arch/s390/kvm/guestdbg.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * kvm guest debug support
   4  *
   5  * Copyright IBM Corp. 2014
   6  *
   7  *    Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
   8  */
   9 #include <linux/kvm_host.h>
  10 #include <linux/errno.h>
  11 #include "kvm-s390.h"
  12 #include "gaccess.h"
  13
  14 /*
  15  * Extends the address range given by *start and *stop to include the address
  16  * range starting with estart and the length len. Takes care of overflowing
  17  * intervals and tries to minimize the overall interval size.
  18  */
  19 static void extend_address_range(u64 *start, u64 *stop, u64 estart, int len)
  20 {
  21         u64 estop;
  22
  23         if (len > 0)
  24                 len--;
  25         else
  26                 len = 0;
  27
  28         estop = estart + len;
  29
  30         /* 0-0 range represents "not set" */
  31         if ((*start == 0) && (*stop == 0)) {
  32                 *start = estart;
  33                 *stop = estop;
  34         } else if (*start <= *stop) {
  35                 /* increase the existing range */
  36                 if (estart < *start)
  37                         *start = estart;
  38                 if (estop > *stop)
  39                         *stop = estop;
  40         } else {
  41                 /* "overflowing" interval, whereby *stop > *start */
  42                 if (estart <= *stop) {
  43                         if (estop > *stop)
  44                                 *stop = estop;
  45                 } else if (estop > *start) {
  46                         if (estart < *start)
  47                                 *start = estart;
  48                 }
  49                 /* minimize the range */
  50                 else if ((estop - *stop) < (*start - estart))
  51                         *stop = estop;
  52                 else
  53                         *start = estart;
  54         }
  55 }
  56
  57 #define MAX_INST_SIZE 6
  58
  59 static void enable_all_hw_bp(struct kvm_vcpu *vcpu)
  60 {
  61         unsigned long start, len;
  62         u64 *cr9 = &vcpu->arch.sie_block->gcr[9];
  63         u64 *cr10 = &vcpu->arch.sie_block->gcr[10];
  64         u64 *cr11 = &vcpu->arch.sie_block->gcr[11];
  65         int i;
  66
  67         if (vcpu->arch.guestdbg.nr_hw_bp <= 0 ||
  68             vcpu->arch.guestdbg.hw_bp_info == NULL)
  69                 return;
  70
  71         /*
  72          * If the guest is not interested in branching events, we can safely
  73          * limit them to the PER address range.
  74          */
  75         if (!(*cr9 & PER_EVENT_BRANCH))
  76                 *cr9 |= PER_CONTROL_BRANCH_ADDRESS;
  77         *cr9 |= PER_EVENT_IFETCH | PER_EVENT_BRANCH;
  78
  79         for (i = 0; i < vcpu->arch.guestdbg.nr_hw_bp; i++) {
  80                 start = vcpu->arch.guestdbg.hw_bp_info[i].addr;
  81                 len = vcpu->arch.guestdbg.hw_bp_info[i].len;
  82
  83                 /*
  84                  * The instruction in front of the desired bp has to
  85                  * report instruction-fetching events
  86                  */
  87                 if (start < MAX_INST_SIZE) {
  88                         len += start;
  89                         start = 0;
  90                 } else {
  91                         start -= MAX_INST_SIZE;
  92                         len += MAX_INST_SIZE;
  93                 }
  94
  95                 extend_address_range(cr10, cr11, start, len);
  96         }
  97 }
  98
  99 static void enable_all_hw_wp(struct kvm_vcpu *vcpu)
 100 {
 101         unsigned long start, len;
 102         u64 *cr9 = &vcpu->arch.sie_block->gcr[9];
 103         u64 *cr10 = &vcpu->arch.sie_block->gcr[10];
 104         u64 *cr11 = &vcpu->arch.sie_block->gcr[11];
