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 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, 159 unsigned long *gpa, int write); 160 161 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, 162 unsigned long len, int write); 163 164 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, 165 void *data, unsigned long len, int write); 166 167 /** 168 * write_guest - copy data from kernel space to guest space 169 * @vcpu: virtual cpu 170 * @ga: guest address 171 * @data: source address in kernel space 172 * @len: number of bytes to copy 173 * 174 * Copy @len bytes from @data (kernel space) to @ga (guest address). 175 * In order to copy data to guest space the PSW of the vcpu is inspected: 176 * If DAT is off data will be copied to guest real or absolute memory. 177 * If DAT is on data will be copied to the address space as specified by 178 * the address space bits of the PSW: 179 * Primary, secondory or home space (access register mode is currently not 180 * implemented). 181 * The addressing mode of the PSW is also inspected, so that address wrap 182 * around is taken into account for 24-, 31- and 64-bit addressing mode, 183 * if the to be copied data crosses page boundaries in guest address space. 184 * In addition also low address and DAT protection are inspected before 185 * copying any data (key protection is currently not implemented). 186 * 187 * This function modifies the 'struct kvm_s390_pgm_info pgm' member of @vcpu. 188 * In case of an access exception (e.g. protection exception) pgm will contain 189 * all data necessary so that a subsequent call to 'kvm_s390_inject_prog_vcpu()' 190 * will inject a correct exception into the guest. 191 * If no access exception happened, the contents of pgm are undefined when 192 * this function returns. 193 * 194 * Returns: - zero on success 195 * - a negative value if e.g. the guest mapping is broken or in 196 * case of out-of-memory. In this case the contents of pgm are 197 * undefined. Also parts of @data may have been copied to guest 198 * space. 199 * - a positive value if an access exception happened. In this case 200 * the returned value is the program interruption code and the 201 * contents of pgm may be used to inject an exception into the 202 * guest. No data has been copied to guest space. 203 * 204 * Note: in case an access exception is recognized no data has been copied to 205 * guest space (this is also true, if the to be copied data would cross 206 * one or more page boundaries in guest space). 207 * Therefore this function may be used for nullifying and suppressing 208 * instruction emulation. 209 * It may also be used for terminating instructions, if it is undefined 210 * if data has been changed in guest space in case of an exception. 211 */ 212 static inline __must_check 213 int write_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, 214 unsigned long len) 215 { 216 return access_guest(vcpu, ga, data, len, 1); 217 } 218 219 /** 220 * read_guest - copy data from guest space to kernel space 221 * @vcpu: virtual cpu 222 * @ga: guest address 223 * @data: destination address in kernel space 224 * @len: number of bytes to copy 225 * 226 * Copy @len bytes from @ga (guest address) to @data (kernel space). 227 * 228 * The behaviour of read_guest is identical to write_guest, except that 229 * data will be copied from guest space to kernel space. 230 */ 231 static inline __must_check 232 int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data, 233 unsigned long len) 234 { 235 return access_guest(vcpu, ga, data, len, 0); 236 } 237 238 /** 239 * write_guest_abs - copy data from kernel space to guest space absolute 240 * @vcpu: virtual cpu 241 * @gpa: guest physical (absolute) address 242 * @data: source address in kernel space 243 * @len: number of bytes to copy 244 * 245 * Copy @len bytes from @data (kernel space) to @gpa (guest absolute address). 246 * It is up to the caller to ensure that the entire guest memory range is 247 * valid memory before calling this function. 248 * Guest low address and key protection are not checked. 249 * 250 * Returns zero on success or -EFAULT on error. 251 * 252 * If an error occurs data may have been copied partially to guest memory. 253 */ 254 static inline __must_check 255 int write_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data, 256 unsigned long len) 257 { 258 return kvm_write_guest(vcpu->kvm, gpa, data, len); 259 } 260 261 /** 262 * read_guest_abs - copy data from guest space absolute to kernel space 263 * @vcpu: virtual cpu 264 * @gpa: guest physical (absolute) address 265 * @data: destination address in kernel space 266 * @len: number of bytes to copy 267 * 268 * Copy @len bytes from @gpa (guest absolute address) to @data (kernel space). 269 * It is up to the caller to ensure that the entire guest memory range is 270 * valid memory before calling this function. 271 * Guest key protection is not checked. 272 * 273 * Returns zero on success or -EFAULT on error. 274 * 275 * If an error occurs data may have been copied partially to kernel space. 276 */ 277 static inline __must_check 278 int read_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data, 279 unsigned long len) 280 { 281 return kvm_read_guest(vcpu->kvm, gpa, data, len); 282 } 283 284 /** 285 * write_guest_real - copy data from kernel space to guest space real 286 * @vcpu: virtual cpu 287 * @gra: guest real address 288 * @data: source address in kernel space 289 * @len: number of bytes to copy 290 * 291 * Copy @len bytes from @data (kernel space) to @gra (guest real address). 292 * It is up to the caller to ensure that the entire guest memory range is 293 * valid memory before calling this function. 294 * Guest low address and key protection are not checked. 295 * 296 * Returns zero on success or -EFAULT on error. 297 * 298 * If an error occurs data may have been copied partially to guest memory. 299 */ 300 static inline __must_check 301 int write_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 302 unsigned long len) 303 { 304 return access_guest_real(vcpu, gra, data, len, 1); 305 } 306 307 /** 308 * read_guest_real - copy data from guest space real to kernel space 309 * @vcpu: virtual cpu 310 * @gra: guest real address 311 * @data: destination address in kernel space 312 * @len: number of bytes to copy 313 * 314 * Copy @len bytes from @gra (guest real address) to @data (kernel space). 315 * It is up to the caller to ensure that the entire guest memory range is 316 * valid memory before calling this function. 317 * Guest key protection is not checked. 318 * 319 * Returns zero on success or -EFAULT on error. 320 * 321 * If an error occurs data may have been copied partially to kernel space. 322 */ 323 static inline __must_check 324 int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data, 325 unsigned long len) 326 { 327 return access_guest_real(vcpu, gra, data, len, 0); 328 } 329 330 void ipte_lock(struct kvm_vcpu *vcpu); 331 void ipte_unlock(struct kvm_vcpu *vcpu); 332 int ipte_lock_held(struct kvm_vcpu *vcpu); 333 int kvm_s390_check_low_addr_protection(struct kvm_vcpu *vcpu, unsigned long ga); 334 335 #endif /* __KVM_S390_GACCESS_H */ 336