1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AMD Memory Encryption Support 4 * 5 * Copyright (C) 2019 SUSE 6 * 7 * Author: Joerg Roedel <jroedel@suse.de> 8 */ 9 10 #define pr_fmt(fmt) "SEV: " fmt 11 12 #include <linux/sched/debug.h> /* For show_regs() */ 13 #include <linux/percpu-defs.h> 14 #include <linux/cc_platform.h> 15 #include <linux/printk.h> 16 #include <linux/mm_types.h> 17 #include <linux/set_memory.h> 18 #include <linux/memblock.h> 19 #include <linux/kernel.h> 20 #include <linux/mm.h> 21 #include <linux/cpumask.h> 22 #include <linux/efi.h> 23 #include <linux/platform_device.h> 24 #include <linux/io.h> 25 #include <linux/psp-sev.h> 26 #include <linux/dmi.h> 27 #include <uapi/linux/sev-guest.h> 28 #include <crypto/gcm.h> 29 30 #include <asm/init.h> 31 #include <asm/cpu_entry_area.h> 32 #include <asm/stacktrace.h> 33 #include <asm/sev.h> 34 #include <asm/sev-internal.h> 35 #include <asm/insn-eval.h> 36 #include <asm/fpu/xcr.h> 37 #include <asm/processor.h> 38 #include <asm/realmode.h> 39 #include <asm/setup.h> 40 #include <asm/traps.h> 41 #include <asm/svm.h> 42 #include <asm/smp.h> 43 #include <asm/cpu.h> 44 #include <asm/apic.h> 45 #include <asm/cpuid/api.h> 46 #include <asm/cmdline.h> 47 #include <asm/msr.h> 48 49 /* AP INIT values as documented in the APM2 section "Processor Initialization State" */ 50 #define AP_INIT_CS_LIMIT 0xffff 51 #define AP_INIT_DS_LIMIT 0xffff 52 #define AP_INIT_LDTR_LIMIT 0xffff 53 #define AP_INIT_GDTR_LIMIT 0xffff 54 #define AP_INIT_IDTR_LIMIT 0xffff 55 #define AP_INIT_TR_LIMIT 0xffff 56 #define AP_INIT_RFLAGS_DEFAULT 0x2 57 #define AP_INIT_DR6_DEFAULT 0xffff0ff0 58 #define AP_INIT_GPAT_DEFAULT 0x0007040600070406ULL 59 #define AP_INIT_XCR0_DEFAULT 0x1 60 #define AP_INIT_X87_FTW_DEFAULT 0x5555 61 #define AP_INIT_X87_FCW_DEFAULT 0x0040 62 #define AP_INIT_CR0_DEFAULT 0x60000010 63 #define AP_INIT_MXCSR_DEFAULT 0x1f80 64 65 static const char * const sev_status_feat_names[] = { 66 [MSR_AMD64_SEV_ENABLED_BIT] = "SEV", 67 [MSR_AMD64_SEV_ES_ENABLED_BIT] = "SEV-ES", 68 [MSR_AMD64_SEV_SNP_ENABLED_BIT] = "SEV-SNP", 69 [MSR_AMD64_SNP_VTOM_BIT] = "vTom", 70 [MSR_AMD64_SNP_REFLECT_VC_BIT] = "ReflectVC", 71 [MSR_AMD64_SNP_RESTRICTED_INJ_BIT] = "RI", 72 [MSR_AMD64_SNP_ALT_INJ_BIT] = "AI", 73 [MSR_AMD64_SNP_DEBUG_SWAP_BIT] = "DebugSwap", 74 [MSR_AMD64_SNP_PREVENT_HOST_IBS_BIT] = "NoHostIBS", 75 [MSR_AMD64_SNP_BTB_ISOLATION_BIT] = "BTBIsol", 76 [MSR_AMD64_SNP_VMPL_SSS_BIT] = "VmplSSS", 77 [MSR_AMD64_SNP_SECURE_TSC_BIT] = "SecureTSC", 78 [MSR_AMD64_SNP_VMGEXIT_PARAM_BIT] = "VMGExitParam", 79 [MSR_AMD64_SNP_IBS_VIRT_BIT] = "IBSVirt", 80 [MSR_AMD64_SNP_VMSA_REG_PROT_BIT] = "VMSARegProt", 81 [MSR_AMD64_SNP_SMT_PROT_BIT] = "SMTProt", 82 }; 83 84 /* 85 * For Secure TSC guests, the BSP fetches TSC_INFO using SNP guest messaging and 86 * initializes snp_tsc_scale and snp_tsc_offset. These values are replicated 87 * across the APs VMSA fields (TSC_SCALE and TSC_OFFSET). 88 */ 89 static u64 snp_tsc_scale __ro_after_init; 90 static u64 snp_tsc_offset __ro_after_init; 91 static unsigned long snp_tsc_freq_khz __ro_after_init; 92 93 DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data); 94 DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); 95 96 /* 97 * SVSM related information: 98 * When running under an SVSM, the VMPL that Linux is executing at must be 99 * non-zero. The VMPL is therefore used to indicate the presence of an SVSM. 100 */ 101 u8 snp_vmpl __ro_after_init; 102 EXPORT_SYMBOL_GPL(snp_vmpl); 103 104 static u64 __init get_snp_jump_table_addr(void) 105 { 106 struct snp_secrets_page *secrets; 107 void __iomem *mem; 108 u64 addr; 109 110 mem = ioremap_encrypted(sev_secrets_pa, PAGE_SIZE); 111 if (!mem) { 112 pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n"); 113 return 0; 114 } 115 116 secrets = (__force struct snp_secrets_page *)mem; 117 118 addr = secrets->os_area.ap_jump_table_pa; 119 iounmap(mem); 120 121 return addr; 122 } 123 124 static u64 __init get_jump_table_addr(void) 125 { 126 struct ghcb_state state; 127 unsigned long flags; 128 struct ghcb *ghcb; 129 u64 ret = 0; 130 131 if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 132 return get_snp_jump_table_addr(); 133 134 local_irq_save(flags); 135 136 ghcb = __sev_get_ghcb(&state); 137 138 vc_ghcb_invalidate(ghcb); 139 ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE); 140 ghcb_set_sw_exit_info_1(ghcb, SVM_VMGEXIT_GET_AP_JUMP_TABLE); 141 ghcb_set_sw_exit_info_2(ghcb, 0); 142 143 sev_es_wr_ghcb_msr(__pa(ghcb)); 144 VMGEXIT(); 145 146 if (ghcb_sw_exit_info_1_is_valid(ghcb) && 147 ghcb_sw_exit_info_2_is_valid(ghcb)) 148 ret = ghcb->save.sw_exit_info_2; 149 150 __sev_put_ghcb(&state); 151 152 local_irq_restore(flags); 153 154 return ret; 155 } 156 157 static inline void __pval_terminate(u64 pfn, bool action, unsigned int page_size, 158 int ret, u64 svsm_ret) 159 { 160 WARN(1, "PVALIDATE failure: pfn: 0x%llx, action: %u, size: %u, ret: %d, svsm_ret: 0x%llx\n", 161 pfn, action, page_size, ret, svsm_ret); 162 163 sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE); 164 } 165 166 static void svsm_pval_terminate(struct svsm_pvalidate_call *pc, int ret, u64 svsm_ret) 167 { 168 unsigned int page_size; 169 bool action; 170 u64 pfn; 171 172 pfn = pc->entry[pc->cur_index].pfn; 173 action = pc->entry[pc->cur_index].action; 174 page_size = pc->entry[pc->cur_index].page_size; 175 176 __pval_terminate(pfn, action, page_size, ret, svsm_ret); 177 } 178 179 static void pval_pages(struct snp_psc_desc *desc) 180 { 181 struct psc_entry *e; 182 unsigned long vaddr; 183 unsigned int size; 184 unsigned int i; 185 bool validate; 186 u64 pfn; 187 int rc; 188 189 for (i = 0; i <= desc->hdr.end_entry; i++) { 190 e = &desc->entries[i]; 191 192 pfn = e->gfn; 193 vaddr = (unsigned long)pfn_to_kaddr(pfn); 194 size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K; 195 validate = e->operation == SNP_PAGE_STATE_PRIVATE; 196 197 rc = pvalidate(vaddr, size, validate); 198 if (!rc) 199 continue; 200 201 if (rc == PVALIDATE_FAIL_SIZEMISMATCH && size == RMP_PG_SIZE_2M) { 202 unsigned long vaddr_end = vaddr + PMD_SIZE; 203 204 for (; vaddr < vaddr_end; vaddr += PAGE_SIZE, pfn++) { 205 rc = pvalidate(vaddr, RMP_PG_SIZE_4K, validate); 206 if (rc) 207 __pval_terminate(pfn, validate, RMP_PG_SIZE_4K, rc, 0); 208 } 209 } else { 210 __pval_terminate(pfn, validate, size, rc, 0); 211 } 212 } 213 } 214 215 static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action, 216 struct svsm_pvalidate_call *pc) 217 { 218 struct svsm_pvalidate_entry *pe; 219 220 /* Nothing in the CA yet */ 221 pc->num_entries = 0; 222 pc->cur_index = 0; 223 224 pe = &pc->entry[0]; 225 226 while (pfn < pfn_end) { 227 pe->page_size = RMP_PG_SIZE_4K; 228 pe->action = action; 229 pe->ignore_cf = 0; 230 pe->pfn = pfn; 231 232 pe++; 233 pfn++; 234 235 pc->num_entries++; 236 if (pc->num_entries == SVSM_PVALIDATE_MAX_COUNT) 237 break; 238 } 239 240 return pfn; 241 } 242 243 static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int desc_entry, 244 struct svsm_pvalidate_call *pc) 245 { 246 struct svsm_pvalidate_entry *pe; 247 struct psc_entry *e; 248 249 /* Nothing in the CA yet */ 250 pc->num_entries = 0; 251 pc->cur_index = 0; 252 253 pe = &pc->entry[0]; 254 e = &desc->entries[desc_entry]; 255 256 while (desc_entry <= desc->hdr.end_entry) { 257 pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K; 258 pe->action = e->operation == SNP_PAGE_STATE_PRIVATE; 259 pe->ignore_cf = 0; 260 pe->pfn = e->gfn; 261 262 pe++; 263 e++; 264 265 desc_entry++; 266 pc->num_entries++; 267 if (pc->num_entries == SVSM_PVALIDATE_MAX_COUNT) 268 break; 269 } 270 271 return desc_entry; 272 } 273 274 static void svsm_pval_pages(struct snp_psc_desc *desc) 275 { 276 struct svsm_pvalidate_entry pv_4k[VMGEXIT_PSC_MAX_ENTRY]; 277 unsigned int i, pv_4k_count = 0; 278 struct svsm_pvalidate_call *pc; 279 struct svsm_call call = {}; 280 unsigned long flags; 281 bool action; 282 u64 pc_pa; 283 int ret; 284 285 /* 286 * This can be called very early in the boot, use native functions in 287 * order to avoid paravirt issues. 