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 #ifdef CONFIG_KEXEC_CORE 37 #include <linux/kexec.h> 38 #endif 39 40 #include <xen/xen.h> 41 #include <xen/events.h> 42 #include <xen/interface/xen.h> 43 #include <xen/interface/version.h> 44 #include <xen/interface/physdev.h> 45 #include <xen/interface/vcpu.h> 46 #include <xen/interface/memory.h> 47 #include <xen/interface/nmi.h> 48 #include <xen/interface/xen-mca.h> 49 #include <xen/features.h> 50 #include <xen/page.h> 51 #include <xen/hvm.h> 52 #include <xen/hvc-console.h> 53 #include <xen/acpi.h> 54 55 #include <asm/paravirt.h> 56 #include <asm/apic.h> 57 #include <asm/page.h> 58 #include <asm/xen/pci.h> 59 #include <asm/xen/hypercall.h> 60 #include <asm/xen/hypervisor.h> 61 #include <asm/fixmap.h> 62 #include <asm/processor.h> 63 #include <asm/proto.h> 64 #include <asm/msr-index.h> 65 #include <asm/traps.h> 66 #include <asm/setup.h> 67 #include <asm/desc.h> 68 #include <asm/pgalloc.h> 69 #include <asm/pgtable.h> 70 #include <asm/tlbflush.h> 71 #include <asm/reboot.h> 72 #include <asm/stackprotector.h> 73 #include <asm/hypervisor.h> 74 #include <asm/mach_traps.h> 75 #include <asm/mwait.h> 76 #include <asm/pci_x86.h> 77 #include <asm/pat.h> 78 79 #ifdef CONFIG_ACPI 80 #include <linux/acpi.h> 81 #include <asm/acpi.h> 82 #include <acpi/pdc_intel.h> 83 #include <acpi/processor.h> 84 #include <xen/interface/platform.h> 85 #endif 86 87 #include "xen-ops.h" 88 #include "mmu.h" 89 #include "smp.h" 90 #include "multicalls.h" 91 #include "pmu.h" 92 93 EXPORT_SYMBOL_GPL(hypercall_page); 94 95 /* 96 * Pointer to the xen_vcpu_info structure or 97 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 98 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 99 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 100 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 101 * acknowledge pending events. 102 * Also more subtly it is used by the patched version of irq enable/disable 103 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 104 * 105 * The desire to be able to do those mask/unmask operations as a single 106 * instruction by using the per-cpu offset held in %gs is the real reason 107 * vcpu info is in a per-cpu pointer and the original reason for this 108 * hypercall. 109 * 110 */ 111 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 112 113 /* 114 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 115 * hypercall. This can be used both in PV and PVHVM mode. The structure 116 * overrides the default per_cpu(xen_vcpu, cpu) value. 117 */ 118 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 119 120 enum xen_domain_type xen_domain_type = XEN_NATIVE; 121 EXPORT_SYMBOL_GPL(xen_domain_type); 122 123 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 124 EXPORT_SYMBOL(machine_to_phys_mapping); 125 unsigned long machine_to_phys_nr; 126 EXPORT_SYMBOL(machine_to_phys_nr); 127 128 struct start_info *xen_start_info; 129 EXPORT_SYMBOL_GPL(xen_start_info); 130 131 struct shared_info xen_dummy_shared_info; 132 133 void *xen_initial_gdt; 134 135 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 136 __read_mostly int xen_have_vector_callback; 137 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 138 139 /* 140 * Point at some empty memory to start with. We map the real shared_info 141 * page as soon as fixmap is up and running. 142 */ 143 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 144 145 /* 146 * Flag to determine whether vcpu info placement is available on all 147 * VCPUs. We assume it is to start with, and then set it to zero on 148 * the first failure. This is because it can succeed on some VCPUs 149 * and not others, since it can involve hypervisor memory allocation, 150 * or because the guest failed to guarantee all the appropriate 151 * constraints on all VCPUs (ie buffer can't cross a page boundary). 152 * 153 * Note that any particular CPU may be using a placed vcpu structure, 154 * but we can only optimise if the all are. 155 * 156 * 0: not available, 1: available 157 */ 158 static int have_vcpu_info_placement = 1; 159 160 struct tls_descs { 161 struct desc_struct desc[3]; 162 }; 163 164 /* 165 * Updating the 3 TLS descriptors in the GDT on every task switch is 166 * surprisingly expensive so we avoid updating them if they haven't 167 * changed. Since Xen writes different descriptors than the one 168 * passed in the update_descriptor hypercall we keep shadow copies to 169 * compare against. 170 */ 171 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 172 173 static void clamp_max_cpus(void) 174 { 175 #ifdef CONFIG_SMP 176 if (setup_max_cpus > MAX_VIRT_CPUS) 177 setup_max_cpus = MAX_VIRT_CPUS; 178 #endif 179 } 180 181 static void xen_vcpu_setup(int cpu) 182 { 183 struct vcpu_register_vcpu_info info; 184 int err; 185 struct vcpu_info *vcpup; 186 187 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 188 189 /* 190 * This path is called twice on PVHVM - first during bootup via 191 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 192 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 193 * As we can only do the VCPUOP_register_vcpu_info once lets 194 * not over-write its result. 195 * 196 * For PV it is called during restore (xen_vcpu_restore) and bootup 197 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 198 * use this function. 199 */ 200 if (xen_hvm_domain()) { 201 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 202 return; 203 } 204 if (cpu < MAX_VIRT_CPUS) 205 per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 206 207 if (!have_vcpu_info_placement) { 208 if (cpu >= MAX_VIRT_CPUS) 209 clamp_max_cpus(); 210 return; 211 } 212 213 vcpup = &per_cpu(xen_vcpu_info, cpu); 214 info.mfn = arbitrary_virt_to_mfn(vcpup); 215 info.offset = offset_in_page(vcpup); 216 217 /* Check to see if the hypervisor will put the vcpu_info 218 structure where we want it, which allows direct access via 219 a percpu-variable. 220 N.B. This hypercall can _only_ be called once per CPU. Subsequent 221 calls will error out with -EINVAL. This is due to the fact that 222 hypervisor has no unregister variant and this hypercall does not 223 allow to over-write info.mfn and info.offset. 