1 /* 2 * access guest memory 3 * 4 * Copyright IBM Corp. 2008, 2014 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License (version 2 only) 8 * as published by the Free Software Foundation. 9 * 10 * Author(s): Carsten Otte <cotte@de.ibm.com> 11 */ 12 13 #ifndef __KVM_S390_GACCESS_H 14 #define __KVM_S390_GACCESS_H 15 16 #include <linux/compiler.h> 17 #include <linux/kvm_host.h> 18 #include <linux/uaccess.h> 19 #include <linux/ptrace.h> 20 #include "kvm-s390.h" 21 22 /** 23 * kvm_s390_real_to_abs - convert guest real address to guest absolute address 24 * @vcpu - guest virtual cpu 25 * @gra - guest real address 26 * 27 * Returns the guest absolute address that corresponds to the passed guest real 28 * address @gra of a virtual guest cpu by applying its prefix. 29 */ 30 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu, 31 unsigned long gra) 32 { 33 unsigned long prefix = kvm_s390_get_prefix(vcpu); 34 35 if (gra < 2 * PAGE_SIZE) 36 gra += prefix; 37 else if (gra >= prefix && gra < prefix + 2 * PAGE_SIZE) 38 gra -= prefix; 39 return gra; 40 } 41 42 /** 43 * kvm_s390_logical_to_effective - convert guest logical to effective address 44 * @vcpu: guest virtual cpu 45 * @ga: guest logical address 46 * 47 * Convert a guest vcpu logical address to a guest vcpu effective address by 48 * applying the rules of the vcpu's addressing mode defined by PSW bits 31 49 * and 32 (extendended/basic addressing mode). 50 * 51 * Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing 52 * mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode) 53 * of @ga will be zeroed and the remaining bits will be returned. 54 */ 55 static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu, 56 unsigned long ga) 57 { 58 psw_t *psw = &vcpu->arch.sie_block->gpsw; 59 60 if (psw_bits(*psw).eaba == PSW_AMODE_64BIT) 61 return ga; 62 if (psw_bits(*psw).eaba == PSW_AMODE_31BIT) 63 return ga & ((1UL << 31) - 1); 64 return ga & ((1UL << 24) - 1); 65 } 66 67 /* 68 * put_guest_lc, read_guest_lc and write_guest_lc are guest access functions 69 * which shall only be used to access the lowcore of a vcpu. 70 * These functions should be used for e.g. interrupt handlers where no 71 * guest memory access protection facilities, like key or low address 72 * protection, are applicable. 73 * At a later point guest vcpu lowcore access should happen via pinned 74 * prefix pages, so that these pages can be accessed directly via the 75 * kernel mapping. All of these *_lc functions can be removed then. 76 */ 77 78 /** 79 * put_guest_lc - write a simple variable to a guest vcpu's lowcore 80 * @vcpu: virtual cpu 81 * @x: value to copy to guest 82 * @gra: vcpu's destination guest real address 83 * 84 * Copies a simple value from kernel space to a guest vcpu's lowcore. 85 * The size of the variable may be 1, 2, 4 or 8 bytes. The destination 86 * must be located in the vcpu's lowcore. Otherwise the result is undefined. 87 * 88 * Returns zero on success or -EFAULT on error. 89 * 90 * Note: an error indicates that either the kernel is out of memory or 91 * the guest memory mapping is broken. In any case the best solution 92 * would be to terminate the guest. 93 * It is wrong to inject a guest exception. 94 */ 95 #define put_guest_lc(vcpu, x, gra) \ 96 ({ \ 97 struct kvm_vcpu *__vcpu = (vcpu); \ 98 __typeof__(*(gra)) __x = (x); \ 99 unsigned long __gpa; \ 100 \ 101 __gpa = (unsigned long)(gra); \ 102 __gpa += kvm_s390_get_prefix(__vcpu); \ 103 kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \ 104 }) 105 106 /** 107 * write_guest_lc - copy data from kernel space to guest vcpu's lowcore 108 * @vcpu: virtual cpu 109 * @gra: vcpu's source guest real address 110 * @data: source address in kernel space 111 * @len: number of bytes to copy 112 * 113 * Copy data from kernel space to guest vcpu's lowcore. The entire range must 114 * be located within the vcpu's lowcore, otherwise the result is undefined. 115 * 116 * Returns zero on success or -EFAULT on error. 117 * 118 * Note: an error indicates that either the kernel is out of memory or 119 * the guest memory mapping is broken. In any case the best solution 120 * would be to terminate the guest. 121 * It is wrong to inject a guest exception. 