288 */ 289 flags = native_local_irq_save(); 290 291 /* 292 * The SVSM calling area (CA) can support processing 510 entries at a 293 * time. Loop through the Page State Change descriptor until the CA is 294 * full or the last entry in the descriptor is reached, at which time 295 * the SVSM is invoked. This repeats until all entries in the descriptor 296 * are processed. 297 */ 298 call.caa = svsm_get_caa(); 299 300 pc = (struct svsm_pvalidate_call *)call.caa->svsm_buffer; 301 pc_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer); 302 303 /* Protocol 0, Call ID 1 */ 304 call.rax = SVSM_CORE_CALL(SVSM_CORE_PVALIDATE); 305 call.rcx = pc_pa; 306 307 for (i = 0; i <= desc->hdr.end_entry;) { 308 i = svsm_build_ca_from_psc_desc(desc, i, pc); 309 310 do { 311 ret = svsm_perform_call_protocol(&call); 312 if (!ret) 313 continue; 314 315 /* 316 * Check if the entry failed because of an RMP mismatch (a 317 * PVALIDATE at 2M was requested, but the page is mapped in 318 * the RMP as 4K). 319 */ 320 321 if (call.rax_out == SVSM_PVALIDATE_FAIL_SIZEMISMATCH && 322 pc->entry[pc->cur_index].page_size == RMP_PG_SIZE_2M) { 323 /* Save this entry for post-processing at 4K */ 324 pv_4k[pv_4k_count++] = pc->entry[pc->cur_index]; 325 326 /* Skip to the next one unless at the end of the list */ 327 pc->cur_index++; 328 if (pc->cur_index < pc->num_entries) 329 ret = -EAGAIN; 330 else 331 ret = 0; 332 } 333 } while (ret == -EAGAIN); 334 335 if (ret) 336 svsm_pval_terminate(pc, ret, call.rax_out); 337 } 338 339 /* Process any entries that failed to be validated at 2M and validate them at 4K */ 340 for (i = 0; i < pv_4k_count; i++) { 341 u64 pfn, pfn_end; 342 343 action = pv_4k[i].action; 344 pfn = pv_4k[i].pfn; 345 pfn_end = pfn + 512; 346 347 while (pfn < pfn_end) { 348 pfn = svsm_build_ca_from_pfn_range(pfn, pfn_end, action, pc); 349 350 ret = svsm_perform_call_protocol(&call); 351 if (ret) 352 svsm_pval_terminate(pc, ret, call.rax_out); 353 } 354 } 355 356 native_local_irq_restore(flags); 357 } 358 359 static void pvalidate_pages(struct snp_psc_desc *desc) 360 { 361 if (snp_vmpl) 362 svsm_pval_pages(desc); 363 else 364 pval_pages(desc); 365 } 366 367 static int vmgexit_psc(struct ghcb *ghcb, struct snp_psc_desc *desc) 368 { 369 int cur_entry, end_entry, ret = 0; 370 struct snp_psc_desc *data; 371 struct es_em_ctxt ctxt; 372 373 vc_ghcb_invalidate(ghcb); 374 375 /* Copy the input desc into GHCB shared buffer */ 376 data = (struct snp_psc_desc *)ghcb->shared_buffer; 377 memcpy(ghcb->shared_buffer, desc, min_t(int, GHCB_SHARED_BUF_SIZE, sizeof(*desc))); 378 379 /* 380 * As per the GHCB specification, the hypervisor can resume the guest 381 * before processing all the entries. Check whether all the entries 382 * are processed. If not, then keep retrying. Note, the hypervisor 383 * will update the data memory directly to indicate the status, so 384 * reference the data->hdr everywhere. 385 * 386 * The strategy here is to wait for the hypervisor to change the page 387 * state in the RMP table before guest accesses the memory pages. If the 388 * page state change was not successful, then later memory access will 389 * result in a crash. 390 */ 391 cur_entry = data->hdr.cur_entry; 392 end_entry = data->hdr.end_entry; 393 394 while (data->hdr.cur_entry <= data->hdr.end_entry) { 395 ghcb_set_sw_scratch(ghcb, (u64)__pa(data)); 396 397 /* This will advance the shared buffer data points to. */ 398 ret = sev_es_ghcb_hv_call(ghcb, &ctxt, SVM_VMGEXIT_PSC, 0, 0); 399 400 /* 401 * Page State Change VMGEXIT can pass error code through 402 * exit_info_2. 403 */ 404 if (WARN(ret || ghcb->save.sw_exit_info_2, 405 "SNP: PSC failed ret=%d exit_info_2=%llx\n", 406 ret, ghcb->save.sw_exit_info_2)) { 407 ret = 1; 408 goto out; 409 } 410 411 /* Verify that reserved bit is not set */ 412 if (WARN(data->hdr.reserved, "Reserved bit is set in the PSC header\n")) { 413 ret = 1; 414 goto out; 415 } 416 417 /* 418 * Sanity check that entry processing is not going backwards. 419 * This will happen only if hypervisor is tricking us. 420 */ 421 if (WARN(data->hdr.end_entry > end_entry || cur_entry > data->hdr.cur_entry, 422 "SNP: PSC processing going backward, end_entry %d (got %d) cur_entry %d (got %d)\n", 423 end_entry, data->hdr.end_entry, cur_entry, data->hdr.cur_entry)) { 424 ret = 1; 425 goto out; 426 } 427 } 428 429 out: 430 return ret; 431 } 432 433 static unsigned long __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr, 434 unsigned long vaddr_end, int op) 435 { 436 struct ghcb_state state; 437 bool use_large_entry; 438 struct psc_hdr *hdr; 439 struct psc_entry *e; 440 unsigned long flags; 441 unsigned long pfn; 442 struct ghcb *ghcb; 443 int i; 444 445 hdr = &data->hdr; 446 e = data->entries; 447 448 memset(data, 0, sizeof(*data)); 449 i = 0; 450 451 while (vaddr < vaddr_end && i < ARRAY_SIZE(data->entries)) { 452 hdr->end_entry = i; 453 454 if (is_vmalloc_addr((void *)vaddr)) { 455 pfn = vmalloc_to_pfn((void *)vaddr); 456 use_large_entry = false; 457 } else { 458 pfn = __pa(vaddr) >> PAGE_SHIFT; 459 use_large_entry = true; 460 } 461 462 e->gfn = pfn; 463 e->operation = op; 464 465 if (use_large_entry && IS_ALIGNED(vaddr, PMD_SIZE) && 466 (vaddr_end - vaddr) >= PMD_SIZE) { 467 e->pagesize = RMP_PG_SIZE_2M; 468 vaddr += PMD_SIZE; 469 } else { 470 e->pagesize = RMP_PG_SIZE_4K; 471 vaddr += PAGE_SIZE; 472 } 473 474 e++; 475 i++; 476 } 477 478 /* Page validation must be rescinded before changing to shared */ 479 if (op == SNP_PAGE_STATE_SHARED) 480 pvalidate_pages(data); 481 482 local_irq_save(flags); 483 484 if (sev_cfg.ghcbs_initialized) 485 ghcb = __sev_get_ghcb(&state); 486 else 487 ghcb = boot_ghcb; 488 489 /* Invoke the hypervisor to perform the page state changes */ 490 if (!ghcb || vmgexit_psc(ghcb, data)) 491 sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); 492 493 if (sev_cfg.ghcbs_initialized) 494 __sev_put_ghcb(&state); 495 496 local_irq_restore(flags); 497 498 /* Page validation must be performed after changing to private */ 499 if (op == SNP_PAGE_STATE_PRIVATE) 500 pvalidate_pages(data); 501 502 return vaddr; 503 } 504 505 static void set_pages_state(unsigned long vaddr, unsigned long npages, int op) 506 { 507 struct snp_psc_desc desc; 508 unsigned long vaddr_end; 509 510 /* Use the MSR protocol when a GHCB is not available. */ 511 if (!boot_ghcb) 512 return early_set_pages_state(vaddr, __pa(vaddr), npages, op); 513 514 vaddr = vaddr & PAGE_MASK; 515 vaddr_end = vaddr + (npages << PAGE_SHIFT); 516 517 while (vaddr < vaddr_end) 518 vaddr = __set_pages_state(&desc, vaddr, vaddr_end, op); 519 } 520 521 void snp_set_memory_shared(unsigned long vaddr, unsigned long npages) 522 { 523 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 524 return; 525 526 set_pages_state(vaddr, npages, SNP_PAGE_STATE_SHARED); 527 } 528 529 void snp_set_memory_private(unsigned long vaddr, unsigned long npages) 530 { 531 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 532 return; 533 534 set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); 535 } 536 537 void snp_accept_memory(phys_addr_t start, phys_addr_t end) 538 { 539 unsigned long vaddr, npages; 540 541 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 542 return; 543 544 vaddr = (unsigned long)__va(start); 545 npages = (end - start) >> PAGE_SHIFT; 546 547 set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); 548 } 549 550 static int vmgexit_ap_control(u64 event, struct sev_es_save_area *vmsa, u32 apic_id) 551 { 552 bool create = event != SVM_VMGEXIT_AP_DESTROY; 553 struct ghcb_state state; 554 unsigned long flags; 555 struct ghcb *ghcb; 556 int ret = 0; 557 558 local_irq_save(flags); 559 560 ghcb = __sev_get_ghcb(&state); 