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/xen-mca.h> 44 #include <xen/features.h> 45 #include <xen/page.h> 46 #include <xen/hvm.h> 47 #include <xen/hvc-console.h> 48 #include <xen/acpi.h> 49 50 #include <asm/paravirt.h> 51 #include <asm/apic.h> 52 #include <asm/page.h> 53 #include <asm/xen/pci.h> 54 #include <asm/xen/hypercall.h> 55 #include <asm/xen/hypervisor.h> 56 #include <asm/fixmap.h> 57 #include <asm/processor.h> 58 #include <asm/proto.h> 59 #include <asm/msr-index.h> 60 #include <asm/traps.h> 61 #include <asm/setup.h> 62 #include <asm/desc.h> 63 #include <asm/pgalloc.h> 64 #include <asm/pgtable.h> 65 #include <asm/tlbflush.h> 66 #include <asm/reboot.h> 67 #include <asm/stackprotector.h> 68 #include <asm/hypervisor.h> 69 #include <asm/mwait.h> 70 #include <asm/pci_x86.h> 71 #include <asm/pat.h> 72 73 #ifdef CONFIG_ACPI 74 #include <linux/acpi.h> 75 #include <asm/acpi.h> 76 #include <acpi/pdc_intel.h> 77 #include <acpi/processor.h> 78 #include <xen/interface/platform.h> 79 #endif 80 81 #include "xen-ops.h" 82 #include "mmu.h" 83 #include "smp.h" 84 #include "multicalls.h" 85 86 EXPORT_SYMBOL_GPL(hypercall_page); 87 88 /* 89 * Pointer to the xen_vcpu_info structure or 90 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 91 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 92 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 93 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 94 * acknowledge pending events. 95 * Also more subtly it is used by the patched version of irq enable/disable 96 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 97 * 98 * The desire to be able to do those mask/unmask operations as a single 99 * instruction by using the per-cpu offset held in %gs is the real reason 100 * vcpu info is in a per-cpu pointer and the original reason for this 101 * hypercall. 102 * 103 */ 104 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 105 106 /* 107 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 108 * hypercall. This can be used both in PV and PVHVM mode. The structure 109 * overrides the default per_cpu(xen_vcpu, cpu) value. 110 */ 111 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 112 113 enum xen_domain_type xen_domain_type = XEN_NATIVE; 114 EXPORT_SYMBOL_GPL(xen_domain_type); 115 116 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 117 EXPORT_SYMBOL(machine_to_phys_mapping); 118 unsigned long machine_to_phys_nr; 119 EXPORT_SYMBOL(machine_to_phys_nr); 120 121 struct start_info *xen_start_info; 122 EXPORT_SYMBOL_GPL(xen_start_info); 123 124 struct shared_info xen_dummy_shared_info; 125 126 void *xen_initial_gdt; 127 128 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 129 __read_mostly int xen_have_vector_callback; 130 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 131 132 /* 133 * Point at some empty memory to start with. We map the real shared_info 134 * page as soon as fixmap is up and running. 135 */ 136 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 137 138 /* 139 * Flag to determine whether vcpu info placement is available on all 140 * VCPUs. We assume it is to start with, and then set it to zero on 141 * the first failure. This is because it can succeed on some VCPUs 142 * and not others, since it can involve hypervisor memory allocation, 143 * or because the guest failed to guarantee all the appropriate 144 * constraints on all VCPUs (ie buffer can't cross a page boundary). 145 * 146 * Note that any particular CPU may be using a placed vcpu structure, 147 * but we can only optimise if the all are. 148 * 149 * 0: not available, 1: available 150 */ 151 static int have_vcpu_info_placement = 1; 152 153 struct tls_descs { 154 struct desc_struct desc[3]; 155 }; 156 157 /* 158 * Updating the 3 TLS descriptors in the GDT on every task switch is 159 * surprisingly expensive so we avoid updating them if they haven't 160 * changed. Since Xen writes different descriptors than the one 161 * passed in the update_descriptor hypercall we keep shadow copies to 162 * compare against. 163 */ 164 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 165 166 static void clamp_max_cpus(void) 167 { 168 #ifdef CONFIG_SMP 169 if (setup_max_cpus > MAX_VIRT_CPUS) 170 setup_max_cpus = MAX_VIRT_CPUS; 171 #endif 172 } 173 174 static void xen_vcpu_setup(int cpu) 175 { 176 struct vcpu_register_vcpu_info info; 177 int err; 178 struct vcpu_info *vcpup; 179 180 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 181 182 /* 183 * This path is called twice on PVHVM - first during bootup via 184 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 185 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 186 * As we can only do the VCPUOP_register_vcpu_info once lets 187 * not over-write its result. 188 * 189 * For PV it is called during restore (xen_vcpu_restore) and bootup 190 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 191 * use this function. 192 */ 193 if (xen_hvm_domain()) { 194 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 195 return; 196 } 197 if (cpu < MAX_VIRT_CPUS) 198 per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 199 200 if (!have_vcpu_info_placement) { 201 if (cpu >= MAX_VIRT_CPUS) 202 clamp_max_cpus(); 203 return; 204 } 205 206 vcpup = &per_cpu(xen_vcpu_info, cpu); 207 info.mfn = arbitrary_virt_to_mfn(vcpup); 208 info.offset = offset_in_page(vcpup); 209 210 /* Check to see if the hypervisor will put the vcpu_info 211 structure where we want it, which allows direct access via 212 a percpu-variable. 213 N.B. This hypercall can _only_ be called once per CPU. Subsequent 214 calls will error out with -EINVAL. This is due to the fact that 215 hypervisor has no unregister variant and this hypercall does not 216 allow to over-write info.mfn and info.offset. 217 */ 218 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 219 220 if (err) { 221 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 222 have_vcpu_info_placement = 0; 223 clamp_max_cpus(); 224 } else { 225 /* This cpu is using the registered vcpu info, even if 226 later ones fail to. */ 227 per_cpu(xen_vcpu, cpu) = vcpup; 228 } 229 } 230 231 /* 232 * On restore, set the vcpu placement up again. 