arch/s390/kvm/gaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * access guest memory
   4  *
   5  * Copyright IBM Corp. 2008, 2014
   6  *
   7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
   8  */
   9
  10 #ifndef __KVM_S390_GACCESS_H
  11 #define __KVM_S390_GACCESS_H
  12
  13 #include <linux/compiler.h>
  14 #include <linux/kvm_host.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/ptrace.h>
  17 #include "kvm-s390.h"
  18
  19 /**
  20  * kvm_s390_real_to_abs - convert guest real address to guest absolute address
  21  * @vcpu - guest virtual cpu
  22  * @gra - guest real address
  23  *
  24  * Returns the guest absolute address that corresponds to the passed guest real
  25  * address @gra of a virtual guest cpu by applying its prefix.
  26  */
  27 static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
  28                                                  unsigned long gra)
  29 {
  30         unsigned long prefix  = kvm_s390_get_prefix(vcpu);
  31
  32         if (gra < 2 * PAGE_SIZE)
  33                 gra += prefix;
  34         else if (gra >= prefix && gra < prefix + 2 * PAGE_SIZE)
  35                 gra -= prefix;
  36         return gra;
  37 }
  38
  39 /**
  40  * kvm_s390_logical_to_effective - convert guest logical to effective address
  41  * @vcpu: guest virtual cpu
  42  * @ga: guest logical address
  43  *
  44  * Convert a guest vcpu logical address to a guest vcpu effective address by
  45  * applying the rules of the vcpu's addressing mode defined by PSW bits 31
  46  * and 32 (extendended/basic addressing mode).
  47  *
  48  * Depending on the vcpu's addressing mode the upper 40 bits (24 bit addressing
  49  * mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing mode)
  50  * of @ga will be zeroed and the remaining bits will be returned.
  51  */
  52 static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
  53                                                           unsigned long ga)
  54 {
  55         psw_t *psw = &vcpu->arch.sie_block->gpsw;
  56
  57         if (psw_bits(*psw).eaba == PSW_BITS_AMODE_64BIT)
  58                 return ga;
  59         if (psw_bits(*psw).eaba == PSW_BITS_AMODE_31BIT)
  60                 return ga & ((1UL << 31) - 1);
  61         return ga & ((1UL << 24) - 1);
  62 }
  63
  64 /*
  65  * put_guest_lc, read_guest_lc and write_guest_lc are guest access functions
  66  * which shall only be used to access the lowcore of a vcpu.
  67  * These functions should be used for e.g. interrupt handlers where no
  68  * guest memory access protection facilities, like key or low address
  69  * protection, are applicable.
  70  * At a later point guest vcpu lowcore access should happen via pinned
  71  * prefix pages, so that these pages can be accessed directly via the
  72  * kernel mapping. All of these *_lc functions can be removed then.
  73  */
  74
  75 /**
  76  * put_guest_lc - write a simple variable to a guest vcpu's lowcore
  77  * @vcpu: virtual cpu
  78  * @x: value to copy to guest
  79  * @gra: vcpu's destination guest real address
  80  *
  81  * Copies a simple value from kernel space to a guest vcpu's lowcore.
  82  * The size of the variable may be 1, 2, 4 or 8 bytes. The destination
  83  * must be located in the vcpu's lowcore. Otherwise the result is undefined.
  84  *
  85  * Returns zero on success or -EFAULT on error.
  86  *
  87  * Note: an error indicates that either the kernel is out of memory or
  88  *       the guest memory mapping is broken. In any case the best solution
  89  *       would be to terminate the guest.
  90  *       It is wrong to inject a guest exception.
  91  */
  92 #define put_guest_lc(vcpu, x, gra)                              \
  93 ({                                                              \
  94         struct kvm_vcpu *__vcpu = (vcpu);                       \
  95         __typeof__(*(gra)) __x = (x);                           \
  96         unsigned long __gpa;                                    \
  97                                                                 \
  98         __gpa = (unsigned long)(gra);                           \
  99         __gpa += kvm_s390_get_prefix(__vcpu);                   \
 100         kvm_write_guest(__vcpu->kvm, __gpa, &__x, sizeof(__x)); \
 101 })
 102
 103 /**
 104  * write_guest_lc - copy data from kernel space to guest vcpu's lowcore
 105  * @vcpu: virtual cpu
 106  * @gra: vcpu's source guest real address
 107  * @data: source address in kernel space
 108  * @len: number of bytes to copy
 109  *
 110  * Copy data from kernel space to guest vcpu's lowcore. The entire range must
 111  * be located within the vcpu's lowcore, otherwise the result is undefined.
 112  *
 113  * Returns zero on success or -EFAULT on error.
 114  *
 115  * Note: an error indicates that either the kernel is out of memory or
 116  *       the guest memory mapping is broken. In any case the best solution
 117  *       would be to terminate the guest.
