1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Core of Xen paravirt_ops implementation. 4 * 5 * This file contains the xen_paravirt_ops structure itself, and the 6 * implementations for: 7 * - privileged instructions 8 * - interrupt flags 9 * - segment operations 10 * - booting and setup 11 * 12 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 13 */ 14 15 #include <linux/cpu.h> 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/smp.h> 19 #include <linux/preempt.h> 20 #include <linux/hardirq.h> 21 #include <linux/percpu.h> 22 #include <linux/delay.h> 23 #include <linux/start_kernel.h> 24 #include <linux/sched.h> 25 #include <linux/kprobes.h> 26 #include <linux/kstrtox.h> 27 #include <linux/memblock.h> 28 #include <linux/export.h> 29 #include <linux/mm.h> 30 #include <linux/page-flags.h> 31 #include <linux/pci.h> 32 #include <linux/gfp.h> 33 #include <linux/edd.h> 34 #include <linux/reboot.h> 35 #include <linux/virtio_anchor.h> 36 #include <linux/stackprotector.h> 37 38 #include <xen/xen.h> 39 #include <xen/events.h> 40 #include <xen/interface/xen.h> 41 #include <xen/interface/version.h> 42 #include <xen/interface/physdev.h> 43 #include <xen/interface/vcpu.h> 44 #include <xen/interface/memory.h> 45 #include <xen/interface/nmi.h> 46 #include <xen/interface/xen-mca.h> 47 #include <xen/features.h> 48 #include <xen/page.h> 49 #include <xen/hvc-console.h> 50 #include <xen/acpi.h> 51 52 #include <asm/cpuid.h> 53 #include <asm/paravirt.h> 54 #include <asm/apic.h> 55 #include <asm/page.h> 56 #include <asm/xen/pci.h> 57 #include <asm/xen/hypercall.h> 58 #include <asm/xen/hypervisor.h> 59 #include <asm/xen/cpuid.h> 60 #include <asm/fixmap.h> 61 #include <asm/processor.h> 62 #include <asm/proto.h> 63 #include <asm/msr-index.h> 64 #include <asm/traps.h> 65 #include <asm/setup.h> 66 #include <asm/desc.h> 67 #include <asm/pgalloc.h> 68 #include <asm/tlbflush.h> 69 #include <asm/reboot.h> 70 #include <asm/hypervisor.h> 71 #include <asm/mach_traps.h> 72 #include <asm/mtrr.h> 73 #include <asm/mwait.h> 74 #include <asm/pci_x86.h> 75 #include <asm/cpu.h> 76 #include <asm/irq_stack.h> 77 #ifdef CONFIG_X86_IOPL_IOPERM 78 #include <asm/io_bitmap.h> 79 #endif 80 81 #ifdef CONFIG_ACPI 82 #include <linux/acpi.h> 83 #include <asm/acpi.h> 84 #include <acpi/proc_cap_intel.h> 85 #include <acpi/processor.h> 86 #include <xen/interface/platform.h> 87 #endif 88 89 #include "xen-ops.h" 90 91 #include "../kernel/cpu/cpu.h" /* get_cpu_cap() */ 92 93 void *xen_initial_gdt; 94 95 static int xen_cpu_up_prepare_pv(unsigned int cpu); 96 static int xen_cpu_dead_pv(unsigned int cpu); 97 98 #ifndef CONFIG_PREEMPTION 99 /* 100 * Some hypercalls issued by the toolstack can take many 10s of 101 * seconds. Allow tasks running hypercalls via the privcmd driver to 102 * be voluntarily preempted even if full kernel preemption is 103 * disabled. 104 * 105 * Such preemptible hypercalls are bracketed by 106 * xen_preemptible_hcall_begin() and xen_preemptible_hcall_end() 107 * calls. 108 */ 109 DEFINE_PER_CPU(bool, xen_in_preemptible_hcall); 110 EXPORT_SYMBOL_GPL(xen_in_preemptible_hcall); 111 112 /* 113 * In case of scheduling the flag must be cleared and restored after 114 * returning from schedule as the task might move to a different CPU. 115 */ 116 static __always_inline bool get_and_clear_inhcall(void) 117 { 118 bool inhcall = __this_cpu_read(xen_in_preemptible_hcall); 119 120 __this_cpu_write(xen_in_preemptible_hcall, false); 121 return inhcall; 122 } 123 124 static __always_inline void restore_inhcall(bool inhcall) 125 { 126 __this_cpu_write(xen_in_preemptible_hcall, inhcall); 127 } 128 129 #else 130 131 static __always_inline bool get_and_clear_inhcall(void) { return false; } 132 static __always_inline void restore_inhcall(bool inhcall) { } 133 134 #endif 135 136 struct tls_descs { 137 struct desc_struct desc[3]; 138 }; 139 140 DEFINE_PER_CPU(enum xen_lazy_mode, xen_lazy_mode) = XEN_LAZY_NONE; 141 142 enum xen_lazy_mode xen_get_lazy_mode(void) 143 { 144 if (in_interrupt()) 145 return XEN_LAZY_NONE; 146 147 return this_cpu_read(xen_lazy_mode); 148 } 149 150 /* 151 * Updating the 3 TLS descriptors in the GDT on every task switch is 152 * surprisingly expensive so we avoid updating them if they haven't 153 * changed. Since Xen writes different descriptors than the one 154 * passed in the update_descriptor hypercall we keep shadow copies to 155 * compare against. 156 */ 157 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 158 159 static __read_mostly bool xen_msr_safe = IS_ENABLED(CONFIG_XEN_PV_MSR_SAFE); 160 161 static int __init parse_xen_msr_safe(char *str) 162 { 163 if (str) 164 return kstrtobool(str, &xen_msr_safe); 165 return -EINVAL; 166 } 167 early_param("xen_msr_safe", parse_xen_msr_safe); 168 169 /* Get MTRR settings from Xen and put them into mtrr_state. */ 170 static void __init xen_set_mtrr_data(void) 171 { 172 #ifdef CONFIG_MTRR 173 struct xen_platform_op op = { 174 .cmd = XENPF_read_memtype, 175 .interface_version = XENPF_INTERFACE_VERSION, 176 }; 177 unsigned int reg; 178 unsigned long mask; 179 uint32_t eax, width; 180 static struct mtrr_var_range var[MTRR_MAX_VAR_RANGES] __initdata; 181 182 /* Get physical address width (only 64-bit cpus supported). */ 183 width = 36; 184 eax = cpuid_eax(0x80000000); 185 if ((eax >> 16) == 0x8000 && eax >= 0x80000008) { 186 eax = cpuid_eax(0x80000008); 187 width = eax & 0xff; 188 } 189 190 for (reg = 0; reg < MTRR_MAX_VAR_RANGES; reg++) { 191 op.u.read_memtype.reg = reg; 192 if (HYPERVISOR_platform_op(&op)) 193 break; 194 195 /* 196 * Only called in dom0, which has all RAM PFNs mapped at 197 * RAM MFNs, and all PCI space etc. is identity mapped. 