1 /* 2 * Core of Xen paravirt_ops implementation. 3 * 4 * This file contains the xen_paravirt_ops structure itself, and the 5 * implementations for: 6 * - privileged instructions 7 * - interrupt flags 8 * - segment operations 9 * - booting and setup 10 * 11 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 12 */ 13 14 #include <linux/cpu.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/smp.h> 18 #include <linux/preempt.h> 19 #include <linux/hardirq.h> 20 #include <linux/percpu.h> 21 #include <linux/delay.h> 22 #include <linux/start_kernel.h> 23 #include <linux/sched.h> 24 #include <linux/kprobes.h> 25 #include <linux/bootmem.h> 26 #include <linux/module.h> 27 #include <linux/mm.h> 28 #include <linux/page-flags.h> 29 #include <linux/highmem.h> 30 #include <linux/console.h> 31 #include <linux/pci.h> 32 #include <linux/gfp.h> 33 #include <linux/memblock.h> 34 #include <linux/edd.h> 35 36 #include <xen/xen.h> 37 #include <xen/events.h> 38 #include <xen/interface/xen.h> 39 #include <xen/interface/version.h> 40 #include <xen/interface/physdev.h> 41 #include <xen/interface/vcpu.h> 42 #include <xen/interface/memory.h> 43 #include <xen/interface/nmi.h> 44 #include <xen/interface/xen-mca.h> 45 #include <xen/features.h> 46 #include <xen/page.h> 47 #include <xen/hvm.h> 48 #include <xen/hvc-console.h> 49 #include <xen/acpi.h> 50 51 #include <asm/paravirt.h> 52 #include <asm/apic.h> 53 #include <asm/page.h> 54 #include <asm/xen/pci.h> 55 #include <asm/xen/hypercall.h> 56 #include <asm/xen/hypervisor.h> 57 #include <asm/fixmap.h> 58 #include <asm/processor.h> 59 #include <asm/proto.h> 60 #include <asm/msr-index.h> 61 #include <asm/traps.h> 62 #include <asm/setup.h> 63 #include <asm/desc.h> 64 #include <asm/pgalloc.h> 65 #include <asm/pgtable.h> 66 #include <asm/tlbflush.h> 67 #include <asm/reboot.h> 68 #include <asm/stackprotector.h> 69 #include <asm/hypervisor.h> 70 #include <asm/mach_traps.h> 71 #include <asm/mwait.h> 72 #include <asm/pci_x86.h> 73 #include <asm/pat.h> 74 75 #ifdef CONFIG_ACPI 76 #include <linux/acpi.h> 77 #include <asm/acpi.h> 78 #include <acpi/pdc_intel.h> 79 #include <acpi/processor.h> 80 #include <xen/interface/platform.h> 81 #endif 82 83 #include "xen-ops.h" 84 #include "mmu.h" 85 #include "smp.h" 86 #include "multicalls.h" 87 88 EXPORT_SYMBOL_GPL(hypercall_page); 89 90 /* 91 * Pointer to the xen_vcpu_info structure or 92 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 93 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 94 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 95 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 96 * acknowledge pending events. 97 * Also more subtly it is used by the patched version of irq enable/disable 98 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 99 * 100 * The desire to be able to do those mask/unmask operations as a single 101 * instruction by using the per-cpu offset held in %gs is the real reason 102 * vcpu info is in a per-cpu pointer and the original reason for this 103 * hypercall. 104 * 105 */ 106 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 107 108 /* 109 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 110 * hypercall. This can be used both in PV and PVHVM mode. The structure 111 * overrides the default per_cpu(xen_vcpu, cpu) value. 112 */ 113 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 114 115 enum xen_domain_type xen_domain_type = XEN_NATIVE; 116 EXPORT_SYMBOL_GPL(xen_domain_type); 117 118 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 119 EXPORT_SYMBOL(machine_to_phys_mapping); 120 unsigned long machine_to_phys_nr; 121 EXPORT_SYMBOL(machine_to_phys_nr); 122 123 struct start_info *xen_start_info; 124 EXPORT_SYMBOL_GPL(xen_start_info); 125 126 struct shared_info xen_dummy_shared_info; 127 128 void *xen_initial_gdt; 129 130 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 131 __read_mostly int xen_have_vector_callback; 132 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 133 134 /* 135 * Point at some empty memory to start with. We map the real shared_info 136 * page as soon as fixmap is up and running. 137 */ 138 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 139 140 /* 141 * Flag to determine whether vcpu info placement is available on all 142 * VCPUs. We assume it is to start with, and then set it to zero on 143 * the first failure. This is because it can succeed on some VCPUs 144 * and not others, since it can involve hypervisor memory allocation, 145 * or because the guest failed to guarantee all the appropriate 146 * constraints on all VCPUs (ie buffer can't cross a page boundary). 147 * 148 * Note that any particular CPU may be using a placed vcpu structure, 149 * but we can only optimise if the all are. 150 * 151 * 0: not available, 1: available 152 */ 153 static int have_vcpu_info_placement = 1; 154 155 struct tls_descs { 156 struct desc_struct desc[3]; 157 }; 158 159 /* 160 * Updating the 3 TLS descriptors in the GDT on every task switch is 161 * surprisingly expensive so we avoid updating them if they haven't 162 * changed. Since Xen writes different descriptors than the one 163 * passed in the update_descriptor hypercall we keep shadow copies to 164 * compare against. 165 */ 166 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 167 168 static void clamp_max_cpus(void) 169 { 170 #ifdef CONFIG_SMP 171 if (setup_max_cpus > MAX_VIRT_CPUS) 172 setup_max_cpus = MAX_VIRT_CPUS; 173 #endif 174 } 175 176 static void xen_vcpu_setup(int cpu) 177 { 178 struct vcpu_register_vcpu_info info; 179 int err; 180 struct vcpu_info *vcpup; 181 182 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 183 184 /* 185 * This path is called twice on PVHVM - first during bootup via 186 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 187 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 188 * As we can only do the VCPUOP_register_vcpu_info once lets 189 * not over-write its result. 190 * 191 * For PV it is called during restore (xen_vcpu_restore) and bootup 192 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 193 * use this function. 