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
  12 #include <nvhe/early_alloc.h>
  13 #include <nvhe/gfp.h>
  14 #include <nvhe/memory.h>
  15 #include <nvhe/mem_protect.h>
  16 #include <nvhe/mm.h>
  17 #include <nvhe/trap_handler.h>
  18
  19 struct hyp_pool hpool;
  20 unsigned long hyp_nr_cpus;
  21
  22 #define hyp_percpu_size ((unsigned long)__per_cpu_end - \
  23                          (unsigned long)__per_cpu_start)
  24
  25 static void *vmemmap_base;
  26 static void *hyp_pgt_base;
  27 static void *host_s2_pgt_base;
  28 static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
  29
  30 static int divide_memory_pool(void *virt, unsigned long size)
  31 {
  32         unsigned long vstart, vend, nr_pages;
  33
  34         hyp_early_alloc_init(virt, size);
  35
  36         hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
  37         nr_pages = (vend - vstart) >> PAGE_SHIFT;
  38         vmemmap_base = hyp_early_alloc_contig(nr_pages);
  39         if (!vmemmap_base)
  40                 return -ENOMEM;
  41
  42         nr_pages = hyp_s1_pgtable_pages();
  43         hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
  44         if (!hyp_pgt_base)
  45                 return -ENOMEM;
  46
  47         nr_pages = host_s2_pgtable_pages();
  48         host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
  49         if (!host_s2_pgt_base)
  50                 return -ENOMEM;
  51
  52         return 0;
  53 }
  54
  55 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
  56                                  unsigned long *per_cpu_base,
  57                                  u32 hyp_va_bits)
  58 {
  59         void *start, *end, *virt = hyp_phys_to_virt(phys);
  60         unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
  61         int ret, i;
  62
  63         /* Recreate the hyp page-table using the early page allocator */
  64         hyp_early_alloc_init(hyp_pgt_base, pgt_size);
  65         ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
  66                                    &hyp_early_alloc_mm_ops);
  67         if (ret)
  68                 return ret;
  69
  70         ret = hyp_create_idmap(hyp_va_bits);
  71         if (ret)
  72                 return ret;
  73
  74         ret = hyp_map_vectors();
  75         if (ret)
  76                 return ret;
  77
  78         ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
  79         if (ret)
  80                 return ret;
  81
  82         ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
  83         if (ret)
  84                 return ret;
  85
  86         ret = pkvm_create_mappings(__start_rodata, __end_rodata, PAGE_HYP_RO);
  87         if (ret)
  88                 return ret;
  89
  90         ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
  91         if (ret)
  92                 return ret;
  93
  94         ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
  95         if (ret)
  96                 return ret;
  97
  98         ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, PAGE_HYP_RO);
  99         if (ret)
 100                 return ret;
 101
 102         ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
 103         if (ret)
 104                 return ret;
 105
 106         for (i = 0; i < hyp_nr_cpus; i++) {
 107                 start = (void *)kern_hyp_va(per_cpu_base[i]);
 108                 end = start + PAGE_ALIGN(hyp_percpu_size);
 109                 ret = pkvm_create_mappings(start, end, PAGE_HYP);
 110                 if (ret)
 111                         return ret;
 112
 113                 end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va;
 114                 start = end - PAGE_SIZE;
 115                 ret = pkvm_create_mappings(start, end, PAGE_HYP);
 116                 if (ret)
 117                         return ret;
 118         }
 119
 120         return 0;
 121 }
 122
 123 static void update_nvhe_init_params(void)
 124 {
 125         struct kvm_nvhe_init_params *params;
 126         unsigned long i;
 127
 128         for (i = 0; i < hyp_nr_cpus; i++) {
 129                 params = per_cpu_ptr(&kvm_init_params, i);
 130                 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
 131                 dcache_clean_inval_poc((unsigned long)params,
 132                                     (unsigned long)params + sizeof(*params));
 133         }
 134 }
 135
 136 static void *hyp_zalloc_hyp_page(void *arg)
 137 {
 138         return hyp_alloc_pages(&hpool, 0);
 139 }
 140
 141 static void hpool_get_page(void *addr)
 142 {
 143         hyp_get_page(&hpool, addr);
 144 }
 145
 146 static void hpool_put_page(void *addr)
 147 {
 148         hyp_put_page(&hpool, addr);
 149 }
 150
 151 void __noreturn __pkvm_init_finalise(void)
 152 {
 153         struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
 154         struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
 155         unsigned long nr_pages, reserved_pages, pfn;
 156         int ret;
 157
 158         /* Now that the vmemmap is backed, install the full-fledged allocator */
 159         pfn = hyp_virt_to_pfn(hyp_pgt_base);
 160         nr_pages = hyp_s1_pgtable_pages();
 161         reserved_pages = hyp_early_alloc_nr_used_pages();
 162         ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
 163         if (ret)
 164                 goto out;
 165
 166         ret = kvm_host_prepare_stage2(host_s2_pgt_base);
 167         if (ret)
 168                 goto out;
 169
 170         pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
 171                 .zalloc_page = hyp_zalloc_hyp_page,
 172                 .phys_to_virt = hyp_phys_to_virt,
 173                 .virt_to_phys = hyp_virt_to_phys,
 174                 .get_page = hpool_get_page,
 175                 .put_page = hpool_put_page,
 176         };
 177         pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
 178
 179 out:
 180         /*
 181          * We tail-called to here from handle___pkvm_init() and will not return,
 182          * so make sure to propagate the return value to the host.
 183          */
 184         cpu_reg(host_ctxt, 1) = ret;
 185
 186         __host_enter(host_ctxt);
 187 }
 188
 189 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
 190                 unsigned long *per_cpu_base, u32 hyp_va_bits)
 191 {
 192         struct kvm_nvhe_init_params *params;
 193         void *virt = hyp_phys_to_virt(phys);
 194         void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
 195         int ret;
 196
 197         if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
 198                 return -EINVAL;
 199
 200         hyp_spin_lock_init(&pkvm_pgd_lock);
 201         hyp_nr_cpus = nr_cpus;
 202
 203         ret = divide_memory_pool(virt, size);
 204         if (ret)
 205                 return ret;
 206
 207         ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
 208         if (ret)
 209                 return ret;
 210
 211         update_nvhe_init_params();
 212
 213         /* Jump in the idmap page to switch to the new page-tables */
 214         params = this_cpu_ptr(&kvm_init_params);
 215         fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
 216         fn(__hyp_pa(params), __pkvm_init_finalise);
 217
 218         unreachable();
 219 }