198 * This means we can treat MFN == PFN regarding MTRR settings. 199 */ 200 var[reg].base_lo = op.u.read_memtype.type; 201 var[reg].base_lo |= op.u.read_memtype.mfn << PAGE_SHIFT; 202 var[reg].base_hi = op.u.read_memtype.mfn >> (32 - PAGE_SHIFT); 203 mask = ~((op.u.read_memtype.nr_mfns << PAGE_SHIFT) - 1); 204 mask &= (1UL << width) - 1; 205 if (mask) 206 mask |= MTRR_PHYSMASK_V; 207 var[reg].mask_lo = mask; 208 var[reg].mask_hi = mask >> 32; 209 } 210 211 /* Only overwrite MTRR state if any MTRR could be got from Xen. */ 212 if (reg) 213 guest_force_mtrr_state(var, reg, MTRR_TYPE_UNCACHABLE); 214 #endif 215 } 216 217 static void __init xen_pv_init_platform(void) 218 { 219 /* PV guests can't operate virtio devices without grants. */ 220 if (IS_ENABLED(CONFIG_XEN_VIRTIO)) 221 virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc); 222 223 populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP)); 224 225 set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info); 226 HYPERVISOR_shared_info = (void *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 227 228 /* xen clock uses per-cpu vcpu_info, need to init it for boot cpu */ 229 xen_vcpu_info_reset(0); 230 231 /* pvclock is in shared info area */ 232 xen_init_time_ops(); 233 234 if (xen_initial_domain()) 235 xen_set_mtrr_data(); 236 else 237 guest_force_mtrr_state(NULL, 0, MTRR_TYPE_WRBACK); 238 239 /* Adjust nr_cpu_ids before "enumeration" happens */ 240 xen_smp_count_cpus(); 241 } 242 243 static void __init xen_pv_guest_late_init(void) 244 { 245 #ifndef CONFIG_SMP 246 /* Setup shared vcpu info for non-smp configurations */ 247 xen_setup_vcpu_info_placement(); 248 #endif 249 } 250 251 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 252 static __read_mostly unsigned int cpuid_leaf5_edx_val; 253 254 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 255 unsigned int *cx, unsigned int *dx) 256 { 257 unsigned int maskebx = ~0; 258 unsigned int or_ebx = 0; 259 260 /* 261 * Mask out inconvenient features, to try and disable as many 262 * unsupported kernel subsystems as possible. 263 */ 264 switch (*ax) { 265 case 0x1: 266 /* Replace initial APIC ID in bits 24-31 of EBX. */ 267 /* See xen_pv_smp_config() for related topology preparations. */ 268 maskebx = 0x00ffffff; 269 or_ebx = smp_processor_id() << 24; 270 break; 271 272 case CPUID_LEAF_MWAIT: 273 /* Synthesize the values.. */ 274 *ax = 0; 275 *bx = 0; 276 *cx = cpuid_leaf5_ecx_val; 277 *dx = cpuid_leaf5_edx_val; 278 return; 279 280 case 0xb: 281 /* Suppress extended topology stuff */ 282 maskebx = 0; 283 break; 284 } 285 286 asm(XEN_EMULATE_PREFIX "cpuid" 287 : "=a" (*ax), 288 "=b" (*bx), 289 "=c" (*cx), 290 "=d" (*dx) 291 : "0" (*ax), "2" (*cx)); 292 293 *bx &= maskebx; 294 *bx |= or_ebx; 295 } 296 297 static bool __init xen_check_mwait(void) 298 { 299 #ifdef CONFIG_ACPI 300 struct xen_platform_op op = { 301 .cmd = XENPF_set_processor_pminfo, 302 .u.set_pminfo.id = -1, 303 .u.set_pminfo.type = XEN_PM_PDC, 304 }; 305 uint32_t buf[3]; 306 unsigned int ax, bx, cx, dx; 307 unsigned int mwait_mask; 308 309 /* We need to determine whether it is OK to expose the MWAIT 310 * capability to the kernel to harvest deeper than C3 states from ACPI 311 * _CST using the processor_harvest_xen.c module. For this to work, we 312 * need to gather the MWAIT_LEAF values (which the cstate.c code 313 * checks against). The hypervisor won't expose the MWAIT flag because 314 * it would break backwards compatibility; so we will find out directly 315 * from the hardware and hypercall. 316 */ 317 if (!xen_initial_domain()) 318 return false; 319 320 /* 321 * When running under platform earlier than Xen4.2, do not expose 322 * mwait, to avoid the risk of loading native acpi pad driver 323 */ 324 if (!xen_running_on_version_or_later(4, 2)) 325 return false; 326 327 ax = 1; 328 cx = 0; 329 330 native_cpuid(&ax, &bx, &cx, &dx); 331 332 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 333 (1 << (X86_FEATURE_MWAIT % 32)); 334 335 if ((cx & mwait_mask) != mwait_mask) 336 return false; 337 338 /* We need to emulate the MWAIT_LEAF and for that we need both 339 * ecx and edx. The hypercall provides only partial information. 340 */ 341 342 ax = CPUID_LEAF_MWAIT; 343 bx = 0; 344 cx = 0; 345 dx = 0; 346 347 native_cpuid(&ax, &bx, &cx, &dx); 348 349 /* Ask the Hypervisor whether to clear ACPI_PROC_CAP_C_C2C3_FFH. If so, 350 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 351 */ 352 buf[0] = ACPI_PDC_REVISION_ID; 353 buf[1] = 1; 354 buf[2] = (ACPI_PROC_CAP_C_CAPABILITY_SMP | ACPI_PROC_CAP_EST_CAPABILITY_SWSMP); 355 356 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 357 358 if ((HYPERVISOR_platform_op(&op) == 0) && 359 (buf[2] & (ACPI_PROC_CAP_C_C1_FFH | ACPI_PROC_CAP_C_C2C3_FFH))) { 360 cpuid_leaf5_ecx_val = cx; 361 cpuid_leaf5_edx_val = dx; 362 } 363 return true; 364 #else 365 return false; 366 #endif 367 } 368 369 static bool __init xen_check_xsave(void) 370 { 371 unsigned int cx, xsave_mask; 372 373 cx = cpuid_ecx(1); 374 375 xsave_mask = (1 << (X86_FEATURE_XSAVE % 32)) | 376 (1 << (X86_FEATURE_OSXSAVE % 32)); 377 378 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 379 return (cx & xsave_mask) == xsave_mask; 380 } 381 382 static void __init xen_init_capabilities(void) 383 { 384 setup_force_cpu_cap(X86_FEATURE_XENPV); 385 setup_clear_cpu_cap(X86_FEATURE_DCA); 386 setup_clear_cpu_cap(X86_FEATURE_APERFMPERF); 387 setup_clear_cpu_cap(X86_FEATURE_MTRR); 388 setup_clear_cpu_cap(X86_FEATURE_ACC); 389 setup_clear_cpu_cap(X86_FEATURE_X2APIC); 390 setup_clear_cpu_cap(X86_FEATURE_SME); 391 setup_clear_cpu_cap(X86_FEATURE_LKGS); 392 393 /* 394 * Xen PV would need some work to support PCID: CR3 handling as well 395 * as xen_flush_tlb_others() would need updating. 