194 */ 195 if (xen_hvm_domain()) { 196 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 197 return; 198 } 199 if (cpu < MAX_VIRT_CPUS) 200 per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 201 202 if (!have_vcpu_info_placement) { 203 if (cpu >= MAX_VIRT_CPUS) 204 clamp_max_cpus(); 205 return; 206 } 207 208 vcpup = &per_cpu(xen_vcpu_info, cpu); 209 info.mfn = arbitrary_virt_to_mfn(vcpup); 210 info.offset = offset_in_page(vcpup); 211 212 /* Check to see if the hypervisor will put the vcpu_info 213 structure where we want it, which allows direct access via 214 a percpu-variable. 215 N.B. This hypercall can _only_ be called once per CPU. Subsequent 216 calls will error out with -EINVAL. This is due to the fact that 217 hypervisor has no unregister variant and this hypercall does not 218 allow to over-write info.mfn and info.offset. 219 */ 220 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 221 222 if (err) { 223 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 224 have_vcpu_info_placement = 0; 225 clamp_max_cpus(); 226 } else { 227 /* This cpu is using the registered vcpu info, even if 228 later ones fail to. */ 229 per_cpu(xen_vcpu, cpu) = vcpup; 230 } 231 } 232 233 /* 234 * On restore, set the vcpu placement up again. 235 * If it fails, then we're in a bad state, since 236 * we can't back out from using it... 237 */ 238 void xen_vcpu_restore(void) 239 { 240 int cpu; 241 242 for_each_possible_cpu(cpu) { 243 bool other_cpu = (cpu != smp_processor_id()); 244 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL); 245 246 if (other_cpu && is_up && 247 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 248 BUG(); 249 250 xen_setup_runstate_info(cpu); 251 252 if (have_vcpu_info_placement) 253 xen_vcpu_setup(cpu); 254 255 if (other_cpu && is_up && 256 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 257 BUG(); 258 } 259 } 260 261 static void __init xen_banner(void) 262 { 263 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 264 struct xen_extraversion extra; 265 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 266 267 pr_info("Booting paravirtualized kernel %son %s\n", 268 xen_feature(XENFEAT_auto_translated_physmap) ? 269 "with PVH extensions " : "", pv_info.name); 270 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 271 version >> 16, version & 0xffff, extra.extraversion, 272 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 273 } 274 /* Check if running on Xen version (major, minor) or later */ 275 bool 276 xen_running_on_version_or_later(unsigned int major, unsigned int minor) 277 { 278 unsigned int version; 279 280 if (!xen_domain()) 281 return false; 282 283 version = HYPERVISOR_xen_version(XENVER_version, NULL); 284 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 285 ((version >> 16) > major)) 286 return true; 287 return false; 288 } 289 290 #define CPUID_THERM_POWER_LEAF 6 291 #define APERFMPERF_PRESENT 0 292 293 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 294 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 295 296 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask; 297 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 298 static __read_mostly unsigned int cpuid_leaf5_edx_val; 299 300 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 301 unsigned int *cx, unsigned int *dx) 302 { 303 unsigned maskebx = ~0; 304 unsigned maskecx = ~0; 305 unsigned maskedx = ~0; 306 unsigned setecx = 0; 307 /* 308 * Mask out inconvenient features, to try and disable as many 309 * unsupported kernel subsystems as possible. 310 */ 311 switch (*ax) { 312 case 1: 313 maskecx = cpuid_leaf1_ecx_mask; 314 setecx = cpuid_leaf1_ecx_set_mask; 315 maskedx = cpuid_leaf1_edx_mask; 316 break; 317 318 case CPUID_MWAIT_LEAF: 319 /* Synthesize the values.. */ 320 *ax = 0; 321 *bx = 0; 322 *cx = cpuid_leaf5_ecx_val; 323 *dx = cpuid_leaf5_edx_val; 324 return; 325 326 case CPUID_THERM_POWER_LEAF: 327 /* Disabling APERFMPERF for kernel usage */ 328 maskecx = ~(1 << APERFMPERF_PRESENT); 329 break; 330 331 case 0xb: 332 /* Suppress extended topology stuff */ 333 maskebx = 0; 334 break; 335 } 336 337 asm(XEN_EMULATE_PREFIX "cpuid" 338 : "=a" (*ax), 339 "=b" (*bx), 340 "=c" (*cx), 341 "=d" (*dx) 342 : "0" (*ax), "2" (*cx)); 343 344 *bx &= maskebx; 345 *cx &= maskecx; 346 *cx |= setecx; 347 *dx &= maskedx; 348 349 } 350 351 static bool __init xen_check_mwait(void) 352 { 353 #ifdef CONFIG_ACPI 354 struct xen_platform_op op = { 355 .cmd = XENPF_set_processor_pminfo, 356 .u.set_pminfo.id = -1, 357 .u.set_pminfo.type = XEN_PM_PDC, 358 }; 359 uint32_t buf[3]; 360 unsigned int ax, bx, cx, dx; 361 unsigned int mwait_mask; 362 363 /* We need to determine whether it is OK to expose the MWAIT 364 * capability to the kernel to harvest deeper than C3 states from ACPI 365 * _CST using the processor_harvest_xen.c module. For this to work, we 366 * need to gather the MWAIT_LEAF values (which the cstate.c code 367 * checks against). The hypervisor won't expose the MWAIT flag because 368 * it would break backwards compatibility; so we will find out directly 369 * from the hardware and hypercall. 370 */ 371 if (!xen_initial_domain()) 372 return false; 373 374 /* 375 * When running under platform earlier than Xen4.2, do not expose 376 * mwait, to avoid the risk of loading native acpi pad driver 377 */ 378 if (!xen_running_on_version_or_later(4, 2)) 379 return false; 380 381 ax = 1; 382 cx = 0; 383 384 native_cpuid(&ax, &bx, &cx, &dx); 385 386 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 387 (1 << (X86_FEATURE_MWAIT % 32)); 388 389 if ((cx & mwait_mask) != mwait_mask) 390 return false; 391 392 /* We need to emulate the MWAIT_LEAF and for that we need both 393 * ecx and edx. The hypercall provides only partial information. 