1 /* 2 * Core of Xen paravirt_ops implementation. 3 * 4 * This file contains the xen_paravirt_ops structure itself, and the 5 * implementations for: 6 * - privileged instructions 7 * - interrupt flags 8 * - segment operations 9 * - booting and setup 10 * 11 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 12 */ 13 14 #include <linux/cpu.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/smp.h> 18 #include <linux/preempt.h> 19 #include <linux/hardirq.h> 20 #include <linux/percpu.h> 21 #include <linux/delay.h> 22 #include <linux/start_kernel.h> 23 #include <linux/sched.h> 24 #include <linux/kprobes.h> 25 #include <linux/bootmem.h> 26 #include <linux/module.h> 27 #include <linux/mm.h> 28 #include <linux/page-flags.h> 29 #include <linux/highmem.h> 30 #include <linux/console.h> 31 #include <linux/pci.h> 32 #include <linux/gfp.h> 33 #include <linux/memblock.h> 34 #include <linux/edd.h> 35 36 #include <xen/xen.h> 37 #include <xen/events.h> 38 #include <xen/interface/xen.h> 39 #include <xen/interface/version.h> 40 #include <xen/interface/physdev.h> 41 #include <xen/interface/vcpu.h> 42 #include <xen/interface/memory.h> 43 #include <xen/interface/nmi.h> 44 #include <xen/interface/xen-mca.h> 45 #include <xen/features.h> 46 #include <xen/page.h> 47 #include <xen/hvm.h> 48 #include <xen/hvc-console.h> 49 #include <xen/acpi.h> 50 51 #include <asm/paravirt.h> 52 #include <asm/apic.h> 53 #include <asm/page.h> 54 #include <asm/xen/pci.h> 55 #include <asm/xen/hypercall.h> 56 #include <asm/xen/hypervisor.h> 57 #include <asm/fixmap.h> 58 #include <asm/processor.h> 59 #include <asm/proto.h> 60 #include <asm/msr-index.h> 61 #include <asm/traps.h> 62 #include <asm/setup.h> 63 #include <asm/desc.h> 64 #include <asm/pgalloc.h> 65 #include <asm/pgtable.h> 66 #include <asm/tlbflush.h> 67 #include <asm/reboot.h> 68 #include <asm/stackprotector.h> 69 #include <asm/hypervisor.h> 70 #include <asm/mach_traps.h> 71 #include <asm/mwait.h> 72 #include <asm/pci_x86.h> 73 #include <asm/pat.h> 74 75 #ifdef CONFIG_ACPI 76 #include <linux/acpi.h> 77 #include <asm/acpi.h> 78 #include <acpi/pdc_intel.h> 79 #include <acpi/processor.h> 80 #include <xen/interface/platform.h> 81 #endif 82 83 #include "xen-ops.h" 84 #include "mmu.h" 85 #include "smp.h" 86 #include "multicalls.h" 87 #include "pmu.h" 88 89 EXPORT_SYMBOL_GPL(hypercall_page); 90 91 /* 92 * Pointer to the xen_vcpu_info structure or 93 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 94 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 95 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 96 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 97 * acknowledge pending events. 98 * Also more subtly it is used by the patched version of irq enable/disable 99 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 100 * 101 * The desire to be able to do those mask/unmask operations as a single 102 * instruction by using the per-cpu offset held in %gs is the real reason 103 * vcpu info is in a per-cpu pointer and the original reason for this 104 * hypercall. 105 * 106 */ 107 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 108 109 /* 110 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 111 * hypercall. This can be used both in PV and PVHVM mode. The structure 112 * overrides the default per_cpu(xen_vcpu, cpu) value. 113 */ 114 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 115 116 enum xen_domain_type xen_domain_type = XEN_NATIVE; 117 EXPORT_SYMBOL_GPL(xen_domain_type); 118 119 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 120 EXPORT_SYMBOL(machine_to_phys_mapping); 121 unsigned long machine_to_phys_nr; 122 EXPORT_SYMBOL(machine_to_phys_nr); 123 124 struct start_info *xen_start_info; 125 EXPORT_SYMBOL_GPL(xen_start_info); 126 127 struct shared_info xen_dummy_shared_info; 128 129 void *xen_initial_gdt; 130 131 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 132 __read_mostly int xen_have_vector_callback; 133 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 134 135 /* 136 * Point at some empty memory to start with. We map the real shared_info 137 * page as soon as fixmap is up and running. 