396 */ 397 setup_clear_cpu_cap(X86_FEATURE_PCID); 398 399 if (!xen_initial_domain()) 400 setup_clear_cpu_cap(X86_FEATURE_ACPI); 401 402 if (xen_check_mwait()) 403 setup_force_cpu_cap(X86_FEATURE_MWAIT); 404 else 405 setup_clear_cpu_cap(X86_FEATURE_MWAIT); 406 407 if (!xen_check_xsave()) { 408 setup_clear_cpu_cap(X86_FEATURE_XSAVE); 409 setup_clear_cpu_cap(X86_FEATURE_OSXSAVE); 410 } 411 } 412 413 static noinstr void xen_set_debugreg(int reg, unsigned long val) 414 { 415 HYPERVISOR_set_debugreg(reg, val); 416 } 417 418 static noinstr unsigned long xen_get_debugreg(int reg) 419 { 420 return HYPERVISOR_get_debugreg(reg); 421 } 422 423 static void xen_start_context_switch(struct task_struct *prev) 424 { 425 BUG_ON(preemptible()); 426 427 if (this_cpu_read(xen_lazy_mode) == XEN_LAZY_MMU) { 428 arch_leave_lazy_mmu_mode(); 429 set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES); 430 } 431 enter_lazy(XEN_LAZY_CPU); 432 } 433 434 static void xen_end_context_switch(struct task_struct *next) 435 { 436 BUG_ON(preemptible()); 437 438 xen_mc_flush(); 439 leave_lazy(XEN_LAZY_CPU); 440 if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES)) 441 arch_enter_lazy_mmu_mode(); 442 } 443 444 static unsigned long xen_store_tr(void) 445 { 446 return 0; 447 } 448 449 /* 450 * Set the page permissions for a particular virtual address. If the 451 * address is a vmalloc mapping (or other non-linear mapping), then 452 * find the linear mapping of the page and also set its protections to 453 * match. 454 */ 455 static void set_aliased_prot(void *v, pgprot_t prot) 456 { 457 int level; 458 pte_t *ptep; 459 pte_t pte; 460 unsigned long pfn; 461 unsigned char dummy; 462 void *va; 463 464 ptep = lookup_address((unsigned long)v, &level); 465 BUG_ON(ptep == NULL); 466 467 pfn = pte_pfn(*ptep); 468 pte = pfn_pte(pfn, prot); 469 470 /* 471 * Careful: update_va_mapping() will fail if the virtual address 472 * we're poking isn't populated in the page tables. We don't 473 * need to worry about the direct map (that's always in the page 474 * tables), but we need to be careful about vmap space. In 475 * particular, the top level page table can lazily propagate 476 * entries between processes, so if we've switched mms since we 477 * vmapped the target in the first place, we might not have the 478 * top-level page table entry populated. 479 * 480 * We disable preemption because we want the same mm active when 481 * we probe the target and when we issue the hypercall. We'll 482 * have the same nominal mm, but if we're a kernel thread, lazy 483 * mm dropping could change our pgd. 484 * 485 * Out of an abundance of caution, this uses __get_user() to fault 486 * in the target address just in case there's some obscure case 487 * in which the target address isn't readable. 488 */ 489 490 preempt_disable(); 491 492 copy_from_kernel_nofault(&dummy, v, 1); 493 494 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 495 BUG(); 496 497 va = __va(PFN_PHYS(pfn)); 498 499 if (va != v && HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 500 BUG(); 501 502 preempt_enable(); 503 } 504 505 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 506 { 507 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 508 int i; 509 510 /* 511 * We need to mark the all aliases of the LDT pages RO. We 512 * don't need to call vm_flush_aliases(), though, since that's 513 * only responsible for flushing aliases out the TLBs, not the 514 * page tables, and Xen will flush the TLB for us if needed. 515 * 516 * To avoid confusing future readers: none of this is necessary 517 * to load the LDT. The hypervisor only checks this when the 518 * LDT is faulted in due to subsequent descriptor access. 519 */ 520 521 for (i = 0; i < entries; i += entries_per_page) 522 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 523 } 524 525 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 526 { 527 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 528 int i; 529 530 for (i = 0; i < entries; i += entries_per_page) 531 set_aliased_prot(ldt + i, PAGE_KERNEL); 532 } 533 534 static void xen_set_ldt(const void *addr, unsigned entries) 535 { 536 struct mmuext_op *op; 537 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 538 539 trace_xen_cpu_set_ldt(addr, entries); 540 541 op = mcs.args; 542 op->cmd = MMUEXT_SET_LDT; 543 op->arg1.linear_addr = (unsigned long)addr; 544 op->arg2.nr_ents = entries; 545 546 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 547 548 xen_mc_issue(XEN_LAZY_CPU); 549 } 550 551 static void xen_load_gdt(const struct desc_ptr *dtr) 552 { 553 unsigned long va = dtr->address; 554 unsigned int size = dtr->size + 1; 555 unsigned long pfn, mfn; 556 int level; 557 pte_t *ptep; 558 void *virt; 559 560 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */ 561 BUG_ON(size > PAGE_SIZE); 562 BUG_ON(va & ~PAGE_MASK); 563 564 /* 565 * The GDT is per-cpu and is in the percpu data area. 566 * That can be virtually mapped, so we need to do a 567 * page-walk to get the underlying MFN for the 568 * hypercall. The page can also be in the kernel's 569 * linear range, so we need to RO that mapping too. 570 */ 571 ptep = lookup_address(va, &level); 572 BUG_ON(ptep == NULL); 573 574 pfn = pte_pfn(*ptep); 575 mfn = pfn_to_mfn(pfn); 576 virt = __va(PFN_PHYS(pfn)); 577 578 make_lowmem_page_readonly((void *)va); 579 make_lowmem_page_readonly(virt); 580 581 if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct))) 582 BUG(); 583 } 584 585 /* 586 * load_gdt for early boot, when the gdt is only mapped once 587 */ 588 