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 struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
  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_mem_pgt_base;
  29 static void *host_s2_dev_pgt_base;
  30
  31 static int divide_memory_pool(void *virt, unsigned long size)
  32 {
  33         unsigned long vstart, vend, nr_pages;
  34
  35         hyp_early_alloc_init(virt, size);
  36
  37         hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
  38         nr_pages = (vend - vstart) >> PAGE_SHIFT;
  39         vmemmap_base = hyp_early_alloc_contig(nr_pages);
  40         if (!vmemmap_base)
  41                 return -ENOMEM;
  42
  43         nr_pages = hyp_s1_pgtable_pages();
  44         hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
  45         if (!hyp_pgt_base)
  46                 return -ENOMEM;
  47
  48         nr_pages = host_s2_mem_pgtable_pages();
  49         host_s2_mem_pgt_base = hyp_early_alloc_contig(nr_pages);
  50         if (!host_s2_mem_pgt_base)
  51                 return -ENOMEM;
  52
  53         nr_pages = host_s2_dev_pgtable_pages();
  54         host_s2_dev_pgt_base = hyp_early_alloc_contig(nr_pages);
  55         if (!host_s2_dev_pgt_base)
  56                 return -ENOMEM;
  57
  58         return 0;
  59 }
  60
  61 static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
  62                                  unsigned long *per_cpu_base,
  63                                  u32 hyp_va_bits)
  64 {
  65         void *start, *end, *virt = hyp_phys_to_virt(phys);
  66         unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
  67         int ret, i;
  68
  69         /* Recreate the hyp page-table using the early page allocator */
  70         hyp_early_alloc_init(hyp_pgt_base, pgt_size);
  71         ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
  72                                    &hyp_early_alloc_mm_ops);
  73         if (ret)
  74                 return ret;
  75
  76         ret = hyp_create_idmap(hyp_va_bits);
  77         if (ret)
  78                 return ret;
  79
  80         ret = hyp_map_vectors();
  81         if (ret)
  82                 return ret;
  83
  84         ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
  85         if (ret)
  86                 return ret;
  87
  88         ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
  89         if (ret)
  90                 return ret;
  91
  92         ret = pkvm_create_mappings(__start_rodata, __end_rodata, PAGE_HYP_RO);
  93         if (ret)
  94                 return ret;
  95
  96         ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
  97         if (ret)
  98                 return ret;
  99
 100         ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
 101         if (ret)
 102                 return ret;
 103
 104         ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, PAGE_HYP_RO);
 105         if (ret)
 106                 return ret;
 107
 108         ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
 109         if (ret)
 110                 return ret;
 111
 112         for (i = 0; i < hyp_nr_cpus; i++) {
 113                 start = (void *)kern_hyp_va(per_cpu_base[i]);
 114                 end = start + PAGE_ALIGN(hyp_percpu_size);
 115                 ret = pkvm_create_mappings(start, end, PAGE_HYP);
 116                 if (ret)
 117                         return ret;
 118
 119                 end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va;
 120                 start = end - PAGE_SIZE;
 121                 ret = pkvm_create_mappings(start, end, PAGE_HYP);
 122                 if (ret)
 123                         return ret;
 124         }
 125
 126         return 0;
 127 }
 128
 129 static void update_nvhe_init_params(void)
 130 {
 131         struct kvm_nvhe_init_params *params;
 132         unsigned long i;
 133
 134         for (i = 0; i < hyp_nr_cpus; i++) {
 135                 params = per_cpu_ptr(&kvm_init_params, i);
 136                 params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
 137                 __flush_dcache_area(params, sizeof(*params));
 138         }
 139 }
 140
 141 static void *hyp_zalloc_hyp_page(void *arg)
 142 {
 143         return hyp_alloc_pages(&hpool, 0);
 144 }
 145
 146 void __noreturn __pkvm_init_finalise(void)
 147 {
 148         struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
 149         struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
 150         unsigned long nr_pages, reserved_pages, pfn;
 151         int ret;
 152
 153         /* Now that the vmemmap is backed, install the full-fledged allocator */
 154         pfn = hyp_virt_to_pfn(hyp_pgt_base);
 155         nr_pages = hyp_s1_pgtable_pages();
 156         reserved_pages = hyp_early_alloc_nr_used_pages();
 157         ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
 158         if (ret)
 159                 goto out;
 160
 161         ret = kvm_host_prepare_stage2(host_s2_mem_pgt_base, host_s2_dev_pgt_base);
 162         if (ret)
 163                 goto out;
 164
 165         pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
 166                 .zalloc_page = hyp_zalloc_hyp_page,
 167                 .phys_to_virt = hyp_phys_to_virt,
 168                 .virt_to_phys = hyp_virt_to_phys,
 169                 .get_page = hyp_get_page,
 170                 .put_page = hyp_put_page,
 171         };
 172         pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
 173
 174 out:
 175         /*
 176          * We tail-called to here from handle___pkvm_init() and will not return,
 177          * so make sure to propagate the return value to the host.
 178          */
 179         cpu_reg(host_ctxt, 1) = ret;
 180
 181         __host_enter(host_ctxt);
 182 }
 183
 184 int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
 185                 unsigned long *per_cpu_base, u32 hyp_va_bits)
 186 {
 187         struct kvm_nvhe_init_params *params;
 188         void *virt = hyp_phys_to_virt(phys);
 189         void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
 190         int ret;
 191
 192         if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
 193                 return -EINVAL;
 194
 195         hyp_spin_lock_init(&pkvm_pgd_lock);
 196         hyp_nr_cpus = nr_cpus;
 197
 198         ret = divide_memory_pool(virt, size);
 199         if (ret)
 200                 return ret;
 201
 202         ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
 203         if (ret)
 204                 return ret;
 205
 206         update_nvhe_init_params();
 207
 208         /* Jump in the idmap page to switch to the new page-tables */
 209         params = this_cpu_ptr(&kvm_init_params);
 210         fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
 211         fn(__hyp_pa(params), __pkvm_init_finalise);
 212
 213         unreachable();
 214 }