         if (ret)
 134                 return ret;
 135
 136         for (i = 0; i < hyp_nr_cpus; i++) {
 137                 struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i);
 138
 139                 start = (void *)kern_hyp_va(per_cpu_base[i]);
 140                 end = start + PAGE_ALIGN(hyp_percpu_size);
 141                 ret = pkvm_create_mappings(start, end, PAGE_HYP);
 142                 if (ret)
 143                         return ret;
 144
 145                 ret = pkvm_create_stack(params->stack_pa, &params->stack_hyp_va);
 146                 if (ret)
 147                         return ret;
 148         }
 149
 150         pkvm_create_host_sve_mappings();
 151
 152         /*
 153          * Map the host sections RO in the hypervisor, but transfer the
 154          * ownership from the host to the hypervisor itself to make sure they
 155          * can't be donated or shared with another entity.
 156          *
 157          * The ownership transition requires matching changes in the host
 158          * stage-2. This will be done later (see finalize_host_mappings()) once
 159          * the hyp_vmemmap is addressable.
 160          */
 161         prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
 162         ret = pkvm_create_mappings(&kvm_vgic_global_state,
 163                                    &kvm_vgic_global_state + 1, prot);
 164         if (ret)
 165                 return ret;
 166
 167         return 0;
 168 }
 169
 170 static void update_nvhe_init_params(void)
 171 {
 172         struct kvm_nvhe_init_params *params;
 173         unsigned long i;
 174
 175         for (i = 0; i < hyp_nr_cpus; i++) {
 176                 params = per_cpu_ptr(&kvm_init_params, i);
 177                 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
 178                 dcache_clean_inval_poc((unsigned long)params,
 179                                     (unsigned long)params + sizeof(*params));
 180         }
 181 }
 182
 183 static void *hyp_zalloc_hyp_page(void *arg)
 184 {
 185         return hyp_alloc_pages(&hpool, 0);
 186 }
 187
 188 static void hpool_get_page(void *addr)
 189 {
 190         hyp_get_page(&hpool, addr);
 191 }
 192
 193 static void hpool_put_page(void *addr)
 194 {
 195         hyp_put_page(&hpool, addr);
 196 }
 197
 198 static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
 199                                      enum kvm_pgtable_walk_flags visit)
 200 {
 201         enum kvm_pgtable_prot prot;
 202         enum pkvm_page_state state;
 203         phys_addr_t phys;
 204
 205         if (!kvm_pte_valid(ctx->old))
 206                 return 0;
 207
 208         if (ctx->level != KVM_PGTABLE_LAST_LEVEL)
 209                 return -EINVAL;
 210
 211         phys = kvm_pte_to_phys(ctx->old);
 212         if (!addr_is_memory(phys))
 213                 return -EINVAL;
 214
 215         /*
 216          * Adjust the host stage-2 mappings to match the ownership attributes
 217          * configured in the hypervisor stage-1.
 218          */
 219         state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(ctx->old));
 220         switch (state) {
 221         case PKVM_PAGE_OWNED:
 222                 return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP);
 223         case PKVM_PAGE_SHARED_OWNED:
 224                 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
 225                 break;
 226         case PKVM_PAGE_SHARED_BORROWED:
 227                 prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
 228                 break;
 229         default:
 230                 return -EINVAL;
 231         }
 232
 233         return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
 234 }
 235
 236 static int fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx *ctx,
 237                                          enum kvm_pgtable_walk_flags visit)
 238 {
 239         /*
 240          * Fix-up the refcount for the page-table pages as the early allocator
 241          * was unable to access the hyp_vmemmap and so the buddy allocator has
 242          * initialised the refcount to '1'.