 105         int i;
 106
 107         if (vcpu->arch.guestdbg.nr_hw_wp <= 0 ||
 108             vcpu->arch.guestdbg.hw_wp_info == NULL)
 109                 return;
 110
 111         /* if host uses storage alternation for special address
 112          * spaces, enable all events and give all to the guest */
 113         if (*cr9 & PER_EVENT_STORE && *cr9 & PER_CONTROL_ALTERATION) {
 114                 *cr9 &= ~PER_CONTROL_ALTERATION;
 115                 *cr10 = 0;
 116                 *cr11 = -1UL;
 117         } else {
 118                 *cr9 &= ~PER_CONTROL_ALTERATION;
 119                 *cr9 |= PER_EVENT_STORE;
 120
 121                 for (i = 0; i < vcpu->arch.guestdbg.nr_hw_wp; i++) {
 122                         start = vcpu->arch.guestdbg.hw_wp_info[i].addr;
 123                         len = vcpu->arch.guestdbg.hw_wp_info[i].len;
 124
 125                         extend_address_range(cr10, cr11, start, len);
 126                 }
 127         }
 128 }
 129
 130 void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu)
 131 {
 132         vcpu->arch.guestdbg.cr0 = vcpu->arch.sie_block->gcr[0];
 133         vcpu->arch.guestdbg.cr9 = vcpu->arch.sie_block->gcr[9];
 134         vcpu->arch.guestdbg.cr10 = vcpu->arch.sie_block->gcr[10];
 135         vcpu->arch.guestdbg.cr11 = vcpu->arch.sie_block->gcr[11];
 136 }
 137
 138 void kvm_s390_restore_guest_per_regs(struct kvm_vcpu *vcpu)
 139 {
 140         vcpu->arch.sie_block->gcr[0] = vcpu->arch.guestdbg.cr0;
 141         vcpu->arch.sie_block->gcr[9] = vcpu->arch.guestdbg.cr9;
 142         vcpu->arch.sie_block->gcr[10] = vcpu->arch.guestdbg.cr10;
 143         vcpu->arch.sie_block->gcr[11] = vcpu->arch.guestdbg.cr11;
 144 }
 145
 146 void kvm_s390_patch_guest_per_regs(struct kvm_vcpu *vcpu)
 147 {
 148         /*
 149          * TODO: if guest psw has per enabled, otherwise 0s!
 150          * This reduces the amount of reported events.
 151          * Need to intercept all psw changes!
 152          */
 153
 154         if (guestdbg_sstep_enabled(vcpu)) {
 155                 /* disable timer (clock-comparator) interrupts */
 156                 vcpu->arch.sie_block->gcr[0] &= ~CR0_CLOCK_COMPARATOR_SUBMASK;
 157                 vcpu->arch.sie_block->gcr[9] |= PER_EVENT_IFETCH;
 158                 vcpu->arch.sie_block->gcr[10] = 0;
 159                 vcpu->arch.sie_block->gcr[11] = -1UL;
 160         }
 161
 162         if (guestdbg_hw_bp_enabled(vcpu)) {
 163                 enable_all_hw_bp(vcpu);
 164                 enable_all_hw_wp(vcpu);
 165         }
 166
 167         /* TODO: Instruction-fetching-nullification not allowed for now */
 168         if (vcpu->arch.sie_block->gcr[9] & PER_EVENT_NULLIFICATION)
 169                 vcpu->arch.sie_block->gcr[9] &= ~PER_EVENT_NULLIFICATION;
 170 }
 171
 172 #define MAX_WP_SIZE 100
 173
 174 static int __import_wp_info(struct kvm_vcpu *vcpu,
 175                             struct kvm_hw_breakpoint *bp_data,
 176                             struct kvm_hw_wp_info_arch *wp_info)
 177 {
 178         int ret = 0;
 179         wp_info->len = bp_data->len;
 180         wp_info->addr = bp_data->addr;
 181         wp_info->phys_addr = bp_data->phys_addr;
 182         wp_info->old_data = NULL;
 183
 184         if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE)
 185                 return -EINVAL;
 186
 187         wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL_ACCOUNT);
 188         if (!wp_info->old_data)
 189                 return -ENOMEM;
 190         /* try to backup the original value */
 191         ret = read_guest_abs(vcpu, wp_info->phys_addr, wp_info->old_data,
 192                              wp_info->len);
 193         if (ret) {
 194                 kfree(wp_info->old_data);
 195                 wp_info->old_data = NULL;
 196         }