 118  *       It is wrong to inject a guest exception.
 119  */
 120 static inline __must_check
 121 int write_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 122                    unsigned long len)
 123 {
 124         unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
 125
 126         return kvm_write_guest(vcpu->kvm, gpa, data, len);
 127 }
 128
 129 /**
 130  * read_guest_lc - copy data from guest vcpu's lowcore to kernel space
 131  * @vcpu: virtual cpu
 132  * @gra: vcpu's source guest real address
 133  * @data: destination address in kernel space
 134  * @len: number of bytes to copy
 135  *
 136  * Copy data from guest vcpu's lowcore to kernel space. The entire range must
 137  * be located within the vcpu's lowcore, otherwise the result is undefined.
 138  *
 139  * Returns zero on success or -EFAULT on error.
 140  *
 141  * Note: an error indicates that either the kernel is out of memory or
 142  *       the guest memory mapping is broken. In any case the best solution
 143  *       would be to terminate the guest.
 144  *       It is wrong to inject a guest exception.
 145  */
 146 static inline __must_check
 147 int read_guest_lc(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 148                   unsigned long len)
 149 {
 150         unsigned long gpa = gra + kvm_s390_get_prefix(vcpu);
 151
 152         return kvm_read_guest(vcpu->kvm, gpa, data, len);
 153 }
 154
 155 enum gacc_mode {
 156         GACC_FETCH,
 157         GACC_STORE,
 158         GACC_IFETCH,
 159 };
 160
 161 int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva,
 162                             u8 ar, unsigned long *gpa, enum gacc_mode mode);
 163 int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, u8 ar,
 164                     unsigned long length, enum gacc_mode mode);
 165
 166 int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
 167                  unsigned long len, enum gacc_mode mode);
 168
 169 int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
 170                       void *data, unsigned long len, enum gacc_mode mode);
 171
 172 /**
 173  * write_guest - copy data from kernel space to guest space
 174  * @vcpu: virtual cpu
 175  * @ga: guest address
 176  * @ar: access register
 177  * @data: source address in kernel space
 178  * @len: number of bytes to copy
 179  *
 180  * Copy @len bytes from @data (kernel space) to @ga (guest address).
 181  * In order to copy data to guest space the PSW of the vcpu is inspected:
 182  * If DAT is off data will be copied to guest real or absolute memory.
 183  * If DAT is on data will be copied to the address space as specified by
 184  * the address space bits of the PSW:
 185  * Primary, secondary, home space or access register mode.
 186  * The addressing mode of the PSW is also inspected, so that address wrap
 187  * around is taken into account for 24-, 31- and 64-bit addressing mode,
 188  * if the to be copied data crosses page boundaries in guest address space.
 189  * In addition also low address and DAT protection are inspected before
 190  * copying any data (key protection is currently not implemented).
 191  *
 192  * This function modifies the 'struct kvm_s390_pgm_info pgm' member of @vcpu.
 193  * In case of an access exception (e.g. protection exception) pgm will contain
 194  * all data necessary so that a subsequent call to 'kvm_s390_inject_prog_vcpu()'
 195  * will inject a correct exception into the guest.
 196  * If no access exception happened, the contents of pgm are undefined when
 197  * this function returns.
 198  *
 199  * Returns:  - zero on success
 200  *           - a negative value if e.g. the guest mapping is broken or in
 201  *             case of out-of-memory. In this case the contents of pgm are
 202  *             undefined. Also parts of @data may have been copied to guest
 203  *             space.
 204  *           - a positive value if an access exception happened. In this case
 205  *             the returned value is the program interruption code and the
 206  *             contents of pgm may be used to inject an exception into the
 207  *             guest. No data has been copied to guest space.
 208  *
 209  * Note: in case an access exception is recognized no data has been copied to
 210  *       guest space (this is also true, if the to be copied data would cross
 211  *       one or more page boundaries in guest space).
 212  *       Therefore this function may be used for nullifying and suppressing
 213  *       instruction emulation.
 214  *       It may also be used for terminating instructions, if it is undefined
 215  *       if data has been changed in guest space in case of an exception.
 216  */
 217 static inline __must_check
 218 int write_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
 219                 unsigned long len)
 220 {
 221         return access_guest(vcpu, ga, ar, data, len, GACC_STORE);
 222 }
 223
 224 /**
 225  * read_guest - copy data from guest space to kernel space
 226  * @vcpu: virtual cpu
 227  * @ga: guest address
 228  * @ar: access register
 229  * @data: destination address in kernel space
 230  * @len: number of bytes to copy
 231  *
 232  * Copy @len bytes from @ga (guest address) to @data (kernel space).
 233  *
 234  * The behaviour of read_guest is identical to write_guest, except that
 235  * data will be copied from guest space to kernel space.