233 * If it fails, then we're in a bad state, since 234 * we can't back out from using it... 235 */ 236 void xen_vcpu_restore(void) 237 { 238 int cpu; 239 240 for_each_possible_cpu(cpu) { 241 bool other_cpu = (cpu != smp_processor_id()); 242 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL); 243 244 if (other_cpu && is_up && 245 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 246 BUG(); 247 248 xen_setup_runstate_info(cpu); 249 250 if (have_vcpu_info_placement) 251 xen_vcpu_setup(cpu); 252 253 if (other_cpu && is_up && 254 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 255 BUG(); 256 } 257 } 258 259 static void __init xen_banner(void) 260 { 261 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 262 struct xen_extraversion extra; 263 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 264 265 pr_info("Booting paravirtualized kernel %son %s\n", 266 xen_feature(XENFEAT_auto_translated_physmap) ? 267 "with PVH extensions " : "", pv_info.name); 268 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 269 version >> 16, version & 0xffff, extra.extraversion, 270 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 271 } 272 /* Check if running on Xen version (major, minor) or later */ 273 bool 274 xen_running_on_version_or_later(unsigned int major, unsigned int minor) 275 { 276 unsigned int version; 277 278 if (!xen_domain()) 279 return false; 280 281 version = HYPERVISOR_xen_version(XENVER_version, NULL); 282 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 283 ((version >> 16) > major)) 284 return true; 285 return false; 286 } 287 288 #define CPUID_THERM_POWER_LEAF 6 289 #define APERFMPERF_PRESENT 0 290 291 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 292 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 293 294 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask; 295 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 296 static __read_mostly unsigned int cpuid_leaf5_edx_val; 297 298 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 299 unsigned int *cx, unsigned int *dx) 300 { 301 unsigned maskebx = ~0; 302 unsigned maskecx = ~0; 303 unsigned maskedx = ~0; 304 unsigned setecx = 0; 305 /* 306 * Mask out inconvenient features, to try and disable as many 307 * unsupported kernel subsystems as possible. 308 */ 309 switch (*ax) { 310 case 1: 311 maskecx = cpuid_leaf1_ecx_mask; 312 setecx = cpuid_leaf1_ecx_set_mask; 313 maskedx = cpuid_leaf1_edx_mask; 314 break; 315 316 case CPUID_MWAIT_LEAF: 317 /* Synthesize the values.. */ 318 *ax = 0; 319 *bx = 0; 320 *cx = cpuid_leaf5_ecx_val; 321 *dx = cpuid_leaf5_edx_val; 322 return; 323 324 case CPUID_THERM_POWER_LEAF: 325 /* Disabling APERFMPERF for kernel usage */ 326 maskecx = ~(1 << APERFMPERF_PRESENT); 327 break; 328 329 case 0xb: 330 /* Suppress extended topology stuff */ 331 maskebx = 0; 332 break; 333 } 334 335 asm(XEN_EMULATE_PREFIX "cpuid" 336 : "=a" (*ax), 337 "=b" (*bx), 338 "=c" (*cx), 339 "=d" (*dx) 340 : "0" (*ax), "2" (*cx)); 341 342 *bx &= maskebx; 343 *cx &= maskecx; 344 *cx |= setecx; 345 *dx &= maskedx; 346 347 } 348 349 static bool __init xen_check_mwait(void) 350 { 351 #ifdef CONFIG_ACPI 352 struct xen_platform_op op = { 353 .cmd = XENPF_set_processor_pminfo, 354 .u.set_pminfo.id = -1, 355 .u.set_pminfo.type = XEN_PM_PDC, 356 }; 357 uint32_t buf[3]; 358 unsigned int ax, bx, cx, dx; 359 unsigned int mwait_mask; 360 361 /* We need to determine whether it is OK to expose the MWAIT 362 * capability to the kernel to harvest deeper than C3 states from ACPI 363 * _CST using the processor_harvest_xen.c module. For this to work, we 364 * need to gather the MWAIT_LEAF values (which the cstate.c code 365 * checks against). The hypervisor won't expose the MWAIT flag because 366 * it would break backwards compatibility; so we will find out directly 367 * from the hardware and hypercall. 368 */ 369 if (!xen_initial_domain()) 370 return false; 371 372 /* 373 * When running under platform earlier than Xen4.2, do not expose 374 * mwait, to avoid the risk of loading native acpi pad driver 375 */ 376 if (!xen_running_on_version_or_later(4, 2)) 377 return false; 378 379 ax = 1; 380 cx = 0; 381 382 native_cpuid(&ax, &bx, &cx, &dx); 383 384 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 385 (1 << (X86_FEATURE_MWAIT % 32)); 386 387 if ((cx & mwait_mask) != mwait_mask) 388 return false; 389 390 /* We need to emulate the MWAIT_LEAF and for that we need both 391 * ecx and edx. The hypercall provides only partial information. 392 */ 393 394 ax = CPUID_MWAIT_LEAF; 395 bx = 0; 396 cx = 0; 397 dx = 0; 398 399 native_cpuid(&ax, &bx, &cx, &dx); 400 401 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so, 402 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 403 */ 404 buf[0] = ACPI_PDC_REVISION_ID; 405 buf[1] = 1; 406 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP); 407 408 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 409 410 if ((HYPERVISOR_dom0_op(&op) == 0) && 411 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) { 412 cpuid_leaf5_ecx_val = cx; 413 cpuid_leaf5_edx_val = dx; 414 } 415 return true; 416 #else 417 return false; 418 #endif 419 } 420 static void __init xen_init_cpuid_mask(void) 421 { 422 unsigned int ax, bx, cx, dx; 423 unsigned int xsave_mask; 424 425 cpuid_leaf1_edx_mask = 426 ~((1 << X86_FEATURE_MTRR) | /* disable MTRR */ 427 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 428 429 if (!xen_initial_domain()) 430 cpuid_leaf1_edx_mask &= 431 ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ 432 433 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); 434 435 ax = 1; 436 cx = 0; 437 cpuid(1, &ax, &bx, &cx, &dx); 438 439 xsave_mask = 440 (1 << (X86_FEATURE_XSAVE % 32)) | 441 (1 << (X86_FEATURE_OSXSAVE % 32)); 442 443 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 444 if ((cx & xsave_mask) != xsave_mask) 445 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 446 if (xen_check_mwait()) 447 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); 448 } 449 450 static void xen_set_debugreg(int reg, unsigned long val) 451 { 452 HYPERVISOR_set_debugreg(reg, val); 453 } 454 455 static unsigned long xen_get_debugreg(int reg) 456 { 457 return HYPERVISOR_get_debugreg(reg); 458 } 459 460 static void xen_end_context_switch(struct task_struct *next) 461 { 462 xen_mc_flush(); 463 paravirt_end_context_switch(next); 464 } 465 466 static unsigned long xen_store_tr(void) 467 { 468 return 0; 469 } 470 471 /* 472 * Set the page permissions for a particular virtual address. If the 473 * address is a vmalloc mapping (or other non-linear mapping), then 474 * find the linear mapping of the page and also set its protections to 475 * match. 