224 */ 225 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 226 227 if (err) { 228 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 229 have_vcpu_info_placement = 0; 230 clamp_max_cpus(); 231 } else { 232 /* This cpu is using the registered vcpu info, even if 233 later ones fail to. */ 234 per_cpu(xen_vcpu, cpu) = vcpup; 235 } 236 } 237 238 /* 239 * On restore, set the vcpu placement up again. 240 * If it fails, then we're in a bad state, since 241 * we can't back out from using it... 242 */ 243 void xen_vcpu_restore(void) 244 { 245 int cpu; 246 247 for_each_possible_cpu(cpu) { 248 bool other_cpu = (cpu != smp_processor_id()); 249 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL); 250 251 if (other_cpu && is_up && 252 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 253 BUG(); 254 255 xen_setup_runstate_info(cpu); 256 257 if (have_vcpu_info_placement) 258 xen_vcpu_setup(cpu); 259 260 if (other_cpu && is_up && 261 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 262 BUG(); 263 } 264 } 265 266 static void __init xen_banner(void) 267 { 268 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 269 struct xen_extraversion extra; 270 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 271 272 pr_info("Booting paravirtualized kernel %son %s\n", 273 xen_feature(XENFEAT_auto_translated_physmap) ? 274 "with PVH extensions " : "", pv_info.name); 275 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 276 version >> 16, version & 0xffff, extra.extraversion, 277 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 278 } 279 /* Check if running on Xen version (major, minor) or later */ 280 bool 281 xen_running_on_version_or_later(unsigned int major, unsigned int minor) 282 { 283 unsigned int version; 284 285 if (!xen_domain()) 286 return false; 287 288 version = HYPERVISOR_xen_version(XENVER_version, NULL); 289 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 290 ((version >> 16) > major)) 291 return true; 292 return false; 293 } 294 295 #define CPUID_THERM_POWER_LEAF 6 296 #define APERFMPERF_PRESENT 0 297 298 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 299 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 300 301 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask; 302 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 303 static __read_mostly unsigned int cpuid_leaf5_edx_val; 304 305 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 306 unsigned int *cx, unsigned int *dx) 307 { 308 unsigned maskebx = ~0; 309 unsigned maskecx = ~0; 310 unsigned maskedx = ~0; 311 unsigned setecx = 0; 312 /* 313 * Mask out inconvenient features, to try and disable as many 314 * unsupported kernel subsystems as possible. 315 */ 316 switch (*ax) { 317 case 1: 318 maskecx = cpuid_leaf1_ecx_mask; 319 setecx = cpuid_leaf1_ecx_set_mask; 320 maskedx = cpuid_leaf1_edx_mask; 321 break; 322 323 case CPUID_MWAIT_LEAF: 324 /* Synthesize the values.. */ 325 *ax = 0; 326 *bx = 0; 327 *cx = cpuid_leaf5_ecx_val; 328 *dx = cpuid_leaf5_edx_val; 329 return; 330 331 case CPUID_THERM_POWER_LEAF: 332 /* Disabling APERFMPERF for kernel usage */ 333 maskecx = ~(1 << APERFMPERF_PRESENT); 334 break; 335 336 case 0xb: 337 /* Suppress extended topology stuff */ 338 maskebx = 0; 339 break; 340 } 341 342 asm(XEN_EMULATE_PREFIX "cpuid" 343 : "=a" (*ax), 344 "=b" (*bx), 345 "=c" (*cx), 346 "=d" (*dx) 347 : "0" (*ax), "2" (*cx)); 348 349 *bx &= maskebx; 350 *cx &= maskecx; 351 *cx |= setecx; 352 *dx &= maskedx; 353 354 } 355 356 static bool __init xen_check_mwait(void) 357 { 358 #ifdef CONFIG_ACPI 359 struct xen_platform_op op = { 360 .cmd = XENPF_set_processor_pminfo, 361 .u.set_pminfo.id = -1, 362 .u.set_pminfo.type = XEN_PM_PDC, 363 }; 364 uint32_t buf[3]; 365 unsigned int ax, bx, cx, dx; 366 unsigned int mwait_mask; 367 368 /* We need to determine whether it is OK to expose the MWAIT 369 * capability to the kernel to harvest deeper than C3 states from ACPI 370 * _CST using the processor_harvest_xen.c module. For this to work, we 371 * need to gather the MWAIT_LEAF values (which the cstate.c code 372 * checks against). The hypervisor won't expose the MWAIT flag because 373 * it would break backwards compatibility; so we will find out directly 374 * from the hardware and hypercall. 375 */ 376 if (!xen_initial_domain()) 377 return false; 378 379 /* 380 * When running under platform earlier than Xen4.2, do not expose 381 * mwait, to avoid the risk of loading native acpi pad driver 382 */ 383 if (!xen_running_on_version_or_later(4, 2)) 384 return false; 385 386 ax = 1; 387 cx = 0; 388 389 native_cpuid(&ax, &bx, &cx, &dx); 390 391 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 392 (1 << (X86_FEATURE_MWAIT % 32)); 393 394 if ((cx & mwait_mask) != mwait_mask) 395 return false; 396 397 /* We need to emulate the MWAIT_LEAF and for that we need both 398 * ecx and edx. The hypercall provides only partial information. 399 */ 400 401 ax = CPUID_MWAIT_LEAF; 402 bx = 0; 403 cx = 0; 404 dx = 0; 405 406 native_cpuid(&ax, &bx, &cx, &dx); 407 408 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so, 409 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 410 */ 411 buf[0] = ACPI_PDC_REVISION_ID; 412 buf[1] = 1; 413 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP); 414 415 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 416 417 if ((HYPERVISOR_dom0_op(&op) == 0) && 418 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) { 419 cpuid_leaf5_ecx_val = cx; 420 cpuid_leaf5_edx_val = dx; 421 } 422 return true; 423 #else 424 return false; 425 #endif 426 } 427 static void __init xen_init_cpuid_mask(void) 428 { 429 unsigned int ax, bx, cx, dx; 430 unsigned int xsave_mask; 431 432 cpuid_leaf1_edx_mask = 433 ~((1 << X86_FEATURE_MTRR) | /* disable MTRR */ 434 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 435 436 if (!xen_initial_domain()) 437 cpuid_leaf1_edx_mask &= 438 ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ 439 440 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); 441 442 ax = 1; 443 cx = 0; 444 cpuid(1, &ax, &bx, &cx, &dx); 445 446 xsave_mask = 447 (1 << (X86_FEATURE_XSAVE % 32)) | 448 (1 << (X86_FEATURE_OSXSAVE % 32)); 449 450 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 451 if ((cx & xsave_mask) != xsave_mask) 452 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 453 if (xen_check_mwait()) 454 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); 455 } 456 457 static void xen_set_debugreg(int reg, unsigned long val) 458 { 459 HYPERVISOR_set_debugreg(reg, val); 460 } 461 462 static unsigned long xen_get_debugreg(int reg) 463 { 464 return HYPERVISOR_get_debugreg(reg); 465 } 466 467 static void xen_end_context_switch(struct task_struct *next) 468 { 469 xen_mc_flush(); 470 paravirt_end_context_switch(next); 471 } 472 473 static unsigned long xen_store_tr(void) 474 { 475 return 0; 476 } 477 478 /* 479 * Set the page permissions for a particular virtual address. If the 480 * address is a vmalloc mapping (or other non-linear mapping), then 481 * find the linear mapping of the page and also set its protections to 482 * match. 