561 562 vc_ghcb_invalidate(ghcb); 563 564 if (create) 565 ghcb_set_rax(ghcb, vmsa->sev_features); 566 567 ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION); 568 ghcb_set_sw_exit_info_1(ghcb, 569 ((u64)apic_id << 32) | 570 ((u64)snp_vmpl << 16) | 571 event); 572 ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa)); 573 574 sev_es_wr_ghcb_msr(__pa(ghcb)); 575 VMGEXIT(); 576 577 if (!ghcb_sw_exit_info_1_is_valid(ghcb) || 578 lower_32_bits(ghcb->save.sw_exit_info_1)) { 579 pr_err("SNP AP %s error\n", (create ? "CREATE" : "DESTROY")); 580 ret = -EINVAL; 581 } 582 583 __sev_put_ghcb(&state); 584 585 local_irq_restore(flags); 586 587 return ret; 588 } 589 590 static int snp_set_vmsa(void *va, void *caa, int apic_id, bool make_vmsa) 591 { 592 int ret; 593 594 if (snp_vmpl) { 595 struct svsm_call call = {}; 596 unsigned long flags; 597 598 local_irq_save(flags); 599 600 call.caa = this_cpu_read(svsm_caa); 601 call.rcx = __pa(va); 602 603 if (make_vmsa) { 604 /* Protocol 0, Call ID 2 */ 605 call.rax = SVSM_CORE_CALL(SVSM_CORE_CREATE_VCPU); 606 call.rdx = __pa(caa); 607 call.r8 = apic_id; 608 } else { 609 /* Protocol 0, Call ID 3 */ 610 call.rax = SVSM_CORE_CALL(SVSM_CORE_DELETE_VCPU); 611 } 612 613 ret = svsm_perform_call_protocol(&call); 614 615 local_irq_restore(flags); 616 } else { 617 /* 618 * If the kernel runs at VMPL0, it can change the VMSA 619 * bit for a page using the RMPADJUST instruction. 620 * However, for the instruction to succeed it must 621 * target the permissions of a lesser privileged (higher 622 * numbered) VMPL level, so use VMPL1. 623 */ 624 u64 attrs = 1; 625 626 if (make_vmsa) 627 attrs |= RMPADJUST_VMSA_PAGE_BIT; 628 629 ret = rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs); 630 } 631 632 return ret; 633 } 634 635 static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa, int apic_id) 636 { 637 int err; 638 639 err = snp_set_vmsa(vmsa, NULL, apic_id, false); 640 if (err) 641 pr_err("clear VMSA page failed (%u), leaking page\n", err); 642 else 643 free_page((unsigned long)vmsa); 644 } 645 646 static void set_pte_enc(pte_t *kpte, int level, void *va) 647 { 648 struct pte_enc_desc d = { 649 .kpte = kpte, 650 .pte_level = level, 651 .va = va, 652 .encrypt = true 653 }; 654 655 prepare_pte_enc(&d); 656 set_pte_enc_mask(kpte, d.pfn, d.new_pgprot); 657 } 658 659 static void unshare_all_memory(void) 660 { 661 unsigned long addr, end, size, ghcb; 662 struct sev_es_runtime_data *data; 663 unsigned int npages, level; 664 bool skipped_addr; 665 pte_t *pte; 666 int cpu; 667 668 /* Unshare the direct mapping. */ 669 addr = PAGE_OFFSET; 670 end = PAGE_OFFSET + get_max_mapped(); 671 672 while (addr < end) { 673 pte = lookup_address(addr, &level); 674 size = page_level_size(level); 675 npages = size / PAGE_SIZE; 676 skipped_addr = false; 677 678 if (!pte || !pte_decrypted(*pte) || pte_none(*pte)) { 679 addr += size; 680 continue; 681 } 682 683 /* 684 * Ensure that all the per-CPU GHCBs are made private at the 685 * end of the unsharing loop so that the switch to the slower 686 * MSR protocol happens last. 687 */ 688 for_each_possible_cpu(cpu) { 689 data = per_cpu(runtime_data, cpu); 690 ghcb = (unsigned long)&data->ghcb_page; 691 692 /* Handle the case of a huge page containing the GHCB page */ 693 if (addr <= ghcb && ghcb < addr + size) { 694 skipped_addr = true; 695 break; 696 } 697 } 698 699 if (!skipped_addr) { 700 set_pte_enc(pte, level, (void *)addr); 701 snp_set_memory_private(addr, npages); 702 } 703 addr += size; 704 } 705 706 /* Unshare all bss decrypted memory. */ 707 addr = (unsigned long)__start_bss_decrypted; 708 end = (unsigned long)__start_bss_decrypted_unused; 709 npages = (end - addr) >> PAGE_SHIFT; 710 711 for (; addr < end; addr += PAGE_SIZE) { 712 pte = lookup_address(addr, &level); 713 if (!pte || !pte_decrypted(*pte) || pte_none(*pte)) 714 continue; 715 716 set_pte_enc(pte, level, (void *)addr); 717 } 718 addr = (unsigned long)__start_bss_decrypted; 719 snp_set_memory_private(addr, npages); 720 721 __flush_tlb_all(); 722 } 723 724 /* Stop new private<->shared conversions */ 725 void snp_kexec_begin(void) 726 { 727 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 728 return; 729 730 if (!IS_ENABLED(CONFIG_KEXEC_CORE)) 731 return; 732 733 /* 734 * Crash kernel ends up here with interrupts disabled: can't wait for 735 * conversions to finish. 736 * 737 * If race happened, just report and proceed. 738 */ 739 if (!set_memory_enc_stop_conversion()) 740 pr_warn("Failed to stop shared<->private conversions\n"); 741 } 742 743 /* 744 * Shutdown all APs except the one handling kexec/kdump and clearing 745 * the VMSA tag on AP's VMSA pages as they are not being used as 746 * VMSA page anymore. 747 */ 748 static void shutdown_all_aps(void) 749 { 750 struct sev_es_save_area *vmsa; 751 int apic_id, this_cpu, cpu; 752 753 this_cpu = get_cpu(); 754 755 /* 756 * APs are already in HLT loop when enc_kexec_finish() callback 757 * is invoked. 758 */ 759 for_each_present_cpu(cpu) { 760 vmsa = per_cpu(sev_vmsa, cpu); 761 762 /* 763 * The BSP or offlined APs do not have guest allocated VMSA 764 * and there is no need to clear the VMSA tag for this page. 765 */ 766 if (!vmsa) 767 continue; 768 769 /* 770 * Cannot clear the VMSA tag for the currently running vCPU. 771 */ 772 if (this_cpu == cpu) { 773 unsigned long pa; 774 struct page *p; 775 776 pa = __pa(vmsa); 777 /* 778 * Mark the VMSA page of the running vCPU as offline 779 * so that is excluded and not touched by makedumpfile 780 * while generating vmcore during kdump. 781 */ 782 p = pfn_to_online_page(pa >> PAGE_SHIFT); 783 if (p) 784 __SetPageOffline(p); 785 continue; 786 } 787 788 apic_id = cpuid_to_apicid[cpu]; 789 790 /* 791 * Issue AP destroy to ensure AP gets kicked out of guest mode 792 * to allow using RMPADJUST to remove the VMSA tag on it's 793 * VMSA page. 794 */ 795 vmgexit_ap_control(SVM_VMGEXIT_AP_DESTROY, vmsa, apic_id); 796 snp_cleanup_vmsa(vmsa, apic_id); 797 } 798 799 put_cpu(); 800 } 801 802 void snp_kexec_finish(void) 803 { 804 struct sev_es_runtime_data *data; 805 unsigned long size, addr; 806 unsigned int level, cpu; 807 struct ghcb *ghcb; 808 pte_t *pte; 809 810 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 811 return; 812 813 if (!IS_ENABLED(CONFIG_KEXEC_CORE)) 814 return; 815 816 shutdown_all_aps(); 817 818 unshare_all_memory(); 819 820 /* 821 * Switch to using the MSR protocol to change per-CPU GHCBs to 822 * private. All the per-CPU GHCBs have been switched back to private, 823 * so can't do any more GHCB calls to the hypervisor beyond this point 824 * until the kexec'ed kernel starts running. 825 */ 826 boot_ghcb = NULL; 827 sev_cfg.ghcbs_initialized = false; 828 829 for_each_possible_cpu(cpu) { 830 data = per_cpu(runtime_data, cpu); 831 ghcb = &data->ghcb_page; 832 pte = lookup_address((unsigned long)ghcb, &level); 833 size = page_level_size(level); 834 /* Handle the case of a huge page containing the GHCB page */ 835 addr = (unsigned long)ghcb & page_level_mask(level); 836 set_pte_enc(pte, level, (void *)addr); 837 snp_set_memory_private(addr, (size / PAGE_SIZE)); 838 } 839 } 840 841 #define __ATTR_BASE (SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK) 842 #define INIT_CS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_READ_MASK | SVM_SELECTOR_CODE_MASK) 843 #define INIT_DS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_WRITE_MASK) 844 845 #define INIT_LDTR_ATTRIBS (SVM_SELECTOR_P_MASK | 2) 846 #define INIT_TR_ATTRIBS (SVM_SELECTOR_P_MASK | 3) 847 848 static void *snp_alloc_vmsa_page(int cpu) 849 { 850 struct page *p; 851 852 /* 853 * Allocate VMSA page to work around the SNP erratum where the CPU will 854 * incorrectly signal an RMP violation #PF if a large page (2MB or 1GB) 855 * collides with the RMP entry of VMSA page. The recommended workaround 856 * is to not use a large page. 857 * 858 * Allocate an 8k page which is also 8k-aligned. 