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 589 { 590 unsigned long va = dtr->address; 591 unsigned int size = dtr->size + 1; 592 unsigned long pfn, mfn; 593 pte_t pte; 594 595 /* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */ 596 BUG_ON(size > PAGE_SIZE); 597 BUG_ON(va & ~PAGE_MASK); 598 599 pfn = virt_to_pfn((void *)va); 600 mfn = pfn_to_mfn(pfn); 601 602 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 603 604 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 605 BUG(); 606 607 if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct))) 608 BUG(); 609 } 610 611 static inline bool desc_equal(const struct desc_struct *d1, 612 const struct desc_struct *d2) 613 { 614 return !memcmp(d1, d2, sizeof(*d1)); 615 } 616 617 static void load_TLS_descriptor(struct thread_struct *t, 618 unsigned int cpu, unsigned int i) 619 { 620 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 621 struct desc_struct *gdt; 622 xmaddr_t maddr; 623 struct multicall_space mc; 624 625 if (desc_equal(shadow, &t->tls_array[i])) 626 return; 627 628 *shadow = t->tls_array[i]; 629 630 gdt = get_cpu_gdt_rw(cpu); 631 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 632 mc = __xen_mc_entry(0); 633 634 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 635 } 636 637 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 638 { 639 /* 640 * In lazy mode we need to zero %fs, otherwise we may get an 641 * exception between the new %fs descriptor being loaded and 642 * %fs being effectively cleared at __switch_to(). 643 */ 644 if (xen_get_lazy_mode() == XEN_LAZY_CPU) 645 loadsegment(fs, 0); 646 647 xen_mc_batch(); 648 649 load_TLS_descriptor(t, cpu, 0); 650 load_TLS_descriptor(t, cpu, 1); 651 load_TLS_descriptor(t, cpu, 2); 652 653 xen_mc_issue(XEN_LAZY_CPU); 654 } 655 656 static void xen_load_gs_index(unsigned int idx) 657 { 658 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 659 BUG(); 660 } 661 662 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 663 const void *ptr) 664 { 665 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 666 u64 entry = *(u64 *)ptr; 667 668 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 669 670 preempt_disable(); 671 672 xen_mc_flush(); 673 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 674 BUG(); 675 676 preempt_enable(); 677 } 678 679 void noist_exc_debug(struct pt_regs *regs); 680 681 DEFINE_IDTENTRY_RAW(xenpv_exc_nmi) 682 { 683 /* On Xen PV, NMI doesn't use IST. The C part is the same as native. */ 684 exc_nmi(regs); 685 } 686 687 DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault) 688 { 689 /* On Xen PV, DF doesn't use IST. The C part is the same as native. */ 690 exc_double_fault(regs, error_code); 691 } 692 693 DEFINE_IDTENTRY_RAW(xenpv_exc_debug) 694 { 695 /* 696 * There's no IST on Xen PV, but we still need to dispatch 697 * to the correct handler. 698 */ 699 if (user_mode(regs)) 700 noist_exc_debug(regs); 701 else 702 exc_debug(regs); 703 } 704 705 DEFINE_IDTENTRY_RAW(exc_xen_unknown_trap) 706 { 707 /* This should never happen and there is no way to handle it. */ 708 instrumentation_begin(); 709 pr_err("Unknown trap in Xen PV mode."); 710 BUG(); 711 instrumentation_end(); 712 } 713 714 #ifdef CONFIG_X86_MCE 715 DEFINE_IDTENTRY_RAW(xenpv_exc_machine_check) 716 { 717 /* 718 * There's no IST on Xen PV, but we still need to dispatch 719 * to the correct handler. 720 */ 721 if (user_mode(regs)) 722 noist_exc_machine_check(regs); 723 else 724 exc_machine_check(regs); 725 } 726 #endif 727 728 static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs) 729 { 730 struct pt_regs *old_regs = set_irq_regs(regs); 731 732 inc_irq_stat(irq_hv_callback_count); 733 734 xen_evtchn_do_upcall(); 735 736 set_irq_regs(old_regs); 737 } 738 739 __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs) 740 { 741 irqentry_state_t state = irqentry_enter(regs); 742 bool inhcall; 743 744 instrumentation_begin(); 745 run_sysvec_on_irqstack_cond(__xen_pv_evtchn_do_upcall, regs); 746 747 inhcall = get_and_clear_inhcall(); 748 if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) { 749 irqentry_exit_cond_resched(); 750 instrumentation_end(); 751 restore_inhcall(inhcall); 752 } else { 753 instrumentation_end(); 754 irqentry_exit(regs, state); 755 } 756 } 757 758 struct trap_array_entry { 759 void (*orig)(void); 760 void (*xen)(void); 761 bool ist_okay; 762 }; 763 764 #define TRAP_ENTRY(func, ist_ok) { \ 765 .orig = asm_##func, \ 766 .xen = xen_asm_##func, \ 767 .ist_okay = ist_ok } 768 769 #define TRAP_ENTRY_REDIR(func, ist_ok) { \ 770 .orig = asm_##func, \ 771 .xen = xen_asm_xenpv_##func, \ 772 .ist_okay = ist_ok } 773 774 static struct trap_array_entry trap_array[] = { 775 TRAP_ENTRY_REDIR(exc_debug, true ), 776 TRAP_ENTRY_REDIR(exc_double_fault, true ), 777 #ifdef CONFIG_X86_MCE 778 TRAP_ENTRY_REDIR(exc_machine_check, true ), 779 #endif 780 TRAP_ENTRY_REDIR(exc_nmi, true ), 781 TRAP_ENTRY(exc_int3, false ), 782 TRAP_ENTRY(exc_overflow, false ), 783 #ifdef CONFIG_IA32_EMULATION 784 TRAP_ENTRY(int80_emulation, false ), 785 #endif 786 TRAP_ENTRY(exc_page_fault, false ), 787 TRAP_ENTRY(exc_divide_error, false ), 788 TRAP_ENTRY(exc_bounds, false ), 789 TRAP_ENTRY(exc_invalid_op, false ), 790 TRAP_ENTRY(exc_device_not_available, false ), 791 TRAP_ENTRY(exc_coproc_segment_overrun, false ), 792 TRAP_ENTRY(exc_invalid_tss, false ), 793 TRAP_ENTRY(exc_segment_not_present, false ), 794 TRAP_ENTRY(exc_stack_segment, false ), 795 TRAP_ENTRY(exc_general_protection, false ), 796 TRAP_ENTRY(exc_spurious_interrupt_bug, false ), 797 TRAP_ENTRY(exc_coprocessor_error, false ), 798 TRAP_ENTRY(exc_alignment_check, false ), 799 TRAP_ENTRY(exc_simd_coprocessor_error, false ), 800 #ifdef CONFIG_X86_CET 801 TRAP_ENTRY(exc_control_protection, false ), 802 #endif 803 }; 804 805 static bool __ref get_trap_addr(void **addr, unsigned int ist) 806 { 807 unsigned int nr; 808 bool ist_okay = false; 809 bool found = false; 810 811 /* 812 * Replace trap handler addresses by Xen specific ones. 813 * Check for known traps using IST and whitelist them. 814 * The debugger ones are the only ones we care about. 