1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2019 Western Digital Corporation or its affiliates. 4 * Copyright (c) 2022 Ventana Micro Systems Inc. 5 */ 6 7#include <linux/bitops.h> 8#include <linux/kvm_host.h> 9 10#include <asm/cpufeature.h> 11 12#define INSN_OPCODE_MASK 0x007c 13#define INSN_OPCODE_SHIFT 2 14#define INSN_OPCODE_SYSTEM 28 15 16#define INSN_MASK_WFI 0xffffffff 17#define INSN_MATCH_WFI 0x10500073 18 19#define INSN_MATCH_CSRRW 0x1073 20#define INSN_MASK_CSRRW 0x707f 21#define INSN_MATCH_CSRRS 0x2073 22#define INSN_MASK_CSRRS 0x707f 23#define INSN_MATCH_CSRRC 0x3073 24#define INSN_MASK_CSRRC 0x707f 25#define INSN_MATCH_CSRRWI 0x5073 26#define INSN_MASK_CSRRWI 0x707f 27#define INSN_MATCH_CSRRSI 0x6073 28#define INSN_MASK_CSRRSI 0x707f 29#define INSN_MATCH_CSRRCI 0x7073 30#define INSN_MASK_CSRRCI 0x707f 31 32#define INSN_MATCH_LB 0x3 33#define INSN_MASK_LB 0x707f 34#define INSN_MATCH_LH 0x1003 35#define INSN_MASK_LH 0x707f 36#define INSN_MATCH_LW 0x2003 37#define INSN_MASK_LW 0x707f 38#define INSN_MATCH_LD 0x3003 39#define INSN_MASK_LD 0x707f 40#define INSN_MATCH_LBU 0x4003 41#define INSN_MASK_LBU 0x707f 42#define INSN_MATCH_LHU 0x5003 43#define INSN_MASK_LHU 0x707f 44#define INSN_MATCH_LWU 0x6003 45#define INSN_MASK_LWU 0x707f 46#define INSN_MATCH_SB 0x23 47#define INSN_MASK_SB 0x707f 48#define INSN_MATCH_SH 0x1023 49#define INSN_MASK_SH 0x707f 50#define INSN_MATCH_SW 0x2023 51#define INSN_MASK_SW 0x707f 52#define INSN_MATCH_SD 0x3023 53#define INSN_MASK_SD 0x707f 54 55#define INSN_MATCH_C_LD 0x6000 56#define INSN_MASK_C_LD 0xe003 57#define INSN_MATCH_C_SD 0xe000 58#define INSN_MASK_C_SD 0xe003 59#define INSN_MATCH_C_LW 0x4000 60#define INSN_MASK_C_LW 0xe003 61#define INSN_MATCH_C_SW 0xc000 62#define INSN_MASK_C_SW 0xe003 63#define INSN_MATCH_C_LDSP 0x6002 64#define INSN_MASK_C_LDSP 0xe003 65#define INSN_MATCH_C_SDSP 0xe002 66#define INSN_MASK_C_SDSP 0xe003 67#define INSN_MATCH_C_LWSP 0x4002 68#define INSN_MASK_C_LWSP 0xe003 69#define INSN_MATCH_C_SWSP 0xc002 70#define INSN_MASK_C_SWSP 0xe003 71 72#define INSN_16BIT_MASK 0x3 73 74#define INSN_IS_16BIT(insn) (((insn) & INSN_16BIT_MASK) != INSN_16BIT_MASK) 75 76#define INSN_LEN(insn) (INSN_IS_16BIT(insn) ? 2 : 4) 77 78#ifdef CONFIG_64BIT 79#define LOG_REGBYTES 3 80#else 81#define LOG_REGBYTES 2 82#endif 83#define REGBYTES (1 << LOG_REGBYTES) 84 85#define SH_RD 7 86#define SH_RS1 15 87#define SH_RS2 20 88#define SH_RS2C 2 89#define MASK_RX 0x1f 90 91#define RV_X(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1)) 92#define RVC_LW_IMM(x) ((RV_X(x, 6, 1) << 2) | \ 93 (RV_X(x, 10, 3) << 3) | \ 94 (RV_X(x, 5, 1) << 6)) 95#define RVC_LD_IMM(x) ((RV_X(x, 10, 3) << 3) | \ 96 (RV_X(x, 5, 2) << 6)) 97#define RVC_LWSP_IMM(x) ((RV_X(x, 4, 3) << 2) | \ 98 (RV_X(x, 12, 1) << 5) | \ 99 (RV_X(x, 2, 2) << 6)) 100#define RVC_LDSP_IMM(x) ((RV_X(x, 5, 2) << 3) | \ 101 (RV_X(x, 12, 1) << 5) | \ 102 (RV_X(x, 2, 3) << 6)) 103#define RVC_SWSP_IMM(x) ((RV_X(x, 9, 4) << 2) | \ 104 (RV_X(x, 7, 2) << 6)) 105#define RVC_SDSP_IMM(x) ((RV_X(x, 10, 3) << 3) | \ 106 (RV_X(x, 7, 3) << 6)) 107#define RVC_RS1S(insn) (8 + RV_X(insn, SH_RD, 3)) 108#define