483 */ 484 static void set_aliased_prot(void *v, pgprot_t prot) 485 { 486 int level; 487 pte_t *ptep; 488 pte_t pte; 489 unsigned long pfn; 490 struct page *page; 491 unsigned char dummy; 492 493 ptep = lookup_address((unsigned long)v, &level); 494 BUG_ON(ptep == NULL); 495 496 pfn = pte_pfn(*ptep); 497 page = pfn_to_page(pfn); 498 499 pte = pfn_pte(pfn, prot); 500 501 /* 502 * Careful: update_va_mapping() will fail if the virtual address 503 * we're poking isn't populated in the page tables. We don't 504 * need to worry about the direct map (that's always in the page 505 * tables), but we need to be careful about vmap space. In 506 * particular, the top level page table can lazily propagate 507 * entries between processes, so if we've switched mms since we 508 * vmapped the target in the first place, we might not have the 509 * top-level page table entry populated. 510 * 511 * We disable preemption because we want the same mm active when 512 * we probe the target and when we issue the hypercall. We'll 513 * have the same nominal mm, but if we're a kernel thread, lazy 514 * mm dropping could change our pgd. 515 * 516 * Out of an abundance of caution, this uses __get_user() to fault 517 * in the target address just in case there's some obscure case 518 * in which the target address isn't readable. 519 */ 520 521 preempt_disable(); 522 523 pagefault_disable(); /* Avoid warnings due to being atomic. */ 524 __get_user(dummy, (unsigned char __user __force *)v); 525 pagefault_enable(); 526 527 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 528 BUG(); 529 530 if (!PageHighMem(page)) { 531 void *av = __va(PFN_PHYS(pfn)); 532 533 if (av != v) 534 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 535 BUG(); 536 } else 537 kmap_flush_unused(); 538 539 preempt_enable(); 540 } 541 542 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 543 { 544 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 545 int i; 546 547 /* 548 * We need to mark the all aliases of the LDT pages RO. We 549 * don't need to call vm_flush_aliases(), though, since that's 550 * only responsible for flushing aliases out the TLBs, not the 551 * page tables, and Xen will flush the TLB for us if needed. 552 * 553 * To avoid confusing future readers: none of this is necessary 554 * to load the LDT. The hypervisor only checks this when the 555 * LDT is faulted in due to subsequent descriptor access. 556 */ 557 558 for(i = 0; i < entries; i += entries_per_page) 559 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 560 } 561 562 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 563 { 564 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 565 int i; 566 567 for(i = 0; i < entries; i += entries_per_page) 568 set_aliased_prot(ldt + i, PAGE_KERNEL); 569 } 570 571 static void xen_set_ldt(const void *addr, unsigned entries) 572 { 573 struct mmuext_op *op; 574 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 575 576 trace_xen_cpu_set_ldt(addr, entries); 577 578 op = mcs.args; 579 op->cmd = MMUEXT_SET_LDT; 580 op->arg1.linear_addr = (unsigned long)addr; 581 op->arg2.nr_ents = entries; 582 583 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 584 585 xen_mc_issue(PARAVIRT_LAZY_CPU); 586 } 587 588 static void xen_load_gdt(const struct desc_ptr *dtr) 589 { 590 unsigned long va = dtr->address; 591 unsigned int size = dtr->size + 1; 592 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 593 unsigned long frames[pages]; 594 int f; 595 596 /* 597 * A GDT can be up to 64k in size, which corresponds to 8192 598 * 8-byte entries, or 16 4k pages.. 599 */ 600 601 BUG_ON(size > 65536); 602 BUG_ON(va & ~PAGE_MASK); 603 604 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 605 int level; 606 pte_t *ptep; 607 unsigned long pfn, mfn; 608 void *virt; 609 610 /* 611 * The GDT is per-cpu and is in the percpu data area. 612 * That can be virtually mapped, so we need to do a 613 * page-walk to get the underlying MFN for the 614 * hypercall. The page can also be in the kernel's 615 * linear range, so we need to RO that mapping too. 616 */ 617 ptep = lookup_address(va, &level); 618 BUG_ON(ptep == NULL); 619 620 pfn = pte_pfn(*ptep); 621 mfn = pfn_to_mfn(pfn); 622 virt = __va(PFN_PHYS(pfn)); 623 624 frames[f] = mfn; 625 626 make_lowmem_page_readonly((void *)va); 627 make_lowmem_page_readonly(virt); 628 } 629 630 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 631 BUG(); 632 } 633 634 /* 635 * load_gdt for early boot, when the gdt is only mapped once 636 */ 637 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 638 { 639 unsigned long va = dtr->address; 640 unsigned int size = dtr->size + 1; 641 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 642 unsigned long frames[pages]; 643 int f; 644 645 /* 646 * A GDT can be up to 64k in size, which corresponds to 8192 647 * 8-byte entries, or 16 4k pages.. 648 */ 649 650 BUG_ON(size > 65536); 651 BUG_ON(va & ~PAGE_MASK); 652 653 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 654 pte_t pte; 655 unsigned long pfn, mfn; 656 657 pfn = virt_to_pfn(va); 658 mfn = pfn_to_mfn(pfn); 659 660 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 661 662 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 663 BUG(); 664 665 frames[f] = mfn; 666 } 667 668 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 669 BUG(); 670 } 671 672 static inline bool desc_equal(const struct desc_struct *d1, 673 const struct desc_struct *d2) 674 { 675 return d1->a == d2->a && d1->b == d2->b; 676 } 677 678 static void load_TLS_descriptor(struct thread_struct *t, 679 unsigned int cpu, unsigned int i) 680 { 681 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 682 struct desc_struct *gdt; 683 xmaddr_t maddr; 684 struct multicall_space mc; 685 686 if (desc_equal(shadow, &t->tls_array[i])) 687 return; 688 689 *shadow = t->tls_array[i]; 690 691 gdt = get_cpu_gdt_table(cpu); 692 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 693 mc = __xen_mc_entry(0); 694 695 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 696 } 697 698 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 699 { 700 /* 701 * XXX sleazy hack: If we're being called in a lazy-cpu zone 702 * and lazy gs handling is enabled, it means we're in a 703 * context switch, and %gs has just been saved. This means we 704 * can zero it out to prevent faults on exit from the 705 * hypervisor if the next process has no %gs. Either way, it 706 * has been saved, and the new value will get loaded properly. 