815 * Xen will handle faults like double_fault, so we should never see 816 * them. Warn if there's an unexpected IST-using fault handler. 817 */ 818 for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) { 819 struct trap_array_entry *entry = trap_array + nr; 820 821 if (*addr == entry->orig) { 822 *addr = entry->xen; 823 ist_okay = entry->ist_okay; 824 found = true; 825 break; 826 } 827 } 828 829 if (nr == ARRAY_SIZE(trap_array) && 830 *addr >= (void *)early_idt_handler_array[0] && 831 *addr < (void *)early_idt_handler_array[NUM_EXCEPTION_VECTORS]) { 832 nr = (*addr - (void *)early_idt_handler_array[0]) / 833 EARLY_IDT_HANDLER_SIZE; 834 *addr = (void *)xen_early_idt_handler_array[nr]; 835 found = true; 836 } 837 838 if (!found) 839 *addr = (void *)xen_asm_exc_xen_unknown_trap; 840 841 if (WARN_ON(found && ist != 0 && !ist_okay)) 842 return false; 843 844 return true; 845 } 846 847 static int cvt_gate_to_trap(int vector, const gate_desc *val, 848 struct trap_info *info) 849 { 850 unsigned long addr; 851 852 if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT) 853 return 0; 854 855 info->vector = vector; 856 857 addr = gate_offset(val); 858 if (!get_trap_addr((void **)&addr, val->bits.ist)) 859 return 0; 860 info->address = addr; 861 862 info->cs = gate_segment(val); 863 info->flags = val->bits.dpl; 864 /* interrupt gates clear IF */ 865 if (val->bits.type == GATE_INTERRUPT) 866 info->flags |= 1 << 2; 867 868 return 1; 869 } 870 871 /* Locations of each CPU's IDT */ 872 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 873 874 /* Set an IDT entry. If the entry is part of the current IDT, then 875 also update Xen. */ 876 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 877 { 878 unsigned long p = (unsigned long)&dt[entrynum]; 879 unsigned long start, end; 880 881 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 882 883 preempt_disable(); 884 885 start = __this_cpu_read(idt_desc.address); 886 end = start + __this_cpu_read(idt_desc.size) + 1; 887 888 xen_mc_flush(); 889 890 native_write_idt_entry(dt, entrynum, g); 891 892 if (p >= start && (p + 8) <= end) { 893 struct trap_info info[2]; 894 895 info[1].address = 0; 896 897 if (cvt_gate_to_trap(entrynum, g, &info[0])) 898 if (HYPERVISOR_set_trap_table(info)) 899 BUG(); 900 } 901 902 preempt_enable(); 903 } 904 905 static unsigned xen_convert_trap_info(const struct desc_ptr *desc, 906 struct trap_info *traps, bool full) 907 { 908 unsigned in, out, count; 909 910 count = (desc->size+1) / sizeof(gate_desc); 911 BUG_ON(count > 256); 912 913 for (in = out = 0; in < count; in++) { 914 gate_desc *entry = (gate_desc *)(desc->address) + in; 915 916 if (cvt_gate_to_trap(in, entry, &traps[out]) || full) 917 out++; 918 } 919 920 return out; 921 } 922 923 void xen_copy_trap_info(struct trap_info *traps) 924 { 925 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc); 926 927 xen_convert_trap_info(desc, traps, true); 928 } 929 930 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 931 hold a spinlock to protect the static traps[] array (static because 932 it avoids allocation, and saves stack space). */ 933 static void xen_load_idt(const struct desc_ptr *desc) 934 { 935 static DEFINE_SPINLOCK(lock); 936 static struct trap_info traps[257]; 937 static const struct trap_info zero = { }; 938 unsigned out; 939 940 trace_xen_cpu_load_idt(desc); 941 942 spin_lock(&lock); 943 944 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); 945 946 out = xen_convert_trap_info(desc, traps, false); 947 traps[out] = zero; 948 949 xen_mc_flush(); 950 if (HYPERVISOR_set_trap_table(traps)) 951 BUG(); 952 953 spin_unlock(&lock); 954 } 955 956 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 957 they're handled differently. */ 958 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 959 const void *desc, int type) 960 { 961 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 962 963 preempt_disable(); 964 965 switch (type) { 966 case DESC_LDT: 967 case DESC_TSS: 968 /* ignore */ 969 break; 970 971 default: { 972 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 973 974 xen_mc_flush(); 975 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 976 BUG(); 977 } 978 979 } 980 981 preempt_enable(); 982 } 983 984 /* 985 * Version of write_gdt_entry for use at early boot-time needed to 986 * update an entry as simply as possible. 987 */ 988 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 989 const void *desc, int type) 990 { 991 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 992 993 switch (type) { 994 case DESC_LDT: 995 case DESC_TSS: 996 /* ignore */ 997 break; 998 999 default: { 1000 xmaddr_t maddr = virt_to_machine(&dt[entry]); 1001 1002 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 1003 dt[entry] = *(struct desc_struct *)desc; 1004 } 1005 1006 } 1007 } 1008 1009 static void xen_load_sp0(unsigned long sp0) 1010 { 1011 struct multicall_space mcs; 1012 1013 mcs = xen_mc_entry(0); 1014 MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0); 1015 xen_mc_issue(XEN_LAZY_CPU); 1016 this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0); 1017 } 1018 1019 #ifdef CONFIG_X86_IOPL_IOPERM 1020 static void xen_invalidate_io_bitmap(void) 1021 { 1022 struct