RVC_RS2S(insn) (8 + RV_X(insn, SH_RS2C, 3)) 109#define RVC_RS2(insn) RV_X(insn, SH_RS2C, 5) 110 111#define SHIFT_RIGHT(x, y) \ 112 ((y) < 0 ? ((x) << -(y)) : ((x) >> (y))) 113 114#define REG_MASK \ 115 ((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES)) 116 117#define REG_OFFSET(insn, pos) \ 118 (SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK) 119 120#define REG_PTR(insn, pos, regs) \ 121 ((ulong *)((ulong)(regs) + REG_OFFSET(insn, pos))) 122 123#define GET_FUNCT3(insn) (((insn) >> 12) & 7) 124 125#define GET_RS1(insn, regs) (*REG_PTR(insn, SH_RS1, regs)) 126#define GET_RS2(insn, regs) (*REG_PTR(insn, SH_RS2, regs)) 127#define GET_RS1S(insn, regs) (*REG_PTR(RVC_RS1S(insn), 0, regs)) 128#define GET_RS2S(insn, regs) (*REG_PTR(RVC_RS2S(insn), 0, regs)) 129#define GET_RS2C(insn, regs) (*REG_PTR(insn, SH_RS2C, regs)) 130#define GET_SP(regs) (*REG_PTR(2, 0, regs)) 131#define SET_RD(insn, regs, val) (*REG_PTR(insn, SH_RD, regs) = (val)) 132#define IMM_I(insn) ((s32)(insn) >> 20) 133#define IMM_S(insn) (((s32)(insn) >> 25 << 5) | \ 134 (s32)(((insn) >> 7) & 0x1f)) 135 136struct insn_func { 137 unsigned long mask; 138 unsigned long match; 139 /* 140 * Possible return values are as follows: 141 * 1) Returns < 0 for error case 142 * 2) Returns 0 for exit to user-space 143 * 3) Returns 1 to continue with next sepc 144 * 4) Returns 2 to continue with same sepc 145 * 5) Returns 3 to inject illegal instruction trap and continue 146 * 6) Returns 4 to inject virtual instruction trap and continue 147 * 148 * Use enum kvm_insn_return for return values 149 */ 150 int (*func)(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn); 151}; 152 153static int truly_illegal_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, 154 ulong insn) 155{ 156 struct kvm_cpu_trap utrap = { 0 }; 157 158 /* Redirect trap to Guest VCPU */ 159 utrap.sepc = vcpu->arch.guest_context.sepc; 160 utrap.scause = EXC_INST_ILLEGAL; 161 utrap.stval = insn; 162 utrap.htval = 0; 163 utrap.htinst = 0; 164 kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); 165 166 return 1; 167} 168 169static int truly_virtual_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, 170 ulong insn) 171{ 172 struct kvm_cpu_trap utrap = { 0 }; 173 174 /* Redirect trap to Guest VCPU */ 175 utrap.sepc = vcpu->arch.guest_context.sepc; 176 utrap.scause = EXC_VIRTUAL_INST_FAULT; 177 utrap.stval = insn; 178 utrap.htval = 0; 179 utrap.htinst = 0; 180 kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); 181 182 return 1; 183} 184 185/** 186 * kvm_riscv_vcpu_wfi -- Emulate wait for interrupt (WFI) behaviour 187 * 188 * @vcpu: The VCPU pointer 189 */ 190void kvm_riscv_vcpu_wfi(struct kvm_vcpu *vcpu) 191{ 192 if (!kvm_arch_vcpu_runnable(vcpu)) { 193 kvm_vcpu_srcu_read_unlock(vcpu); 194 kvm_vcpu_halt(vcpu); 195 kvm_vcpu_srcu_read_lock(vcpu); 196 } 197} 198 199static int wfi_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn) 200{ 201 vcpu->stat.wfi_exit_stat++; 202 kvm_riscv_vcpu_wfi(vcpu); 203 return KVM_INSN_CONTINUE_NEXT_SEPC; 204} 205 206struct csr_func { 207 unsigned int base; 208 unsigned int count; 209 /* 210 * Possible return values are as same as "func" callback in 211 * "struct insn_func". 