122 */ 123 static inline __must_check 124 int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 125 unsigned long len) 126 { 127 unsigned long gpa = gra + kvm_s390_get_prefix(vcpu); 128 129 return kvm_write_guest(vcpu->kvm, gpa, data, len); 130 } 131 132 /** 133 * read_guest_lc - copy data from guest vcpu's lowcore to kernel space 134 * @vcpu: virtual cpu 135 * @gra: vcpu's source guest real address 136 * @data: destination address in kernel space 137 * @len: number of bytes to copy 138 * 139 * Copy data from guest vcpu's lowcore to kernel space. The entire range must 140 * be located within the vcpu's lowcore, otherwise the result is undefined. 141 * 142 * Returns zero on success or -EFAULT on error. 143 * 144 * Note: an error indicates that either the kernel is out of memory or 145 * the guest memory mapping is broken. In any case the best solution 146 * would be to terminate the guest. 147 * It is wrong to inject a guest exception. 148 */ 149 static inline __must_check 150 int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 151 unsigned long len) 152 { 153 unsigned long gpa = gra + kvm_s390_get_prefix(vcpu); 154 155 return kvm_read_guest(vcpu->kvm, gpa, data, len); 156 } 157 158 enum gacc_mode { 159 GACC_FETCH, 160 GACC_STORE, 161 GACC_IFETCH, 162 }; 163 164 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, 165 ar_t ar, unsigned long *gpa, enum gacc_mode mode); 166 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar, 167 unsigned long length, enum gacc_mode mode); 168 169 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data, 170 unsigned long len, enum gacc_mode mode); 171 172 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, 173 void *data, unsigned long len, enum gacc_mode mode); 174 175 /** 176 * write_guest - copy data from kernel space to guest space 177 * @vcpu: virtual cpu 178 * @ga: guest address 179 * @ar: access register 180 * @data: source address in kernel space 181 * @len: number of bytes to copy 182 * 183 * Copy @len bytes from @data (kernel space) to @ga (guest address). 184 * In order to copy data to guest space the PSW of the vcpu is inspected: 185 * If DAT is off data will be copied to guest real or absolute memory. 186 * If DAT is on data will be copied to the address space as specified by 187 * the address space bits of the PSW: 188 * Primary, secondary, home space or access register mode. 189 * The addressing mode of the PSW is also inspected, so that address wrap 190 * around is taken into account for 24-, 31- and 64-bit addressing mode, 191 * if the to be copied data crosses page boundaries in guest address space. 192 * In addition also low address and DAT protection are inspected before 193 * copying any data (key protection is currently not implemented). 194 * 195 * This function modifies the 'struct kvm_s390_pgm_info pgm' member of @vcpu. 196 * In case of an access exception (e.g. protection exception) pgm will contain 197 * all data necessary so that a subsequent call to 'kvm_s390_inject_prog_vcpu()' 198 * will inject a correct exception into the guest. 199 * If no access exception happened, the contents of pgm are undefined when 200 * this function returns. 201 * 202 * Returns: - zero on success 203 * - a negative value if e.g. the guest mapping is broken or in 204 * case of out-of-memory. In this case the contents of pgm are 205 * undefined. Also parts of @data may have been copied to guest 206 * space. 207 * - a positive value if an access exception happened. In this case 208 * the returned value is the program interruption code and the 209 * contents of pgm may be used to inject an exception into the 210 * guest. No data has been copied to guest space. 211 * 212 * Note: in case an access exception is recognized no data has been copied to 213 * guest space (this is also true, if the to be copied data would cross 214 * one or more page boundaries in guest space). 215 * Therefore this function may be used for nullifying and suppressing 216 * instruction emulation. 217 * It may also be used for terminating instructions, if it is undefined 218 * if data has been changed in guest space in case of an exception. 219 */ 220 static inline __must_check 221 int write_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data, 222 unsigned long len) 223 { 224 return access_guest(vcpu, ga, ar, data, len, GACC_STORE); 225 } 226 227 /** 228 * read_guest - copy data from guest space to kernel space 229 * @vcpu: virtual cpu 230 * @ga: guest address 231 * @ar: access register 232 * @data: destination address in kernel space 233 * @len: number of bytes to copy 234 * 235 * Copy @len bytes from @ga (guest address) to @data (kernel space). 236 * 237 * The behaviour of read_guest is identical to write_guest, except that 238 * data will be copied from guest space to kernel space. 