1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2020 - Google LLC 4 * Author: Quentin Perret <qperret@google.com> 5 */ 6 7 #include <linux/init.h> 8 #include <linux/kmemleak.h> 9 #include <linux/kvm_host.h> 10 #include <linux/memblock.h> 11 #include <linux/mutex.h> 12 #include <linux/sort.h> 13 14 #include <asm/kvm_pkvm.h> 15 16 #include "hyp_constants.h" 17 18 DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); 19 20 static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory); 21 static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr); 22 23 phys_addr_t hyp_mem_base; 24 phys_addr_t hyp_mem_size; 25 26 static int cmp_hyp_memblock(const void *p1, const void *p2) 27 { 28 const struct memblock_region *r1 = p1; 29 const struct memblock_region *r2 = p2; 30 31 return r1->base < r2->base ? -1 : (r1->base > r2->base); 32 } 33 34 static void __init sort_memblock_regions(void) 35 { 36 sort(hyp_memory, 37 *hyp_memblock_nr_ptr, 38 sizeof(struct memblock_region), 39 cmp_hyp_memblock, 40 NULL); 41 } 42 43 static int __init register_memblock_regions(void) 44 { 45 struct memblock_region *reg; 46 47 for_each_mem_region(reg) { 48 if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS) 49 return -ENOMEM; 50 51 hyp_memory[*hyp_memblock_nr_ptr] = *reg; 52 (*hyp_memblock_nr_ptr)++; 53 } 54 sort_memblock_regions(); 55 56 return 0; 57 } 58 59 void __init kvm_hyp_reserve(void) 60 { 61 u64 hyp_mem_pages = 0; 62 int ret; 63 64 if (!is_hyp_mode_available() || is_kernel_in_hyp_mode()) 65 return; 66 67 if (kvm_get_mode() != KVM_MODE_PROTECTED) 68 return; 69 70 ret = register_memblock_regions(); 71 if (ret) { 72 *hyp_memblock_nr_ptr = 0; 73 kvm_err("Failed to register hyp memblocks: %d\n", ret); 74 return; 75 } 76 77 hyp_mem_pages += hyp_s1_pgtable_pages(); 78 hyp_mem_pages += host_s2_pgtable_pages(); 79 hyp_mem_pages += hyp_vm_table_pages(); 80 hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE); 81 hyp_mem_pages += hyp_ffa_proxy_pages(); 82 83 /* 84 * Try to allocate a PMD-aligned region to reduce TLB pressure once 85 * this is unmapped from the host stage-2, and fallback to PAGE_SIZE. 86 */ 87 hyp_mem_size = hyp_mem_pages << PAGE_SHIFT; 88 hyp_mem_base = memblock_phys_alloc(ALIGN(hyp_mem_size, PMD_SIZE), 89 PMD_SIZE); 90 if (!hyp_mem_base) 91 hyp_mem_base = memblock_phys_alloc(hyp_mem_size, PAGE_SIZE); 92 else 93 hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE); 94 95 if (!hyp_mem_base) { 96 kvm_err("Failed to reserve hyp memory\n"); 97 return; 98 } 99 100 kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20, 101 hyp_mem_base); 102 } 103 104 static void __pkvm_destroy_hyp_vm(struct kvm *host_kvm) 105 { 106 if (host_kvm->arch.pkvm.handle) { 107 WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm, 108 host_kvm->arch.pkvm.handle)); 109 } 110 111 host_kvm->arch.pkvm.handle = 0; 112 free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc); 113 } 114 115 /* 116 * Allocates and donates memory for hypervisor VM structs at EL2. 117 * 118 * Allocates space for the VM state, which includes the hyp vm as well as 119 * the hyp vcpus. 120 * 121 * Stores an opaque handler in the kvm struct for future reference. 122 * 123 * Return 0 on success, negative error code on failure. 124 */ 125 static int __pkvm_create_hyp_vm(struct kvm *host_kvm) 126 { 127 size_t pgd_sz, hyp_vm_sz, hyp_vcpu_sz; 128 struct kvm_vcpu *host_vcpu; 129 pkvm_handle_t handle; 130 void *pgd, *hyp_vm; 131 unsigned long idx; 132 int ret; 133 134 if (host_kvm->created_vcpus < 1) 135 return -EINVAL; 136 137 pgd_sz = kvm_pgtable_stage2_pgd_size(host_kvm->arch.vtcr); 138 139 /* 140 * The PGD pages will be reclaimed using a hyp_memcache which implies 141 * page granularity. So, use alloc_pages_exact() to get individual 142 * refcounts. 