859 */ 860 p = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1); 861 if (!p) 862 return NULL; 863 864 split_page(p, 1); 865 866 /* Free the first 4k. This page may be 2M/1G aligned and cannot be used. */ 867 __free_page(p); 868 869 return page_address(p + 1); 870 } 871 872 static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip, unsigned int cpu) 873 { 874 struct sev_es_save_area *cur_vmsa, *vmsa; 875 struct svsm_ca *caa; 876 u8 sipi_vector; 877 int ret; 878 u64 cr4; 879 880 /* 881 * The hypervisor SNP feature support check has happened earlier, just check 882 * the AP_CREATION one here. 883 */ 884 if (!(sev_hv_features & GHCB_HV_FT_SNP_AP_CREATION)) 885 return -EOPNOTSUPP; 886 887 /* 888 * Verify the desired start IP against the known trampoline start IP 889 * to catch any future new trampolines that may be introduced that 890 * would require a new protected guest entry point. 891 */ 892 if (WARN_ONCE(start_ip != real_mode_header->trampoline_start, 893 "Unsupported SNP start_ip: %lx\n", start_ip)) 894 return -EINVAL; 895 896 /* Override start_ip with known protected guest start IP */ 897 start_ip = real_mode_header->sev_es_trampoline_start; 898 cur_vmsa = per_cpu(sev_vmsa, cpu); 899 900 /* 901 * A new VMSA is created each time because there is no guarantee that 902 * the current VMSA is the kernels or that the vCPU is not running. If 903 * an attempt was done to use the current VMSA with a running vCPU, a 904 * #VMEXIT of that vCPU would wipe out all of the settings being done 905 * here. 906 */ 907 vmsa = (struct sev_es_save_area *)snp_alloc_vmsa_page(cpu); 908 if (!vmsa) 909 return -ENOMEM; 910 911 /* If an SVSM is present, the SVSM per-CPU CAA will be !NULL */ 912 caa = per_cpu(svsm_caa, cpu); 913 914 /* CR4 should maintain the MCE value */ 915 cr4 = native_read_cr4() & X86_CR4_MCE; 916 917 /* Set the CS value based on the start_ip converted to a SIPI vector */ 918 sipi_vector = (start_ip >> 12); 919 vmsa->cs.base = sipi_vector << 12; 920 vmsa->cs.limit = AP_INIT_CS_LIMIT; 921 vmsa->cs.attrib = INIT_CS_ATTRIBS; 922 vmsa->cs.selector = sipi_vector << 8; 923 924 /* Set the RIP value based on start_ip */ 925 vmsa->rip = start_ip & 0xfff; 926 927 /* Set AP INIT defaults as documented in the APM */ 928 vmsa->ds.limit = AP_INIT_DS_LIMIT; 929 vmsa->ds.attrib = INIT_DS_ATTRIBS; 930 vmsa->es = vmsa->ds; 931 vmsa->fs = vmsa->ds; 932 vmsa->gs = vmsa->ds; 933 vmsa->ss = vmsa->ds; 934 935 vmsa->gdtr.limit = AP_INIT_GDTR_LIMIT; 936 vmsa->ldtr.limit = AP_INIT_LDTR_LIMIT; 937 vmsa->ldtr.attrib = INIT_LDTR_ATTRIBS; 938 vmsa->idtr.limit = AP_INIT_IDTR_LIMIT; 939 vmsa->tr.limit = AP_INIT_TR_LIMIT; 940 vmsa->tr.attrib = INIT_TR_ATTRIBS; 941 942 vmsa->cr4 = cr4; 943 vmsa->cr0 = AP_INIT_CR0_DEFAULT; 944 vmsa->dr7 = DR7_RESET_VALUE; 945 vmsa->dr6 = AP_INIT_DR6_DEFAULT; 946 vmsa->rflags = AP_INIT_RFLAGS_DEFAULT; 947 vmsa->g_pat = AP_INIT_GPAT_DEFAULT; 948 vmsa->xcr0 = AP_INIT_XCR0_DEFAULT; 949 vmsa->mxcsr = AP_INIT_MXCSR_DEFAULT; 950 vmsa->x87_ftw = AP_INIT_X87_FTW_DEFAULT; 951 vmsa->x87_fcw = AP_INIT_X87_FCW_DEFAULT; 952 953 /* SVME must be set. */ 954 vmsa->efer = EFER_SVME; 955 956 /* 957 * Set the SNP-specific fields for this VMSA: 958 * VMPL level 959 * SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits) 960 */ 961 vmsa->vmpl = snp_vmpl; 962 vmsa->sev_features = sev_status >> 2; 963 964 /* Populate AP's TSC scale/offset to get accurate TSC values. */ 965 if (cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) { 966 vmsa->tsc_scale = snp_tsc_scale; 967 vmsa->tsc_offset = snp_tsc_offset; 968 } 969 970 /* Switch the page over to a VMSA page now that it is initialized */ 971 ret = snp_set_vmsa(vmsa, caa, apic_id, true); 972 if (ret) { 973 pr_err("set VMSA page failed (%u)\n", ret); 974 free_page((unsigned long)vmsa); 975 976 return -EINVAL; 977 } 978 979 /* Issue VMGEXIT AP Creation NAE event */ 980 ret = vmgexit_ap_control(SVM_VMGEXIT_AP_CREATE, vmsa, apic_id); 981 if (ret) { 982 snp_cleanup_vmsa(vmsa, apic_id); 983 vmsa = NULL; 984 } 985 986 /* Free up any previous VMSA page */ 987 if (cur_vmsa) 988 snp_cleanup_vmsa(cur_vmsa, apic_id); 989 990 /* Record the current VMSA page */ 991 per_cpu(sev_vmsa, cpu) = vmsa; 992 993 return ret; 994 } 995 996 void __init snp_set_wakeup_secondary_cpu(void) 997 { 998 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 999 return; 1000 1001 /* 1002 * Always set this override if SNP is enabled. This makes it the 1003 * required method to start APs under SNP. If the hypervisor does 1004 * not support AP creation, then no APs will be started. 1005 */ 1006 apic_update_callback(wakeup_secondary_cpu, wakeup_cpu_via_vmgexit); 1007 } 1008 1009 int __init sev_es_setup_ap_jump_table(struct real_mode_header *rmh) 1010 { 1011 u16 startup_cs, startup_ip; 1012 phys_addr_t jump_table_pa; 1013 u64 jump_table_addr; 1014 u16 __iomem *jump_table; 1015 1016 jump_table_addr = get_jump_table_addr(); 1017 1018 /* On UP guests there is no jump table so this is not a failure */ 1019 if (!jump_table_addr) 1020 return 0; 1021 1022 /* Check if AP Jump Table is page-aligned */ 1023 if (jump_table_addr & ~PAGE_MASK) 1024 return -EINVAL; 1025 1026 jump_table_pa = jump_table_addr & PAGE_MASK; 1027 1028 startup_cs = (u16)(rmh->trampoline_start >> 4); 1029 startup_ip = (u16)(rmh->sev_es_trampoline_start - 1030 rmh->trampoline_start); 1031 1032 jump_table = ioremap_encrypted(jump_table_pa, PAGE_SIZE); 1033 if (!jump_table) 1034 return -EIO; 1035 1036 writew(startup_ip, &jump_table[0]); 1037 writew(startup_cs, &jump_table[1]); 1038 1039 iounmap(jump_table); 1040 1041 return 0; 1042 } 1043 1044 /* 1045 * This is needed by the OVMF UEFI firmware which will use whatever it finds in 1046 * the GHCB MSR as its GHCB to talk to the hypervisor. So make sure the per-cpu 1047 * runtime GHCBs used by the kernel are also mapped in the EFI page-table. 1048 */ 1049 int __init sev_es_efi_map_ghcbs(pgd_t *pgd) 1050 { 1051 struct sev_es_runtime_data *data; 1052 unsigned long address, pflags; 1053 int cpu; 1054 u64 pfn; 1055 1056 if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) 1057 return 0; 1058 1059 pflags = _PAGE_NX | _PAGE_RW; 1060 1061 for_each_possible_cpu(cpu) { 1062 data = per_cpu(runtime_data, cpu); 1063 1064 address = __pa(&data->ghcb_page); 1065 pfn = address >> PAGE_SHIFT; 1066 1067 if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags)) 1068 return 1; 1069 } 1070 1071 return 0; 1072 } 1073 1074 static void snp_register_per_cpu_ghcb(void) 1075 { 1076 struct sev_es_runtime_data *data; 1077 struct ghcb *ghcb; 1078 1079 data = this_cpu_read(runtime_data); 1080 ghcb = &data->ghcb_page; 1081 1082 snp_register_ghcb_early(__pa(ghcb)); 1083 } 1084 1085 void setup_ghcb(void) 1086 { 1087 if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) 1088 return; 1089 1090 /* 1091 * Check whether the runtime #VC exception handler is active. It uses 1092 * the per-CPU GHCB page which is set up by sev_es_init_vc_handling(). 1093 * 1094 * If SNP is active, register the per-CPU GHCB page so that the runtime 1095 * exception handler can use it. 1096 */ 1097 if (initial_vc_handler == (unsigned long)kernel_exc_vmm_communication) { 1098 if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 1099 snp_register_per_cpu_ghcb(); 1100 1101 sev_cfg.ghcbs_initialized = true; 1102 1103 return; 1104 } 1105 1106 /* 1107 * Make sure the hypervisor talks a supported protocol. 1108 * This gets called only in the BSP boot phase. 1109 */ 1110 if (!sev_es_negotiate_protocol()) 1111 sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); 1112 1113 /* 1114 * Clear the boot_ghcb. The first exception comes in before the bss 1115 * section is cleared. 