476 */ 477 static void set_aliased_prot(void *v, pgprot_t prot) 478 { 479 int level; 480 pte_t *ptep; 481 pte_t pte; 482 unsigned long pfn; 483 struct page *page; 484 485 ptep = lookup_address((unsigned long)v, &level); 486 BUG_ON(ptep == NULL); 487 488 pfn = pte_pfn(*ptep); 489 page = pfn_to_page(pfn); 490 491 pte = pfn_pte(pfn, prot); 492 493 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 494 BUG(); 495 496 if (!PageHighMem(page)) { 497 void *av = __va(PFN_PHYS(pfn)); 498 499 if (av != v) 500 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 501 BUG(); 502 } else 503 kmap_flush_unused(); 504 } 505 506 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 507 { 508 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 509 int i; 510 511 for(i = 0; i < entries; i += entries_per_page) 512 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 513 } 514 515 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 516 { 517 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 518 int i; 519 520 for(i = 0; i < entries; i += entries_per_page) 521 set_aliased_prot(ldt + i, PAGE_KERNEL); 522 } 523 524 static void xen_set_ldt(const void *addr, unsigned entries) 525 { 526 struct mmuext_op *op; 527 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 528 529 trace_xen_cpu_set_ldt(addr, entries); 530 531 op = mcs.args; 532 op->cmd = MMUEXT_SET_LDT; 533 op->arg1.linear_addr = (unsigned long)addr; 534 op->arg2.nr_ents = entries; 535 536 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 537 538 xen_mc_issue(PARAVIRT_LAZY_CPU); 539 } 540 541 static void xen_load_gdt(const struct desc_ptr *dtr) 542 { 543 unsigned long va = dtr->address; 544 unsigned int size = dtr->size + 1; 545 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 546 unsigned long frames[pages]; 547 int f; 548 549 /* 550 * A GDT can be up to 64k in size, which corresponds to 8192 551 * 8-byte entries, or 16 4k pages.. 552 */ 553 554 BUG_ON(size > 65536); 555 BUG_ON(va & ~PAGE_MASK); 556 557 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 558 int level; 559 pte_t *ptep; 560 unsigned long pfn, mfn; 561 void *virt; 562 563 /* 564 * The GDT is per-cpu and is in the percpu data area. 565 * That can be virtually mapped, so we need to do a 566 * page-walk to get the underlying MFN for the 567 * hypercall. The page can also be in the kernel's 568 * linear range, so we need to RO that mapping too. 569 */ 570 ptep = lookup_address(va, &level); 571 BUG_ON(ptep == NULL); 572 573 pfn = pte_pfn(*ptep); 574 mfn = pfn_to_mfn(pfn); 575 virt = __va(PFN_PHYS(pfn)); 576 577 frames[f] = mfn; 578 579 make_lowmem_page_readonly((void *)va); 580 make_lowmem_page_readonly(virt); 581 } 582 583 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 584 BUG(); 585 } 586 587 /* 588 * load_gdt for early boot, when the gdt is only mapped once 589 */ 590 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 591 { 592 unsigned long va = dtr->address; 593 unsigned int size = dtr->size + 1; 594 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 595 unsigned long frames[pages]; 596 int f; 597 598 /* 599 * A GDT can be up to 64k in size, which corresponds to 8192 600 * 8-byte entries, or 16 4k pages.. 601 */ 602 603 BUG_ON(size > 65536); 604 BUG_ON(va & ~PAGE_MASK); 605 606 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 607 pte_t pte; 608 unsigned long pfn, mfn; 609 610 pfn = virt_to_pfn(va); 611 mfn = pfn_to_mfn(pfn); 612 613 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 614 615 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 616 BUG(); 617 618 frames[f] = mfn; 619 } 620 621 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 622 BUG(); 623 } 624 625 static inline bool desc_equal(const struct desc_struct *d1, 626 const struct desc_struct *d2) 627 { 628 return d1->a == d2->a && d1->b == d2->b; 629 } 630 631 static void load_TLS_descriptor(struct thread_struct *t, 632 unsigned int cpu, unsigned int i) 633 { 634 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 635 struct desc_struct *gdt; 636 xmaddr_t maddr; 637 struct multicall_space mc; 638 639 if (desc_equal(shadow, &t->tls_array[i])) 640 return; 641 642 *shadow = t->tls_array[i]; 643 644 gdt = get_cpu_gdt_table(cpu); 645 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 646 mc = __xen_mc_entry(0); 647 648 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 649 } 650 651 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 652 { 653 /* 654 * XXX sleazy hack: If we're being called in a lazy-cpu zone 655 * and lazy gs handling is enabled, it means we're in a 656 * context switch, and %gs has just been saved. This means we 657 * can zero it out to prevent faults on exit from the 658 * hypervisor if the next process has no %gs. Either way, it 659 * has been saved, and the new value will get loaded properly. 660 * This will go away as soon as Xen has been modified to not 661 * save/restore %gs for normal hypercalls. 662 * 663 * On x86_64, this hack is not used for %gs, because gs points 664 * to KERNEL_GS_BASE (and uses it for PDA references), so we 665 * must not zero %gs on x86_64 666 * 667 * For x86_64, we need to zero %fs, otherwise we may get an 668 * exception between the new %fs descriptor being loaded and 669 * %fs being effectively cleared at __switch_to(). 