138 */ 139 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 140 141 /* 142 * Flag to determine whether vcpu info placement is available on all 143 * VCPUs. We assume it is to start with, and then set it to zero on 144 * the first failure. This is because it can succeed on some VCPUs 145 * and not others, since it can involve hypervisor memory allocation, 146 * or because the guest failed to guarantee all the appropriate 147 * constraints on all VCPUs (ie buffer can't cross a page boundary). 148 * 149 * Note that any particular CPU may be using a placed vcpu structure, 150 * but we can only optimise if the all are. 151 * 152 * 0: not available, 1: available 153 */ 154 static int have_vcpu_info_placement = 1; 155 156 struct tls_descs { 157 struct desc_struct desc[3]; 158 }; 159 160 /* 161 * Updating the 3 TLS descriptors in the GDT on every task switch is 162 * surprisingly expensive so we avoid updating them if they haven't 163 * changed. Since Xen writes different descriptors than the one 164 * passed in the update_descriptor hypercall we keep shadow copies to 165 * compare against. 166 */ 167 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 168 169 static void clamp_max_cpus(void) 170 { 171 #ifdef CONFIG_SMP 172 if (setup_max_cpus > MAX_VIRT_CPUS) 173 setup_max_cpus = MAX_VIRT_CPUS; 174 #endif 175 } 176 177 static void xen_vcpu_setup(int cpu) 178 { 179 struct vcpu_register_vcpu_info info; 180 int err; 181 struct vcpu_info *vcpup; 182 183 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 184 185 /* 186 * This path is called twice on PVHVM - first during bootup via 187 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 188 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 189 * As we can only do the VCPUOP_register_vcpu_info once lets 190 * not over-write its result. 191 * 192 * For PV it is called during restore (xen_vcpu_restore) and bootup 193 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 194 * use this function. 195 */ 196 if (xen_hvm_domain()) { 197 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 198 return; 199 } 200 if (cpu < MAX_VIRT_CPUS) 201 per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 202 203 if (!have_vcpu_info_placement) { 204 if (cpu >= MAX_VIRT_CPUS) 205 clamp_max_cpus(); 206 return; 207 } 208 209 vcpup = &per_cpu(xen_vcpu_info, cpu); 210 info.mfn = arbitrary_virt_to_mfn(vcpup); 211 info.offset = offset_in_page(vcpup); 212 213 /* Check to see if the hypervisor will put the vcpu_info 214 structure where we want it, which allows direct access via 215 a percpu-variable. 216 N.B. This hypercall can _only_ be called once per CPU. Subsequent 217 calls will error out with -EINVAL. This is due to the fact that 218 hypervisor has no unregister variant and this hypercall does not 219 allow to over-write info.mfn and info.offset. 220 */ 221 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 222 223 if (err) { 224 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 225 have_vcpu_info_placement = 0; 226 clamp_max_cpus(); 227 } else { 228 /* This cpu is using the registered vcpu info, even if 229 later ones fail to. */ 230 per_cpu(xen_vcpu, cpu) = vcpup; 231 } 232 } 233 234 /* 235 * On restore, set the vcpu placement up again. 236 * If it fails, then we're in a bad state, since 237 * we can't back out from using it... 238 */ 239 void xen_vcpu_restore(void) 240 { 241 int cpu; 242 243 for_each_possible_cpu(cpu) { 244 bool other_cpu = (cpu != smp_processor_id()); 245 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL); 246 247 if (other_cpu && is_up && 248 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 249 BUG(); 250 251 xen_setup_runstate_info(cpu); 252 253 if (have_vcpu_info_placement) 254 xen_vcpu_setup(cpu); 255 256 if (other_cpu && is_up && 257 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 258 BUG(); 259 } 260 } 261 262 static void __init xen_banner(void) 263 { 264 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 265 struct xen_extraversion extra; 266 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 267 268 pr_info("Booting paravirtualized kernel %son %s\n", 269 xen_feature(XENFEAT_auto_translated_physmap) ? 