1116 */ 1117 memset(&boot_ghcb_page, 0, PAGE_SIZE); 1118 1119 /* Alright - Make the boot-ghcb public */ 1120 boot_ghcb = &boot_ghcb_page; 1121 1122 /* SNP guest requires that GHCB GPA must be registered. */ 1123 if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 1124 snp_register_ghcb_early(__pa(&boot_ghcb_page)); 1125 } 1126 1127 #ifdef CONFIG_HOTPLUG_CPU 1128 static void sev_es_ap_hlt_loop(void) 1129 { 1130 struct ghcb_state state; 1131 struct ghcb *ghcb; 1132 1133 ghcb = __sev_get_ghcb(&state); 1134 1135 while (true) { 1136 vc_ghcb_invalidate(ghcb); 1137 ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_HLT_LOOP); 1138 ghcb_set_sw_exit_info_1(ghcb, 0); 1139 ghcb_set_sw_exit_info_2(ghcb, 0); 1140 1141 sev_es_wr_ghcb_msr(__pa(ghcb)); 1142 VMGEXIT(); 1143 1144 /* Wakeup signal? */ 1145 if (ghcb_sw_exit_info_2_is_valid(ghcb) && 1146 ghcb->save.sw_exit_info_2) 1147 break; 1148 } 1149 1150 __sev_put_ghcb(&state); 1151 } 1152 1153 /* 1154 * Play_dead handler when running under SEV-ES. This is needed because 1155 * the hypervisor can't deliver an SIPI request to restart the AP. 1156 * Instead the kernel has to issue a VMGEXIT to halt the VCPU until the 1157 * hypervisor wakes it up again. 1158 */ 1159 static void sev_es_play_dead(void) 1160 { 1161 play_dead_common(); 1162 1163 /* IRQs now disabled */ 1164 1165 sev_es_ap_hlt_loop(); 1166 1167 /* 1168 * If we get here, the VCPU was woken up again. Jump to CPU 1169 * startup code to get it back online. 1170 */ 1171 soft_restart_cpu(); 1172 } 1173 #else /* CONFIG_HOTPLUG_CPU */ 1174 #define sev_es_play_dead native_play_dead 1175 #endif /* CONFIG_HOTPLUG_CPU */ 1176 1177 #ifdef CONFIG_SMP 1178 static void __init sev_es_setup_play_dead(void) 1179 { 1180 smp_ops.play_dead = sev_es_play_dead; 1181 } 1182 #else 1183 static inline void sev_es_setup_play_dead(void) { } 1184 #endif 1185 1186 static void __init alloc_runtime_data(int cpu) 1187 { 1188 struct sev_es_runtime_data *data; 1189 1190 data = memblock_alloc_node(sizeof(*data), PAGE_SIZE, cpu_to_node(cpu)); 1191 if (!data) 1192 panic("Can't allocate SEV-ES runtime data"); 1193 1194 per_cpu(runtime_data, cpu) = data; 1195 1196 if (snp_vmpl) { 1197 struct svsm_ca *caa; 1198 1199 /* Allocate the SVSM CA page if an SVSM is present */ 1200 caa = memblock_alloc_or_panic(sizeof(*caa), PAGE_SIZE); 1201 1202 per_cpu(svsm_caa, cpu) = caa; 1203 per_cpu(svsm_caa_pa, cpu) = __pa(caa); 1204 } 1205 } 1206 1207 static void __init init_ghcb(int cpu) 1208 { 1209 struct sev_es_runtime_data *data; 1210 int err; 1211 1212 data = per_cpu(runtime_data, cpu); 1213 1214 err = early_set_memory_decrypted((unsigned long)&data->ghcb_page, 1215 sizeof(data->ghcb_page)); 1216 if (err) 1217 panic("Can't map GHCBs unencrypted"); 1218 1219 memset(&data->ghcb_page, 0, sizeof(data->ghcb_page)); 1220 1221 data->ghcb_active = false; 1222 data->backup_ghcb_active = false; 1223 } 1224 1225 void __init sev_es_init_vc_handling(void) 1226 { 1227 int cpu; 1228 1229 BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE); 1230 1231 if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) 1232 return; 1233 1234 if (!sev_es_check_cpu_features()) 1235 panic("SEV-ES CPU Features missing"); 1236 1237 /* 1238 * SNP is supported in v2 of the GHCB spec which mandates support for HV 1239 * features. 1240 */ 1241 if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) { 1242 sev_hv_features = get_hv_features(); 1243 1244 if (!(sev_hv_features & GHCB_HV_FT_SNP)) 1245 sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); 1246 } 1247 1248 /* Initialize per-cpu GHCB pages */ 1249 for_each_possible_cpu(cpu) { 1250 alloc_runtime_data(cpu); 1251 init_ghcb(cpu); 1252 } 1253 1254 /* If running under an SVSM, switch to the per-cpu CA */ 1255 if (snp_vmpl) { 1256 struct svsm_call call = {}; 1257 unsigned long flags; 1258 int ret; 1259 1260 local_irq_save(flags); 1261 1262 /* 1263 * SVSM_CORE_REMAP_CA call: 1264 * RAX = 0 (Protocol=0, CallID=0) 1265 * RCX = New CA GPA 1266 */ 1267 call.caa = svsm_get_caa(); 1268 call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA); 1269 call.rcx = this_cpu_read(svsm_caa_pa); 1270 ret = svsm_perform_call_protocol(&call); 1271 if (ret) 1272 panic("Can't remap the SVSM CA, ret=%d, rax_out=0x%llx\n", 1273 ret, call.rax_out); 1274 1275 sev_cfg.use_cas = true; 1276 1277 local_irq_restore(flags); 1278 } 1279 1280 sev_es_setup_play_dead(); 1281 1282 /* Secondary CPUs use the runtime #VC handler */ 1283 initial_vc_handler = (unsigned long)kernel_exc_vmm_communication; 1284 } 1285 1286 /* 1287 * SEV-SNP guests should only execute dmi_setup() if EFI_CONFIG_TABLES are 1288 * enabled, as the alternative (fallback) logic for DMI probing in the legacy 1289 * ROM region can cause a crash since this region is not pre-validated. 1290 */ 1291 void __init snp_dmi_setup(void) 1292 { 1293 if (efi_enabled(EFI_CONFIG_TABLES)) 1294 dmi_setup(); 1295 } 1296 1297 static void dump_cpuid_table(void) 1298 { 1299 const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); 1300 int i = 0; 1301 1302 pr_info("count=%d reserved=0x%x reserved2=0x%llx\n", 1303 cpuid_table->count, cpuid_table->__reserved1, cpuid_table->__reserved2); 1304 1305 for (i = 0; i < SNP_CPUID_COUNT_MAX; i++) { 1306 const struct snp_cpuid_fn *fn = &cpuid_table->fn[i]; 1307 1308 pr_info("index=%3d fn=0x%08x subfn=0x%08x: eax=0x%08x ebx=0x%08x ecx=0x%08x edx=0x%08x xcr0_in=0x%016llx xss_in=0x%016llx reserved=0x%016llx\n", 1309 i, fn->eax_in, fn->ecx_in, fn->eax, fn->ebx, fn->ecx, 1310 fn->edx, fn->xcr0_in, fn->xss_in, fn->__reserved); 1311 } 1312 } 1313 1314 /* 1315 * It is useful from an auditing/testing perspective to provide an easy way 1316 * for the guest owner to know that the CPUID table has been initialized as 1317 * expected, but that initialization happens too early in boot to print any 1318 * sort of indicator, and there's not really any other good place to do it, 1319 * so do it here. 1320 * 1321 * If running as an SNP guest, report the current VM privilege level (VMPL). 1322 */ 1323 static int __init report_snp_info(void) 1324 { 1325 const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); 1326 1327 if (cpuid_table->count) { 1328 pr_info("Using SNP CPUID table, %d entries present.\n", 1329 cpuid_table->count); 1330 1331 if (sev_cfg.debug) 1332 dump_cpuid_table(); 1333 } 1334 1335 if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 1336 pr_info("SNP running at VMPL%u.\n", snp_vmpl); 1337 1338 return 0; 1339 } 1340 arch_initcall(report_snp_info); 1341 1342 static void update_attest_input(struct svsm_call *call, struct svsm_attest_call *input) 1343 { 1344 /* If (new) lengths have been returned, propagate them up */ 1345 if (call->rcx_out != call->rcx) 1346 input->manifest_buf.len = call->rcx_out; 1347 1348 if (call->rdx_out != call->rdx) 1349 input->certificates_buf.len = call->rdx_out; 1350 1351 if (call->r8_out != call->r8) 1352 input->report_buf.len = call->r8_out; 1353 } 1354 1355 int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, 1356 struct svsm_attest_call *input) 1357 { 1358 struct svsm_attest_call *ac; 1359 unsigned long flags; 1360 u64 attest_call_pa; 1361 int ret; 1362 1363 if (!snp_vmpl) 1364 return -EINVAL; 1365 1366 local_irq_save(flags); 1367 1368 call->caa = svsm_get_caa(); 1369 1370 ac = (struct svsm_attest_call *)call->caa->svsm_buffer; 1371 attest_call_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer); 1372 1373 *ac = *input; 1374 1375 /* 1376 * Set input registers for the request and set RDX and R8 to known 1377 * values in order to detect length values being returned in them. 1378 */ 1379 call->rax = call_id; 1380 call->rcx = attest_call_pa; 1381 call->rdx = -1; 1382 call->r8 = -1; 1383 ret = svsm_perform_call_protocol(call); 1384 update_attest_input(call, input); 1385 1386 local_irq_restore(flags); 1387 1388 return ret; 1389 } 1390 EXPORT_SYMBOL_GPL(snp_issue_svsm_attest_req); 1391 1392 static int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input, 1393 struct snp_guest_request_ioctl *rio) 1394 { 1395 struct ghcb_state state; 1396 struct es_em_ctxt