 197
 198         return ret;
 199 }
 200
 201 #define MAX_BP_COUNT 50
 202
 203 int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu,
 204                             struct kvm_guest_debug *dbg)
 205 {
 206         int ret = 0, nr_wp = 0, nr_bp = 0, i;
 207         struct kvm_hw_breakpoint *bp_data = NULL;
 208         struct kvm_hw_wp_info_arch *wp_info = NULL;
 209         struct kvm_hw_bp_info_arch *bp_info = NULL;
 210
 211         if (dbg->arch.nr_hw_bp <= 0 || !dbg->arch.hw_bp)
 212                 return 0;
 213         else if (dbg->arch.nr_hw_bp > MAX_BP_COUNT)
 214                 return -EINVAL;
 215
 216         bp_data = memdup_user(dbg->arch.hw_bp,
 217                               sizeof(*bp_data) * dbg->arch.nr_hw_bp);
 218         if (IS_ERR(bp_data))
 219                 return PTR_ERR(bp_data);
 220
 221         for (i = 0; i < dbg->arch.nr_hw_bp; i++) {
 222                 switch (bp_data[i].type) {
 223                 case KVM_HW_WP_WRITE:
 224                         nr_wp++;
 225                         break;
 226                 case KVM_HW_BP:
 227                         nr_bp++;
 228                         break;
 229                 default:
 230                         break;
 231                 }
 232         }
 233
 234         if (nr_wp > 0) {
 235                 wp_info = kmalloc_array(nr_wp,
 236                                         sizeof(*wp_info),
 237                                         GFP_KERNEL_ACCOUNT);
 238                 if (!wp_info) {
 239                         ret = -ENOMEM;
 240                         goto error;
 241                 }
 242         }
 243         if (nr_bp > 0) {
 244                 bp_info = kmalloc_array(nr_bp,
 245                                         sizeof(*bp_info),
 246                                         GFP_KERNEL_ACCOUNT);
 247                 if (!bp_info) {
 248                         ret = -ENOMEM;
 249                         goto error;
 250                 }
 251         }
 252
 253         for (nr_wp = 0, nr_bp = 0, i = 0; i < dbg->arch.nr_hw_bp; i++) {
 254                 switch (bp_data[i].type) {
 255                 case KVM_HW_WP_WRITE:
 256                         ret = __import_wp_info(vcpu, &bp_data[i],
 257                                                &wp_info[nr_wp]);
 258                         if (ret)
 259                                 goto error;
 260                         nr_wp++;
 261                         break;
 262                 case KVM_HW_BP:
 263                         bp_info[nr_bp].len = bp_data[i].len;
 264                         bp_info[nr_bp].addr = bp_data[i].addr;
 265                         nr_bp++;
 266                         break;
 267                 }
 268         }
 269
 270         vcpu->arch.guestdbg.nr_hw_bp = nr_bp;
 271         vcpu->arch.guestdbg.hw_bp_info = bp_info;
 272         vcpu->arch.guestdbg.nr_hw_wp = nr_wp;
 273         vcpu->arch.guestdbg.hw_wp_info = wp_info;
 274         return 0;
 275 error:
 276         kfree(bp_data);
 277         kfree(wp_info);
 278         kfree(bp_info);
 279         return ret;
 280 }
 281
 282 void kvm_s390_clear_bp_data(struct kvm_vcpu *vcpu)
 283 {
 284         int i;
 285         struct kvm_hw_wp_info_arch *hw_wp_info = NULL;
 286
 287         for (i = 0; i < vcpu->arch.guestdbg.nr_hw_wp; i++) {
 288                 hw_wp_info = &vcpu->arch.guestdbg.hw_wp_info[i];
 289                 kfree(hw_wp_info->old_data);
 290                 hw_wp_info->old_data = NULL;
 291         }
 292         kfree(vcpu->arch.guestdbg.hw_wp_info);
 293         vcpu->arch.guestdbg.hw_wp_info = NULL;
 294
 295         kfree(vcpu->arch.guestdbg.hw_bp_info);
 296         vcpu->arch.guestdbg.hw_bp_info = NULL;
 297
 298         vcpu->arch.guestdbg.nr_hw_wp = 0;