270 "with PVH extensions " : "", pv_info.name); 271 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 272 version >> 16, version & 0xffff, extra.extraversion, 273 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 274 } 275 /* Check if running on Xen version (major, minor) or later */ 276 bool 277 xen_running_on_version_or_later(unsigned int major, unsigned int minor) 278 { 279 unsigned int version; 280 281 if (!xen_domain()) 282 return false; 283 284 version = HYPERVISOR_xen_version(XENVER_version, NULL); 285 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 286 ((version >> 16) > major)) 287 return true; 288 return false; 289 } 290 291 #define CPUID_THERM_POWER_LEAF 6 292 #define APERFMPERF_PRESENT 0 293 294 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 295 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 296 297 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask; 298 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 299 static __read_mostly unsigned int cpuid_leaf5_edx_val; 300 301 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 302 unsigned int *cx, unsigned int *dx) 303 { 304 unsigned maskebx = ~0; 305 unsigned maskecx = ~0; 306 unsigned maskedx = ~0; 307 unsigned setecx = 0; 308 /* 309 * Mask out inconvenient features, to try and disable as many 310 * unsupported kernel subsystems as possible. 311 */ 312 switch (*ax) { 313 case 1: 314 maskecx = cpuid_leaf1_ecx_mask; 315 setecx = cpuid_leaf1_ecx_set_mask; 316 maskedx = cpuid_leaf1_edx_mask; 317 break; 318 319 case CPUID_MWAIT_LEAF: 320 /* Synthesize the values.. */ 321 *ax = 0; 322 *bx = 0; 323 *cx = cpuid_leaf5_ecx_val; 324 *dx = cpuid_leaf5_edx_val; 325 return; 326 327 case CPUID_THERM_POWER_LEAF: 328 /* Disabling APERFMPERF for kernel usage */ 329 maskecx = ~(1 << APERFMPERF_PRESENT); 330 break; 331 332 case 0xb: 333 /* Suppress extended topology stuff */ 334 maskebx = 0; 335 break; 336 } 337 338 asm(XEN_EMULATE_PREFIX "cpuid" 339 : "=a" (*ax), 340 "=b" (*bx), 341 "=c" (*cx), 342 "=d" (*dx) 343 : "0" (*ax), "2" (*cx)); 344 345 *bx &= maskebx; 346 *cx &= maskecx; 347 *cx |= setecx; 348 *dx &= maskedx; 349 350 } 351 352 static bool __init xen_check_mwait(void) 353 { 354 #ifdef CONFIG_ACPI 355 struct xen_platform_op op = { 356 .cmd = XENPF_set_processor_pminfo, 357 .u.set_pminfo.id = -1, 358 .u.set_pminfo.type = XEN_PM_PDC, 359 }; 360 uint32_t buf[3]; 361 unsigned int ax, bx, cx, dx; 362 unsigned int mwait_mask; 363 364 /* We need to determine whether it is OK to expose the MWAIT 365 * capability to the kernel to harvest deeper than C3 states from ACPI 366 * _CST using the processor_harvest_xen.c module. For this to work, we 367 * need to gather the MWAIT_LEAF values (which the cstate.c code 368 * checks against). The hypervisor won't expose the MWAIT flag because 369 * it would break backwards compatibility; so we will find out directly 370 * from the hardware and hypercall. 371 */ 372 if (!xen_initial_domain()) 373 return false; 374 375 /* 376 * When running under platform earlier than Xen4.2, do not expose 377 * mwait, to avoid the risk of loading native acpi pad driver 378 */ 379 if (!xen_running_on_version_or_later(4, 2)) 380 return false; 381 382 ax = 1; 383 cx = 0; 384 385 native_cpuid(&ax, &bx, &cx, &dx); 386 387 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 388 (1 << (X86_FEATURE_MWAIT % 32)); 389 390 if ((cx & mwait_mask) != mwait_mask) 391 return false; 392 393 /* We need to emulate the MWAIT_LEAF and for that we need both 394 * ecx and edx. The hypercall provides only partial information. 395 */ 396 397 ax = CPUID_MWAIT_LEAF; 398 bx = 0; 399 cx = 0; 400 dx = 0; 401 402 native_cpuid(&ax, &bx, &cx, &dx); 403 404 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so, 405 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 406 */ 407 buf[0] = ACPI_PDC_REVISION_ID; 408 buf[1] = 1; 409 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP); 410 411 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 412 413 if ((HYPERVISOR_dom0_op(&op) == 0) && 414 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) { 415 cpuid_leaf5_ecx_val = cx; 416 cpuid_leaf5_edx_val = dx; 417 } 418 return true; 419 #else 420 return false; 421 #endif 422 } 423 static void __init xen_init_cpuid_mask(void) 424 { 425 unsigned int ax, bx, cx, dx; 426 unsigned int xsave_mask; 427 428 cpuid_leaf1_edx_mask = 429 ~((1 << X86_FEATURE_MTRR) | /* disable MTRR */ 430 