ctxt; 1397 unsigned long flags; 1398 struct ghcb *ghcb; 1399 int ret; 1400 1401 rio->exitinfo2 = SEV_RET_NO_FW_CALL; 1402 1403 /* 1404 * __sev_get_ghcb() needs to run with IRQs disabled because it is using 1405 * a per-CPU GHCB. 1406 */ 1407 local_irq_save(flags); 1408 1409 ghcb = __sev_get_ghcb(&state); 1410 if (!ghcb) { 1411 ret = -EIO; 1412 goto e_restore_irq; 1413 } 1414 1415 vc_ghcb_invalidate(ghcb); 1416 1417 if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { 1418 ghcb_set_rax(ghcb, input->data_gpa); 1419 ghcb_set_rbx(ghcb, input->data_npages); 1420 } 1421 1422 ret = sev_es_ghcb_hv_call(ghcb, &ctxt, req->exit_code, input->req_gpa, input->resp_gpa); 1423 if (ret) 1424 goto e_put; 1425 1426 rio->exitinfo2 = ghcb->save.sw_exit_info_2; 1427 switch (rio->exitinfo2) { 1428 case 0: 1429 break; 1430 1431 case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_BUSY): 1432 ret = -EAGAIN; 1433 break; 1434 1435 case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN): 1436 /* Number of expected pages are returned in RBX */ 1437 if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { 1438 input->data_npages = ghcb_get_rbx(ghcb); 1439 ret = -ENOSPC; 1440 break; 1441 } 1442 fallthrough; 1443 default: 1444 ret = -EIO; 1445 break; 1446 } 1447 1448 e_put: 1449 __sev_put_ghcb(&state); 1450 e_restore_irq: 1451 local_irq_restore(flags); 1452 1453 return ret; 1454 } 1455 1456 /** 1457 * snp_svsm_vtpm_probe() - Probe if SVSM provides a vTPM device 1458 * 1459 * Check that there is SVSM and that it supports at least TPM_SEND_COMMAND 1460 * which is the only request used so far. 1461 * 1462 * Return: true if the platform provides a vTPM SVSM device, false otherwise. 1463 */ 1464 static bool snp_svsm_vtpm_probe(void) 1465 { 1466 struct svsm_call call = {}; 1467 1468 /* The vTPM device is available only if a SVSM is present */ 1469 if (!snp_vmpl) 1470 return false; 1471 1472 call.caa = svsm_get_caa(); 1473 call.rax = SVSM_VTPM_CALL(SVSM_VTPM_QUERY); 1474 1475 if (svsm_perform_call_protocol(&call)) 1476 return false; 1477 1478 /* Check platform commands contains TPM_SEND_COMMAND - platform command 8 */ 1479 return call.rcx_out & BIT_ULL(8); 1480 } 1481 1482 /** 1483 * snp_svsm_vtpm_send_command() - Execute a vTPM operation on SVSM 1484 * @buffer: A buffer used to both send the command and receive the response. 1485 * 1486 * Execute a SVSM_VTPM_CMD call as defined by 1487 * "Secure VM Service Module for SEV-SNP Guests" Publication # 58019 Revision: 1.00 1488 * 1489 * All command request/response buffers have a common structure as specified by 1490 * the following table: 1491 * Byte Size In/Out Description 1492 * Offset (Bytes) 1493 * 0x000 4 In Platform command 1494 * Out Platform command response size 1495 * 1496 * Each command can build upon this common request/response structure to create 1497 * a structure specific to the command. See include/linux/tpm_svsm.h for more 1498 * details. 1499 * 1500 * Return: 0 on success, -errno on failure 1501 */ 1502 int snp_svsm_vtpm_send_command(u8 *buffer) 1503 { 1504 struct svsm_call call = {}; 1505 1506 call.caa = svsm_get_caa(); 1507 call.rax = SVSM_VTPM_CALL(SVSM_VTPM_CMD); 1508 call.rcx = __pa(buffer); 1509 1510 return svsm_perform_call_protocol(&call); 1511 } 1512 EXPORT_SYMBOL_GPL(snp_svsm_vtpm_send_command); 1513 1514 static struct platform_device sev_guest_device = { 1515 .name = "sev-guest", 1516 .id = -1, 1517 }; 1518 1519 static struct platform_device tpm_svsm_device = { 1520 .name = "tpm-svsm", 1521 .id = -1, 1522 }; 1523 1524 static int __init snp_init_platform_device(void) 1525 { 1526 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 1527 return -ENODEV; 1528 1529 if (platform_device_register(&sev_guest_device)) 1530 return -ENODEV; 1531 1532 if (snp_svsm_vtpm_probe() && 1533 platform_device_register(&tpm_svsm_device)) 1534 return -ENODEV; 1535 1536 pr_info("SNP guest platform devices initialized.\n"); 1537 return 0; 1538 } 1539 device_initcall(snp_init_platform_device); 1540 1541 void sev_show_status(void) 1542 { 1543 int i; 1544 1545 pr_info("Status: "); 1546 for (i = 0; i < MSR_AMD64_SNP_RESV_BIT; i++) { 1547 if (sev_status & BIT_ULL(i)) { 1548 if (!sev_status_feat_names[i]) 1549 continue; 1550 1551 pr_cont("%s ", sev_status_feat_names[i]); 1552 } 1553 } 1554 pr_cont("\n"); 1555 } 1556 1557 void __init snp_update_svsm_ca(void) 1558 { 1559 if (!snp_vmpl) 1560 return; 1561 1562 /* Update the CAA to a proper kernel address */ 1563 boot_svsm_caa = &boot_svsm_ca_page; 1564 } 1565 1566 #ifdef CONFIG_SYSFS 1567 static ssize_t vmpl_show(struct kobject *kobj, 1568 struct kobj_attribute *attr, char *buf) 1569 { 1570 return sysfs_emit(buf, "%d\n", snp_vmpl); 1571 } 1572 1573 static struct kobj_attribute vmpl_attr = __ATTR_RO(vmpl); 1574 1575 static struct attribute *vmpl_attrs[] = { 1576 &vmpl_attr.attr, 1577 NULL 1578 }; 1579 1580 static struct attribute_group sev_attr_group = { 1581 .attrs = vmpl_attrs, 1582 }; 1583 1584 static int __init sev_sysfs_init(void) 1585 { 1586 struct kobject *sev_kobj; 1587 struct device *dev_root; 1588 int ret; 1589 1590 if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 1591 return -ENODEV; 1592 1593 dev_root = bus_get_dev_root(&cpu_subsys); 1594 if (!dev_root) 1595 return -ENODEV; 1596 1597 sev_kobj = kobject_create_and_add("sev", &dev_root->kobj); 1598 put_device(dev_root); 1599 1600 if (!sev_kobj) 1601 return -ENOMEM; 1602 1603 ret = sysfs_create_group(sev_kobj, &sev_attr_group); 1604 if (ret) 1605 kobject_put(sev_kobj); 1606 1607 return ret; 1608 } 1609 arch_initcall(sev_sysfs_init); 1610 #endif // CONFIG_SYSFS 1611 1612 static void free_shared_pages(void *buf, size_t sz) 1613 { 1614 unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; 1615 int ret; 1616 1617 if (!buf) 1618 return; 1619 1620 ret = set_memory_encrypted((unsigned long)buf, npages); 1621 if (ret) { 1622 WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n"); 1623 return; 1624 } 1625 1626 __free_pages(virt_to_page(buf), get_order(sz)); 1627 } 1628 1629 static void *alloc_shared_pages(size_t sz) 1630 { 1631 unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; 1632 struct page *page; 1633 int ret; 1634 1635 page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz)); 1636 if (!page) 1637 return NULL; 1638 1639 ret = set_memory_decrypted((unsigned long)page_address(page), npages); 1640 if (ret) { 1641 pr_err("failed to mark page shared, ret=%d\n", ret); 1642 __free_pages(page, get_order(sz)); 1643 return NULL; 1644 } 1645 1646 return page_address(page); 1647 } 1648 1649 static u8 *get_vmpck(int id, struct snp_secrets_page *secrets, u32 **seqno) 1650 { 1651 u8 *key = NULL; 1652 1653 switch (id) { 1654 case 0: 1655 *seqno = &secrets->os_area.msg_seqno_0; 1656 key = secrets->vmpck0; 1657 break; 1658 case 1: 1659 *seqno = &secrets->os_area.msg_seqno_1; 1660 key = secrets->vmpck1; 1661 break; 1662 case 2: 1663 *seqno = &secrets->os_area.msg_seqno_2; 1664 key = secrets->vmpck2; 1665 break; 1666 case 3: 1667 *seqno = &secrets->os_area.msg_seqno_3; 1668 key = secrets->vmpck3; 1669 break; 1670 default: 1671 break; 1672 } 1673 1674 return key; 1675 } 1676 1677 static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen) 1678 { 1679 struct aesgcm_ctx *ctx; 1680 1681 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); 1682 if (!ctx) 1683 return NULL; 1684 1685 if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) { 1686 pr_err("Crypto context initialization failed\n"); 1687 kfree(ctx); 1688 return NULL; 1689 } 1690 1691 return ctx; 1692 } 1693 1694 int snp_msg_init(struct snp_msg_desc *mdesc, int vmpck_id) 1695 { 1696 /* Adjust the default VMPCK key based on the executing VMPL level */ 1697 if (vmpck_id == -1) 1698 vmpck_id = snp_vmpl; 1699 1700 mdesc->vmpck = get_vmpck(vmpck_id, mdesc->secrets, &mdesc->os_area_msg_seqno); 1701 if (!mdesc->vmpck) { 1702 pr_err("Invalid VMPCK%d communication