394 */ 395 396 ax = CPUID_MWAIT_LEAF; 397 bx = 0; 398 cx = 0; 399 dx = 0; 400 401 native_cpuid(&ax, &bx, &cx, &dx); 402 403 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so, 404 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 405 */ 406 buf[0] = ACPI_PDC_REVISION_ID; 407 buf[1] = 1; 408 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP); 409 410 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 411 412 if ((HYPERVISOR_dom0_op(&op) == 0) && 413 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) { 414 cpuid_leaf5_ecx_val = cx; 415 cpuid_leaf5_edx_val = dx; 416 } 417 return true; 418 #else 419 return false; 420 #endif 421 } 422 static void __init xen_init_cpuid_mask(void) 423 { 424 unsigned int ax, bx, cx, dx; 425 unsigned int xsave_mask; 426 427 cpuid_leaf1_edx_mask = 428 ~((1 << X86_FEATURE_MTRR) | /* disable MTRR */ 429 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 430 431 if (!xen_initial_domain()) 432 cpuid_leaf1_edx_mask &= 433 ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ 434 435 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); 436 437 ax = 1; 438 cx = 0; 439 cpuid(1, &ax, &bx, &cx, &dx); 440 441 xsave_mask = 442 (1 << (X86_FEATURE_XSAVE % 32)) | 443 (1 << (X86_FEATURE_OSXSAVE % 32)); 444 445 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 446 if ((cx & xsave_mask) != xsave_mask) 447 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 448 if (xen_check_mwait()) 449 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); 450 } 451 452 static void xen_set_debugreg(int reg, unsigned long val) 453 { 454 HYPERVISOR_set_debugreg(reg, val); 455 } 456 457 static unsigned long xen_get_debugreg(int reg) 458 { 459 return HYPERVISOR_get_debugreg(reg); 460 } 461 462 static void xen_end_context_switch(struct task_struct *next) 463 { 464 xen_mc_flush(); 465 paravirt_end_context_switch(next); 466 } 467 468 static unsigned long xen_store_tr(void) 469 { 470 return 0; 471 } 472 473 /* 474 * Set the page permissions for a particular virtual address. If the 475 * address is a vmalloc mapping (or other non-linear mapping), then 476 * find the linear mapping of the page and also set its protections to 477 * match. 478 */ 479 static void set_aliased_prot(void *v, pgprot_t prot) 480 { 481 int level; 482 pte_t *ptep; 483 pte_t pte; 484 unsigned long pfn; 485 struct page *page; 486 487 ptep = lookup_address((unsigned long)v, &level); 488 BUG_ON(ptep == NULL); 489 490 pfn = pte_pfn(*ptep); 491 page = pfn_to_page(pfn); 492 493 pte = pfn_pte(pfn, prot); 494 495 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 496 BUG(); 497 498 if (!PageHighMem(page)) { 499 void *av = __va(PFN_PHYS(pfn)); 500 501 if (av != v) 502 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 503 BUG(); 504 } else 505 kmap_flush_unused(); 506 } 507 508 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 509 { 510 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 511 int i; 512 513 for(i = 0; i < entries; i += entries_per_page) 514 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 515 } 516 517 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 518 { 519 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 520 int i; 521 522 for(i = 0; i < entries; i += entries_per_page) 523 set_aliased_prot(ldt + i, PAGE_KERNEL); 524 } 525 526 static void xen_set_ldt(const void *addr, unsigned entries) 527 { 528 struct mmuext_op *op; 529 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 530 531 trace_xen_cpu_set_ldt(addr, entries); 532 533 op = mcs.args; 534 op->cmd = MMUEXT_SET_LDT; 535 op->arg1.linear_addr = (unsigned long)addr; 536 op->arg2.nr_ents = entries; 537 538 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 539 540 xen_mc_issue(PARAVIRT_LAZY_CPU); 541 } 542 543 static void xen_load_gdt(const struct desc_ptr *dtr) 544 { 545 unsigned long va = dtr->address; 546 unsigned int size = dtr->size + 1; 547 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 548 unsigned long frames[pages]; 549 int f; 550 551 /* 552 * A GDT can be up to 64k in size, which corresponds to 8192 553 * 8-byte entries, or 16 4k pages.. 554 */ 555 556 BUG_ON(size > 65536); 557 BUG_ON(va & ~PAGE_MASK); 558 559 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 560 int level; 561 pte_t *ptep; 562 unsigned long pfn, mfn; 563 void *virt; 564 565 /* 566 * The GDT is per-cpu and is in the percpu data area. 567 * That can be virtually mapped, so we need to do a 568 * page-walk to get the underlying MFN for the 569 * hypercall. The page can also be in the kernel's 570 * linear range, so we need to RO that mapping too. 571 */ 572 ptep = lookup_address(va, &level); 573 BUG_ON(ptep == NULL); 574 575 pfn = pte_pfn(*ptep); 576 mfn = pfn_to_mfn(pfn); 577 virt = __va(PFN_PHYS(pfn)); 578 579 frames[f] = mfn; 580 581 make_lowmem_page_readonly((void *)va); 582 make_lowmem_page_readonly(virt); 583 } 584 585 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 586 BUG(); 587 } 588 589 /* 590 * load_gdt for early boot, when the gdt is only mapped once 591 */ 592 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 593 { 594 unsigned long va = dtr->address; 595 unsigned int size = dtr->size + 1; 596 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 597 unsigned long frames[pages]; 598 int f; 599 600 /* 601 * A GDT can be up to 64k in size, which corresponds to 8192 602 * 8-byte entries, or 16 4k pages.. 603 */ 604 605 BUG_ON(size > 65536); 606 BUG_ON(va & ~PAGE_MASK); 607 608 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 609 pte_t pte; 610 unsigned long pfn, mfn; 611 612 pfn = virt_to_pfn(va); 613 mfn = pfn_to_mfn(pfn); 614 615 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 616 617 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 618 BUG(); 619 620 frames[f] = mfn; 621 } 622 623 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 624 BUG(); 625 } 626 627 static inline bool desc_equal(const struct desc_struct *d1, 628 const struct desc_struct *d2) 629 { 630 return d1->a == d2->a && d1->b == d2->b; 631 } 632 633 static void load_TLS_descriptor(struct thread_struct *t, 634 unsigned int cpu, unsigned int i) 635 { 636 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 637 struct desc_struct *gdt; 638 xmaddr_t maddr; 639 struct multicall_space mc; 640 641 if (desc_equal(shadow, &t->tls_array[i])) 642 return; 643 644 *shadow = t->tls_array[i]; 645 646 gdt = get_cpu_gdt_table(cpu); 647 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 648 mc = __xen_mc_entry(0); 649 650 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 651 } 652 653 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 654 { 655 /* 656 * XXX sleazy hack: If we're being called in a lazy-cpu zone 657 * and lazy gs handling is enabled, it means we're in a 658 * context switch, and %gs has just been saved. This means we 659 * can zero it out to prevent faults on exit from the 660 * hypervisor if the next process has no %gs. Either way, it 661 * has been saved, and the new value will get loaded properly. 