239 */ 240 static inline __must_check 241 int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, ar_t ar, void *data, 242 unsigned long len) 243 { 244 return access_guest(vcpu, ga, ar, data, len, GACC_FETCH); 245 } 246 247 /** 248 * read_guest_instr - copy instruction data from guest space to kernel space 249 * @vcpu: virtual cpu 250 * @data: destination address in kernel space 251 * @len: number of bytes to copy 252 * 253 * Copy @len bytes from the current psw address (guest space) to @data (kernel 254 * space). 255 * 256 * The behaviour of read_guest_instr is identical to read_guest, except that 257 * instruction data will be read from primary space when in home-space or 258 * address-space mode. 259 */ 260 static inline __must_check 261 int read_guest_instr(struct kvm_vcpu *vcpu, void *data, unsigned long len) 262 { 263 return access_guest(vcpu, vcpu->arch.sie_block->gpsw.addr, 0, data, len, 264 GACC_IFETCH); 265 } 266 267 /** 268 * write_guest_abs - copy data from kernel space to guest space absolute 269 * @vcpu: virtual cpu 270 * @gpa: guest physical (absolute) address 271 * @data: source address in kernel space 272 * @len: number of bytes to copy 273 * 274 * Copy @len bytes from @data (kernel space) to @gpa (guest absolute address). 275 * It is up to the caller to ensure that the entire guest memory range is 276 * valid memory before calling this function. 277 * Guest low address and key protection are not checked. 278 * 279 * Returns zero on success or -EFAULT on error. 280 * 281 * If an error occurs data may have been copied partially to guest memory. 282 */ 283 static inline __must_check 284 int write_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data, 285 unsigned long len) 286 { 287 return kvm_write_guest(vcpu->kvm, gpa, data, len); 288 } 289 290 /** 291 * read_guest_abs - copy data from guest space absolute to kernel space 292 * @vcpu: virtual cpu 293 * @gpa: guest physical (absolute) address 294 * @data: destination address in kernel space 295 * @len: number of bytes to copy 296 * 297 * Copy @len bytes from @gpa (guest absolute address) to @data (kernel space). 298 * It is up to the caller to ensure that the entire guest memory range is 299 * valid memory before calling this function. 300 * Guest key protection is not checked. 301 * 302 * Returns zero on success or -EFAULT on error. 303 * 304 * If an error occurs data may have been copied partially to kernel space. 305 */ 306 static inline __must_check 307 int read_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data, 308 unsigned long len) 309 { 310 return kvm_read_guest(vcpu->kvm, gpa, data, len); 311 } 312 313 /** 314 * write_guest_real - copy data from kernel space to guest space real 315 * @vcpu: virtual cpu 316 * @gra: guest real address 317 * @data: source address in kernel space 318 * @len: number of bytes to copy 319 * 320 * Copy @len bytes from @data (kernel space) to @gra (guest real address). 321 * It is up to the caller to ensure that the entire guest memory range is 322 * valid memory before calling this function. 323 * Guest low address and key protection are not checked. 324 * 325 * Returns zero on success or -EFAULT on error. 326 * 327 * If an error occurs data may have been copied partially to guest memory. 328 */ 329 static inline __must_check 330 int write_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 331 unsigned long len) 332 { 333 return access_guest_real(vcpu, gra, data, len, 1); 334 } 335 336 /** 337 * read_guest_real - copy data from guest space real to kernel space 338 * @vcpu: virtual cpu 339 * @gra: guest real address 340 * @data: destination address in kernel space 341 * @len: number of bytes to copy 342 * 343 * Copy @len bytes from @gra (guest real address) to @data (kernel space). 344 * It is up to the caller to ensure that the entire guest memory range is 345 * valid memory before calling this function. 346 * Guest key protection is not checked. 347 * 348 * Returns zero on success or -EFAULT on error. 349 * 350 * If an error occurs data may have been copied partially to kernel space. 351 */ 352 static inline __must_check 353 int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 354 unsigned long len) 355 { 356 return access_guest_real(vcpu, gra, data, len, 0); 357 } 358 359 void ipte_lock(struct kvm_vcpu *vcpu); 360 void ipte_unlock(struct kvm_vcpu *vcpu); 361 int ipte_lock_held(struct kvm_vcpu *vcpu); 362 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra); 363 364 #endif /* __KVM_S390_GACCESS_H */ 365