key\n", vmpck_id); 1703 return -EINVAL; 1704 } 1705 1706 /* Verify that VMPCK is not zero. */ 1707 if (!memchr_inv(mdesc->vmpck, 0, VMPCK_KEY_LEN)) { 1708 pr_err("Empty VMPCK%d communication key\n", vmpck_id); 1709 return -EINVAL; 1710 } 1711 1712 mdesc->vmpck_id = vmpck_id; 1713 1714 mdesc->ctx = snp_init_crypto(mdesc->vmpck, VMPCK_KEY_LEN); 1715 if (!mdesc->ctx) 1716 return -ENOMEM; 1717 1718 return 0; 1719 } 1720 EXPORT_SYMBOL_GPL(snp_msg_init); 1721 1722 struct snp_msg_desc *snp_msg_alloc(void) 1723 { 1724 struct snp_msg_desc *mdesc; 1725 void __iomem *mem; 1726 1727 BUILD_BUG_ON(sizeof(struct snp_guest_msg) > PAGE_SIZE); 1728 1729 mdesc = kzalloc(sizeof(struct snp_msg_desc), GFP_KERNEL); 1730 if (!mdesc) 1731 return ERR_PTR(-ENOMEM); 1732 1733 mem = ioremap_encrypted(sev_secrets_pa, PAGE_SIZE); 1734 if (!mem) 1735 goto e_free_mdesc; 1736 1737 mdesc->secrets = (__force struct snp_secrets_page *)mem; 1738 1739 /* Allocate the shared page used for the request and response message. */ 1740 mdesc->request = alloc_shared_pages(sizeof(struct snp_guest_msg)); 1741 if (!mdesc->request) 1742 goto e_unmap; 1743 1744 mdesc->response = alloc_shared_pages(sizeof(struct snp_guest_msg)); 1745 if (!mdesc->response) 1746 goto e_free_request; 1747 1748 return mdesc; 1749 1750 e_free_request: 1751 free_shared_pages(mdesc->request, sizeof(struct snp_guest_msg)); 1752 e_unmap: 1753 iounmap(mem); 1754 e_free_mdesc: 1755 kfree(mdesc); 1756 1757 return ERR_PTR(-ENOMEM); 1758 } 1759 EXPORT_SYMBOL_GPL(snp_msg_alloc); 1760 1761 void snp_msg_free(struct snp_msg_desc *mdesc) 1762 { 1763 if (!mdesc) 1764 return; 1765 1766 kfree(mdesc->ctx); 1767 free_shared_pages(mdesc->response, sizeof(struct snp_guest_msg)); 1768 free_shared_pages(mdesc->request, sizeof(struct snp_guest_msg)); 1769 iounmap((__force void __iomem *)mdesc->secrets); 1770 1771 memset(mdesc, 0, sizeof(*mdesc)); 1772 kfree(mdesc); 1773 } 1774 EXPORT_SYMBOL_GPL(snp_msg_free); 1775 1776 /* Mutex to serialize the shared buffer access and command handling. */ 1777 static DEFINE_MUTEX(snp_cmd_mutex); 1778 1779 /* 1780 * If an error is received from the host or AMD Secure Processor (ASP) there 1781 * are two options. Either retry the exact same encrypted request or discontinue 1782 * using the VMPCK. 1783 * 1784 * This is because in the current encryption scheme GHCB v2 uses AES-GCM to 1785 * encrypt the requests. The IV for this scheme is the sequence number. GCM 1786 * cannot tolerate IV reuse. 1787 * 1788 * The ASP FW v1.51 only increments the sequence numbers on a successful 1789 * guest<->ASP back and forth and only accepts messages at its exact sequence 1790 * number. 1791 * 1792 * So if the sequence number were to be reused the encryption scheme is 1793 * vulnerable. If the sequence number were incremented for a fresh IV the ASP 1794 * will reject the request. 1795 */ 1796 static void snp_disable_vmpck(struct snp_msg_desc *mdesc) 1797 { 1798 pr_alert("Disabling VMPCK%d communication key to prevent IV reuse.\n", 1799 mdesc->vmpck_id); 1800 memzero_explicit(mdesc->vmpck, VMPCK_KEY_LEN); 1801 mdesc->vmpck = NULL; 1802 } 1803 1804 static inline u64 __snp_get_msg_seqno(struct snp_msg_desc *mdesc) 1805 { 1806 u64 count; 1807 1808 lockdep_assert_held(&snp_cmd_mutex); 1809 1810 /* Read the current message sequence counter from secrets pages */ 1811 count = *mdesc->os_area_msg_seqno; 1812 1813 return count + 1; 1814 } 1815 1816 /* Return a non-zero on success */ 1817 static u64 snp_get_msg_seqno(struct snp_msg_desc *mdesc) 1818 { 1819 u64 count = __snp_get_msg_seqno(mdesc); 1820 1821 /* 1822 * The message sequence counter for the SNP guest request is a 64-bit 1823 * value but the version 2 of GHCB specification defines a 32-bit storage 1824 * for it. If the counter exceeds the 32-bit value then return zero. 1825 * The caller should check the return value, but if the caller happens to 1826 * not check the value and use it, then the firmware treats zero as an 1827 * invalid number and will fail the message request. 1828 */ 1829 if (count >= UINT_MAX) { 1830 pr_err("request message sequence counter overflow\n"); 1831 return 0; 1832 } 1833 1834 return count; 1835 } 1836 1837 static void snp_inc_msg_seqno(struct snp_msg_desc *mdesc) 1838 { 1839 /* 1840 * The counter is also incremented by the PSP, so increment it by 2 1841 * and save in secrets page. 1842 */ 1843 *mdesc->os_area_msg_seqno += 2; 1844 } 1845 1846 static int verify_and_dec_payload(struct snp_msg_desc *mdesc, struct snp_guest_req *req) 1847 { 1848 struct snp_guest_msg *resp_msg = &mdesc->secret_response; 1849 struct snp_guest_msg *req_msg = &mdesc->secret_request; 1850 struct snp_guest_msg_hdr *req_msg_hdr = &req_msg->hdr; 1851 struct snp_guest_msg_hdr *resp_msg_hdr = &resp_msg->hdr; 1852 struct aesgcm_ctx *ctx = mdesc->ctx; 1853 u8 iv[GCM_AES_IV_SIZE] = {}; 1854 1855 pr_debug("response [seqno %lld type %d version %d sz %d]\n", 1856 resp_msg_hdr->msg_seqno, resp_msg_hdr->msg_type, resp_msg_hdr->msg_version, 1857 resp_msg_hdr->msg_sz); 1858 1859 /* Copy response from shared memory to encrypted memory. */ 1860 memcpy(resp_msg, mdesc->response, sizeof(*resp_msg)); 1861 1862 /* Verify that the sequence counter is incremented by 1 */ 1863 if (unlikely(resp_msg_hdr->msg_seqno != (req_msg_hdr->msg_seqno + 1))) 1864 return -EBADMSG; 1865 1866 /* Verify response message type and version number. */ 1867 if (resp_msg_hdr->msg_type != (req_msg_hdr->msg_type + 1) || 1868 resp_msg_hdr->msg_version != req_msg_hdr->msg_version) 1869 return -EBADMSG; 1870 1871 /* 1872 * If the message size is greater than our buffer length then return 1873 * an error. 1874 */ 1875 if (unlikely((resp_msg_hdr->msg_sz + ctx->authsize) > req->resp_sz)) 1876 return -EBADMSG; 1877 1878 /* Decrypt the payload */ 1879 memcpy(iv, &resp_msg_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_msg_hdr->msg_seqno))); 1880 if (!aesgcm_decrypt(ctx, req->resp_buf, resp_msg->payload, resp_msg_hdr->msg_sz, 1881 &resp_msg_hdr->algo, AAD_LEN, iv, resp_msg_hdr->authtag)) 1882 return -EBADMSG; 1883 1884 return 0; 1885 } 1886 1887 static int enc_payload(struct snp_msg_desc *mdesc, u64 seqno, struct snp_guest_req *req) 1888 { 1889 struct snp_guest_msg *msg = &mdesc->secret_request; 1890 struct snp_guest_msg_hdr *hdr = &msg->hdr; 1891 struct aesgcm_ctx *ctx = mdesc->ctx; 1892 u8 iv[GCM_AES_IV_SIZE] = {}; 1893 1894 memset(msg, 0, sizeof(*msg)); 1895 1896 hdr->algo = SNP_AEAD_AES_256_GCM; 1897 hdr->hdr_version = MSG_HDR_VER; 1898 hdr->hdr_sz = sizeof(*hdr); 1899 hdr->msg_type = req->msg_type; 1900 hdr->msg_version = req->msg_version; 1901 hdr->msg_seqno = seqno; 1902 hdr->msg_vmpck = req->vmpck_id; 1903 hdr->msg_sz = req->req_sz; 1904 1905 /* Verify the sequence number is non-zero */ 1906 if (!hdr->msg_seqno) 1907 return -ENOSR; 1908 1909 pr_debug("request [seqno %lld type %d version %d sz %d]\n", 1910 hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz); 1911 1912 if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload))) 1913 return -EBADMSG; 1914 1915 memcpy(iv, &hdr->msg_seqno, min(sizeof(iv), sizeof(hdr->msg_seqno))); 1916 aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo, 1917 AAD_LEN, iv, hdr->authtag); 1918 1919 return 0; 1920 } 1921 1922 static int __handle_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, 1923 struct snp_guest_request_ioctl *rio) 1924 { 1925 unsigned long req_start = jiffies; 1926 unsigned int override_npages = 0; 1927 u64 override_err = 0; 1928 int rc; 1929 1930 retry_request: 1931 /* 1932 * Call firmware to process the request. In this function the encrypted 1933 * message enters shared memory with the host. So after this call the 1934 * sequence number must be incremented or the VMPCK must be deleted to 1935 * prevent reuse of the IV. 1936 */ 1937 rc = snp_issue_guest_request(req, &req->input, rio); 1938 switch (rc) { 1939 case -ENOSPC: 1940 /* 1941 * If the extended guest request fails due to having too 1942 * small of a certificate data buffer, retry the same 1943 * guest request without the extended data request in 1944 * order to increment the sequence number and thus avoid 1945 * IV reuse. 