662 * This will go away as soon as Xen has been modified to not 663 * save/restore %gs for normal hypercalls. 664 * 665 * On x86_64, this hack is not used for %gs, because gs points 666 * to KERNEL_GS_BASE (and uses it for PDA references), so we 667 * must not zero %gs on x86_64 668 * 669 * For x86_64, we need to zero %fs, otherwise we may get an 670 * exception between the new %fs descriptor being loaded and 671 * %fs being effectively cleared at __switch_to(). 672 */ 673 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 674 #ifdef CONFIG_X86_32 675 lazy_load_gs(0); 676 #else 677 loadsegment(fs, 0); 678 #endif 679 } 680 681 xen_mc_batch(); 682 683 load_TLS_descriptor(t, cpu, 0); 684 load_TLS_descriptor(t, cpu, 1); 685 load_TLS_descriptor(t, cpu, 2); 686 687 xen_mc_issue(PARAVIRT_LAZY_CPU); 688 } 689 690 #ifdef CONFIG_X86_64 691 static void xen_load_gs_index(unsigned int idx) 692 { 693 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 694 BUG(); 695 } 696 #endif 697 698 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 699 const void *ptr) 700 { 701 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 702 u64 entry = *(u64 *)ptr; 703 704 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 705 706 preempt_disable(); 707 708 xen_mc_flush(); 709 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 710 BUG(); 711 712 preempt_enable(); 713 } 714 715 static int cvt_gate_to_trap(int vector, const gate_desc *val, 716 struct trap_info *info) 717 { 718 unsigned long addr; 719 720 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 721 return 0; 722 723 info->vector = vector; 724 725 addr = gate_offset(*val); 726 #ifdef CONFIG_X86_64 727 /* 728 * Look for known traps using IST, and substitute them 729 * appropriately. The debugger ones are the only ones we care 730 * about. Xen will handle faults like double_fault, 731 * so we should never see them. Warn if 732 * there's an unexpected IST-using fault handler. 733 */ 734 if (addr == (unsigned long)debug) 735 addr = (unsigned long)xen_debug; 736 else if (addr == (unsigned long)int3) 737 addr = (unsigned long)xen_int3; 738 else if (addr == (unsigned long)stack_segment) 739 addr = (unsigned long)xen_stack_segment; 740 else if (addr == (unsigned long)double_fault) { 741 /* Don't need to handle these */ 742 return 0; 743 #ifdef CONFIG_X86_MCE 744 } else if (addr == (unsigned long)machine_check) { 745 /* 746 * when xen hypervisor inject vMCE to guest, 747 * use native mce handler to handle it 748 */ 749 ; 750 #endif 751 } else if (addr == (unsigned long)nmi) 752 /* 753 * Use the native version as well. 754 */ 755 ; 756 else { 757 /* Some other trap using IST? */ 758 if (WARN_ON(val->ist != 0)) 759 return 0; 760 } 761 #endif /* CONFIG_X86_64 */ 762 info->address = addr; 763 764 info->cs = gate_segment(*val); 765 info->flags = val->dpl; 766 /* interrupt gates clear IF */ 767 if (val->type == GATE_INTERRUPT) 768 info->flags |= 1 << 2; 769 770 return 1; 771 } 772 773 /* Locations of each CPU's IDT */ 774 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 775 776 /* Set an IDT entry. If the entry is part of the current IDT, then 777 also update Xen. */ 778 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 779 { 780 unsigned long p = (unsigned long)&dt[entrynum]; 781 unsigned long start, end; 782 783 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 784 785 preempt_disable(); 786 787 start = __this_cpu_read(idt_desc.address); 788 end = start + __this_cpu_read(idt_desc.size) + 1; 789 790 xen_mc_flush(); 791 792 native_write_idt_entry(dt, entrynum, g); 793 794 if (p >= start && (p + 8) <= end) { 795 struct trap_info info[2]; 796 797 info[1].address = 0; 798 799 if (cvt_gate_to_trap(entrynum, g, &info[0])) 800 if (HYPERVISOR_set_trap_table(info)) 801 BUG(); 802 } 803 804 preempt_enable(); 805 } 806 807 static void xen_convert_trap_info(const struct desc_ptr *desc, 808 struct trap_info *traps) 809 { 810 unsigned in, out, count; 811 812 count = (desc->size+1) / sizeof(gate_desc); 813 BUG_ON(count > 256); 814 815 for (in = out = 0; in < count; in++) { 816 gate_desc *entry = (gate_desc*)(desc->address) + in; 817 818 if (cvt_gate_to_trap(in, entry, &traps[out])) 819 out++; 820 } 821 traps[out].address = 0; 822 } 823 824 void xen_copy_trap_info(struct trap_info *traps) 825 { 826 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc); 827 828 xen_convert_trap_info(desc, traps); 829 } 830 831 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 832 hold a spinlock to protect the static traps[] array (static because 833 it avoids allocation, and saves stack space). */ 834 static void xen_load_idt(const struct desc_ptr *desc) 835 { 836 static DEFINE_SPINLOCK(lock); 837 static struct trap_info traps[257]; 838 839 trace_xen_cpu_load_idt(desc); 840 841 spin_lock(&lock); 842 843 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); 844 845 xen_convert_trap_info(desc, traps); 846 847 xen_mc_flush(); 848 if (HYPERVISOR_set_trap_table(traps)) 849 BUG(); 850 851 spin_unlock(&lock); 852 } 853 854 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 855 they're handled differently. */ 856 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 857 const void *desc, int type) 858 { 859 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 860 861 preempt_disable(); 862 863 switch (type) { 864 case DESC_LDT: 865 case DESC_TSS: 866 /* ignore */ 867 break; 868 869 default: { 870 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 871 872 xen_mc_flush(); 873 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 874 BUG(); 875 } 876 877 } 878 879 preempt_enable(); 880 } 881 882 /* 883 * Version of write_gdt_entry for use at early boot-time needed to 884 * update an entry as simply as possible. 