707 * This will go away as soon as Xen has been modified to not 708 * save/restore %gs for normal hypercalls. 709 * 710 * On x86_64, this hack is not used for %gs, because gs points 711 * to KERNEL_GS_BASE (and uses it for PDA references), so we 712 * must not zero %gs on x86_64 713 * 714 * For x86_64, we need to zero %fs, otherwise we may get an 715 * exception between the new %fs descriptor being loaded and 716 * %fs being effectively cleared at __switch_to(). 717 */ 718 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 719 #ifdef CONFIG_X86_32 720 lazy_load_gs(0); 721 #else 722 loadsegment(fs, 0); 723 #endif 724 } 725 726 xen_mc_batch(); 727 728 load_TLS_descriptor(t, cpu, 0); 729 load_TLS_descriptor(t, cpu, 1); 730 load_TLS_descriptor(t, cpu, 2); 731 732 xen_mc_issue(PARAVIRT_LAZY_CPU); 733 } 734 735 #ifdef CONFIG_X86_64 736 static void xen_load_gs_index(unsigned int idx) 737 { 738 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 739 BUG(); 740 } 741 #endif 742 743 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 744 const void *ptr) 745 { 746 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 747 u64 entry = *(u64 *)ptr; 748 749 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 750 751 preempt_disable(); 752 753 xen_mc_flush(); 754 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 755 BUG(); 756 757 preempt_enable(); 758 } 759 760 static int cvt_gate_to_trap(int vector, const gate_desc *val, 761 struct trap_info *info) 762 { 763 unsigned long addr; 764 765 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 766 return 0; 767 768 info->vector = vector; 769 770 addr = gate_offset(*val); 771 #ifdef CONFIG_X86_64 772 /* 773 * Look for known traps using IST, and substitute them 774 * appropriately. The debugger ones are the only ones we care 775 * about. Xen will handle faults like double_fault, 776 * so we should never see them. Warn if 777 * there's an unexpected IST-using fault handler. 778 */ 779 if (addr == (unsigned long)debug) 780 addr = (unsigned long)xen_debug; 781 else if (addr == (unsigned long)int3) 782 addr = (unsigned long)xen_int3; 783 else if (addr == (unsigned long)stack_segment) 784 addr = (unsigned long)xen_stack_segment; 785 else if (addr == (unsigned long)double_fault) { 786 /* Don't need to handle these */ 787 return 0; 788 #ifdef CONFIG_X86_MCE 789 } else if (addr == (unsigned long)machine_check) { 790 /* 791 * when xen hypervisor inject vMCE to guest, 792 * use native mce handler to handle it 793 */ 794 ; 795 #endif 796 } else if (addr == (unsigned long)nmi) 797 /* 798 * Use the native version as well. 799 */ 800 ; 801 else { 802 /* Some other trap using IST? */ 803 if (WARN_ON(val->ist != 0)) 804 return 0; 805 } 806 #endif /* CONFIG_X86_64 */ 807 info->address = addr; 808 809 info->cs = gate_segment(*val); 810 info->flags = val->dpl; 811 /* interrupt gates clear IF */ 812 if (val->type == GATE_INTERRUPT) 813 info->flags |= 1 << 2; 814 815 return 1; 816 } 817 818 /* Locations of each CPU's IDT */ 819 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 820 821 /* Set an IDT entry. If the entry is part of the current IDT, then 822 also update Xen. */ 823 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 824 { 825 unsigned long p = (unsigned long)&dt[entrynum]; 826 unsigned long start, end; 827 828 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 829 830 preempt_disable(); 831 832 start = __this_cpu_read(idt_desc.address); 833 end = start + __this_cpu_read(idt_desc.size) + 1; 834 835 xen_mc_flush(); 836 837 native_write_idt_entry(dt, entrynum, g); 838 839 if (p >= start && (p + 8) <= end) { 840 struct trap_info info[2]; 841 842 info[1].address = 0; 843 844 if (cvt_gate_to_trap(entrynum, g, &info[0])) 845 if (HYPERVISOR_set_trap_table(info)) 846 BUG(); 847 } 848 849 preempt_enable(); 850 } 851 852 static void xen_convert_trap_info(const struct desc_ptr *desc, 853 struct trap_info *traps) 854 { 855 unsigned in, out, count; 856 857 count = (desc->size+1) / sizeof(gate_desc); 858 BUG_ON(count > 256); 859 860 for (in = out = 0; in < count; in++) { 861 gate_desc *entry = (gate_desc*)(desc->address) + in; 862 863 if (cvt_gate_to_trap(in, entry, &traps[out])) 864 out++; 865 } 866 traps[out].address = 0; 867 } 868 869 void xen_copy_trap_info(struct trap_info *traps) 870 { 871 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc); 872 873 xen_convert_trap_info(desc, traps); 874 } 875 876 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 877 hold a spinlock to protect the static traps[] array (static because 878 it avoids allocation, and saves stack space). */ 879 static void xen_load_idt(const struct desc_ptr *desc) 880 { 881 static DEFINE_SPINLOCK(lock); 882 static struct trap_info traps[257]; 883 884 trace_xen_cpu_load_idt(desc); 885 886 spin_lock(&lock); 887 888 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); 889 890 xen_convert_trap_info(desc, traps); 891 892 xen_mc_flush(); 893 if (HYPERVISOR_set_trap_table(traps)) 894 BUG(); 895 896 spin_unlock(&lock); 897 } 898 899 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 900 they're handled differently. */ 901 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 902 const void *desc, int type) 903 { 904 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 905 906 preempt_disable(); 907 908 switch (type) { 909 case DESC_LDT: 910 case DESC_TSS: 911 /* ignore */ 912 break; 913 914 default: { 915 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 916 917 xen_mc_flush(); 918 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 919 BUG(); 920 } 921 922 } 923 924 preempt_enable(); 925 } 926 927 /* 928 * Version of write_gdt_entry for use at early boot-time needed to 929 * update an entry as simply as possible. 