 243          */
 244         if (kvm_pte_valid(ctx->old))
 245                 ctx->mm_ops->get_page(ctx->ptep);
 246
 247         return 0;
 248 }
 249
 250 static int fix_host_ownership(void)
 251 {
 252         struct kvm_pgtable_walker walker = {
 253                 .cb     = fix_host_ownership_walker,
 254                 .flags  = KVM_PGTABLE_WALK_LEAF,
 255         };
 256         int i, ret;
 257
 258         for (i = 0; i < hyp_memblock_nr; i++) {
 259                 struct memblock_region *reg = &hyp_memory[i];
 260                 u64 start = (u64)hyp_phys_to_virt(reg->base);
 261
 262                 ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
 263                 if (ret)
 264                         return ret;
 265         }
 266
 267         return 0;
 268 }
 269
 270 static int fix_hyp_pgtable_refcnt(void)
 271 {
 272         struct kvm_pgtable_walker walker = {
 273                 .cb     = fix_hyp_pgtable_refcnt_walker,
 274                 .flags  = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
 275                 .arg    = pkvm_pgtable.mm_ops,
 276         };
 277
 278         return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits),
 279                                 &walker);
 280 }
 281
 282 void __noreturn __pkvm_init_finalise(void)
 283 {
 284         struct kvm_cpu_context *host_ctxt = host_data_ptr(host_ctxt);
 285         unsigned long nr_pages, reserved_pages, pfn;
 286         int ret;
 287
 288         /* Now that the vmemmap is backed, install the full-fledged allocator */
 289         pfn = hyp_virt_to_pfn(hyp_pgt_base);
 290         nr_pages = hyp_s1_pgtable_pages();
 291         reserved_pages = hyp_early_alloc_nr_used_pages();
 292         ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
 293         if (ret)
 294                 goto out;
 295
 296         ret = kvm_host_prepare_stage2(host_s2_pgt_base);
 297         if (ret)
 298                 goto out;
 299
 300         pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
 301                 .zalloc_page = hyp_zalloc_hyp_page,
 302                 .phys_to_virt = hyp_phys_to_virt,
 303                 .virt_to_phys = hyp_virt_to_phys,
 304                 .get_page = hpool_get_page,
 305                 .put_page = hpool_put_page,
 306                 .page_count = hyp_page_count,
 307         };
 308         pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
 309
 310         ret = fix_host_ownership();
 311         if (ret)
 312                 goto out;
 313
 314         ret = fix_hyp_pgtable_refcnt();
 315         if (ret)
 316                 goto out;
 317
 318         ret = hyp_create_pcpu_fixmap();
 319         if (ret)
 320                 goto out;
 321
 322         ret = hyp_ffa_init(ffa_proxy_pages);
 323         if (ret)
 324                 goto out;
 325
 326         pkvm_hyp_vm_table_init(vm_table_base);
 327 out:
 328         /*
 329          * We tail-called to here from handle___pkvm_init() and will not return,
 330          * so make sure to propagate the return value to the host.
 331          */
 332         cpu_reg(host_ctxt, 1) = ret;
 333
 334         __host_enter(host_ctxt);
 335 }
 336
 337 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
 338                 unsigned long *per_cpu_base, u32 hyp_va_bits)
 339 {
 340         struct kvm_nvhe_init_params *params;
 341         void *virt = hyp_phys_to_virt(phys);
 342         typeof(__pkvm_init_switch_pgd) *fn;
 343         int ret;
 344
 345         BUG_ON(kvm_check_pvm_sysreg_table());
 346
 347         if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
 348                 return -EINVAL;
 349
 350         hyp_spin_lock_init(&pkvm_pgd_lock);
 351         hyp_nr_cpus = nr_cpus;
 352
 353         ret = divide_memory_pool(virt, size);
 354         if (ret)
 355                 return ret;
 356
 357         ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
 358         if (ret)
 359                 return ret;
 360
 361         update_nvhe_init_params();
 362
 363         /* Jump in the idmap page to switch to the new page-tables */
 364         params = this_cpu_ptr(&kvm_init_params);
 365         fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
 366         fn(params->pgd_pa, params->stack_hyp_va, __pkvm_init_finalise);
 367
 368         unreachable();
 369 }