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 431 432 if (!xen_initial_domain()) 433 cpuid_leaf1_edx_mask &= 434 ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ 435 436 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); 437 438 ax = 1; 439 cx = 0; 440 cpuid(1, &ax, &bx, &cx, &dx); 441 442 xsave_mask = 443 (1 << (X86_FEATURE_XSAVE % 32)) | 444 (1 << (X86_FEATURE_OSXSAVE % 32)); 445 446 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 447 if ((cx & xsave_mask) != xsave_mask) 448 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 449 if (xen_check_mwait()) 450 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); 451 } 452 453 static void xen_set_debugreg(int reg, unsigned long val) 454 { 455 HYPERVISOR_set_debugreg(reg, val); 456 } 457 458 static unsigned long xen_get_debugreg(int reg) 459 { 460 return HYPERVISOR_get_debugreg(reg); 461 } 462 463 static void xen_end_context_switch(struct task_struct *next) 464 { 465 xen_mc_flush(); 466 paravirt_end_context_switch(next); 467 } 468 469 static unsigned long xen_store_tr(void) 470 { 471 return 0; 472 } 473 474 /* 475 * Set the page permissions for a particular virtual address. If the 476 * address is a vmalloc mapping (or other non-linear mapping), then 477 * find the linear mapping of the page and also set its protections to 478 * match. 479 */ 480 static void set_aliased_prot(void *v, pgprot_t prot) 481 { 482 int level; 483 pte_t *ptep; 484 pte_t pte; 485 unsigned long pfn; 486 struct page *page; 487 unsigned char dummy; 488 489 ptep = lookup_address((unsigned long)v, &level); 490 BUG_ON(ptep == NULL); 491 492 pfn = pte_pfn(*ptep); 493 page = pfn_to_page(pfn); 494 495 pte = pfn_pte(pfn, prot); 496 497 /* 498 * Careful: update_va_mapping() will fail if the virtual address 499 * we're poking isn't populated in the page tables. We don't 500 * need to worry about the direct map (that's always in the page 501 * tables), but we need to be careful about vmap space. In 502 * particular, the top level page table can lazily propagate 503 * entries between processes, so if we've switched mms since we 504 * vmapped the target in the first place, we might not have the 505 * top-level page table entry populated. 506 * 507 * We disable preemption because we want the same mm active when 508 * we probe the target and when we issue the hypercall. We'll 509 * have the same nominal mm, but if we're a kernel thread, lazy 510 * mm dropping could change our pgd. 511 * 512 * Out of an abundance of caution, this uses __get_user() to fault 513 * in the target address just in case there's some obscure case 514 * in which the target address isn't readable. 515 */ 516 517 preempt_disable(); 518 519 pagefault_disable(); /* Avoid warnings due to being atomic. */ 520 __get_user(dummy, (unsigned char __user __force *)v); 521 pagefault_enable(); 522 523 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 524 BUG(); 525 526 if (!PageHighMem(page)) { 527 void *av = __va(PFN_PHYS(pfn)); 528 529 if (av != v) 530 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 531 BUG(); 532 } else 533 kmap_flush_unused(); 534 535 preempt_enable(); 536 } 537 538 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 539 { 540 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 541 int i; 542 543 /* 544 * We need to mark the all aliases of the LDT pages RO. We 545 * don't need to call vm_flush_aliases(), though, since that's 546 * only responsible for flushing aliases out the TLBs, not the 547 * page tables, and Xen will flush the TLB for us if needed. 548 * 549 * To avoid confusing future readers: none of this is necessary 550 * to load the LDT. The hypervisor only checks this when the 551 * LDT is faulted in due to subsequent descriptor access. 