930 */ 931 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 932 const void *desc, int type) 933 { 934 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 935 936 switch (type) { 937 case DESC_LDT: 938 case DESC_TSS: 939 /* ignore */ 940 break; 941 942 default: { 943 xmaddr_t maddr = virt_to_machine(&dt[entry]); 944 945 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 946 dt[entry] = *(struct desc_struct *)desc; 947 } 948 949 } 950 } 951 952 static void xen_load_sp0(struct tss_struct *tss, 953 struct thread_struct *thread) 954 { 955 struct multicall_space mcs; 956 957 mcs = xen_mc_entry(0); 958 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 959 xen_mc_issue(PARAVIRT_LAZY_CPU); 960 tss->x86_tss.sp0 = thread->sp0; 961 } 962 963 static void xen_set_iopl_mask(unsigned mask) 964 { 965 struct physdev_set_iopl set_iopl; 966 967 /* Force the change at ring 0. */ 968 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 969 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 970 } 971 972 static void xen_io_delay(void) 973 { 974 } 975 976 static void xen_clts(void) 977 { 978 struct multicall_space mcs; 979 980 mcs = xen_mc_entry(0); 981 982 MULTI_fpu_taskswitch(mcs.mc, 0); 983 984 xen_mc_issue(PARAVIRT_LAZY_CPU); 985 } 986 987 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 988 989 static unsigned long xen_read_cr0(void) 990 { 991 unsigned long cr0 = this_cpu_read(xen_cr0_value); 992 993 if (unlikely(cr0 == 0)) { 994 cr0 = native_read_cr0(); 995 this_cpu_write(xen_cr0_value, cr0); 996 } 997 998 return cr0; 999 } 1000 1001 static void xen_write_cr0(unsigned long cr0) 1002 { 1003 struct multicall_space mcs; 1004 1005 this_cpu_write(xen_cr0_value, cr0); 1006 1007 /* Only pay attention to cr0.TS; everything else is 1008 ignored. */ 1009 mcs = xen_mc_entry(0); 1010 1011 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 1012 1013 xen_mc_issue(PARAVIRT_LAZY_CPU); 1014 } 1015 1016 static void xen_write_cr4(unsigned long cr4) 1017 { 1018 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE); 1019 1020 native_write_cr4(cr4); 1021 } 1022 #ifdef CONFIG_X86_64 1023 static inline unsigned long xen_read_cr8(void) 1024 { 1025 return 0; 1026 } 1027 static inline void xen_write_cr8(unsigned long val) 1028 { 1029 BUG_ON(val); 1030 } 1031 #endif 1032 1033 static u64 xen_read_msr_safe(unsigned int msr, int *err) 1034 { 1035 u64 val; 1036 1037 if (pmu_msr_read(msr, &val, err)) 1038 return val; 1039 1040 val = native_read_msr_safe(msr, err); 1041 switch (msr) { 1042 case MSR_IA32_APICBASE: 1043 #ifdef CONFIG_X86_X2APIC 1044 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31)))) 1045 #endif 1046 val &= ~X2APIC_ENABLE; 1047 break; 1048 } 1049 return val; 1050 } 1051 1052 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 1053 { 1054 int ret; 1055 1056 ret = 0; 1057 1058 switch (msr) { 1059 #ifdef CONFIG_X86_64 1060 unsigned which; 1061 u64 base; 1062 1063 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 1064 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 1065 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 1066 1067 set: 1068 base = ((u64)high << 32) | low; 1069 if (HYPERVISOR_set_segment_base(which, base) != 0) 1070 ret = -EIO; 1071 break; 1072 #endif 1073 1074 case MSR_STAR: 1075 case MSR_CSTAR: 1076 case MSR_LSTAR: 1077 case MSR_SYSCALL_MASK: 1078 case MSR_IA32_SYSENTER_CS: 1079 case MSR_IA32_SYSENTER_ESP: 1080 case MSR_IA32_SYSENTER_EIP: 1081 /* Fast syscall setup is all done in hypercalls, so 1082 these are all ignored. Stub them out here to stop 1083 Xen console noise. */ 1084 break; 1085 1086 default: 1087 if (!pmu_msr_write(msr, low, high, &ret)) 1088 ret = native_write_msr_safe(msr, low, high); 1089 } 1090 1091 return ret; 1092 } 1093 1094 void xen_setup_shared_info(void) 1095 { 1096 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1097 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1098 xen_start_info->shared_info); 1099 1100 HYPERVISOR_shared_info = 1101 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1102 } else 1103 HYPERVISOR_shared_info = 1104 (struct shared_info *)__va(xen_start_info->shared_info); 1105 1106 #ifndef CONFIG_SMP 1107 /* In UP this is as good a place as any to set up shared info */ 1108 xen_setup_vcpu_info_placement(); 1109 #endif 1110 1111 xen_setup_mfn_list_list(); 1112 } 1113 1114 /* This is called once we have the cpu_possible_mask */ 1115 void xen_setup_vcpu_info_placement(void) 1116 { 1117 int cpu; 1118 1119 for_each_possible_cpu(cpu) 1120 xen_vcpu_setup(cpu); 1121 1122 /* xen_vcpu_setup managed to place the vcpu_info within the 1123 * percpu area for all cpus, so make use of it. Note that for 1124 * PVH we want to use native IRQ mechanism. */ 1125 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1126 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1127 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1128 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1129 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1130 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1131 } 1132 } 1133 1134 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1135 unsigned long addr, unsigned len) 1136 { 1137 char *start, *end, *reloc; 1138 unsigned ret; 1139 1140 start = end = reloc = NULL; 1141 1142 #define SITE(op, x) \ 1143 case PARAVIRT_PATCH(op.x): \ 1144 if (have_vcpu_info_placement) { \ 1145 start = (char *)xen_##x##_direct; \ 1146 end = xen_##x##_direct_end; \ 1147 reloc = xen_##x##_direct_reloc; \ 1148 } \ 1149 goto patch_site 1150 1151 switch (type) { 1152 SITE(pv_irq_ops, irq_enable); 1153 SITE(pv_irq_ops, irq_disable); 1154 SITE(pv_irq_ops, save_fl); 1155 SITE(pv_irq_ops, restore_fl); 1156 #undef SITE 1157 1158 patch_site: 1159 if (start == NULL || (end-start) > len) 1160 goto default_patch; 1161 1162 ret = paravirt_patch_insns(insnbuf, len, start, end); 1163 1164 /* Note: because reloc is assigned from something that 1165 appears to be an array, gcc assumes it's non-null, 1166 but doesn't know its relationship with start and 1167 end. */ 1168 if (reloc > start && reloc < end) { 1169 int reloc_off = reloc - start; 1170 long *relocp = (long *)(insnbuf + reloc_off); 1171 long delta = start - (char *)addr; 1172 1173 *relocp += delta; 1174 } 1175 