212 */ 213 int (*func)(struct kvm_vcpu *vcpu, unsigned int csr_num, 214 unsigned long *val, unsigned long new_val, 215 unsigned long wr_mask); 216}; 217 218static int seed_csr_rmw(struct kvm_vcpu *vcpu, unsigned int csr_num, 219 unsigned long *val, unsigned long new_val, 220 unsigned long wr_mask) 221{ 222 if (!riscv_isa_extension_available(vcpu->arch.isa, ZKR)) 223 return KVM_INSN_ILLEGAL_TRAP; 224 225 return KVM_INSN_EXIT_TO_USER_SPACE; 226} 227 228static const struct csr_func csr_funcs[] = { 229 KVM_RISCV_VCPU_AIA_CSR_FUNCS 230 KVM_RISCV_VCPU_HPMCOUNTER_CSR_FUNCS 231 { .base = CSR_SEED, .count = 1, .func = seed_csr_rmw }, 232}; 233 234/** 235 * kvm_riscv_vcpu_csr_return -- Handle CSR read/write after user space 236 * emulation or in-kernel emulation 237 * 238 * @vcpu: The VCPU pointer 239 * @run: The VCPU run struct containing the CSR data 240 * 241 * Returns > 0 upon failure and 0 upon success 242 */ 243int kvm_riscv_vcpu_csr_return(struct kvm_vcpu *vcpu, struct kvm_run *run) 244{ 245 ulong insn; 246 247 if (vcpu->arch.csr_decode.return_handled) 248 return 0; 249 vcpu->arch.csr_decode.return_handled = 1; 250 251 /* Update destination register for CSR reads */ 252 insn = vcpu->arch.csr_decode.insn; 253 if ((insn >> SH_RD) & MASK_RX) 254 SET_RD(insn, &vcpu->arch.guest_context, 255 run->riscv_csr.ret_value); 256 257 /* Move to next instruction */ 258 vcpu->arch.guest_context.sepc += INSN_LEN(insn); 259 260 return 0; 261} 262 263static int csr_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn) 264{ 265 int i, rc = KVM_INSN_ILLEGAL_TRAP; 266 unsigned int csr_num = insn >> SH_RS2; 267 unsigned int rs1_num = (insn >> SH_RS1) & MASK_RX; 268 ulong rs1_val = GET_RS1(insn, &vcpu->arch.guest_context); 269 const struct csr_func *tcfn, *cfn = NULL; 270 ulong val = 0, wr_mask = 0, new_val = 0; 271 272 /* Decode the CSR instruction */ 273 switch (GET_FUNCT3(insn)) { 274 case GET_FUNCT3(INSN_MATCH_CSRRW): 275 wr_mask = -1UL; 276 new_val = rs1_val; 277 break; 278 case GET_FUNCT3(INSN_MATCH_CSRRS): 279 wr_mask = rs1_val; 280 new_val = -1UL; 281 break; 282 case GET_FUNCT3(INSN_MATCH_CSRRC): 283 wr_mask = rs1_val; 284 new_val = 0; 285 break; 286 case GET_FUNCT3(INSN_MATCH_CSRRWI): 287 wr_mask = -1UL; 288 new_val = rs1_num; 289 break; 290 case GET_FUNCT3(INSN_MATCH_CSRRSI): 291 wr_mask = rs1_num; 292 new_val = -1UL; 293 break; 294 case GET_FUNCT3(INSN_MATCH_CSRRCI): 295 wr_mask = rs1_num; 296 new_val = 0; 297 break; 298 default: 299 return rc; 300 } 301 302 /* Save instruction decode info */ 303 vcpu->arch.csr_decode.insn = insn; 304 vcpu->arch.csr_decode.return_handled = 0; 305 306 /* Update CSR details in kvm_run struct */ 307 run->riscv_csr.csr_num = csr_num; 308 run->riscv_csr.new_value = new_val; 309 run->riscv_csr.write_mask = wr_mask; 310 run->riscv_csr.ret_value = 0; 311 312 /* Find in-kernel CSR function */ 313 for (i = 0; i < ARRAY_SIZE(csr_funcs); i++) { 314 tcfn = &csr_funcs[i]; 315 if ((tcfn->base <= csr_num) && 316 (csr_num < (tcfn->base + tcfn->count))) { 317 cfn = tcfn; 318 break; 319 } 320 } 321 322 /* First try in-kernel CSR emulation */ 323 if (cfn && cfn->func) { 