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/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 }