143 */ 144 pgd = alloc_pages_exact(pgd_sz, GFP_KERNEL_ACCOUNT); 145 if (!pgd) 146 return -ENOMEM; 147 148 /* Allocate memory to donate to hyp for vm and vcpu pointers. */ 149 hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE, 150 size_mul(sizeof(void *), 151 host_kvm->created_vcpus))); 152 hyp_vm = alloc_pages_exact(hyp_vm_sz, GFP_KERNEL_ACCOUNT); 153 if (!hyp_vm) { 154 ret = -ENOMEM; 155 goto free_pgd; 156 } 157 158 /* Donate the VM memory to hyp and let hyp initialize it. */ 159 ret = kvm_call_hyp_nvhe(__pkvm_init_vm, host_kvm, hyp_vm, pgd); 160 if (ret < 0) 161 goto free_vm; 162 163 handle = ret; 164 165 host_kvm->arch.pkvm.handle = handle; 166 167 /* Donate memory for the vcpus at hyp and initialize it. */ 168 hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE); 169 kvm_for_each_vcpu(idx, host_vcpu, host_kvm) { 170 void *hyp_vcpu; 171 172 /* Indexing of the vcpus to be sequential starting at 0. */ 173 if (WARN_ON(host_vcpu->vcpu_idx != idx)) { 174 ret = -EINVAL; 175 goto destroy_vm; 176 } 177 178 hyp_vcpu = alloc_pages_exact(hyp_vcpu_sz, GFP_KERNEL_ACCOUNT); 179 if (!hyp_vcpu) { 180 ret = -ENOMEM; 181 goto destroy_vm; 182 } 183 184 ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, host_vcpu, 185 hyp_vcpu); 186 if (ret) { 187 free_pages_exact(hyp_vcpu, hyp_vcpu_sz); 188 goto destroy_vm; 189 } 190 } 191 192 return 0; 193 194 destroy_vm: 195 __pkvm_destroy_hyp_vm(host_kvm); 196 return ret; 197 free_vm: 198 free_pages_exact(hyp_vm, hyp_vm_sz); 199 free_pgd: 200 free_pages_exact(pgd, pgd_sz); 201 return ret; 202 } 203 204 int pkvm_create_hyp_vm(struct kvm *host_kvm) 205 { 206 int ret = 0; 207 208 mutex_lock(&host_kvm->arch.config_lock); 209 if (!host_kvm->arch.pkvm.handle) 210 ret = __pkvm_create_hyp_vm(host_kvm); 211 mutex_unlock(&host_kvm->arch.config_lock); 212 213 return ret; 214 } 215 216 void pkvm_destroy_hyp_vm(struct kvm *host_kvm) 217 { 218 mutex_lock(&host_kvm->arch.config_lock); 219 __pkvm_destroy_hyp_vm(host_kvm); 220 mutex_unlock(&host_kvm->arch.config_lock); 221 } 222 223 int pkvm_init_host_vm(struct kvm *host_kvm) 224 { 225 mutex_init(&host_kvm->lock); 226 return 0; 227 } 228 229 static void __init _kvm_host_prot_finalize(void *arg) 230 { 231 int *err = arg; 232 233 if (WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize))) 234 WRITE_ONCE(*err, -EINVAL); 235 } 236 237 static int __init pkvm_drop_host_privileges(void) 238 { 239 int ret = 0; 240 241 /* 242 * Flip the static key upfront as that may no longer be possible 243 * once the host stage 2 is installed. 244 */ 245 static_branch_enable(&kvm_protected_mode_initialized); 246 on_each_cpu(_kvm_host_prot_finalize, &ret, 1); 247 return ret; 248 } 249 250 static int __init finalize_pkvm(void) 251 { 252 int ret; 253 254 if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised()) 255 return 0; 256 257 /* 258 * Exclude HYP sections from kmemleak so that they don't get peeked 259 * at, which would end badly once inaccessible. 260 */ 261 kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start); 262 kmemleak_free_part_phys(hyp_mem_base, hyp_mem_size); 263 264 ret = pkvm_drop_host_privileges(); 265 if (ret) 266 pr_err("Failed to finalize Hyp protection: %d\n", ret); 267 268 return ret; 269 } 270 device_initcall_sync(finalize_pkvm); 271