324 rc = cfn->func(vcpu, csr_num, &val, new_val, wr_mask); 325 if (rc > KVM_INSN_EXIT_TO_USER_SPACE) { 326 if (rc == KVM_INSN_CONTINUE_NEXT_SEPC) { 327 run->riscv_csr.ret_value = val; 328 vcpu->stat.csr_exit_kernel++; 329 kvm_riscv_vcpu_csr_return(vcpu, run); 330 rc = KVM_INSN_CONTINUE_SAME_SEPC; 331 } 332 return rc; 333 } 334 } 335 336 /* Exit to user-space for CSR emulation */ 337 if (rc <= KVM_INSN_EXIT_TO_USER_SPACE) { 338 vcpu->stat.csr_exit_user++; 339 run->exit_reason = KVM_EXIT_RISCV_CSR; 340 } 341 342 return rc; 343} 344 345static const struct insn_func system_opcode_funcs[] = { 346 { 347 .mask = INSN_MASK_CSRRW, 348 .match = INSN_MATCH_CSRRW, 349 .func = csr_insn, 350 }, 351 { 352 .mask = INSN_MASK_CSRRS, 353 .match = INSN_MATCH_CSRRS, 354 .func = csr_insn, 355 }, 356 { 357 .mask = INSN_MASK_CSRRC, 358 .match = INSN_MATCH_CSRRC, 359 .func = csr_insn, 360 }, 361 { 362 .mask = INSN_MASK_CSRRWI, 363 .match = INSN_MATCH_CSRRWI, 364 .func = csr_insn, 365 }, 366 { 367 .mask = INSN_MASK_CSRRSI, 368 .match = INSN_MATCH_CSRRSI, 369 .func = csr_insn, 370 }, 371 { 372 .mask = INSN_MASK_CSRRCI, 373 .match = INSN_MATCH_CSRRCI, 374 .func = csr_insn, 375 }, 376 { 377 .mask = INSN_MASK_WFI, 378 .match = INSN_MATCH_WFI, 379 .func = wfi_insn, 380 }, 381}; 382 383static int system_opcode_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, 384 ulong insn) 385{ 386 int i, rc = KVM_INSN_ILLEGAL_TRAP; 387 const struct insn_func *ifn; 388 389 for (i = 0; i < ARRAY_SIZE(system_opcode_funcs); i++) { 390 ifn = &system_opcode_funcs[i]; 391 if ((insn & ifn->mask) == ifn->match) { 392 rc = ifn->func(vcpu, run, insn); 393 break; 394 } 395 } 396 397 switch (rc) { 398 case KVM_INSN_ILLEGAL_TRAP: 399 return truly_illegal_insn(vcpu, run, insn); 400 case KVM_INSN_VIRTUAL_TRAP: 401 return truly_virtual_insn(vcpu, run, insn); 402 case KVM_INSN_CONTINUE_NEXT_SEPC: 403 vcpu->arch.guest_context.sepc += INSN_LEN(insn); 404 break; 405 default: 406 break; 407 } 408 409 return (rc <= 0) ? rc : 1; 410} 411 412/** 413 * kvm_riscv_vcpu_virtual_insn -- Handle virtual instruction trap 414 * 415 * @vcpu: The VCPU pointer 416 * @run: The VCPU run struct containing the mmio data 417 * @trap: Trap details 418 * 419 * Returns > 0 to continue run-loop 420 * Returns 0 to exit run-loop and handle in user-space. 421 * Returns < 0 to report failure and exit run-loop 422 */ 423int kvm_riscv_vcpu_virtual_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, 424 struct kvm_cpu_trap *trap) 425{ 426 unsigned long insn = trap->stval; 427 struct kvm_cpu_trap utrap = { 0 }; 428 struct kvm_cpu_context *ct; 429 430 if (unlikely(INSN_IS_16BIT(insn))) { 431 if (insn == 0) { 432 ct = &vcpu->arch.guest_context; 433 insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, 434 ct->sepc, 435 &utrap); 436 if (utrap.scause) { 437 utrap.sepc = ct->sepc; 438 kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); 439 return 1; 440 } 441 } 442 if (INSN_IS_16BIT(insn)) 443 return truly_illegal_insn(vcpu, run, insn); 444 } 445 446 switch ((insn & INSN_OPCODE_MASK) >> INSN_OPCODE_SHIFT) { 447 case INSN_OPCODE_SYSTEM: 448 return system_opcode_insn(vcpu, run, insn); 449 default: 450 return truly_illegal_insn(vcpu, run, insn); 451 } 452} 453 454/** 455 * kvm_riscv_vcpu_mmio_load -- Emulate MMIO load instruction 456 * 457 * @vcpu: The VCPU pointer 458 * @run: The VCPU run struct containing the mmio data 459 * @fault_addr: Guest physical address to load 460 * @htinst: Transformed encoding of the load instruction 461 * 462 * Returns > 0 to continue run-loop 463 * Returns 0 to exit run-loop and handle in user-space. 