1946 */ 1947 override_npages = req->input.data_npages; 1948 req->exit_code = SVM_VMGEXIT_GUEST_REQUEST; 1949 1950 /* 1951 * Override the error to inform callers the given extended 1952 * request buffer size was too small and give the caller the 1953 * required buffer size. 1954 */ 1955 override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN); 1956 1957 /* 1958 * If this call to the firmware succeeds, the sequence number can 1959 * be incremented allowing for continued use of the VMPCK. If 1960 * there is an error reflected in the return value, this value 1961 * is checked further down and the result will be the deletion 1962 * of the VMPCK and the error code being propagated back to the 1963 * user as an ioctl() return code. 1964 */ 1965 goto retry_request; 1966 1967 /* 1968 * The host may return SNP_GUEST_VMM_ERR_BUSY if the request has been 1969 * throttled. Retry in the driver to avoid returning and reusing the 1970 * message sequence number on a different message. 1971 */ 1972 case -EAGAIN: 1973 if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) { 1974 rc = -ETIMEDOUT; 1975 break; 1976 } 1977 schedule_timeout_killable(SNP_REQ_RETRY_DELAY); 1978 goto retry_request; 1979 } 1980 1981 /* 1982 * Increment the message sequence number. There is no harm in doing 1983 * this now because decryption uses the value stored in the response 1984 * structure and any failure will wipe the VMPCK, preventing further 1985 * use anyway. 1986 */ 1987 snp_inc_msg_seqno(mdesc); 1988 1989 if (override_err) { 1990 rio->exitinfo2 = override_err; 1991 1992 /* 1993 * If an extended guest request was issued and the supplied certificate 1994 * buffer was not large enough, a standard guest request was issued to 1995 * prevent IV reuse. If the standard request was successful, return -EIO 1996 * back to the caller as would have originally been returned. 1997 */ 1998 if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN)) 1999 rc = -EIO; 2000 } 2001 2002 if (override_npages) 2003 req->input.data_npages = override_npages; 2004 2005 return rc; 2006 } 2007 2008 int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, 2009 struct snp_guest_request_ioctl *rio) 2010 { 2011 u64 seqno; 2012 int rc; 2013 2014 guard(mutex)(&snp_cmd_mutex); 2015 2016 /* Check if the VMPCK is not empty */ 2017 if (!mdesc->vmpck || !memchr_inv(mdesc->vmpck, 0, VMPCK_KEY_LEN)) { 2018 pr_err_ratelimited("VMPCK is disabled\n"); 2019 return -ENOTTY; 2020 } 2021 2022 /* Get message sequence and verify that its a non-zero */ 2023 seqno = snp_get_msg_seqno(mdesc); 2024 if (!seqno) 2025 return -EIO; 2026 2027 /* Clear shared memory's response for the host to populate. */ 2028 memset(mdesc->response, 0, sizeof(struct snp_guest_msg)); 2029 2030 /* Encrypt the userspace provided payload in mdesc->secret_request. */ 2031 rc = enc_payload(mdesc, seqno, req); 2032 if (rc) 2033 return rc; 2034 2035 /* 2036 * Write the fully encrypted request to the shared unencrypted 2037 * request page. 2038 */ 2039 memcpy(mdesc->request, &mdesc->secret_request, sizeof(mdesc->secret_request)); 2040 2041 /* Initialize the input address for guest request */ 2042 req->input.req_gpa = __pa(mdesc->request); 2043 req->input.resp_gpa = __pa(mdesc->response); 2044 req->input.data_gpa = req->certs_data ? __pa(req->certs_data) : 0; 2045 2046 rc = __handle_guest_request(mdesc, req, rio); 2047 if (rc) { 2048 if (rc == -EIO && 2049 rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN)) 2050 return rc; 2051 2052 pr_alert("Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n", 2053 rc, rio->exitinfo2); 2054 2055 snp_disable_vmpck(mdesc); 2056 return rc; 2057 } 2058 2059 rc = verify_and_dec_payload(mdesc, req); 2060 if (rc) { 2061 pr_alert("Detected unexpected decode failure from ASP. rc: %d\n", rc); 2062 snp_disable_vmpck(mdesc); 2063 return rc; 2064 } 2065 2066 return 0; 2067 } 2068 EXPORT_SYMBOL_GPL(snp_send_guest_request); 2069 2070 static int __init snp_get_tsc_info(void) 2071 { 2072 struct snp_guest_request_ioctl *rio; 2073 struct snp_tsc_info_resp *tsc_resp; 2074 struct snp_tsc_info_req *tsc_req; 2075 struct snp_msg_desc *mdesc; 2076 struct snp_guest_req *req; 2077 int rc = -ENOMEM; 2078 2079 tsc_req = kzalloc(sizeof(*tsc_req), GFP_KERNEL); 2080 if (!tsc_req) 2081 return rc; 2082 2083 /* 2084 * The intermediate response buffer is used while decrypting the 2085 * response payload. Make sure that it has enough space to cover 2086 * the authtag. 2087 */ 2088 tsc_resp = kzalloc(sizeof(*tsc_resp) + AUTHTAG_LEN, GFP_KERNEL); 2089 if (!tsc_resp) 2090 goto e_free_tsc_req; 2091 2092 req = kzalloc(sizeof(*req), GFP_KERNEL); 2093 if (!req) 2094 goto e_free_tsc_resp; 2095 2096 rio = kzalloc(sizeof(*rio), GFP_KERNEL); 2097 if (!rio) 2098 goto e_free_req; 2099 2100 mdesc = snp_msg_alloc(); 2101 if (IS_ERR_OR_NULL(mdesc)) 2102 goto e_free_rio; 2103 2104 rc = snp_msg_init(mdesc, snp_vmpl); 2105 if (rc) 2106 goto e_free_mdesc; 2107 2108 req->msg_version = MSG_HDR_VER; 2109 req->msg_type = SNP_MSG_TSC_INFO_REQ; 2110 req->vmpck_id = snp_vmpl; 2111 req->req_buf = tsc_req; 2112 req->req_sz = sizeof(*tsc_req); 2113 req->resp_buf = (void *)tsc_resp; 2114 req->resp_sz = sizeof(*tsc_resp) + AUTHTAG_LEN; 2115 req->exit_code = SVM_VMGEXIT_GUEST_REQUEST; 2116 2117 rc = snp_send_guest_request(mdesc, req, rio); 2118 if (rc) 2119 goto e_request; 2120 2121 pr_debug("%s: response status 0x%x scale 0x%llx offset 0x%llx factor 0x%x\n", 2122 __func__, tsc_resp->status, tsc_resp->tsc_scale, tsc_resp->tsc_offset, 2123 tsc_resp->tsc_factor); 2124 2125 if (!tsc_resp->status) { 2126 snp_tsc_scale = tsc_resp->tsc_scale; 2127 snp_tsc_offset = tsc_resp->tsc_offset; 2128 } else { 2129 pr_err("Failed to get TSC info, response status 0x%x\n", tsc_resp->status); 2130 rc = -EIO; 2131 } 2132 2133 e_request: 2134 /* The response buffer contains sensitive data, explicitly clear it. */ 2135 memzero_explicit(tsc_resp, sizeof(*tsc_resp) + AUTHTAG_LEN); 2136 e_free_mdesc: 2137 snp_msg_free(mdesc); 2138 e_free_rio: 2139 kfree(rio); 2140 e_free_req: 2141 kfree(req); 2142 e_free_tsc_resp: 2143 kfree(tsc_resp); 2144 e_free_tsc_req: 2145 kfree(tsc_req); 2146 2147 return rc; 2148 } 2149 2150 void __init snp_secure_tsc_prepare(void) 2151 { 2152 if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) 2153 return; 2154 2155 if (snp_get_tsc_info()) { 2156 pr_alert("Unable to retrieve Secure TSC info from ASP\n"); 2157 sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC); 2158 } 2159 2160 pr_debug("SecureTSC enabled"); 2161 } 2162 2163 static unsigned long securetsc_get_tsc_khz(void) 2164 { 2165 return snp_tsc_freq_khz; 2166 } 2167 2168 void __init snp_secure_tsc_init(void) 2169 { 2170 struct snp_secrets_page *secrets; 2171 unsigned long tsc_freq_mhz; 2172 void *mem; 2173 2174 if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) 2175 return; 2176 2177 mem = early_memremap_encrypted(sev_secrets_pa, PAGE_SIZE); 2178 if (!mem) { 2179 pr_err("Unable to get TSC_FACTOR: failed to map the SNP secrets page.\n"); 2180 sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC); 2181 } 2182 2183 secrets = (__force struct snp_secrets_page *)mem; 2184 2185 setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); 2186 rdmsrq(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz); 2187 2188 /* Extract the GUEST TSC MHZ from BIT[17:0], rest is reserved space */ 2189 tsc_freq_mhz &= GENMASK_ULL(17, 0); 2190 2191 snp_tsc_freq_khz = SNP_SCALE_TSC_FREQ(tsc_freq_mhz * 1000, secrets->tsc_factor); 2192 2193 x86_platform.calibrate_cpu = securetsc_get_tsc_khz; 2194 x86_platform.calibrate_tsc = securetsc_get_tsc_khz; 2195 2196 early_memunmap(mem, PAGE_SIZE); 2197 } 2198