885 */ 886 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 887 const void *desc, int type) 888 { 889 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 890 891 switch (type) { 892 case DESC_LDT: 893 case DESC_TSS: 894 /* ignore */ 895 break; 896 897 default: { 898 xmaddr_t maddr = virt_to_machine(&dt[entry]); 899 900 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 901 dt[entry] = *(struct desc_struct *)desc; 902 } 903 904 } 905 } 906 907 static void xen_load_sp0(struct tss_struct *tss, 908 struct thread_struct *thread) 909 { 910 struct multicall_space mcs; 911 912 mcs = xen_mc_entry(0); 913 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 914 xen_mc_issue(PARAVIRT_LAZY_CPU); 915 tss->x86_tss.sp0 = thread->sp0; 916 } 917 918 static void xen_set_iopl_mask(unsigned mask) 919 { 920 struct physdev_set_iopl set_iopl; 921 922 /* Force the change at ring 0. */ 923 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 924 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 925 } 926 927 static void xen_io_delay(void) 928 { 929 } 930 931 static void xen_clts(void) 932 { 933 struct multicall_space mcs; 934 935 mcs = xen_mc_entry(0); 936 937 MULTI_fpu_taskswitch(mcs.mc, 0); 938 939 xen_mc_issue(PARAVIRT_LAZY_CPU); 940 } 941 942 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 943 944 static unsigned long xen_read_cr0(void) 945 { 946 unsigned long cr0 = this_cpu_read(xen_cr0_value); 947 948 if (unlikely(cr0 == 0)) { 949 cr0 = native_read_cr0(); 950 this_cpu_write(xen_cr0_value, cr0); 951 } 952 953 return cr0; 954 } 955 956 static void xen_write_cr0(unsigned long cr0) 957 { 958 struct multicall_space mcs; 959 960 this_cpu_write(xen_cr0_value, cr0); 961 962 /* Only pay attention to cr0.TS; everything else is 963 ignored. */ 964 mcs = xen_mc_entry(0); 965 966 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 967 968 xen_mc_issue(PARAVIRT_LAZY_CPU); 969 } 970 971 static void xen_write_cr4(unsigned long cr4) 972 { 973 cr4 &= ~X86_CR4_PGE; 974 cr4 &= ~X86_CR4_PSE; 975 976 native_write_cr4(cr4); 977 } 978 #ifdef CONFIG_X86_64 979 static inline unsigned long xen_read_cr8(void) 980 { 981 return 0; 982 } 983 static inline void xen_write_cr8(unsigned long val) 984 { 985 BUG_ON(val); 986 } 987 #endif 988 989 static u64 xen_read_msr_safe(unsigned int msr, int *err) 990 { 991 u64 val; 992 993 val = native_read_msr_safe(msr, err); 994 switch (msr) { 995 case MSR_IA32_APICBASE: 996 #ifdef CONFIG_X86_X2APIC 997 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31)))) 998 #endif 999 val &= ~X2APIC_ENABLE; 1000 break; 1001 } 1002 return val; 1003 } 1004 1005 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 1006 { 1007 int ret; 1008 1009 ret = 0; 1010 1011 switch (msr) { 1012 #ifdef CONFIG_X86_64 1013 unsigned which; 1014 u64 base; 1015 1016 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 1017 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 1018 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 1019 1020 set: 1021 base = ((u64)high << 32) | low; 1022 if (HYPERVISOR_set_segment_base(which, base) != 0) 1023 ret = -EIO; 1024 break; 1025 #endif 1026 1027 case MSR_STAR: 1028 case MSR_CSTAR: 1029 case MSR_LSTAR: 1030 case MSR_SYSCALL_MASK: 1031 case MSR_IA32_SYSENTER_CS: 1032 case MSR_IA32_SYSENTER_ESP: 1033 case MSR_IA32_SYSENTER_EIP: 1034 /* Fast syscall setup is all done in hypercalls, so 1035 these are all ignored. Stub them out here to stop 1036 Xen console noise. */ 1037 1038 default: 1039 ret = native_write_msr_safe(msr, low, high); 1040 } 1041 1042 return ret; 1043 } 1044 1045 void xen_setup_shared_info(void) 1046 { 1047 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1048 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1049 xen_start_info->shared_info); 1050 1051 HYPERVISOR_shared_info = 1052 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1053 } else 1054 HYPERVISOR_shared_info = 1055 (struct shared_info *)__va(xen_start_info->shared_info); 1056 1057 #ifndef CONFIG_SMP 1058 /* In UP this is as good a place as any to set up shared info */ 1059 xen_setup_vcpu_info_placement(); 1060 #endif 1061 1062 xen_setup_mfn_list_list(); 1063 } 1064 1065 /* This is called once we have the cpu_possible_mask */ 1066 void xen_setup_vcpu_info_placement(void) 1067 { 1068 int cpu; 1069 1070 for_each_possible_cpu(cpu) 1071 xen_vcpu_setup(cpu); 1072 1073 /* xen_vcpu_setup managed to place the vcpu_info within the 1074 * percpu area for all cpus, so make use of it. Note that for 1075 * PVH we want to use native IRQ mechanism. */ 1076 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1077 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1078 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1079 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1080 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1081 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1082 } 1083 } 1084 1085 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1086 unsigned long addr, unsigned len) 1087 { 1088 char *start, *end, *reloc; 1089 unsigned ret; 1090 1091 start = end = reloc = NULL; 1092 1093 #define SITE(op, x) \ 1094 case PARAVIRT_PATCH(op.x): \ 1095 if (have_vcpu_info_placement) { \ 1096 start = (char *)xen_##x##_direct; \ 1097 end = xen_##x##_direct_end; \ 1098 reloc = xen_##x##_direct_reloc; \ 1099 } \ 1100 goto patch_site 1101 1102 switch (type) { 1103 SITE(pv_irq_ops, irq_enable); 1104 SITE(pv_irq_ops, irq_disable); 1105 SITE(pv_irq_ops, save_fl); 1106 SITE(pv_irq_ops, restore_fl); 1107 #undef SITE 1108 1109 patch_site: 1110 if (start == NULL || (end-start) > len) 1111 goto default_patch; 1112 1113 ret = paravirt_patch_insns(insnbuf, len, start, end); 1114 1115 /* Note: because reloc is assigned from something that 1116 appears to be an array, gcc assumes it's non-null, 1117 but doesn't know its relationship with start and 1118 end. */ 1119 if (reloc > start && reloc < end) { 1120 int reloc_off = reloc - start; 1121 long *relocp = (long *)(insnbuf + reloc_off); 1122 long delta = start - (char *)addr; 1123 1124 *relocp += delta; 1125 } 1126 break; 1127 1128 default_patch: 1129 default: 1130 ret = paravirt_patch_default(type, clobbers, insnbuf, 1131 addr, len); 1132 break; 1133 } 1134 1135 return ret; 1136 } 1137 1138 static const struct pv_info xen_info __initconst = { 1139 .paravirt_enabled = 1, 1140 .shared_kernel_pmd = 0, 1141 1142 #ifdef CONFIG_X86_64 1143 .extra_user_64bit_cs = FLAT_USER_CS64, 1144 #endif 1145 1146 .name = "Xen", 1147 }; 1148 1149 static const struct pv_init_ops xen_init_ops __initconst = { 1150 .patch = xen_patch, 1151 }; 1152 1153 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1154 .cpuid = xen_cpuid, 1155 1156 .set_debugreg = xen_set_debugreg, 1157 .get_debugreg = xen_get_debugreg, 1158 1159 .clts = xen_clts, 1160 1161 .read_cr0 = xen_read_cr0, 1162 .write_cr0 = xen_write_cr0, 1163 1164 .read_cr4 = native_read_cr4, 1165 .read_cr4_safe = native_read_cr4_safe, 1166 .write_cr4 = xen_write_cr4, 1167 1168 #ifdef CONFIG_X86_64 1169 .read_cr8 = xen_read_cr8, 1170 .write_cr8 = xen_write_cr8, 1171 #endif 1172 1173 .wbinvd = native_wbinvd, 1174 1175 .read_msr = xen_read_msr_safe, 1176 .write_msr = xen_write_msr_safe, 1177 1178 .read_tsc = native_read_tsc, 1179 .read_pmc = native_read_pmc, 1180 1181 .read_tscp = native_read_tscp, 1182 1183 .iret = xen_iret, 1184 #ifdef CONFIG_X86_64 1185 .usergs_sysret32 = xen_sysret32, 1186 .usergs_sysret64 = xen_sysret64, 1187 #else 1188 .irq_enable_sysexit = xen_sysexit, 1189 #endif 1190 1191 .load_tr_desc = paravirt_nop, 1192 .set_ldt = xen_set_ldt, 1193 .load_gdt = xen_load_gdt, 1194 .load_idt = xen_load_idt, 1195 .load_tls = xen_load_tls, 1196 #ifdef CONFIG_X86_64 1197 .load_gs_index = xen_load_gs_index, 1198 #endif 1199 1200 .alloc_ldt = xen_alloc_ldt, 1201 .free_ldt = xen_free_ldt, 1202 1203 .store_idt = native_store_idt, 1204 .store_tr = xen_store_tr, 1205 1206 .write_ldt_entry = xen_write_ldt_entry, 1207 .write_gdt_entry = xen_write_gdt_entry, 1208 .write_idt_entry = xen_write_idt_entry, 1209 .load_sp0 = xen_load_sp0, 1210 1211 .set_iopl_mask = xen_set_iopl_mask, 1212 .io_delay = xen_io_delay, 1213 1214 /* Xen takes care of %gs when switching to usermode for us */ 1215 .swapgs = paravirt_nop, 1216 1217 .start_context_switch = paravirt_start_context_switch, 1218 .end_context_switch = xen_end_context_switch, 1219 }; 1220 1221 static const struct pv_apic_ops xen_apic_ops __initconst = { 1222 #ifdef CONFIG_X86_LOCAL_APIC 1223 .startup_ipi_hook = paravirt_nop, 1224 #endif 1225 }; 1226 1227 static void xen_reboot(int reason) 1228 { 1229 struct sched_shutdown r = { .reason = reason }; 1230 1231 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1232 BUG(); 1233 } 1234 1235 static void xen_restart(char *msg) 1236 { 1237 xen_reboot(SHUTDOWN_reboot); 1238 } 1239 1240 static void xen_emergency_restart(void) 1241 { 1242 xen_reboot(SHUTDOWN_reboot); 1243 } 1244 1245 static void xen_machine_halt(void) 1246 { 1247 xen_reboot(SHUTDOWN_poweroff); 1248 } 1249 1250 static void xen_machine_power_off(void) 1251 { 1252 if (pm_power_off) 1253 pm_power_off(); 1254 xen_reboot(SHUTDOWN_poweroff); 1255 } 1256 1257 static void xen_crash_shutdown(struct pt_regs *regs) 1258 { 1259 xen_reboot(SHUTDOWN_crash); 1260 } 1261 1262 static int 1263 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1264 { 1265 xen_reboot(SHUTDOWN_crash); 1266 return NOTIFY_DONE; 1267 } 1268 1269 static struct notifier_block xen_panic_block = { 1270 .notifier_call= xen_panic_event, 1271 .priority = INT_MIN 1272 }; 1273 1274 int xen_panic_handler_init(void) 1275 { 1276 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1277 return 0; 1278 } 1279 1280 static const struct machine_ops xen_machine_ops __initconst = { 1281 .restart = xen_restart, 1282 .halt = xen_machine_halt, 1283 .power_off = xen_machine_power_off, 1284 .shutdown = xen_machine_halt, 1285 .crash_shutdown = xen_crash_shutdown, 1286 .emergency_restart = xen_emergency_restart, 1287 }; 1288 1289 static unsigned char xen_get_nmi_reason(void) 1290 { 1291 unsigned char reason = 0; 1292 1293 /* Construct a value which looks like it came from port 0x61. */ 1294 if (test_bit(_XEN_NMIREASON_io_error, 1295 &HYPERVISOR_shared_info->arch.nmi_reason)) 1296 reason |= NMI_REASON_IOCHK; 1297 if (test_bit(_XEN_NMIREASON_pci_serr, 1298 &HYPERVISOR_shared_info->arch.nmi_reason)) 1299 reason |= NMI_REASON_SERR; 1300 1301 return reason; 1302 } 1303 1304 static void __init xen_boot_params_init_edd(void) 1305 { 1306 #if IS_ENABLED(CONFIG_EDD) 1307 struct xen_platform_op op; 1308 struct edd_info *edd_info; 1309 u32 *mbr_signature; 1310 unsigned nr; 1311 int ret; 1312 1313 edd_info = boot_params.eddbuf; 1314 mbr_signature = boot_params.edd_mbr_sig_buffer; 1315 1316 op.cmd = XENPF_firmware_info; 1317 1318 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1319 for (nr = 0; nr < EDDMAXNR; nr++) { 1320 struct edd_info *info = edd_info + nr; 1321 1322 op.u.firmware_info.index = nr; 1323 info->params.length = sizeof(info->params); 1324 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1325 &info->params); 1326 ret = HYPERVISOR_dom0_op(&op); 1327 if (ret) 1328 break; 1329 1330 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1331 C(device); 1332 C(version); 1333 C(interface_support); 1334 C(legacy_max_cylinder); 1335 C(legacy_max_head); 1336 C(legacy_sectors_per_track); 1337 #undef C 1338 } 1339 boot_params.eddbuf_entries = nr; 1340 1341 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1342 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1343 op.u.firmware_info.index = nr; 1344 ret = HYPERVISOR_dom0_op(&op); 1345 if (ret) 1346 break; 1347 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1348 } 1349 boot_params.edd_mbr_sig_buf_entries = nr; 1350 #endif 1351 } 1352 1353 /* 1354 * Set up the GDT and segment registers for -fstack-protector. Until 1355 * we do this, we have to be careful not to call any stack-protected 1356 * function, which is most of the kernel. 1357 * 1358 * Note, that it is __ref because the only caller of this after init 1359 * is PVH which is not going to use xen_load_gdt_boot or other 1360 * __init functions. 1361 */ 1362 static void __ref xen_setup_gdt(int cpu) 1363 { 1364 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1365 #ifdef CONFIG_X86_64 1366 unsigned long dummy; 1367 1368 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1369 switch_to_new_gdt(cpu); /* GDT and GS set */ 1370 1371 /* We are switching of the Xen provided GDT to our HVM mode 1372 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1373 * and we are jumping to reload it. 1374 */ 1375 asm volatile ("pushq %0\n" 1376 "leaq 1f(%%rip),%0\n" 1377 "pushq %0\n" 1378 "lretq\n" 1379 "1:\n" 1380 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1381 1382 /* 1383 * While not needed, we also set the %es, %ds, and %fs 1384 * to zero. We don't care about %ss as it is NULL. 1385 * Strictly speaking this is not needed as Xen zeros those 1386 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1387 * 1388 * Linux zeros them in cpu_init() and in secondary_startup_64 1389 * (for BSP). 