670 */ 671 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 672 #ifdef CONFIG_X86_32 673 lazy_load_gs(0); 674 #else 675 loadsegment(fs, 0); 676 #endif 677 } 678 679 xen_mc_batch(); 680 681 load_TLS_descriptor(t, cpu, 0); 682 load_TLS_descriptor(t, cpu, 1); 683 load_TLS_descriptor(t, cpu, 2); 684 685 xen_mc_issue(PARAVIRT_LAZY_CPU); 686 } 687 688 #ifdef CONFIG_X86_64 689 static void xen_load_gs_index(unsigned int idx) 690 { 691 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 692 BUG(); 693 } 694 #endif 695 696 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 697 const void *ptr) 698 { 699 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 700 u64 entry = *(u64 *)ptr; 701 702 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 703 704 preempt_disable(); 705 706 xen_mc_flush(); 707 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 708 BUG(); 709 710 preempt_enable(); 711 } 712 713 static int cvt_gate_to_trap(int vector, const gate_desc *val, 714 struct trap_info *info) 715 { 716 unsigned long addr; 717 718 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 719 return 0; 720 721 info->vector = vector; 722 723 addr = gate_offset(*val); 724 #ifdef CONFIG_X86_64 725 /* 726 * Look for known traps using IST, and substitute them 727 * appropriately. The debugger ones are the only ones we care 728 * about. Xen will handle faults like double_fault, 729 * so we should never see them. Warn if 730 * there's an unexpected IST-using fault handler. 731 */ 732 if (addr == (unsigned long)debug) 733 addr = (unsigned long)xen_debug; 734 else if (addr == (unsigned long)int3) 735 addr = (unsigned long)xen_int3; 736 else if (addr == (unsigned long)stack_segment) 737 addr = (unsigned long)xen_stack_segment; 738 else if (addr == (unsigned long)double_fault) { 739 /* Don't need to handle these */ 740 return 0; 741 #ifdef CONFIG_X86_MCE 742 } else if (addr == (unsigned long)machine_check) { 743 /* 744 * when xen hypervisor inject vMCE to guest, 745 * use native mce handler to handle it 746 */ 747 ; 748 #endif 749 } else if (addr == (unsigned long)nmi) 750 /* 751 * Use the native version as well. 752 */ 753 ; 754 else { 755 /* Some other trap using IST? */ 756 if (WARN_ON(val->ist != 0)) 757 return 0; 758 } 759 #endif /* CONFIG_X86_64 */ 760 info->address = addr; 761 762 info->cs = gate_segment(*val); 763 info->flags = val->dpl; 764 /* interrupt gates clear IF */ 765 if (val->type == GATE_INTERRUPT) 766 info->flags |= 1 << 2; 767 768 return 1; 769 } 770 771 /* Locations of each CPU's IDT */ 772 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 773 774 /* Set an IDT entry. If the entry is part of the current IDT, then 775 also update Xen. */ 776 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 777 { 778 unsigned long p = (unsigned long)&dt[entrynum]; 779 unsigned long start, end; 780 781 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 782 783 preempt_disable(); 784 785 start = __this_cpu_read(idt_desc.address); 786 end = start + __this_cpu_read(idt_desc.size) + 1; 787 788 xen_mc_flush(); 789 790 native_write_idt_entry(dt, entrynum, g); 791 792 if (p >= start && (p + 8) <= end) { 793 struct trap_info info[2]; 794 795 info[1].address = 0; 796 797 if (cvt_gate_to_trap(entrynum, g, &info[0])) 798 if (HYPERVISOR_set_trap_table(info)) 799 BUG(); 800 } 801 802 preempt_enable(); 803 } 804 805 static void xen_convert_trap_info(const struct desc_ptr *desc, 806 struct trap_info *traps) 807 { 808 unsigned in, out, count; 809 810 count = (desc->size+1) / sizeof(gate_desc); 811 BUG_ON(count > 256); 812 813 for (in = out = 0; in < count; in++) { 814 gate_desc *entry = (gate_desc*)(desc->address) + in; 815 816 if (cvt_gate_to_trap(in, entry, &traps[out])) 817 out++; 818 } 819 traps[out].address = 0; 820 } 821 822 void xen_copy_trap_info(struct trap_info *traps) 823 { 824 const struct desc_ptr *desc = &__get_cpu_var(idt_desc); 825 826 xen_convert_trap_info(desc, traps); 827 } 828 829 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 830 hold a spinlock to protect the static traps[] array (static because 831 it avoids allocation, and saves stack space). */ 832 static void xen_load_idt(const struct desc_ptr *desc) 833 { 834 static DEFINE_SPINLOCK(lock); 835 static struct trap_info traps[257]; 836 837 trace_xen_cpu_load_idt(desc); 838 839 spin_lock(&lock); 840 841 __get_cpu_var(idt_desc) = *desc; 842 843 xen_convert_trap_info(desc, traps); 844 845 xen_mc_flush(); 846 if (HYPERVISOR_set_trap_table(traps)) 847 BUG(); 848 849 spin_unlock(&lock); 850 } 851 852 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 853 they're handled differently. */ 854 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 855 const void *desc, int type) 856 { 857 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 858 859 preempt_disable(); 860 861 switch (type) { 862 case DESC_LDT: 863 case DESC_TSS: 864 /* ignore */ 865 break; 866 867 default: { 868 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 869 870 xen_mc_flush(); 871 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 872 BUG(); 873 } 874 875 } 876 877 preempt_enable(); 878 } 879 880 /* 881 * Version of write_gdt_entry for use at early boot-time needed to 882 * update an entry as simply as possible. 883 */ 884 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 885 const void *desc, int type) 886 { 887 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 888 889 switch (type) { 890 case DESC_LDT: 891 case DESC_TSS: 892 /* ignore */ 893 break; 894 895 default: { 896 xmaddr_t maddr = virt_to_machine(&dt[entry]); 897 898 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 899 dt[entry] = *(struct desc_struct *)desc; 900 } 901 902 } 903 } 904 905 static void xen_load_sp0(struct tss_struct *tss, 906 struct thread_struct *thread) 907 { 908 struct multicall_space mcs; 909 910 mcs = xen_mc_entry(0); 911 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 912 xen_mc_issue(PARAVIRT_LAZY_CPU); 913 } 914 915 static void xen_set_iopl_mask(unsigned mask) 916 { 917 struct physdev_set_iopl set_iopl; 918 919 /* Force the change at ring 0. */ 920 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 921 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 922 } 923 924 static void xen_io_delay(void) 925 { 926 } 927 928 #ifdef CONFIG_X86_LOCAL_APIC 929 static unsigned long xen_set_apic_id(unsigned int x) 930 { 931 WARN_ON(1); 932 return x; 933 } 934 static unsigned int xen_get_apic_id(unsigned long x) 935 { 936 return ((x)>>24) & 0xFFu; 937 } 938 static u32 xen_apic_read(u32 reg) 939 { 940 struct xen_platform_op op = { 941 .cmd = XENPF_get_cpuinfo, 942 .interface_version = XENPF_INTERFACE_VERSION, 943 .u.pcpu_info.xen_cpuid = 0, 944 }; 945 int ret = 0; 946 947 /* Shouldn't need this as APIC is turned off for PV, and we only 948 * get called on the bootup processor. But just in case. */ 949 if (!xen_initial_domain() || smp_processor_id()) 950 return 0; 951 952 if (reg == APIC_LVR) 953 return 0x10; 954 955 if (reg != APIC_ID) 956 return 0; 957 958 ret = HYPERVISOR_dom0_op(&op); 959 if (ret) 960 return 0; 961 962 return op.u.pcpu_info.apic_id << 24; 963 } 964 965 static void xen_apic_write(u32 reg, u32 val) 966 { 967 /* Warn to see if there's any stray references */ 968 WARN_ON(1); 969 } 970 971 static u64 xen_apic_icr_read(void) 972 { 973 return 0; 974 } 975 976 static void xen_apic_icr_write(u32 low, u32 id) 977 { 978 /* Warn to see if there's any stray references */ 979 WARN_ON(1); 980 } 981 982 static void xen_apic_wait_icr_idle(void) 983 { 984 return; 985 } 986 987 static u32 xen_safe_apic_wait_icr_idle(void) 988 { 989 return 0; 990 } 991 992 static void set_xen_basic_apic_ops(void) 993 { 994 apic->read = xen_apic_read; 995 apic->write = xen_apic_write; 996 apic->icr_read = xen_apic_icr_read; 997 apic->icr_write = xen_apic_icr_write; 998 apic->wait_icr_idle = xen_apic_wait_icr_idle; 999 apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle; 1000 apic->set_apic_id = xen_set_apic_id; 1001 apic->get_apic_id = xen_get_apic_id; 1002 1003 #ifdef CONFIG_SMP 1004 apic->send_IPI_allbutself = xen_send_IPI_allbutself; 1005 apic->send_IPI_mask_allbutself = xen_send_IPI_mask_allbutself; 1006 apic->send_IPI_mask = xen_send_IPI_mask; 1007 apic->send_IPI_all = xen_send_IPI_all; 1008 apic->send_IPI_self = xen_send_IPI_self; 1009 #endif 1010 } 1011 1012 #endif 1013 1014 static void xen_clts(void) 1015 { 1016 struct multicall_space mcs; 1017 1018 mcs = xen_mc_entry(0); 1019 1020 MULTI_fpu_taskswitch(mcs.mc, 0); 1021 1022 xen_mc_issue(PARAVIRT_LAZY_CPU); 1023 } 1024 1025 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 1026 1027 static unsigned long xen_read_cr0(void) 1028 { 1029 unsigned long cr0 = this_cpu_read(xen_cr0_value); 1030 1031 if (unlikely(cr0 == 0)) { 1032 cr0 = native_read_cr0(); 1033 this_cpu_write(xen_cr0_value, cr0); 1034 } 1035 1036 return cr0; 1037 } 1038 1039 static void xen_write_cr0(unsigned long cr0) 1040 { 1041 struct multicall_space mcs; 1042 1043 this_cpu_write(xen_cr0_value, cr0); 1044 1045 /* Only pay attention to cr0.TS; everything else is 1046 ignored. */ 1047 mcs = xen_mc_entry(0); 1048 1049 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 1050 1051 xen_mc_issue(PARAVIRT_LAZY_CPU); 1052 } 1053 1054 static void xen_write_cr4(unsigned long cr4) 1055 { 1056 cr4 &= ~X86_CR4_PGE; 1057 cr4 &= ~X86_CR4_PSE; 1058 1059 native_write_cr4(cr4); 1060 } 1061 #ifdef CONFIG_X86_64 1062 static inline unsigned long xen_read_cr8(void) 1063 { 1064 return 0; 1065 } 1066 static inline void xen_write_cr8(unsigned long val) 1067 { 1068 BUG_ON(val); 1069 } 1070 #endif 1071 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 1072 { 1073 int ret; 1074 1075 ret = 0; 1076 1077 switch (msr) { 1078 #ifdef CONFIG_X86_64 1079 unsigned which; 1080 u64 base; 1081 1082 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 1083 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 1084 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 1085 1086 set: 1087 base = ((u64)high << 32) | low; 1088 if (HYPERVISOR_set_segment_base(which, base) != 0) 1089 ret = -EIO; 1090 break; 1091 #endif 1092 1093 case MSR_STAR: 1094 case MSR_CSTAR: 1095 case MSR_LSTAR: 1096 case MSR_SYSCALL_MASK: 1097 case MSR_IA32_SYSENTER_CS: 1098 case MSR_IA32_SYSENTER_ESP: 1099 case MSR_IA32_SYSENTER_EIP: 1100 /* Fast syscall setup is all done in hypercalls, so 1101 these are all ignored. Stub them out here to stop 1102 Xen console noise. */ 1103 break; 1104 1105 case MSR_IA32_CR_PAT: 1106 if (smp_processor_id() == 0) 1107 xen_set_pat(((u64)high << 32) | low); 1108 break; 1109 1110 default: 1111 ret = native_write_msr_safe(msr, low, high); 1112 } 1113 1114 return ret; 1115 } 1116 1117 void xen_setup_shared_info(void) 1118 { 1119 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1120 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1121 xen_start_info->shared_info); 1122 1123 HYPERVISOR_shared_info = 1124 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1125 } else 1126 HYPERVISOR_shared_info = 1127 (struct shared_info *)__va(xen_start_info->shared_info); 1128 1129 #ifndef CONFIG_SMP 1130 /* In UP this is as good a place as any to set up shared info */ 1131 xen_setup_vcpu_info_placement(); 1132 #endif 1133 1134 xen_setup_mfn_list_list(); 1135 } 1136 1137 /* This is called once we have the cpu_possible_mask */ 1138 void xen_setup_vcpu_info_placement(void) 1139 { 1140 int cpu; 1141 1142 for_each_possible_cpu(cpu) 1143 xen_vcpu_setup(cpu); 1144 1145 /* xen_vcpu_setup managed to place the vcpu_info within the 1146 * percpu area for all cpus, so make use of it. Note that for 1147 * PVH we want to use native IRQ mechanism. */ 1148 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1149 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1150 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1151 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1152 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1153 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1154 } 1155 } 1156 1157 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1158 unsigned long addr, unsigned len) 1159 { 1160 char *start, *end, *reloc; 1161 unsigned ret; 1162 1163 start = end = reloc = NULL; 1164 1165 #define SITE(op, x) \ 1166 case PARAVIRT_PATCH(op.x): \ 1167 if (have_vcpu_info_placement) { \ 1168 start = (char *)xen_##x##_direct; \ 1169 end = xen_##x##_direct_end; \ 1170 reloc = xen_##x##_direct_reloc; \ 1171 } \ 1172 goto patch_site 1173 1174 switch (type) { 1175 SITE(pv_irq_ops, irq_enable); 1176 SITE(pv_irq_ops, irq_disable); 1177 SITE(pv_irq_ops, save_fl); 1178 SITE(pv_irq_ops, restore_fl); 1179 #undef SITE 1180 1181 patch_site: 1182 if (start == NULL || (end-start) > len) 1183 goto default_patch; 1184 1185 ret = paravirt_patch_insns(insnbuf, len, start, end); 1186 1187 /* Note: because reloc is assigned from something that 1188 appears to be an array, gcc assumes