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