break; 1176 1177 default_patch: 1178 default: 1179 ret = paravirt_patch_default(type, clobbers, insnbuf, 1180 addr, len); 1181 break; 1182 } 1183 1184 return ret; 1185 } 1186 1187 static const struct pv_info xen_info __initconst = { 1188 .paravirt_enabled = 1, 1189 .shared_kernel_pmd = 0, 1190 1191 #ifdef CONFIG_X86_64 1192 .extra_user_64bit_cs = FLAT_USER_CS64, 1193 #endif 1194 1195 .name = "Xen", 1196 }; 1197 1198 static const struct pv_init_ops xen_init_ops __initconst = { 1199 .patch = xen_patch, 1200 }; 1201 1202 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1203 .cpuid = xen_cpuid, 1204 1205 .set_debugreg = xen_set_debugreg, 1206 .get_debugreg = xen_get_debugreg, 1207 1208 .clts = xen_clts, 1209 1210 .read_cr0 = xen_read_cr0, 1211 .write_cr0 = xen_write_cr0, 1212 1213 .read_cr4 = native_read_cr4, 1214 .read_cr4_safe = native_read_cr4_safe, 1215 .write_cr4 = xen_write_cr4, 1216 1217 #ifdef CONFIG_X86_64 1218 .read_cr8 = xen_read_cr8, 1219 .write_cr8 = xen_write_cr8, 1220 #endif 1221 1222 .wbinvd = native_wbinvd, 1223 1224 .read_msr = xen_read_msr_safe, 1225 .write_msr = xen_write_msr_safe, 1226 1227 .read_pmc = xen_read_pmc, 1228 1229 .iret = xen_iret, 1230 #ifdef CONFIG_X86_64 1231 .usergs_sysret32 = xen_sysret32, 1232 .usergs_sysret64 = xen_sysret64, 1233 #else 1234 .irq_enable_sysexit = xen_sysexit, 1235 #endif 1236 1237 .load_tr_desc = paravirt_nop, 1238 .set_ldt = xen_set_ldt, 1239 .load_gdt = xen_load_gdt, 1240 .load_idt = xen_load_idt, 1241 .load_tls = xen_load_tls, 1242 #ifdef CONFIG_X86_64 1243 .load_gs_index = xen_load_gs_index, 1244 #endif 1245 1246 .alloc_ldt = xen_alloc_ldt, 1247 .free_ldt = xen_free_ldt, 1248 1249 .store_idt = native_store_idt, 1250 .store_tr = xen_store_tr, 1251 1252 .write_ldt_entry = xen_write_ldt_entry, 1253 .write_gdt_entry = xen_write_gdt_entry, 1254 .write_idt_entry = xen_write_idt_entry, 1255 .load_sp0 = xen_load_sp0, 1256 1257 .set_iopl_mask = xen_set_iopl_mask, 1258 .io_delay = xen_io_delay, 1259 1260 /* Xen takes care of %gs when switching to usermode for us */ 1261 .swapgs = paravirt_nop, 1262 1263 .start_context_switch = paravirt_start_context_switch, 1264 .end_context_switch = xen_end_context_switch, 1265 }; 1266 1267 static const struct pv_apic_ops xen_apic_ops __initconst = { 1268 #ifdef CONFIG_X86_LOCAL_APIC 1269 .startup_ipi_hook = paravirt_nop, 1270 #endif 1271 }; 1272 1273 static void xen_reboot(int reason) 1274 { 1275 struct sched_shutdown r = { .reason = reason }; 1276 int cpu; 1277 1278 for_each_online_cpu(cpu) 1279 xen_pmu_finish(cpu); 1280 1281 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1282 BUG(); 1283 } 1284 1285 static void xen_restart(char *msg) 1286 { 1287 xen_reboot(SHUTDOWN_reboot); 1288 } 1289 1290 static void xen_emergency_restart(void) 1291 { 1292 xen_reboot(SHUTDOWN_reboot); 1293 } 1294 1295 static void xen_machine_halt(void) 1296 { 1297 xen_reboot(SHUTDOWN_poweroff); 1298 } 1299 1300 static void xen_machine_power_off(void) 1301 { 1302 if (pm_power_off) 1303 pm_power_off(); 1304 xen_reboot(SHUTDOWN_poweroff); 1305 } 1306 1307 static void xen_crash_shutdown(struct pt_regs *regs) 1308 { 1309 xen_reboot(SHUTDOWN_crash); 1310 } 1311 1312 static int 1313 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1314 { 1315 xen_reboot(SHUTDOWN_crash); 1316 return NOTIFY_DONE; 1317 } 1318 1319 static struct notifier_block xen_panic_block = { 1320 .notifier_call= xen_panic_event, 1321 .priority = INT_MIN 1322 }; 1323 1324 int xen_panic_handler_init(void) 1325 { 1326 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1327 return 0; 1328 } 1329 1330 static const struct machine_ops xen_machine_ops __initconst = { 1331 .restart = xen_restart, 1332 .halt = xen_machine_halt, 1333 .power_off = xen_machine_power_off, 1334 .shutdown = xen_machine_halt, 1335 .crash_shutdown = xen_crash_shutdown, 1336 .emergency_restart = xen_emergency_restart, 1337 }; 1338 1339 static unsigned char xen_get_nmi_reason(void) 1340 { 1341 unsigned char reason = 0; 1342 1343 /* Construct a value which looks like it came from port 0x61. */ 1344 if (test_bit(_XEN_NMIREASON_io_error, 1345 &HYPERVISOR_shared_info->arch.nmi_reason)) 1346 reason |= NMI_REASON_IOCHK; 1347 if (test_bit(_XEN_NMIREASON_pci_serr, 1348 &HYPERVISOR_shared_info->arch.nmi_reason)) 1349 reason |= NMI_REASON_SERR; 1350 1351 return reason; 1352 } 1353 1354 static void __init xen_boot_params_init_edd(void) 1355 { 1356 #if IS_ENABLED(CONFIG_EDD) 1357 struct xen_platform_op op; 1358 struct edd_info *edd_info; 1359 u32 *mbr_signature; 1360 unsigned nr; 1361 int ret; 1362 1363 edd_info = boot_params.eddbuf; 1364 mbr_signature = boot_params.edd_mbr_sig_buffer; 1365 1366 op.cmd = XENPF_firmware_info; 1367 1368 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1369 for (nr = 0; nr < EDDMAXNR; nr++) { 1370 struct edd_info *info = edd_info + nr; 1371 1372 op.u.firmware_info.index = nr; 1373 info->params.length = sizeof(info->params); 1374 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1375 &info->params); 1376 ret = HYPERVISOR_dom0_op(&op); 1377 if (ret) 1378 break; 1379 1380 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1381 C(device); 1382 C(version); 1383 C(interface_support); 1384 C(legacy_max_cylinder); 1385 C(legacy_max_head); 1386 C(legacy_sectors_per_track); 1387 #undef C 1388 } 1389 boot_params.eddbuf_entries = nr; 1390 1391 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1392 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1393 op.u.firmware_info.index = nr; 1394 ret = HYPERVISOR_dom0_op(&op); 1395 if (ret) 1396 break; 1397 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1398 } 1399 boot_params.edd_mbr_sig_buf_entries = nr; 1400 #endif 1401 } 1402 1403 /* 1404 * Set up the GDT and segment registers for -fstack-protector. Until 1405 * we do this, we have to be careful not to call any stack-protected 1406 * function, which is most of the kernel. 1407 * 1408 * Note, that it is __ref because the only caller of this after init 1409 * is PVH which is not going to use xen_load_gdt_boot or other 1410 * __init functions. 