 299         vcpu->arch.guestdbg.nr_hw_bp = 0;
 300 }
 301
 302 static inline int in_addr_range(u64 addr, u64 a, u64 b)
 303 {
 304         if (a <= b)
 305                 return (addr >= a) && (addr <= b);
 306         else
 307                 /* "overflowing" interval */
 308                 return (addr >= a) || (addr <= b);
 309 }
 310
 311 #define end_of_range(bp_info) (bp_info->addr + bp_info->len - 1)
 312
 313 static struct kvm_hw_bp_info_arch *find_hw_bp(struct kvm_vcpu *vcpu,
 314                                               unsigned long addr)
 315 {
 316         struct kvm_hw_bp_info_arch *bp_info = vcpu->arch.guestdbg.hw_bp_info;
 317         int i;
 318
 319         if (vcpu->arch.guestdbg.nr_hw_bp == 0)
 320                 return NULL;
 321
 322         for (i = 0; i < vcpu->arch.guestdbg.nr_hw_bp; i++) {
 323                 /* addr is directly the start or in the range of a bp */
 324                 if (addr == bp_info->addr)
 325                         goto found;
 326                 if (bp_info->len > 0 &&
 327                     in_addr_range(addr, bp_info->addr, end_of_range(bp_info)))
 328                         goto found;
 329
 330                 bp_info++;
 331         }
 332
 333         return NULL;
 334 found:
 335         return bp_info;
 336 }
 337
 338 static struct kvm_hw_wp_info_arch *any_wp_changed(struct kvm_vcpu *vcpu)
 339 {
 340         int i;
 341         struct kvm_hw_wp_info_arch *wp_info = NULL;
 342         void *temp = NULL;
 343
 344         if (vcpu->arch.guestdbg.nr_hw_wp == 0)
 345                 return NULL;
 346
 347         for (i = 0; i < vcpu->arch.guestdbg.nr_hw_wp; i++) {
 348                 wp_info = &vcpu->arch.guestdbg.hw_wp_info[i];
 349                 if (!wp_info || !wp_info->old_data || wp_info->len <= 0)
 350                         continue;
 351
 352                 temp = kmalloc(wp_info->len, GFP_KERNEL_ACCOUNT);
 353                 if (!temp)
 354                         continue;
 355
 356                 /* refetch the wp data and compare it to the old value */
 357                 if (!read_guest_abs(vcpu, wp_info->phys_addr, temp,
 358                                     wp_info->len)) {
 359                         if (memcmp(temp, wp_info->old_data, wp_info->len)) {
 360                                 kfree(temp);
 361                                 return wp_info;
 362                         }
 363                 }
 364                 kfree(temp);
 365                 temp = NULL;
 366         }
 367
 368         return NULL;
 369 }
 370
 371 void kvm_s390_prepare_debug_exit(struct kvm_vcpu *vcpu)
 372 {
 373         vcpu->run->exit_reason = KVM_EXIT_DEBUG;
 374         vcpu->guest_debug &= ~KVM_GUESTDBG_EXIT_PENDING;
 375 }
 376
 377 #define PER_CODE_MASK           (PER_EVENT_MASK >> 24)
 378 #define PER_CODE_BRANCH         (PER_EVENT_BRANCH >> 24)
 379 #define PER_CODE_IFETCH         (PER_EVENT_IFETCH >> 24)
 380 #define PER_CODE_STORE          (PER_EVENT_STORE >> 24)
 381 #define PER_CODE_STORE_REAL     (PER_EVENT_STORE_REAL >> 24)
 382
 383 #define per_bp_event(code) \
 384                         (code & (PER_CODE_IFETCH | PER_CODE_BRANCH))
 385 #define per_write_wp_event(code) \
 386                         (code & (PER_CODE_STORE | PER_CODE_STORE_REAL))
 387
 388 static int debug_exit_required(struct kvm_vcpu *vcpu, u8 perc,
 389                                unsigned long peraddr)
 390 {
 391         struct kvm_debug_exit_arch *debug_exit = &vcpu->run->debug.arch;
 392         struct kvm_hw_wp_info_arch *wp_info = NULL;
 393         struct kvm_hw_bp_info_arch *bp_info = NULL;
 394         unsigned long addr = vcpu->arch.sie_block->gpsw.addr;
 395
 396         if (guestdbg_hw_bp_enabled(vcpu)) {
 397                 if (per_write_wp_event(perc) &&