1390 */ 1391 loadsegment(es, 0); 1392 loadsegment(ds, 0); 1393 loadsegment(fs, 0); 1394 #else 1395 /* PVH: TODO Implement. */ 1396 BUG(); 1397 #endif 1398 return; /* PVH does not need any PV GDT ops. */ 1399 } 1400 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1401 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1402 1403 setup_stack_canary_segment(0); 1404 switch_to_new_gdt(0); 1405 1406 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1407 pv_cpu_ops.load_gdt = xen_load_gdt; 1408 } 1409 1410 #ifdef CONFIG_XEN_PVH 1411 /* 1412 * A PV guest starts with default flags that are not set for PVH, set them 1413 * here asap. 1414 */ 1415 static void xen_pvh_set_cr_flags(int cpu) 1416 { 1417 1418 /* Some of these are setup in 'secondary_startup_64'. The others: 1419 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1420 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1421 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1422 1423 if (!cpu) 1424 return; 1425 /* 1426 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1427 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu(). 1428 */ 1429 if (cpu_has_pse) 1430 cr4_set_bits_and_update_boot(X86_CR4_PSE); 1431 1432 if (cpu_has_pge) 1433 cr4_set_bits_and_update_boot(X86_CR4_PGE); 1434 } 1435 1436 /* 1437 * Note, that it is ref - because the only caller of this after init 1438 * is PVH which is not going to use xen_load_gdt_boot or other 1439 * __init functions. 1440 */ 1441 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1442 { 1443 xen_setup_gdt(cpu); 1444 xen_pvh_set_cr_flags(cpu); 1445 } 1446 1447 static void __init xen_pvh_early_guest_init(void) 1448 { 1449 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1450 return; 1451 1452 if (!xen_feature(XENFEAT_hvm_callback_vector)) 1453 return; 1454 1455 xen_have_vector_callback = 1; 1456 1457 xen_pvh_early_cpu_init(0, false); 1458 xen_pvh_set_cr_flags(0); 1459 1460 #ifdef CONFIG_X86_32 1461 BUG(); /* PVH: Implement proper support. */ 1462 #endif 1463 } 1464 #endif /* CONFIG_XEN_PVH */ 1465 1466 /* First C function to be called on Xen boot */ 1467 asmlinkage __visible void __init xen_start_kernel(void) 1468 { 1469 struct physdev_set_iopl set_iopl; 1470 unsigned long initrd_start = 0; 1471 u64 pat; 1472 int rc; 1473 1474 if (!xen_start_info) 1475 return; 1476 1477 xen_domain_type = XEN_PV_DOMAIN; 1478 1479 xen_setup_features(); 1480 #ifdef CONFIG_XEN_PVH 1481 xen_pvh_early_guest_init(); 1482 #endif 1483 xen_setup_machphys_mapping(); 1484 1485 /* Install Xen paravirt ops */ 1486 pv_info = xen_info; 1487 pv_init_ops = xen_init_ops; 1488 pv_apic_ops = xen_apic_ops; 1489 if (!xen_pvh_domain()) { 1490 pv_cpu_ops = xen_cpu_ops; 1491 1492 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1493 } 1494 1495 if (xen_feature(XENFEAT_auto_translated_physmap)) 1496 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup; 1497 else 1498 x86_init.resources.memory_setup = xen_memory_setup; 1499 x86_init.oem.arch_setup = xen_arch_setup; 1500 x86_init.oem.banner = xen_banner; 1501 1502 xen_init_time_ops(); 1503 1504 /* 1505 * Set up some pagetable state before starting to set any ptes. 1506 */ 1507 1508 xen_init_mmu_ops(); 1509 1510 /* Prevent unwanted bits from being set in PTEs. */ 1511 __supported_pte_mask &= ~_PAGE_GLOBAL; 1512 1513 /* 1514 * Prevent page tables from being allocated in highmem, even 1515 * if CONFIG_HIGHPTE is enabled. 1516 */ 1517 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1518 1519 /* Work out if we support NX */ 1520 x86_configure_nx(); 1521 1522 /* Get mfn list */ 1523 xen_build_dynamic_phys_to_machine(); 1524 1525 /* 1526 * Set up kernel GDT and segment registers, mainly so that 1527 * -fstack-protector code can be executed. 1528 */ 1529 xen_setup_gdt(0); 1530 1531 xen_init_irq_ops(); 1532 xen_init_cpuid_mask(); 1533 1534 #ifdef CONFIG_X86_LOCAL_APIC 1535 /* 1536 * set up the basic apic ops. 1537 */ 1538 xen_init_apic(); 1539 #endif 1540 1541 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1542 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1543 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1544 } 1545 1546 machine_ops = xen_machine_ops; 1547 1548 /* 1549 * The only reliable way to retain the initial address of the 1550 * percpu gdt_page is to remember it here, so we can go and 1551 * mark it RW later, when the initial percpu area is freed. 1552 */ 1553 xen_initial_gdt = &per_cpu(gdt_page, 0); 1554 1555 xen_smp_init(); 1556 1557 #ifdef CONFIG_ACPI_NUMA 1558 /* 1559 * The pages we from Xen are not related to machine pages, so 1560 * any NUMA information the kernel tries to get from ACPI will 1561 * be meaningless. Prevent it from trying. 1562 */ 1563 acpi_numa = -1; 1564 #endif 1565 /* Don't do the full vcpu_info placement stuff until we have a 1566 possible map and a non-dummy shared_info. */ 1567 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1568 1569 local_irq_disable(); 1570 early_boot_irqs_disabled = true; 1571 1572 xen_raw_console_write("mapping kernel into physical memory\n"); 1573 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages); 1574 1575 /* 1576 * Modify the cache mode translation tables to match Xen's PAT 1577 * configuration. 1578 */ 1579 rdmsrl(MSR_IA32_CR_PAT, pat); 1580 pat_init_cache_modes(pat); 1581 1582 /* keep using Xen gdt for now; no urgent need to change it */ 1583 1584 #ifdef CONFIG_X86_32 1585 pv_info.kernel_rpl = 1; 1586 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1587 pv_info.kernel_rpl = 0; 1588 #else 1589 pv_info.kernel_rpl = 0; 1590 #endif 1591 /* set the limit of our address space */ 1592 xen_reserve_top(); 1593 1594 /* PVH: runs at default kernel iopl of 0 */ 1595 if (!xen_pvh_domain()) { 1596 /* 1597 * We used to do this in xen_arch_setup, but that is too late 1598 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1599 * early_amd_init which pokes 0xcf8 port. 1600 */ 1601 set_iopl.iopl = 1; 1602 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1603 if (rc != 0) 1604 xen_raw_printk("physdev_op failed %d\n", rc); 1605 } 1606 1607 #ifdef CONFIG_X86_32 1608 /* set up basic CPUID stuff */ 1609 cpu_detect(&new_cpu_data); 1610 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); 1611 new_cpu_data.wp_works_ok = 1; 1612 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1613 #endif 1614 1615 if (xen_start_info->mod_start) { 1616 if (xen_start_info->flags & SIF_MOD_START_PFN) 1617 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1618 else 1619 initrd_start = __pa(xen_start_info->mod_start); 1620 } 1621 1622 /* Poke various useful things into boot_params */ 1623 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1624 boot_params.hdr.ramdisk_image = initrd_start; 1625 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1626 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1627 1628 if (!xen_initial_domain()) { 1629 add_preferred_console("xenboot", 0, NULL); 1630 add_preferred_console("tty", 0, NULL); 1631 add_preferred_console("hvc", 0, NULL); 1632 if (pci_xen) 1633 x86_init.pci.arch_init = pci_xen_init; 1634 } else { 1635 const struct dom0_vga_console_info *info = 1636 (void *)((char *)xen_start_info + 1637 xen_start_info->console.dom0.info_off); 1638 struct xen_platform_op op = { 1639 .cmd = XENPF_firmware_info, 1640 .interface_version = XENPF_INTERFACE_VERSION, 1641 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1642 }; 1643 1644 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1645 xen_start_info->console.domU.mfn = 0; 1646 xen_start_info->console.domU.evtchn = 0; 1647 1648 if (HYPERVISOR_dom0_op(&op) == 0) 1649 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1650 1651 /* Make sure ACS will be enabled */ 1652 pci_request_acs(); 1653 1654 xen_acpi_sleep_register(); 1655 1656 /* Avoid searching for BIOS MP tables */ 1657 x86_init.mpparse.find_smp_config = x86_init_noop; 1658 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1659 1660 xen_boot_params_init_edd(); 1661 } 1662 #ifdef CONFIG_PCI 1663 /* PCI BIOS service won't work from a PV guest. */ 1664 pci_probe &= ~PCI_PROBE_BIOS; 1665 #endif 1666 xen_raw_console_write("about to get started...\n"); 1667 1668 xen_setup_runstate_info(0); 1669 1670 xen_efi_init(); 1671 1672 /* Start the world */ 1673 #ifdef CONFIG_X86_32 1674 i386_start_kernel(); 1675 #else 1676 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1677 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1678 #endif 1679 } 1680 1681 void __ref xen_hvm_init_shared_info(void) 1682 { 1683 int cpu; 1684 struct xen_add_to_physmap xatp; 1685 static struct shared_info *shared_info_page = 0; 1686 1687 if (!shared_info_page) 1688 shared_info_page = (struct shared_info *) 1689 extend_brk(PAGE_SIZE, PAGE_SIZE); 1690 xatp.domid = DOMID_SELF; 1691 xatp.idx = 0; 1692 xatp.space = XENMAPSPACE_shared_info; 1693 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1694 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1695 BUG(); 1696 1697 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1698 1699 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1700 * page, we use it in the event channel upcall and in some pvclock 1701 * related functions. We don't need the vcpu_info placement 1702 * optimizations because we don't use any pv_mmu or pv_irq op on 1703 * HVM. 1704 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1705 * online but xen_hvm_init_shared_info is run at resume time too and 1706 * in that case multiple vcpus might be online. */ 1707 for_each_online_cpu(cpu) { 1708 /* Leave it to be NULL. */ 1709 if (cpu >= MAX_VIRT_CPUS) 1710 continue; 1711 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1712 } 1713 } 1714 1715 #ifdef CONFIG_XEN_PVHVM 1716 static void __init init_hvm_pv_info(void) 1717 { 1718 int major, minor; 1719 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1720 u64 pfn; 1721 1722 base = xen_cpuid_base(); 1723 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1724 1725 major = eax >> 16; 1726 minor = eax & 0xffff; 1727 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1728 1729 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1730 1731 pfn = __pa(hypercall_page); 1732 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1733 1734 xen_setup_features(); 1735 1736 pv_info.name = "Xen HVM"; 1737 1738 xen_domain_type = XEN_HVM_DOMAIN; 1739 } 1740 1741 static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, 1742 void *hcpu) 1743 { 1744 int cpu = (long)hcpu; 1745 switch (action) { 1746 case CPU_UP_PREPARE: 1747 xen_vcpu_setup(cpu); 1748 if (xen_have_vector_callback) { 1749 if (xen_feature(XENFEAT_hvm_safe_pvclock)) 1750 xen_setup_timer(cpu); 1751 } 1752 break; 1753 default: 1754 break; 1755 } 1756 return NOTIFY_OK; 1757 } 1758 1759 static struct notifier_block xen_hvm_cpu_notifier = { 1760 .notifier_call = xen_hvm_cpu_notify, 1761 }; 1762 1763 static void __init xen_hvm_guest_init(void) 1764 { 1765 if (xen_pv_domain()) 1766 return; 1767 1768 init_hvm_pv_info(); 1769 1770 xen_hvm_init_shared_info(); 1771 1772 xen_panic_handler_init(); 1773 1774 if (xen_feature(XENFEAT_hvm_callback_vector)) 1775 xen_have_vector_callback = 1; 1776 xen_hvm_smp_init(); 1777 register_cpu_notifier(&xen_hvm_cpu_notifier); 1778 xen_unplug_emulated_devices(); 1779 x86_init.irqs.intr_init = xen_init_IRQ; 1780 xen_hvm_init_time_ops(); 1781 xen_hvm_init_mmu_ops(); 1782 } 1783 #endif 1784 1785 static bool xen_nopv = false; 1786 static __init int xen_parse_nopv(char *arg) 1787 { 1788 xen_nopv = true; 1789 return 0; 1790 } 1791 early_param("xen_nopv", xen_parse_nopv); 1792 1793 static uint32_t __init xen_platform(void) 1794 { 1795 if (xen_nopv) 1796 return 0; 1797 1798 return xen_cpuid_base(); 1799 } 1800 1801 bool xen_hvm_need_lapic(void) 1802 { 1803 if (xen_nopv) 1804 return false; 1805 if (xen_pv_domain()) 1806 return false; 1807 if (!xen_hvm_domain()) 1808 return false; 1809 if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) 1810 return false; 1811 return true; 1812 } 1813 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1814 1815 static void xen_set_cpu_features(struct cpuinfo_x86 *c) 1816 { 1817 if (xen_pv_domain()) 1818 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); 1819 } 1820 1821 const struct hypervisor_x86 x86_hyper_xen = { 1822 .name = "Xen", 1823 .detect = xen_platform, 1824 #ifdef CONFIG_XEN_PVHVM 1825 .init_platform = xen_hvm_guest_init, 1826 #endif 1827 .x2apic_available = xen_x2apic_para_available, 1828 .set_cpu_features = xen_set_cpu_features, 1829 }; 1830 EXPORT_SYMBOL(x86_hyper_xen); 1831