1411 */ 1412 static void __ref xen_setup_gdt(int cpu) 1413 { 1414 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1415 #ifdef CONFIG_X86_64 1416 unsigned long dummy; 1417 1418 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1419 switch_to_new_gdt(cpu); /* GDT and GS set */ 1420 1421 /* We are switching of the Xen provided GDT to our HVM mode 1422 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1423 * and we are jumping to reload it. 1424 */ 1425 asm volatile ("pushq %0\n" 1426 "leaq 1f(%%rip),%0\n" 1427 "pushq %0\n" 1428 "lretq\n" 1429 "1:\n" 1430 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1431 1432 /* 1433 * While not needed, we also set the %es, %ds, and %fs 1434 * to zero. We don't care about %ss as it is NULL. 1435 * Strictly speaking this is not needed as Xen zeros those 1436 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1437 * 1438 * Linux zeros them in cpu_init() and in secondary_startup_64 1439 * (for BSP). 1440 */ 1441 loadsegment(es, 0); 1442 loadsegment(ds, 0); 1443 loadsegment(fs, 0); 1444 #else 1445 /* PVH: TODO Implement. */ 1446 BUG(); 1447 #endif 1448 return; /* PVH does not need any PV GDT ops. */ 1449 } 1450 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1451 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1452 1453 setup_stack_canary_segment(0); 1454 switch_to_new_gdt(0); 1455 1456 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1457 pv_cpu_ops.load_gdt = xen_load_gdt; 1458 } 1459 1460 #ifdef CONFIG_XEN_PVH 1461 /* 1462 * A PV guest starts with default flags that are not set for PVH, set them 1463 * here asap. 1464 */ 1465 static void xen_pvh_set_cr_flags(int cpu) 1466 { 1467 1468 /* Some of these are setup in 'secondary_startup_64'. The others: 1469 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1470 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1471 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1472 1473 if (!cpu) 1474 return; 1475 /* 1476 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1477 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu(). 1478 */ 1479 if (cpu_has_pse) 1480 cr4_set_bits_and_update_boot(X86_CR4_PSE); 1481 1482 if (cpu_has_pge) 1483 cr4_set_bits_and_update_boot(X86_CR4_PGE); 1484 } 1485 1486 /* 1487 * Note, that it is ref - because the only caller of this after init 1488 * is PVH which is not going to use xen_load_gdt_boot or other 1489 * __init functions. 1490 */ 1491 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1492 { 1493 xen_setup_gdt(cpu); 1494 xen_pvh_set_cr_flags(cpu); 1495 } 1496 1497 static void __init xen_pvh_early_guest_init(void) 1498 { 1499 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1500 return; 1501 1502 if (!xen_feature(XENFEAT_hvm_callback_vector)) 1503 return; 1504 1505 xen_have_vector_callback = 1; 1506 1507 xen_pvh_early_cpu_init(0, false); 1508 xen_pvh_set_cr_flags(0); 1509 1510 #ifdef CONFIG_X86_32 1511 BUG(); /* PVH: Implement proper support. */ 1512 #endif 1513 } 1514 #endif /* CONFIG_XEN_PVH */ 1515 1516 /* First C function to be called on Xen boot */ 1517 asmlinkage __visible void __init xen_start_kernel(void) 1518 { 1519 struct physdev_set_iopl set_iopl; 1520 unsigned long initrd_start = 0; 1521 u64 pat; 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 #ifdef CONFIG_XEN_PVH 1531 xen_pvh_early_guest_init(); 1532 #endif 1533 xen_setup_machphys_mapping(); 1534 1535 /* Install Xen paravirt ops */ 1536 pv_info = xen_info; 1537 pv_init_ops = xen_init_ops; 1538 pv_apic_ops = xen_apic_ops; 1539 if (!xen_pvh_domain()) { 1540 pv_cpu_ops = xen_cpu_ops; 1541 1542 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1543 } 1544 1545 if (xen_feature(XENFEAT_auto_translated_physmap)) 1546 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup; 1547 else 1548 x86_init.resources.memory_setup = xen_memory_setup; 1549 x86_init.oem.arch_setup = xen_arch_setup; 1550 x86_init.oem.banner = xen_banner; 1551 1552 xen_init_time_ops(); 1553 1554 /* 1555 * Set up some pagetable state before starting to set any ptes. 1556 */ 1557 1558 xen_init_mmu_ops(); 1559 1560 /* Prevent unwanted bits from being set in PTEs. */ 1561 __supported_pte_mask &= ~_PAGE_GLOBAL; 1562 1563 /* 1564 * Prevent page tables from being allocated in highmem, even 1565 * if CONFIG_HIGHPTE is enabled. 1566 */ 1567 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1568 1569 /* Work out if we support NX */ 1570 x86_configure_nx(); 1571 1572 /* Get mfn list */ 1573 xen_build_dynamic_phys_to_machine(); 1574 1575 /* 1576 * Set up kernel GDT and segment registers, mainly so that 1577 * -fstack-protector code can be executed. 1578 */ 1579 xen_setup_gdt(0); 1580 1581 xen_init_irq_ops(); 1582 xen_init_cpuid_mask(); 1583 1584 #ifdef CONFIG_X86_LOCAL_APIC 1585 /* 1586 * set up the basic apic ops. 1587 */ 1588 xen_init_apic(); 1589 #endif 1590 1591 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1592 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1593 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1594 } 1595 1596 machine_ops = xen_machine_ops; 1597 1598 /* 1599 * The only reliable way to retain the initial address of the 1600 * percpu gdt_page is to remember it here, so we can go and 1601 * mark it RW later, when the initial percpu area is freed. 1602 */ 1603 xen_initial_gdt = &per_cpu(gdt_page, 0); 1604 1605 xen_smp_init(); 1606 1607 #ifdef CONFIG_ACPI_NUMA 1608 /* 1609 * The pages we from Xen are not related to machine pages, so 1610 * any NUMA information the kernel tries to get from ACPI will 1611 * be meaningless. Prevent it from trying. 1612 */ 1613 acpi_numa = -1; 1614 #endif 1615 /* Don't do the full vcpu_info placement stuff until we have a 1616 possible map and a non-dummy shared_info. */ 1617 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1618 1619 local_irq_disable(); 1620 early_boot_irqs_disabled = true; 1621 1622 xen_raw_console_write("mapping kernel into physical memory\n"); 1623 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, 1624 xen_start_info->nr_pages); 1625 xen_reserve_special_pages(); 1626 1627 /* 1628 * Modify the cache mode translation tables to match Xen's PAT 1629 * configuration. 