 398                     vcpu->arch.guestdbg.nr_hw_wp > 0) {
 399                         wp_info = any_wp_changed(vcpu);
 400                         if (wp_info) {
 401                                 debug_exit->addr = wp_info->addr;
 402                                 debug_exit->type = KVM_HW_WP_WRITE;
 403                                 goto exit_required;
 404                         }
 405                 }
 406                 if (per_bp_event(perc) &&
 407                          vcpu->arch.guestdbg.nr_hw_bp > 0) {
 408                         bp_info = find_hw_bp(vcpu, addr);
 409                         /* remove duplicate events if PC==PER address */
 410                         if (bp_info && (addr != peraddr)) {
 411                                 debug_exit->addr = addr;
 412                                 debug_exit->type = KVM_HW_BP;
 413                                 vcpu->arch.guestdbg.last_bp = addr;
 414                                 goto exit_required;
 415                         }
 416                         /* breakpoint missed */
 417                         bp_info = find_hw_bp(vcpu, peraddr);
 418                         if (bp_info && vcpu->arch.guestdbg.last_bp != peraddr) {
 419                                 debug_exit->addr = peraddr;
 420                                 debug_exit->type = KVM_HW_BP;
 421                                 goto exit_required;
 422                         }
 423                 }
 424         }
 425         if (guestdbg_sstep_enabled(vcpu) && per_bp_event(perc)) {
 426                 debug_exit->addr = addr;
 427                 debug_exit->type = KVM_SINGLESTEP;
 428                 goto exit_required;
 429         }
 430
 431         return 0;
 432 exit_required:
 433         return 1;
 434 }
 435
 436 static int per_fetched_addr(struct kvm_vcpu *vcpu, unsigned long *addr)
 437 {
 438         u8 exec_ilen = 0;
 439         u16 opcode[3];
 440         int rc;
 441
 442         if (vcpu->arch.sie_block->icptcode == ICPT_PROGI) {
 443                 /* PER address references the fetched or the execute instr */
 444                 *addr = vcpu->arch.sie_block->peraddr;
 445                 /*
 446                  * Manually detect if we have an EXECUTE instruction. As
 447                  * instructions are always 2 byte aligned we can read the
 448                  * first two bytes unconditionally
 449                  */
 450                 rc = read_guest_instr(vcpu, *addr, &opcode, 2);
 451                 if (rc)
 452                         return rc;
 453                 if (opcode[0] >> 8 == 0x44)
 454                         exec_ilen = 4;
 455                 if ((opcode[0] & 0xff0f) == 0xc600)
 456                         exec_ilen = 6;
 457         } else {
 458                 /* instr was suppressed, calculate the responsible instr */
 459                 *addr = __rewind_psw(vcpu->arch.sie_block->gpsw,
 460                                      kvm_s390_get_ilen(vcpu));
 461                 if (vcpu->arch.sie_block->icptstatus & 0x01) {
 462                         exec_ilen = (vcpu->arch.sie_block->icptstatus & 0x60) >> 4;
 463                         if (!exec_ilen)
 464                                 exec_ilen = 4;
 465                 }
 466         }
 467
 468         if (exec_ilen) {
 469                 /* read the complete EXECUTE instr to detect the fetched addr */
 470                 rc = read_guest_instr(vcpu, *addr, &opcode, exec_ilen);
 471                 if (rc)
 472                         return rc;
 473                 if (exec_ilen == 6) {
 474                         /* EXECUTE RELATIVE LONG - RIL-b format */
 475                         s32 rl = *((s32 *) (opcode + 1));
 476
 477                         /* rl is a _signed_ 32 bit value specifying halfwords */