it's non-null, 1189 but doesn't know its relationship with start and 1190 end. */ 1191 if (reloc > start && reloc < end) { 1192 int reloc_off = reloc - start; 1193 long *relocp = (long *)(insnbuf + reloc_off); 1194 long delta = start - (char *)addr; 1195 1196 *relocp += delta; 1197 } 1198 break; 1199 1200 default_patch: 1201 default: 1202 ret = paravirt_patch_default(type, clobbers, insnbuf, 1203 addr, len); 1204 break; 1205 } 1206 1207 return ret; 1208 } 1209 1210 static const struct pv_info xen_info __initconst = { 1211 .paravirt_enabled = 1, 1212 .shared_kernel_pmd = 0, 1213 1214 #ifdef CONFIG_X86_64 1215 .extra_user_64bit_cs = FLAT_USER_CS64, 1216 #endif 1217 1218 .name = "Xen", 1219 }; 1220 1221 static const struct pv_init_ops xen_init_ops __initconst = { 1222 .patch = xen_patch, 1223 }; 1224 1225 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1226 .cpuid = xen_cpuid, 1227 1228 .set_debugreg = xen_set_debugreg, 1229 .get_debugreg = xen_get_debugreg, 1230 1231 .clts = xen_clts, 1232 1233 .read_cr0 = xen_read_cr0, 1234 .write_cr0 = xen_write_cr0, 1235 1236 .read_cr4 = native_read_cr4, 1237 .read_cr4_safe = native_read_cr4_safe, 1238 .write_cr4 = xen_write_cr4, 1239 1240 #ifdef CONFIG_X86_64 1241 .read_cr8 = xen_read_cr8, 1242 .write_cr8 = xen_write_cr8, 1243 #endif 1244 1245 .wbinvd = native_wbinvd, 1246 1247 .read_msr = native_read_msr_safe, 1248 .write_msr = xen_write_msr_safe, 1249 1250 .read_tsc = native_read_tsc, 1251 .read_pmc = native_read_pmc, 1252 1253 .read_tscp = native_read_tscp, 1254 1255 .iret = xen_iret, 1256 .irq_enable_sysexit = xen_sysexit, 1257 #ifdef CONFIG_X86_64 1258 .usergs_sysret32 = xen_sysret32, 1259 .usergs_sysret64 = xen_sysret64, 1260 #endif 1261 1262 .load_tr_desc = paravirt_nop, 1263 .set_ldt = xen_set_ldt, 1264 .load_gdt = xen_load_gdt, 1265 .load_idt = xen_load_idt, 1266 .load_tls = xen_load_tls, 1267 #ifdef CONFIG_X86_64 1268 .load_gs_index = xen_load_gs_index, 1269 #endif 1270 1271 .alloc_ldt = xen_alloc_ldt, 1272 .free_ldt = xen_free_ldt, 1273 1274 .store_idt = native_store_idt, 1275 .store_tr = xen_store_tr, 1276 1277 .write_ldt_entry = xen_write_ldt_entry, 1278 .write_gdt_entry = xen_write_gdt_entry, 1279 .write_idt_entry = xen_write_idt_entry, 1280 .load_sp0 = xen_load_sp0, 1281 1282 .set_iopl_mask = xen_set_iopl_mask, 1283 .io_delay = xen_io_delay, 1284 1285 /* Xen takes care of %gs when switching to usermode for us */ 1286 .swapgs = paravirt_nop, 1287 1288 .start_context_switch = paravirt_start_context_switch, 1289 .end_context_switch = xen_end_context_switch, 1290 }; 1291 1292 static const struct pv_apic_ops xen_apic_ops __initconst = { 1293 #ifdef CONFIG_X86_LOCAL_APIC 1294 .startup_ipi_hook = paravirt_nop, 1295 #endif 1296 }; 1297 1298 static void xen_reboot(int reason) 1299 { 1300 struct sched_shutdown r = { .reason = reason }; 1301 1302 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1303 BUG(); 1304 } 1305 1306 static void xen_restart(char *msg) 1307 { 1308 xen_reboot(SHUTDOWN_reboot); 1309 } 1310 1311 static void xen_emergency_restart(void) 1312 { 1313 xen_reboot(SHUTDOWN_reboot); 1314 } 1315 1316 static void xen_machine_halt(void) 1317 { 1318 xen_reboot(SHUTDOWN_poweroff); 1319 } 1320 1321 static void xen_machine_power_off(void) 1322 { 1323 if (pm_power_off) 1324 pm_power_off(); 1325 xen_reboot(SHUTDOWN_poweroff); 1326 } 1327 1328 static void xen_crash_shutdown(struct pt_regs *regs) 1329 { 1330 xen_reboot(SHUTDOWN_crash); 1331 } 1332 1333 static int 1334 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1335 { 1336 xen_reboot(SHUTDOWN_crash); 1337 return NOTIFY_DONE; 1338 } 1339 1340 static struct notifier_block xen_panic_block = { 1341 .notifier_call= xen_panic_event, 1342 .priority = INT_MIN 1343 }; 1344 1345 int xen_panic_handler_init(void) 1346 { 1347 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1348 return 0; 1349 } 1350 1351 static const struct machine_ops xen_machine_ops __initconst = { 1352 .restart = xen_restart, 1353 .halt = xen_machine_halt, 1354 .power_off = xen_machine_power_off, 1355 .shutdown = xen_machine_halt, 1356 .crash_shutdown = xen_crash_shutdown, 1357 .emergency_restart = xen_emergency_restart, 1358 }; 1359 1360 static void __init xen_boot_params_init_edd(void) 1361 { 1362 #if IS_ENABLED(CONFIG_EDD) 1363 struct xen_platform_op op; 1364 struct edd_info *edd_info; 1365 u32 *mbr_signature; 1366 unsigned nr; 1367 int ret; 1368 1369 edd_info = boot_params.eddbuf; 1370 mbr_signature = boot_params.edd_mbr_sig_buffer; 1371 1372 op.cmd = XENPF_firmware_info; 1373 1374 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1375 for (nr = 0; nr < EDDMAXNR; nr++) { 1376 struct edd_info *info = edd_info + nr; 1377 1378 op.u.firmware_info.index = nr; 1379 info->params.length = sizeof(info->params); 1380 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1381 &info->params); 1382 ret = HYPERVISOR_dom0_op(&op); 1383 if (ret) 1384 break; 1385 1386 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1387 C(device); 1388 C(version); 1389 C(interface_support); 1390 C(legacy_max_cylinder); 1391 C(legacy_max_head); 1392 C(legacy_sectors_per_track); 1393 #undef C 1394 } 1395 boot_params.eddbuf_entries = nr; 1396 1397 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1398 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1399 op.u.firmware_info.index = nr; 1400 ret = HYPERVISOR_dom0_op(&op); 1401 if (ret) 1402 break; 1403 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1404 } 1405 boot_params.edd_mbr_sig_buf_entries = nr; 1406 #endif 1407 } 1408 1409 /* 1410 * Set up the GDT and segment registers for -fstack-protector. Until 1411 * we do this, we have to be careful not to call any stack-protected 1412 * function, which is most of the kernel. 1413 * 1414 * Note, that it is __ref because the only caller of this after init 1415 * is PVH which is not going to use xen_load_gdt_boot or other 1416 * __init functions. 