1630 */ 1631 rdmsrl(MSR_IA32_CR_PAT, pat); 1632 pat_init_cache_modes(pat); 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 if (xen_start_info->mod_start) { 1668 if (xen_start_info->flags & SIF_MOD_START_PFN) 1669 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1670 else 1671 initrd_start = __pa(xen_start_info->mod_start); 1672 } 1673 1674 /* Poke various useful things into boot_params */ 1675 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1676 boot_params.hdr.ramdisk_image = initrd_start; 1677 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1678 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1679 1680 if (!xen_initial_domain()) { 1681 add_preferred_console("xenboot", 0, NULL); 1682 add_preferred_console("tty", 0, NULL); 1683 add_preferred_console("hvc", 0, NULL); 1684 if (pci_xen) 1685 x86_init.pci.arch_init = pci_xen_init; 1686 } else { 1687 const struct dom0_vga_console_info *info = 1688 (void *)((char *)xen_start_info + 1689 xen_start_info->console.dom0.info_off); 1690 struct xen_platform_op op = { 1691 .cmd = XENPF_firmware_info, 1692 .interface_version = XENPF_INTERFACE_VERSION, 1693 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1694 }; 1695 1696 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1697 xen_start_info->console.domU.mfn = 0; 1698 xen_start_info->console.domU.evtchn = 0; 1699 1700 if (HYPERVISOR_dom0_op(&op) == 0) 1701 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1702 1703 /* Make sure ACS will be enabled */ 1704 pci_request_acs(); 1705 1706 xen_acpi_sleep_register(); 1707 1708 /* Avoid searching for BIOS MP tables */ 1709 x86_init.mpparse.find_smp_config = x86_init_noop; 1710 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1711 1712 xen_boot_params_init_edd(); 1713 } 1714 #ifdef CONFIG_PCI 1715 /* PCI BIOS service won't work from a PV guest. */ 1716 pci_probe &= ~PCI_PROBE_BIOS; 1717 #endif 1718 xen_raw_console_write("about to get started...\n"); 1719 1720 xen_setup_runstate_info(0); 1721 1722 xen_efi_init(); 1723 1724 /* Start the world */ 1725 #ifdef CONFIG_X86_32 1726 i386_start_kernel(); 1727 #else 1728 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1729 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1730 #endif 1731 } 1732 1733 void __ref xen_hvm_init_shared_info(void) 1734 { 1735 int cpu; 1736 struct xen_add_to_physmap xatp; 1737 static struct shared_info *shared_info_page = 0; 1738 1739 if (!shared_info_page) 1740 shared_info_page = (struct shared_info *) 1741 extend_brk(PAGE_SIZE, PAGE_SIZE); 1742 xatp.domid = DOMID_SELF; 1743 xatp.idx = 0; 1744 xatp.space = XENMAPSPACE_shared_info; 1745 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1746 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1747 BUG(); 1748 1749 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1750 1751 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1752 * page, we use it in the event channel upcall and in some pvclock 1753 * related functions. We don't need the vcpu_info placement 1754 * optimizations because we don't use any pv_mmu or pv_irq op on 1755 * HVM. 1756 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1757 * online but xen_hvm_init_shared_info is run at resume time too and 1758 * in that case multiple vcpus might be online. */ 1759 for_each_online_cpu(cpu) { 1760 /* Leave it to be NULL. */ 1761 if (cpu >= MAX_VIRT_CPUS) 1762 continue; 1763 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1764 } 1765 } 1766 1767 #ifdef CONFIG_XEN_PVHVM 1768 static void __init init_hvm_pv_info(void) 1769 { 1770 int major, minor; 1771 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1772 u64 pfn; 1773 1774 base = xen_cpuid_base(); 1775 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1776 1777 major = eax >> 16; 1778 minor = eax & 0xffff; 1779 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1780 1781 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1782 1783 pfn = __pa(hypercall_page); 1784 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1785 1786 xen_setup_features(); 1787 1788 pv_info.name = "Xen HVM"; 1789 1790 xen_domain_type = XEN_HVM_DOMAIN; 1791 } 1792 1793 static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, 1794 void *hcpu) 1795 { 1796 int cpu = (long)hcpu; 1797 switch (action) { 1798 case CPU_UP_PREPARE: 1799 xen_vcpu_setup(cpu); 1800 if (xen_have_vector_callback) { 1801 if (xen_feature(XENFEAT_hvm_safe_pvclock)) 1802 xen_setup_timer(cpu); 1803 } 1804 break; 1805 default: 1806 break; 1807 } 1808 return NOTIFY_OK; 1809 } 1810 1811 static struct notifier_block xen_hvm_cpu_notifier = { 1812 .notifier_call = xen_hvm_cpu_notify, 1813 }; 1814 1815 #ifdef CONFIG_KEXEC_CORE 1816 static void xen_hvm_shutdown(void) 1817 { 1818 native_machine_shutdown(); 1819 if (kexec_in_progress) 1820 xen_reboot(SHUTDOWN_soft_reset); 1821 } 1822 1823 static void xen_hvm_crash_shutdown(struct pt_regs *regs) 1824 { 1825 native_machine_crash_shutdown(regs); 1826 xen_reboot(SHUTDOWN_soft_reset); 1827 } 1828 #endif 1829 1830 static void __init xen_hvm_guest_init(void) 1831 { 1832 if (xen_pv_domain()) 1833 return; 1834 1835 init_hvm_pv_info(); 1836 1837 xen_hvm_init_shared_info(); 1838 1839 xen_panic_handler_init(); 1840 1841 if (xen_feature(XENFEAT_hvm_callback_vector)) 1842 xen_have_vector_callback = 1; 1843 xen_hvm_smp_init(); 1844 register_cpu_notifier(&xen_hvm_cpu_notifier); 1845 xen_unplug_emulated_devices(); 1846 x86_init.irqs.intr_init = xen_init_IRQ; 1847 xen_hvm_init_time_ops(); 1848 xen_hvm_init_mmu_ops(); 1849 #ifdef CONFIG_KEXEC_CORE 1850 machine_ops.shutdown = xen_hvm_shutdown; 1851 machine_ops.crash_shutdown = xen_hvm_crash_shutdown; 1852 #endif 1853 } 1854 #endif 1855 1856 static bool xen_nopv = false; 1857 static __init int xen_parse_nopv(char *arg) 1858 { 1859 xen_nopv = true; 1860 return 0; 1861 } 1862 early_param("xen_nopv", xen_parse_nopv); 1863 1864 static uint32_t __init xen_platform(void) 1865 { 1866 if (xen_nopv) 1867 return 0; 1868 1869 return xen_cpuid_base(); 1870 } 1871 1872 bool xen_hvm_need_lapic(void) 1873 { 1874 if (xen_nopv) 1875 return false; 1876 if (xen_pv_domain()) 1877 return false; 1878 if (!xen_hvm_domain()) 1879 return false; 1880 if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) 1881 return false; 1882 return true; 1883 } 1884 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1885 1886 static void xen_set_cpu_features(struct cpuinfo_x86 *c) 1887 { 1888 if (xen_pv_domain()) 1889 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); 1890 } 1891 1892 const struct hypervisor_x86 x86_hyper_xen = { 1893 .name = "Xen", 1894 .detect = xen_platform, 1895 #ifdef CONFIG_XEN_PVHVM 1896 .init_platform = xen_hvm_guest_init, 1897 #endif 1898 .x2apic_available = xen_x2apic_para_available, 1899 .set_cpu_features = xen_set_cpu_features, 1900 }; 1901 EXPORT_SYMBOL(x86_hyper_xen); 1902