 478                         *addr += (u64)(s64) rl * 2;
 479                 } else {
 480                         /* EXECUTE - RX-a format */
 481                         u32 base = (opcode[1] & 0xf000) >> 12;
 482                         u32 disp = opcode[1] & 0x0fff;
 483                         u32 index = opcode[0] & 0x000f;
 484
 485                         *addr = base ? vcpu->run->s.regs.gprs[base] : 0;
 486                         *addr += index ? vcpu->run->s.regs.gprs[index] : 0;
 487                         *addr += disp;
 488                 }
 489                 *addr = kvm_s390_logical_to_effective(vcpu, *addr);
 490         }
 491         return 0;
 492 }
 493
 494 #define guest_per_enabled(vcpu) \
 495                              (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER)
 496
 497 int kvm_s390_handle_per_ifetch_icpt(struct kvm_vcpu *vcpu)
 498 {
 499         const u64 cr10 = vcpu->arch.sie_block->gcr[10];
 500         const u64 cr11 = vcpu->arch.sie_block->gcr[11];
 501         const u8 ilen = kvm_s390_get_ilen(vcpu);
 502         struct kvm_s390_pgm_info pgm_info = {
 503                 .code = PGM_PER,
 504                 .per_code = PER_CODE_IFETCH,
 505                 .per_address = __rewind_psw(vcpu->arch.sie_block->gpsw, ilen),
 506         };
 507         unsigned long fetched_addr;
 508         int rc;
 509
 510         /*
 511          * The PSW points to the next instruction, therefore the intercepted
 512          * instruction generated a PER i-fetch event. PER address therefore
 513          * points at the previous PSW address (could be an EXECUTE function).
 514          */
 515         if (!guestdbg_enabled(vcpu))
 516                 return kvm_s390_inject_prog_irq(vcpu, &pgm_info);
 517
 518         if (debug_exit_required(vcpu, pgm_info.per_code, pgm_info.per_address))
 519                 vcpu->guest_debug |= KVM_GUESTDBG_EXIT_PENDING;
 520
 521         if (!guest_per_enabled(vcpu) ||
 522             !(vcpu->arch.sie_block->gcr[9] & PER_EVENT_IFETCH))
 523                 return 0;
 524
 525         rc = per_fetched_addr(vcpu, &fetched_addr);
 526         if (rc < 0)
 527                 return rc;
 528         if (rc)
 529                 /* instruction-fetching exceptions */
 530                 return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 531
 532         if (in_addr_range(fetched_addr, cr10, cr11))
 533                 return kvm_s390_inject_prog_irq(vcpu, &pgm_info);
 534         return 0;
 535 }
 536
 537 static int filter_guest_per_event(struct kvm_vcpu *vcpu)
 538 {
 539         const u8 perc = vcpu->arch.sie_block->perc;
 540         u64 addr = vcpu->arch.sie_block->gpsw.addr;
 541         u64 cr9 = vcpu->arch.sie_block->gcr[9];
 542         u64 cr10 = vcpu->arch.sie_block->gcr[10];
 543         u64 cr11 = vcpu->arch.sie_block->gcr[11];
 544         /* filter all events, demanded by the guest */
 545         u8 guest_perc = perc & (cr9 >> 24) & PER_CODE_MASK;
 546         unsigned long fetched_addr;
 547         int rc;
 548
 549         if (!guest_per_enabled(vcpu))
 550                 guest_perc = 0;
 551
 552         /* filter "successful-branching" events */
 553         if (guest_perc & PER_CODE_BRANCH &&
 554             cr9 & PER_CONTROL_BRANCH_ADDRESS &&
 555             !in_addr_range(addr, cr10, cr11))
 556                 guest_perc &= ~PER_CODE_BRANCH;
 557
 558         /* filter "instruction-fetching" events */
 559         if (guest_perc & PER_CODE_IFETCH) {
 560                 rc = per_fetched_addr(vcpu, &fetched_addr);
 561                 if (rc < 0)
 562                         return rc;
 563                 /*
 564                  * Don't inject an irq on exceptions. This would make handling
 565                  * on icpt code 8 very complex (as PSW was already rewound).