464 * Returns < 0 to report failure and exit run-loop 465 */ 466int kvm_riscv_vcpu_mmio_load(struct kvm_vcpu *vcpu, struct kvm_run *run, 467 unsigned long fault_addr, 468 unsigned long htinst) 469{ 470 u8 data_buf[8]; 471 unsigned long insn; 472 int shift = 0, len = 0, insn_len = 0; 473 struct kvm_cpu_trap utrap = { 0 }; 474 struct kvm_cpu_context *ct = &vcpu->arch.guest_context; 475 476 /* Determine trapped instruction */ 477 if (htinst & 0x1) { 478 /* 479 * Bit[0] == 1 implies trapped instruction value is 480 * transformed instruction or custom instruction. 481 */ 482 insn = htinst | INSN_16BIT_MASK; 483 insn_len = (htinst & BIT(1)) ? INSN_LEN(insn) : 2; 484 } else { 485 /* 486 * Bit[0] == 0 implies trapped instruction value is 487 * zero or special value. 488 */ 489 insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, ct->sepc, 490 &utrap); 491 if (utrap.scause) { 492 /* Redirect trap if we failed to read instruction */ 493 utrap.sepc = ct->sepc; 494 kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); 495 return 1; 496 } 497 insn_len = INSN_LEN(insn); 498 } 499 500 /* Decode length of MMIO and shift */ 501 if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) { 502 len = 4; 503 shift = 8 * (sizeof(ulong) - len); 504 } else if ((insn & INSN_MASK_LB) == INSN_MATCH_LB) { 505 len = 1; 506 shift = 8 * (sizeof(ulong) - len); 507 } else if ((insn & INSN_MASK_LBU) == INSN_MATCH_LBU) { 508 len = 1; 509 shift = 8 * (sizeof(ulong) - len); 510#ifdef CONFIG_64BIT 511 } else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) { 512 len = 8; 513 shift = 8 * (sizeof(ulong) - len); 514 } else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) { 515 len = 4; 516#endif 517 } else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) { 518 len = 2; 519 shift = 8 * (sizeof(ulong) - len); 520 } else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) { 521 len = 2; 522#ifdef CONFIG_64BIT 523 } else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) { 524 len = 8; 525 shift = 8 * (sizeof(ulong) - len); 526 insn = RVC_RS2S(insn) << SH_RD; 527 } else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP && 528 ((insn >> SH_RD) & 0x1f)) { 529 len = 8; 530 shift = 8 * (sizeof(ulong) - len); 531#endif 532 } else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) { 533 len = 4; 534 shift = 8 * (sizeof(ulong) - len); 535 insn = RVC_RS2S(insn) << SH_RD; 536 } else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP && 537 ((insn >> SH_RD) & 0x1f)) { 538 len = 4; 539 shift = 8 * (sizeof(ulong) - len); 540 } else { 541 return -EOPNOTSUPP; 542 } 543 544 /* Fault address should be aligned to length of MMIO */ 545 if (fault_addr & (len - 1)) 546 return -EIO; 