physdev_set_iobitmap iobitmap = { 1023 .bitmap = NULL, 1024 .nr_ports = 0, 1025 }; 1026 1027 native_tss_invalidate_io_bitmap(); 1028 HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &iobitmap); 1029 } 1030 1031 static void xen_update_io_bitmap(void) 1032 { 1033 struct physdev_set_iobitmap iobitmap; 1034 struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); 1035 1036 native_tss_update_io_bitmap(); 1037 1038 iobitmap.bitmap = (uint8_t *)(&tss->x86_tss) + 1039 tss->x86_tss.io_bitmap_base; 1040 if (tss->x86_tss.io_bitmap_base == IO_BITMAP_OFFSET_INVALID) 1041 iobitmap.nr_ports = 0; 1042 else 1043 iobitmap.nr_ports = IO_BITMAP_BITS; 1044 1045 HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &iobitmap); 1046 } 1047 #endif 1048 1049 static void xen_io_delay(void) 1050 { 1051 } 1052 1053 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 1054 1055 static unsigned long xen_read_cr0(void) 1056 { 1057 unsigned long cr0 = this_cpu_read(xen_cr0_value); 1058 1059 if (unlikely(cr0 == 0)) { 1060 cr0 = native_read_cr0(); 1061 this_cpu_write(xen_cr0_value, cr0); 1062 } 1063 1064 return cr0; 1065 } 1066 1067 static void xen_write_cr0(unsigned long cr0) 1068 { 1069 struct multicall_space mcs; 1070 1071 this_cpu_write(xen_cr0_value, cr0); 1072 1073 /* Only pay attention to cr0.TS; everything else is 1074 ignored. */ 1075 mcs = xen_mc_entry(0); 1076 1077 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 1078 1079 xen_mc_issue(XEN_LAZY_CPU); 1080 } 1081 1082 static void xen_write_cr4(unsigned long cr4) 1083 { 1084 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE); 1085 1086 native_write_cr4(cr4); 1087 } 1088 1089 static u64 xen_do_read_msr(unsigned int msr, int *err) 1090 { 1091 u64 val = 0; /* Avoid uninitialized value for safe variant. */ 1092 1093 if (pmu_msr_read(msr, &val, err)) 1094 return val; 1095 1096 if (err) 1097 val = native_read_msr_safe(msr, err); 1098 else 1099 val = native_read_msr(msr); 1100 1101 switch (msr) { 1102 case MSR_IA32_APICBASE: 1103 val &= ~X2APIC_ENABLE; 1104 if (smp_processor_id() == 0) 1105 val |= MSR_IA32_APICBASE_BSP; 1106 else 1107 val &= ~MSR_IA32_APICBASE_BSP; 1108 break; 1109 } 1110 return val; 1111 } 1112 1113 static void set_seg(unsigned int which, unsigned int low, unsigned int high, 1114 int *err) 1115 { 1116 u64 base = ((u64)high << 32) | low; 1117 1118 if (HYPERVISOR_set_segment_base(which, base) == 0) 1119 return; 1120 1121 if (err) 1122 *err = -EIO; 1123 else 1124 WARN(1, "Xen set_segment_base(%u, %llx) failed\n", which, base); 1125 } 1126 1127 /* 1128 * Support write_msr_safe() and write_msr() semantics. 1129 * With err == NULL write_msr() semantics are selected. 1130 * Supplying an err pointer requires err to be pre-initialized with 0. 1131 */ 1132 static void xen_do_write_msr(unsigned int msr, unsigned int low, 1133 unsigned int high, int *err) 1134 { 1135 switch (msr) { 1136 case MSR_FS_BASE: 1137 set_seg(SEGBASE_FS, low, high, err); 1138 break; 1139 1140 case MSR_KERNEL_GS_BASE: 1141 set_seg(SEGBASE_GS_USER, low, high, err); 1142 break; 1143 1144 case MSR_GS_BASE: 1145 set_seg(SEGBASE_GS_KERNEL, low, high, err); 1146 break; 1147 1148 case MSR_STAR: 1149 case MSR_CSTAR: 1150 case MSR_LSTAR: 1151 case MSR_SYSCALL_MASK: 1152 case MSR_IA32_SYSENTER_CS: 1153 case MSR_IA32_SYSENTER_ESP: 1154 case MSR_IA32_SYSENTER_EIP: 1155 /* Fast syscall setup is all done in hypercalls, so 1156 these are all ignored. Stub them out here to stop 1157 Xen console noise. */ 1158 break; 1159 1160 default: 1161 if (!pmu_msr_write(msr, low, high, err)) { 1162 if (err) 1163 *err = native_write_msr_safe(msr, low, high); 1164 else 1165 native_write_msr(msr, low, high); 1166 } 1167 } 1168 } 1169 1170 static u64 xen_read_msr_safe(unsigned int msr, int *err) 1171 { 1172 return xen_do_read_msr(msr, err); 1173 } 1174 1175 static int xen_write_msr_safe(unsigned int msr, unsigned int low, 1176 unsigned int high) 1177 { 1178 int err = 0; 1179 1180 xen_do_write_msr(msr, low, high, &err); 1181 1182 return err; 1183 } 1184 1185 static u64 xen_read_msr(unsigned int msr) 1186 { 1187 int err; 1188 1189 return xen_do_read_msr(msr, xen_msr_safe ? &err : NULL); 1190 } 1191 1192 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high) 1193 { 1194 int err; 1195 1196 xen_do_write_msr(msr, low, high, xen_msr_safe ? &err : NULL); 1197 } 1198 1199 /* This is called once we have the cpu_possible_mask */ 1200 void __init xen_setup_vcpu_info_placement(void) 1201 { 1202 int cpu; 1203 1204 for_each_possible_cpu(cpu) { 1205 /* Set up direct vCPU id mapping for PV guests. */ 1206 per_cpu(xen_vcpu_id, cpu) = cpu; 1207 xen_vcpu_setup(cpu); 1208 } 1209 1210 pv_ops.irq.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1211 pv_ops.irq.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1212 pv_ops.irq.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1213 pv_ops.mmu.read_cr2 = __PV_IS_CALLEE_SAVE(xen_read_cr2_direct); 1214 } 1215 1216 static const struct pv_info xen_info __initconst = { 1217 .extra_user_64bit_cs = FLAT_USER_CS64, 1218 .name = "Xen", 1219 }; 1220 1221 static const typeof(pv_ops) xen_cpu_ops __initconst = { 1222 .cpu = { 1223 .cpuid = xen_cpuid, 1224 1225 .set_debugreg = xen_set_debugreg, 1226 .get_debugreg = xen_get_debugreg, 1227 1228 .read_cr0 = xen_read_cr0, 1229 .write_cr0 = xen_write_cr0, 1230 1231 .write_cr4 = xen_write_cr4, 1232 1233 .read_msr = xen_read_msr, 1234 .write_msr = xen_write_msr, 1235 1236 .read_msr_safe = xen_read_msr_safe, 1237 .write_msr_safe = xen_write_msr_safe, 1238 1239 .read_pmc = xen_read_pmc, 1240 1241 .load_tr_desc = paravirt_nop, 1242 .set_ldt = xen_set_ldt, 1243 .load_gdt = xen_load_gdt, 1244 .load_idt = xen_load_idt, 1245 .load_tls = xen_load_tls, 1246 .load_gs_index = xen_load_gs_index, 1247 1248 .alloc_ldt = xen_alloc_ldt, 1249 .free_ldt = xen_free_ldt, 1250 1251 .store_tr = xen_store_tr, 1252 1253 .write_ldt_entry = xen_write_ldt_entry, 1254 .write_gdt_entry = xen_write_gdt_entry, 1255 .write_idt_entry = xen_write_idt_entry, 1256 .load_sp0 = xen_load_sp0, 1257 1258 #ifdef CONFIG_X86_IOPL_IOPERM 1259 .invalidate_io_bitmap = xen_invalidate_io_bitmap, 1260 .update_io_bitmap = xen_update_io_bitmap, 1261 #endif 1262 .io_delay = xen_io_delay, 1263 1264 .start_context_switch = xen_start_context_switch, 1265 .end_context_switch = xen_end_context_switch, 1266 }, 1267 }; 1268 1269 static void xen_restart(char *msg) 1270 { 1271 xen_reboot(SHUTDOWN_reboot); 1272 } 1273 1274 static void xen_machine_halt(void) 1275 { 1276 xen_reboot(SHUTDOWN_poweroff); 1277 } 1278 1279 static void xen_machine_power_off(void) 1280 { 1281 do_kernel_power_off(); 1282 xen_reboot(SHUTDOWN_poweroff); 1283 } 1284 1285 static void xen_crash_shutdown(struct pt_regs *regs) 1286 { 1287 xen_reboot(SHUTDOWN_crash); 1288 } 1289 1290 static const struct machine_ops xen_machine_ops __initconst = { 1291 .restart = xen_restart, 1292 .halt = xen_machine_halt, 1293 .power_off = xen_machine_power_off, 1294 .shutdown = xen_machine_halt, 1295 .crash_shutdown = xen_crash_shutdown, 1296 .emergency_restart = xen_emergency_restart, 1297 }; 1298 1299 static unsigned char xen_get_nmi_reason(void) 1300 { 1301 unsigned char reason = 0; 1302 1303 /* Construct a value which looks like it came from port 0x61. */ 1304 if (test_bit(_XEN_NMIREASON_io_error, 1305 &HYPERVISOR_shared_info->arch.nmi_reason)) 1306 reason |= NMI_REASON_IOCHK; 1307 if (test_bit(_XEN_NMIREASON_pci_serr, 1308 &HYPERVISOR_shared_info->arch.nmi_reason)) 1309 reason |= NMI_REASON_SERR; 1310 1311 return reason; 1312 } 1313 1314 static void __init xen_boot_params_init_edd(void) 1315 { 1316 #if IS_ENABLED(CONFIG_EDD) 1317 struct xen_platform_op op; 1318 struct edd_info *edd_info; 1319 u32 *mbr_signature; 1320 unsigned nr; 1321 int ret; 1322 1323 edd_info = boot_params.eddbuf; 1324 mbr_signature = boot_params.edd_mbr_sig_buffer; 1325 1326 op.cmd = XENPF_firmware_info; 1327 1328 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1329 for (nr = 0; nr < EDDMAXNR; nr++) { 1330 struct edd_info *info = edd_info + nr; 1331 1332 op.u.firmware_info.index = nr; 1333 info->params.length = sizeof(info->params); 1334 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1335 &info->params); 1336 ret = HYPERVISOR_platform_op(&op); 1337 if (ret) 1338 break; 1339 1340 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1341 C(device); 1342 C(version); 1343 C(interface_support); 1344 C(legacy_max_cylinder); 1345 C(legacy_max_head); 1346 C(legacy_sectors_per_track); 1347 #undef C 1348 } 1349 boot_params.eddbuf_entries = nr; 1350 1351 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1352 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1353 op.u.firmware_info.index = nr; 1354 ret = HYPERVISOR_platform_op(&op); 1355 if (ret) 1356 break; 1357 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1358 } 1359 boot_params.edd_mbr_sig_buf_entries = nr; 1360 #endif 1361 } 1362 1363 /* 1364 * Set up the GDT and segment registers for -fstack-protector. Until 1365 * we do this, we have to be careful not to call any stack-protected 1366 * function, which is most of the kernel. 1367 */ 1368 static void __init xen_setup_gdt(int cpu) 1369 { 1370 pv_ops.cpu.write_gdt_entry = xen_write_gdt_entry_boot; 1371 pv_ops.cpu.load_gdt = xen_load_gdt_boot; 1372 1373 switch_gdt_and_percpu_base(cpu); 1374 1375 pv_ops.cpu.write_gdt_entry = xen_write_gdt_entry; 1376 pv_ops.cpu.load_gdt = xen_load_gdt; 1377 } 1378 1379 static void __init xen_dom0_set_legacy_features(void) 1380 { 1381 x86_platform.legacy.rtc = 1; 1382 } 1383 1384 static void __init xen_domu_set_legacy_features(void) 1385 { 1386 x86_platform.legacy.rtc = 0; 1387 } 1388 1389 extern void early_xen_iret_patch(void); 1390 1391 /* First C function to be called on Xen boot */ 1392 asmlinkage __visible void __init xen_start_kernel(struct start_info *si) 1393 { 1394 struct physdev_set_iopl set_iopl; 1395 unsigned long initrd_start = 0; 1396 int rc; 1397 1398 if (!si) 1399 return; 1400 1401 clear_bss(); 1402 1403 xen_start_info = si; 1404 1405 __text_gen_insn(&early_xen_iret_patch, 1406 JMP32_INSN_OPCODE, &early_xen_iret_patch, &xen_iret, 1407 JMP32_INSN_SIZE); 1408 1409 xen_domain_type = XEN_PV_DOMAIN; 1410 xen_start_flags = xen_start_info->flags; 1411 /* Interrupts are guaranteed to be off initially. */ 1412 early_boot_irqs_disabled = true; 1413 static_call_update_early(xen_hypercall, xen_hypercall_pv); 1414 1415 xen_setup_features(); 1416 1417 /* Install Xen paravirt ops */ 1418 pv_info = xen_info; 1419 pv_ops.cpu = xen_cpu_ops.cpu; 1420 xen_init_irq_ops(); 1421 1422 /* 1423 * Setup xen_vcpu early because it is needed for 1424 * local_irq_disable(), irqs_disabled(), e.g. in printk(). 1425 * 1426 * Don't do the full vcpu_info placement stuff until we have 1427 * the cpu_possible_mask and a non-dummy shared_info. 1428 */ 1429 xen_vcpu_info_reset(0); 1430 1431 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1432 x86_platform.realmode_reserve = x86_init_noop; 1433 x86_platform.realmode_init = x86_init_noop; 1434 1435 x86_init.resources.memory_setup = xen_memory_setup; 1436 x86_init.irqs.intr_mode_select = x86_init_noop; 1437 x86_init.irqs.intr_mode_init = x86_64_probe_apic; 1438 x86_init.oem.arch_setup = xen_arch_setup; 1439 x86_init.oem.banner = xen_banner; 1440 x86_init.hyper.init_platform = xen_pv_init_platform; 1441 x86_init.hyper.guest_late_init = xen_pv_guest_late_init; 1442 1443 /* 1444 * Set up some pagetable state before starting to set any ptes. 1445 */ 1446 1447 xen_setup_machphys_mapping(); 1448 xen_init_mmu_ops(); 1449 1450 /* Prevent unwanted bits from being set in PTEs. */ 1451 __supported_pte_mask &= ~_PAGE_GLOBAL; 1452 __default_kernel_pte_mask &= ~_PAGE_GLOBAL; 1453 1454 /* Get mfn list */ 1455 xen_build_dynamic_phys_to_machine(); 1456 1457 /* Work out if we support NX */ 1458 get_cpu_cap(&boot_cpu_data); 1459 x86_configure_nx(); 1460 1461 /* 1462 * Set up kernel GDT and segment registers, mainly so that 1463 * -fstack-protector code can be executed. 