 566                  */
 567                 if (rc || !in_addr_range(fetched_addr, cr10, cr11))
 568                         guest_perc &= ~PER_CODE_IFETCH;
 569         }
 570
 571         /* All other PER events will be given to the guest */
 572         /* TODO: Check altered address/address space */
 573
 574         vcpu->arch.sie_block->perc = guest_perc;
 575
 576         if (!guest_perc)
 577                 vcpu->arch.sie_block->iprcc &= ~PGM_PER;
 578         return 0;
 579 }
 580
 581 #define pssec(vcpu) (vcpu->arch.sie_block->gcr[1] & _ASCE_SPACE_SWITCH)
 582 #define hssec(vcpu) (vcpu->arch.sie_block->gcr[13] & _ASCE_SPACE_SWITCH)
 583 #define old_ssec(vcpu) ((vcpu->arch.sie_block->tecmc >> 31) & 0x1)
 584 #define old_as_is_home(vcpu) !(vcpu->arch.sie_block->tecmc & 0xffff)
 585
 586 int kvm_s390_handle_per_event(struct kvm_vcpu *vcpu)
 587 {
 588         int rc, new_as;
 589
 590         if (debug_exit_required(vcpu, vcpu->arch.sie_block->perc,
 591                                 vcpu->arch.sie_block->peraddr))
 592                 vcpu->guest_debug |= KVM_GUESTDBG_EXIT_PENDING;
 593
 594         rc = filter_guest_per_event(vcpu);
 595         if (rc)
 596                 return rc;
 597
 598         /*
 599          * Only RP, SAC, SACF, PT, PTI, PR, PC instructions can trigger
 600          * a space-switch event. PER events enforce space-switch events
 601          * for these instructions. So if no PER event for the guest is left,
 602          * we might have to filter the space-switch element out, too.
 603          */
 604         if (vcpu->arch.sie_block->iprcc == PGM_SPACE_SWITCH) {
 605                 vcpu->arch.sie_block->iprcc = 0;
 606                 new_as = psw_bits(vcpu->arch.sie_block->gpsw).as;
 607
 608                 /*
 609                  * If the AS changed from / to home, we had RP, SAC or SACF
 610                  * instruction. Check primary and home space-switch-event
 611                  * controls. (theoretically home -> home produced no event)
 612                  */
 613                 if (((new_as == PSW_BITS_AS_HOME) ^ old_as_is_home(vcpu)) &&
 614                     (pssec(vcpu) || hssec(vcpu)))
 615                         vcpu->arch.sie_block->iprcc = PGM_SPACE_SWITCH;
 616
 617                 /*
 618                  * PT, PTI, PR, PC instruction operate on primary AS only. Check
 619                  * if the primary-space-switch-event control was or got set.
 620                  */
 621                 if (new_as == PSW_BITS_AS_PRIMARY && !old_as_is_home(vcpu) &&
 622                     (pssec(vcpu) || old_ssec(vcpu)))
 623                         vcpu->arch.sie_block->iprcc = PGM_SPACE_SWITCH;
 624         }
 625         return 0;
 626 }