547 548 /* Save instruction decode info */ 549 vcpu->arch.mmio_decode.insn = insn; 550 vcpu->arch.mmio_decode.insn_len = insn_len; 551 vcpu->arch.mmio_decode.shift = shift; 552 vcpu->arch.mmio_decode.len = len; 553 vcpu->arch.mmio_decode.return_handled = 0; 554 555 /* Update MMIO details in kvm_run struct */ 556 run->mmio.is_write = false; 557 run->mmio.phys_addr = fault_addr; 558 run->mmio.len = len; 559 560 /* Try to handle MMIO access in the kernel */ 561 if (!kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_addr, len, data_buf)) { 562 /* Successfully handled MMIO access in the kernel so resume */ 563 memcpy(run->mmio.data, data_buf, len); 564 vcpu->stat.mmio_exit_kernel++; 565 kvm_riscv_vcpu_mmio_return(vcpu, run); 566 return 1; 567 } 568 569 /* Exit to userspace for MMIO emulation */ 570 vcpu->stat.mmio_exit_user++; 571 run->exit_reason = KVM_EXIT_MMIO; 572 573 return 0; 574} 575 576/** 577 * kvm_riscv_vcpu_mmio_store -- Emulate MMIO store instruction 578 * 579 * @vcpu: The VCPU pointer 580 * @run: The VCPU run struct containing the mmio data 581 * @fault_addr: Guest physical address to store 582 * @htinst: Transformed encoding of the store instruction 583 * 584 * Returns > 0 to continue run-loop 585 * Returns 0 to exit run-loop and handle in user-space. 586 * Returns < 0 to report failure and exit run-loop 587 */ 588int kvm_riscv_vcpu_mmio_store(struct kvm_vcpu *vcpu, struct kvm_run *run, 589 unsigned long fault_addr, 590 unsigned long htinst) 591{ 592 u8 data8; 593 u16 data16; 594 u32 data32; 595 u64 data64; 596 ulong data; 597 unsigned long insn; 598 int len = 0, insn_len = 0; 599 struct kvm_cpu_trap utrap = { 0 }; 600 struct kvm_cpu_context *ct = &vcpu->arch.guest_context; 601 602 /* Determine trapped instruction */ 603 if (htinst & 0x1) { 604 /* 605 * Bit[0] == 1 implies trapped instruction value is 606 * transformed instruction or custom instruction. 607 */ 608 insn = htinst | INSN_16BIT_MASK; 609 insn_len = (htinst & BIT(1)) ? INSN_LEN(insn) : 2; 610 } else { 611 /* 612 * Bit[0] == 0 implies trapped instruction value is 613 * zero or special value. 614 */ 615 insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, ct->sepc, 616 &utrap); 617 if (utrap.scause) { 618 /* Redirect trap if we failed to read instruction */ 619 utrap.sepc = ct->sepc; 620 kvm_riscv_vcpu_trap_redirect(vcpu, &utrap); 621 return 1; 622 } 623 insn_len = INSN_LEN(insn); 624 } 625 626 data = GET_RS2(insn, &vcpu->arch.guest_context); 627 data8 = data16 = data32 = data64 = data; 628 629 if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) { 630 len = 4; 631 } else if ((insn & INSN_MASK_SB) == INSN_MATCH_SB) { 632 len = 1; 633#ifdef CONFIG_64BIT 634 } else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) { 635 len = 8; 636#endif 637 } else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) { 638 len = 2; 639#ifdef CONFIG_64BIT 640 } else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) { 641 len = 8; 642 data64 = GET_RS2S(insn, &vcpu->arch.guest_context); 643 } else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP && 644 ((insn >> SH_RD) & 0x1f)) { 645 len = 8; 646 data64 = GET_RS2C(insn, &vcpu->arch.guest_context); 647#endif 648 } else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) { 649 len = 4; 650 data32 = GET_RS2S(insn, &vcpu->arch.guest_context); 651 } else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP && 652 ((insn >> SH_RD) & 0x1f)) { 653 len = 4; 654 data32 = GET_RS2C(insn, &vcpu->arch.guest_context); 655 } else { 656 return -EOPNOTSUPP; 657 } 658 659 /* Fault address should be aligned to length of MMIO */ 660 if (fault_addr & (len - 1)) 661 return -EIO; 662 663 /* Save instruction decode info */ 664 vcpu->arch.mmio_decode.insn = insn; 665 vcpu->arch.mmio_decode.insn_len = insn_len; 666 vcpu->arch.mmio_decode.shift = 0; 667 vcpu->arch.mmio_decode.len = len; 668 vcpu->arch.mmio_decode.return_handled = 0; 669 670 /* Copy data to kvm_run instance */ 671 switch (len) { 672 case 1: 673 *((u8 *)run->mmio.data) = data8; 674 break; 675 case 2: 676 *((u16 *)run->mmio.data) = data16; 677 break; 678 case 4: 679 *((u32 *)run->mmio.data) = data32; 680 break; 681 case 8: 682 *((u64 *)run->mmio.data) = data64; 683 break; 684 default: 685 return -EOPNOTSUPP; 686 } 687 688 /* Update MMIO details in kvm_run struct */ 689 run->mmio.is_write = true; 690 run->mmio.phys_addr = fault_addr; 691 run->mmio.len = len; 692 693 /* Try to handle MMIO access in the kernel */ 694 if (!kvm_io_bus_write(vcpu, KVM_MMIO_BUS, 695 fault_addr, len, run->mmio.data)) { 696 /* Successfully handled MMIO access in the kernel so resume */ 697 vcpu->stat.mmio_exit_kernel++; 698 kvm_riscv_vcpu_mmio_return(vcpu, run); 699 return 1; 700 } 701 702 /* Exit to userspace for MMIO emulation */ 703 vcpu->stat.mmio_exit_user++; 704 run->exit_reason = KVM_EXIT_MMIO; 705 706 return 0; 707} 708 709/** 710 * kvm_riscv_vcpu_mmio_return -- Handle MMIO loads after user space emulation 711 * or in-kernel IO emulation 712 * 713 * @vcpu: The VCPU pointer 714 * @run: The VCPU run struct containing the mmio data 715 */ 716int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run) 717{ 718 u8 data8; 719 u16 data16; 720 u32 data32; 721 u64 data64; 722 ulong insn; 723 int len, shift; 724 725 if (vcpu->arch.mmio_decode.return_handled) 726 return 0; 727 728 vcpu->arch.mmio_decode.return_handled = 1; 729 insn = vcpu->arch.mmio_decode.insn; 730 731 if (run->mmio.is_write) 732 goto done; 733 734 len = vcpu->arch.mmio_decode.len; 735 shift = vcpu->arch.mmio_decode.shift; 736 737 switch (len) { 738 case 1: 739 data8 = *((u8 *)run->mmio.data); 740 SET_RD(insn, &vcpu->arch.guest_context, 741 (ulong)data8 << shift >> shift); 742 break; 743 case 2: 744 data16 = *((u16 *)run->mmio.data); 745 SET_RD(insn, &vcpu->arch.guest_context, 746 (ulong)data16 << shift >> shift); 747 break; 748 case 4: 749 data32 = *((u32 *)run->mmio.data); 750 SET_RD(insn, &vcpu->arch.guest_context, 751 (ulong)data32 << shift >> shift); 752 break; 753 case 8: 754 data64 = *((u64 *)run->mmio.data); 755 SET_RD(insn, &vcpu->arch.guest_context, 756 (ulong)data64 << shift >> shift); 757 break; 758 default: 759 return -EOPNOTSUPP; 760 } 761 762done: 763 /* Move to next instruction */ 764 vcpu->arch.guest_context.sepc += vcpu->arch.mmio_decode.insn_len; 765 766 return 0; 767} 768