1464 */ 1465 xen_setup_gdt(0); 1466 1467 /* Determine virtual and physical address sizes */ 1468 get_cpu_address_sizes(&boot_cpu_data); 1469 1470 /* Let's presume PV guests always boot on vCPU with id 0. */ 1471 per_cpu(xen_vcpu_id, 0) = 0; 1472 1473 idt_setup_early_handler(); 1474 1475 xen_init_capabilities(); 1476 1477 /* 1478 * set up the basic apic ops. 1479 */ 1480 xen_init_apic(); 1481 1482 machine_ops = xen_machine_ops; 1483 1484 /* 1485 * The only reliable way to retain the initial address of the 1486 * percpu gdt_page is to remember it here, so we can go and 1487 * mark it RW later, when the initial percpu area is freed. 1488 */ 1489 xen_initial_gdt = &per_cpu(gdt_page, 0); 1490 1491 xen_smp_init(); 1492 1493 #ifdef CONFIG_ACPI_NUMA 1494 /* 1495 * The pages we from Xen are not related to machine pages, so 1496 * any NUMA information the kernel tries to get from ACPI will 1497 * be meaningless. Prevent it from trying. 1498 */ 1499 disable_srat(); 1500 #endif 1501 WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv)); 1502 1503 local_irq_disable(); 1504 1505 xen_raw_console_write("mapping kernel into physical memory\n"); 1506 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, 1507 xen_start_info->nr_pages); 1508 xen_reserve_special_pages(); 1509 1510 /* 1511 * We used to do this in xen_arch_setup, but that is too late 1512 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1513 * early_amd_init which pokes 0xcf8 port. 1514 */ 1515 set_iopl.iopl = 1; 1516 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1517 if (rc != 0) 1518 xen_raw_printk("physdev_op failed %d\n", rc); 1519 1520 1521 if (xen_start_info->mod_start) { 1522 if (xen_start_info->flags & SIF_MOD_START_PFN) 1523 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1524 else 1525 initrd_start = __pa(xen_start_info->mod_start); 1526 } 1527 1528 /* Poke various useful things into boot_params */ 1529 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1530 boot_params.hdr.ramdisk_image = initrd_start; 1531 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1532 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1533 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN; 1534 1535 if (!xen_initial_domain()) { 1536 if (pci_xen) 1537 x86_init.pci.arch_init = pci_xen_init; 1538 x86_platform.set_legacy_features = 1539 xen_domu_set_legacy_features; 1540 } else { 1541 const struct dom0_vga_console_info *info = 1542 (void *)((char *)xen_start_info + 1543 xen_start_info->console.dom0.info_off); 1544 struct xen_platform_op op = { 1545 .cmd = XENPF_firmware_info, 1546 .interface_version = XENPF_INTERFACE_VERSION, 1547 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1548 }; 1549 1550 x86_platform.set_legacy_features = 1551 xen_dom0_set_legacy_features; 1552 xen_init_vga(info, xen_start_info->console.dom0.info_size, 1553 &boot_params.screen_info); 1554 xen_start_info->console.domU.mfn = 0; 1555 xen_start_info->console.domU.evtchn = 0; 1556 1557 if (HYPERVISOR_platform_op(&op) == 0) 1558 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1559 1560 /* Make sure ACS will be enabled */ 1561 pci_request_acs(); 1562 1563 xen_acpi_sleep_register(); 1564 1565 xen_boot_params_init_edd(); 1566 1567 #ifdef CONFIG_ACPI 1568 /* 1569 * Disable selecting "Firmware First mode" for correctable 1570 * memory errors, as this is the duty of the hypervisor to 1571 * decide. 1572 */ 1573 acpi_disable_cmcff = 1; 1574 #endif 1575 } 1576 1577 xen_add_preferred_consoles(); 1578 1579 #ifdef CONFIG_PCI 1580 /* PCI BIOS service won't work from a PV guest. */ 1581 pci_probe &= ~PCI_PROBE_BIOS; 1582 #endif 1583 xen_raw_console_write("about to get started...\n"); 1584 1585 /* We need this for printk timestamps */ 1586 xen_setup_runstate_info(0); 1587 1588 xen_efi_init(&boot_params); 1589 1590 /* Start the world */ 1591 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1592 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1593 } 1594 1595 static int xen_cpu_up_prepare_pv(unsigned int cpu) 1596 { 1597 int rc; 1598 1599 if (per_cpu(xen_vcpu, cpu) == NULL) 1600 return -ENODEV; 1601 1602 xen_setup_timer(cpu); 1603 1604 rc = xen_smp_intr_init(cpu); 1605 if (rc) { 1606 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n", 1607 cpu, rc); 1608 return rc; 1609 } 1610 1611 rc = xen_smp_intr_init_pv(cpu); 1612 if (rc) { 1613 WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n", 1614 cpu, rc); 1615 return rc; 1616 } 1617 1618 return 0; 1619 } 1620 1621 static int xen_cpu_dead_pv(unsigned int cpu) 1622 { 1623 xen_smp_intr_free(cpu); 1624 xen_smp_intr_free_pv(cpu); 1625 1626 xen_teardown_timer(cpu); 1627 1628 return 0; 1629 } 1630 1631 static uint32_t __init xen_platform_pv(void) 1632 { 1633 if (xen_pv_domain()) 1634 return xen_cpuid_base(); 1635 1636 return 0; 1637 } 1638 1639 const __initconst struct hypervisor_x86 x86_hyper_xen_pv = { 1640 .name = "Xen PV", 1641 .detect = xen_platform_pv, 1642 .type = X86_HYPER_XEN_PV, 1643 .runtime.pin_vcpu = xen_pin_vcpu, 1644 .ignore_nopv = true, 1645 }; 1646