1417 */ 1418 static void __ref xen_setup_gdt(int cpu) 1419 { 1420 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1421 #ifdef CONFIG_X86_64 1422 unsigned long dummy; 1423 1424 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1425 switch_to_new_gdt(cpu); /* GDT and GS set */ 1426 1427 /* We are switching of the Xen provided GDT to our HVM mode 1428 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1429 * and we are jumping to reload it. 1430 */ 1431 asm volatile ("pushq %0\n" 1432 "leaq 1f(%%rip),%0\n" 1433 "pushq %0\n" 1434 "lretq\n" 1435 "1:\n" 1436 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1437 1438 /* 1439 * While not needed, we also set the %es, %ds, and %fs 1440 * to zero. We don't care about %ss as it is NULL. 1441 * Strictly speaking this is not needed as Xen zeros those 1442 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1443 * 1444 * Linux zeros them in cpu_init() and in secondary_startup_64 1445 * (for BSP). 1446 */ 1447 loadsegment(es, 0); 1448 loadsegment(ds, 0); 1449 loadsegment(fs, 0); 1450 #else 1451 /* PVH: TODO Implement. */ 1452 BUG(); 1453 #endif 1454 return; /* PVH does not need any PV GDT ops. */ 1455 } 1456 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1457 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1458 1459 setup_stack_canary_segment(0); 1460 switch_to_new_gdt(0); 1461 1462 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1463 pv_cpu_ops.load_gdt = xen_load_gdt; 1464 } 1465 1466 /* 1467 * A PV guest starts with default flags that are not set for PVH, set them 1468 * here asap. 1469 */ 1470 static void xen_pvh_set_cr_flags(int cpu) 1471 { 1472 1473 /* Some of these are setup in 'secondary_startup_64'. The others: 1474 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1475 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1476 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1477 1478 if (!cpu) 1479 return; 1480 /* 1481 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1482 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu_init. 1483 */ 1484 if (cpu_has_pse) 1485 set_in_cr4(X86_CR4_PSE); 1486 1487 if (cpu_has_pge) 1488 set_in_cr4(X86_CR4_PGE); 1489 } 1490 1491 /* 1492 * Note, that it is ref - because the only caller of this after init 1493 * is PVH which is not going to use xen_load_gdt_boot or other 1494 * __init functions. 1495 */ 1496 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1497 { 1498 xen_setup_gdt(cpu); 1499 xen_pvh_set_cr_flags(cpu); 1500 } 1501 1502 static void __init xen_pvh_early_guest_init(void) 1503 { 1504 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1505 return; 1506 1507 if (!xen_feature(XENFEAT_hvm_callback_vector)) 1508 return; 1509 1510 xen_have_vector_callback = 1; 1511 xen_pvh_set_cr_flags(0); 1512 1513 #ifdef CONFIG_X86_32 1514 BUG(); /* PVH: Implement proper support. */ 1515 #endif 1516 } 1517 1518 /* First C function to be called on Xen boot */ 1519 asmlinkage __visible void __init xen_start_kernel(void) 1520 { 1521 struct physdev_set_iopl set_iopl; 1522 int rc; 1523 1524 if (!xen_start_info) 1525 return; 1526 1527 xen_domain_type = XEN_PV_DOMAIN; 1528 1529 xen_setup_features(); 1530 xen_pvh_early_guest_init(); 1531 xen_setup_machphys_mapping(); 1532 1533 /* Install Xen paravirt ops */ 1534 pv_info = xen_info; 1535 pv_init_ops = xen_init_ops; 1536 pv_apic_ops = xen_apic_ops; 1537 if (!xen_pvh_domain()) 1538 pv_cpu_ops = xen_cpu_ops; 1539 1540 x86_init.resources.memory_setup = xen_memory_setup; 1541 x86_init.oem.arch_setup = xen_arch_setup; 1542 x86_init.oem.banner = xen_banner; 1543 1544 xen_init_time_ops(); 1545 1546 /* 1547 * Set up some pagetable state before starting to set any ptes. 1548 */ 1549 1550 xen_init_mmu_ops(); 1551 1552 /* Prevent unwanted bits from being set in PTEs. */ 1553 __supported_pte_mask &= ~_PAGE_GLOBAL; 1554 #if 0 1555 if (!xen_initial_domain()) 1556 #endif 1557 __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); 1558 1559 __supported_pte_mask |= _PAGE_IOMAP; 1560 1561 /* 1562 * Prevent page tables from being allocated in highmem, even 1563 * if CONFIG_HIGHPTE is enabled. 1564 */ 1565 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1566 1567 /* Work out if we support NX */ 1568 x86_configure_nx(); 1569 1570 /* Get mfn list */ 1571 xen_build_dynamic_phys_to_machine(); 1572 1573 /* 1574 * Set up kernel GDT and segment registers, mainly so that 1575 * -fstack-protector code can be executed. 1576 */ 1577 xen_setup_gdt(0); 1578 1579 xen_init_irq_ops(); 1580 xen_init_cpuid_mask(); 1581 1582 #ifdef CONFIG_X86_LOCAL_APIC 1583 /* 1584 * set up the basic apic ops. 1585 */ 1586 set_xen_basic_apic_ops(); 1587 #endif 1588 1589 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1590 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1591 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1592 } 1593 1594 machine_ops = xen_machine_ops; 1595 1596 /* 1597 * The only reliable way to retain the initial address of the 1598 * percpu gdt_page is to remember it here, so we can go and 1599 * mark it RW later, when the initial percpu area is freed. 1600 */ 1601 xen_initial_gdt = &per_cpu(gdt_page, 0); 1602 1603 xen_smp_init(); 1604 1605 #ifdef CONFIG_ACPI_NUMA 1606 /* 1607 * The pages we from Xen are not related to machine pages, so 1608 * any NUMA information the kernel tries to get from ACPI will 1609 * be meaningless. Prevent it from trying. 1610 */ 1611 acpi_numa = -1; 1612 #endif 1613 #ifdef CONFIG_X86_PAT 1614 /* 1615 * For right now disable the PAT. We should remove this once 1616 * git commit 8eaffa67b43e99ae581622c5133e20b0f48bcef1 1617 * (xen/pat: Disable PAT support for now) is reverted. 