 236  */
 237 static inline __must_check
 238 int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
 239                unsigned long len)
 240 {
 241         return access_guest(vcpu, ga, ar, data, len, GACC_FETCH);
 242 }
 243
 244 /**
 245  * read_guest_instr - copy instruction data from guest space to kernel space
 246  * @vcpu: virtual cpu
 247  * @ga: guest address
 248  * @data: destination address in kernel space
 249  * @len: number of bytes to copy
 250  *
 251  * Copy @len bytes from the given address (guest space) to @data (kernel
 252  * space).
 253  *
 254  * The behaviour of read_guest_instr is identical to read_guest, except that
 255  * instruction data will be read from primary space when in home-space or
 256  * address-space mode.
 257  */
 258 static inline __must_check
 259 int read_guest_instr(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
 260                      unsigned long len)
 261 {
 262         return access_guest(vcpu, ga, 0, data, len, GACC_IFETCH);
 263 }
 264
 265 /**
 266  * write_guest_abs - copy data from kernel space to guest space absolute
 267  * @vcpu: virtual cpu
 268  * @gpa: guest physical (absolute) address
 269  * @data: source address in kernel space
 270  * @len: number of bytes to copy
 271  *
 272  * Copy @len bytes from @data (kernel space) to @gpa (guest absolute address).
 273  * It is up to the caller to ensure that the entire guest memory range is
 274  * valid memory before calling this function.
 275  * Guest low address and key protection are not checked.
 276  *
 277  * Returns zero on success or -EFAULT on error.
 278  *
 279  * If an error occurs data may have been copied partially to guest memory.
 280  */
 281 static inline __must_check
 282 int write_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
 283                     unsigned long len)
 284 {
 285         return kvm_write_guest(vcpu->kvm, gpa, data, len);
 286 }
 287
 288 /**
 289  * read_guest_abs - copy data from guest space absolute to kernel space
 290  * @vcpu: virtual cpu
 291  * @gpa: guest physical (absolute) address
 292  * @data: destination address in kernel space
 293  * @len: number of bytes to copy
 294  *
 295  * Copy @len bytes from @gpa (guest absolute address) to @data (kernel space).
 296  * It is up to the caller to ensure that the entire guest memory range is
 297  * valid memory before calling this function.
 298  * Guest key protection is not checked.
 299  *
 300  * Returns zero on success or -EFAULT on error.
 301  *
 302  * If an error occurs data may have been copied partially to kernel space.
 303  */
 304 static inline __must_check
 305 int read_guest_abs(struct kvm_vcpu *vcpu, unsigned long gpa, void *data,
 306                    unsigned long len)
 307 {
 308         return kvm_read_guest(vcpu->kvm, gpa, data, len);
 309 }
 310
 311 /**
 312  * write_guest_real - copy data from kernel space to guest space real
 313  * @vcpu: virtual cpu
 314  * @gra: guest real address
 315  * @data: source address in kernel space
 316  * @len: number of bytes to copy
 317  *
 318  * Copy @len bytes from @data (kernel space) to @gra (guest real address).
 319  * It is up to the caller to ensure that the entire guest memory range is
 320  * valid memory before calling this function.
 321  * Guest low address and key protection are not checked.
 322  *
 323  * Returns zero on success or -EFAULT on error.
 324  *
 325  * If an error occurs data may have been copied partially to guest memory.
 326  */
 327 static inline __must_check
 328 int write_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 329                      unsigned long len)
 330 {
 331         return access_guest_real(vcpu, gra, data, len, 1);
 332 }
 333
 334 /**
 335  * read_guest_real - copy data from guest space real to kernel space
 336  * @vcpu: virtual cpu
 337  * @gra: guest real address
 338  * @data: destination address in kernel space
 339  * @len: number of bytes to copy
 340  *
 341  * Copy @len bytes from @gra (guest real address) to @data (kernel space).
 342  * It is up to the caller to ensure that the entire guest memory range is
 343  * valid memory before calling this function.
 344  * Guest key protection is not checked.
 345  *
 346  * Returns zero on success or -EFAULT on error.
 347  *
 348  * If an error occurs data may have been copied partially to kernel space.
 349  */
 350 static inline __must_check
 351 int read_guest_real(struct kvm_vcpu *vcpu, unsigned long gra, void *data,
 352                     unsigned long len)
 353 {
 354         return access_guest_real(vcpu, gra, data, len, 0);
 355 }
 356
 357 void ipte_lock(struct kvm_vcpu *vcpu);
 358 void ipte_unlock(struct kvm_vcpu *vcpu);
 359 int ipte_lock_held(struct kvm_vcpu *vcpu);
 360 int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);
 361
 362 int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *shadow,
 363                           unsigned long saddr);
 364
 365 #endif /* __KVM_S390_GACCESS_H */