1618 */ 1619 pat_enabled = 0; 1620 #endif 1621 /* Don't do the full vcpu_info placement stuff until we have a 1622 possible map and a non-dummy shared_info. */ 1623 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1624 1625 local_irq_disable(); 1626 early_boot_irqs_disabled = true; 1627 1628 xen_raw_console_write("mapping kernel into physical memory\n"); 1629 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages); 1630 1631 /* Allocate and initialize top and mid mfn levels for p2m structure */ 1632 xen_build_mfn_list_list(); 1633 1634 /* keep using Xen gdt for now; no urgent need to change it */ 1635 1636 #ifdef CONFIG_X86_32 1637 pv_info.kernel_rpl = 1; 1638 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1639 pv_info.kernel_rpl = 0; 1640 #else 1641 pv_info.kernel_rpl = 0; 1642 #endif 1643 /* set the limit of our address space */ 1644 xen_reserve_top(); 1645 1646 /* PVH: runs at default kernel iopl of 0 */ 1647 if (!xen_pvh_domain()) { 1648 /* 1649 * We used to do this in xen_arch_setup, but that is too late 1650 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1651 * early_amd_init which pokes 0xcf8 port. 1652 */ 1653 set_iopl.iopl = 1; 1654 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1655 if (rc != 0) 1656 xen_raw_printk("physdev_op failed %d\n", rc); 1657 } 1658 1659 #ifdef CONFIG_X86_32 1660 /* set up basic CPUID stuff */ 1661 cpu_detect(&new_cpu_data); 1662 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); 1663 new_cpu_data.wp_works_ok = 1; 1664 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1665 #endif 1666 1667 /* Poke various useful things into boot_params */ 1668 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1669 boot_params.hdr.ramdisk_image = xen_start_info->mod_start 1670 ? __pa(xen_start_info->mod_start) : 0; 1671 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1672 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1673 1674 if (!xen_initial_domain()) { 1675 add_preferred_console("xenboot", 0, NULL); 1676 add_preferred_console("tty", 0, NULL); 1677 add_preferred_console("hvc", 0, NULL); 1678 if (pci_xen) 1679 x86_init.pci.arch_init = pci_xen_init; 1680 } else { 1681 const struct dom0_vga_console_info *info = 1682 (void *)((char *)xen_start_info + 1683 xen_start_info->console.dom0.info_off); 1684 struct xen_platform_op op = { 1685 .cmd = XENPF_firmware_info, 1686 .interface_version = XENPF_INTERFACE_VERSION, 1687 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1688 }; 1689 1690 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1691 xen_start_info->console.domU.mfn = 0; 1692 xen_start_info->console.domU.evtchn = 0; 1693 1694 if (HYPERVISOR_dom0_op(&op) == 0) 1695 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1696 1697 xen_init_apic(); 1698 1699 /* Make sure ACS will be enabled */ 1700 pci_request_acs(); 1701 1702 xen_acpi_sleep_register(); 1703 1704 /* Avoid searching for BIOS MP tables */ 1705 x86_init.mpparse.find_smp_config = x86_init_noop; 1706 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1707 1708 xen_boot_params_init_edd(); 1709 } 1710 #ifdef CONFIG_PCI 1711 /* PCI BIOS service won't work from a PV guest. */ 1712 pci_probe &= ~PCI_PROBE_BIOS; 1713 #endif 1714 xen_raw_console_write("about to get started...\n"); 1715 1716 xen_setup_runstate_info(0); 1717 1718 /* Start the world */ 1719 #ifdef CONFIG_X86_32 1720 i386_start_kernel(); 1721 #else 1722 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1723 #endif 1724 } 1725 1726 void __ref xen_hvm_init_shared_info(void) 1727 { 1728 int cpu; 1729 struct xen_add_to_physmap xatp; 1730 static struct shared_info *shared_info_page = 0; 1731 1732 if (!shared_info_page) 1733 shared_info_page = (struct shared_info *) 1734 extend_brk(PAGE_SIZE, PAGE_SIZE); 1735 xatp.domid = DOMID_SELF; 1736 xatp.idx = 0; 1737 xatp.space = XENMAPSPACE_shared_info; 1738 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1739 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1740 BUG(); 1741 1742 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1743 1744 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1745 * page, we use it in the event channel upcall and in some pvclock 1746 * related functions. We don't need the vcpu_info placement 1747 * optimizations because we don't use any pv_mmu or pv_irq op on 1748 * HVM. 1749 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1750 * online but xen_hvm_init_shared_info is run at resume time too and 1751 * in that case multiple vcpus might be online. */ 1752 for_each_online_cpu(cpu) { 1753 /* Leave it to be NULL. */ 1754 if (cpu >= MAX_VIRT_CPUS) 1755 continue; 1756 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1757 } 1758 } 1759 1760 #ifdef CONFIG_XEN_PVHVM 1761 static void __init init_hvm_pv_info(void) 1762 { 1763 int major, minor; 1764 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1765 u64 pfn; 1766 1767 base = xen_cpuid_base(); 1768 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1769 1770 major = eax >> 16; 1771 minor = eax & 0xffff; 1772 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1773 1774 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1775 1776 pfn = __pa(hypercall_page); 1777 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1778 1779 xen_setup_features(); 1780 1781 pv_info.name = "Xen HVM"; 1782 1783 xen_domain_type = XEN_HVM_DOMAIN; 1784 } 1785 1786 static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, 1787 void *hcpu) 1788 { 1789 int cpu = (long)hcpu; 1790 switch (action) { 1791 case CPU_UP_PREPARE: 1792 xen_vcpu_setup(cpu); 1793 if (xen_have_vector_callback) { 1794 if (xen_feature(XENFEAT_hvm_safe_pvclock)) 1795 xen_setup_timer(cpu); 1796 } 1797 break; 1798 default: 1799 break; 1800 } 1801 return NOTIFY_OK; 1802 } 1803 1804 static struct notifier_block xen_hvm_cpu_notifier = { 1805 .notifier_call = xen_hvm_cpu_notify, 1806 }; 1807 1808 static void __init xen_hvm_guest_init(void) 1809 { 1810 init_hvm_pv_info(); 1811 1812 xen_hvm_init_shared_info(); 1813 1814 xen_panic_handler_init(); 1815 1816 if (xen_feature(XENFEAT_hvm_callback_vector)) 1817 xen_have_vector_callback = 1; 1818 xen_hvm_smp_init(); 1819 register_cpu_notifier(&xen_hvm_cpu_notifier); 1820 xen_unplug_emulated_devices(); 1821 x86_init.irqs.intr_init = xen_init_IRQ; 1822 xen_hvm_init_time_ops(); 1823 xen_hvm_init_mmu_ops(); 1824 } 1825 1826 static uint32_t __init xen_hvm_platform(void) 1827 { 1828 if (xen_pv_domain()) 1829 return 0; 1830 1831 return xen_cpuid_base(); 1832 } 1833 1834 bool xen_hvm_need_lapic(void) 1835 { 1836 if (xen_pv_domain()) 1837 return false; 1838 if (!xen_hvm_domain()) 1839 return false; 1840 if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) 1841 return false; 1842 return true; 1843 } 1844 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1845 1846 const struct hypervisor_x86 x86_hyper_xen_hvm __refconst = { 1847 .name = "Xen HVM", 1848 .detect = xen_hvm_platform, 1849 .init_platform = xen_hvm_guest_init, 1850 .x2apic_available = xen_x2apic_para_available, 1851 }; 1852 EXPORT_SYMBOL(x86_hyper_xen_hvm); 1853 #endif 1854