552 */ 553 554 for(i = 0; i < entries; i += entries_per_page) 555 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 556 } 557 558 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 559 { 560 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 561 int i; 562 563 for(i = 0; i < entries; i += entries_per_page) 564 set_aliased_prot(ldt + i, PAGE_KERNEL); 565 } 566 567 static void xen_set_ldt(const void *addr, unsigned entries) 568 { 569 struct mmuext_op *op; 570 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 571 572 trace_xen_cpu_set_ldt(addr, entries); 573 574 op = mcs.args; 575 op->cmd = MMUEXT_SET_LDT; 576 op->arg1.linear_addr = (unsigned long)addr; 577 op->arg2.nr_ents = entries; 578 579 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 580 581 xen_mc_issue(PARAVIRT_LAZY_CPU); 582 } 583 584 static void xen_load_gdt(const struct desc_ptr *dtr) 585 { 586 unsigned long va = dtr->address; 587 unsigned int size = dtr->size + 1; 588 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 589 unsigned long frames[pages]; 590 int f; 591 592 /* 593 * A GDT can be up to 64k in size, which corresponds to 8192 594 * 8-byte entries, or 16 4k pages.. 595 */ 596 597 BUG_ON(size > 65536); 598 BUG_ON(va & ~PAGE_MASK); 599 600 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 601 int level; 602 pte_t *ptep; 603 unsigned long pfn, mfn; 604 void *virt; 605 606 /* 607 * The GDT is per-cpu and is in the percpu data area. 608 * That can be virtually mapped, so we need to do a 609 * page-walk to get the underlying MFN for the 610 * hypercall. The page can also be in the kernel's 611 * linear range, so we need to RO that mapping too. 612 */ 613 ptep = lookup_address(va, &level); 614 BUG_ON(ptep == NULL); 615 616 pfn = pte_pfn(*ptep); 617 mfn = pfn_to_mfn(pfn); 618 virt = __va(PFN_PHYS(pfn)); 619 620 frames[f] = mfn; 621 622 make_lowmem_page_readonly((void *)va); 623 make_lowmem_page_readonly(virt); 624 } 625 626 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 627 BUG(); 628 } 629 630 /* 631 * load_gdt for early boot, when the gdt is only mapped once 632 */ 633 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 634 { 635 unsigned long va = dtr->address; 636 unsigned int size = dtr->size + 1; 637 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 638 unsigned long frames[pages]; 639 int f; 640 641 /* 642 * A GDT can be up to 64k in size, which corresponds to 8192 643 * 8-byte entries, or 16 4k pages.. 644 */ 645 646 BUG_ON(size > 65536); 647 BUG_ON(va & ~PAGE_MASK); 648 649 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 650 pte_t pte; 651 unsigned long pfn, mfn; 652 653 pfn = virt_to_pfn(va); 654 mfn = pfn_to_mfn(pfn); 655 656 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 657 658 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 659 BUG(); 660 661 frames[f] = mfn; 662 } 663 664 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 665 BUG(); 666 } 667 668 static inline bool desc_equal(const struct desc_struct *d1, 669 const struct desc_struct *d2) 670 { 671 return d1->a == d2->a && d1->b == d2->b; 672 } 673 674 static void load_TLS_descriptor(struct thread_struct *t, 675 unsigned int cpu, unsigned int i) 676 { 677 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 678 struct desc_struct *gdt; 679 xmaddr_t maddr; 680 struct multicall_space mc; 681 682 if (desc_equal(shadow, &t->tls_array[i])) 683 return; 684 685 *shadow = t->tls_array[i]; 686 687 gdt = get_cpu_gdt_table(cpu); 688 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 689 mc = __xen_mc_entry(0); 690 691 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 692 } 693 694 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 695 { 696 /* 697 * XXX sleazy hack: If we're being called in a lazy-cpu zone 698 * and lazy gs handling is enabled, it means we're in a 699 * context switch, and %gs has just been saved. This means we 700 * can zero it out to prevent faults on exit from the 701 * hypervisor if the next process has no %gs. Either way, it 702 * has been saved, and the new value will get loaded properly. 703 * This will go away as soon as Xen has been modified to not 704 * save/restore %gs for normal hypercalls. 705 * 706 * On x86_64, this hack is not used for %gs, because gs points 707 * to KERNEL_GS_BASE (and uses it for PDA references), so we 708 * must not zero %gs on x86_64 709 * 710 * For x86_64, we need to zero %fs, otherwise we may get an 711 * exception between the new %fs descriptor being loaded and 712 * %fs being effectively cleared at __switch_to(). 713 */ 714 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 715 #ifdef CONFIG_X86_32 716 lazy_load_gs(0); 717 #else 718 loadsegment(fs, 0); 719 #endif 720 } 721 722 xen_mc_batch(); 723 724 load_TLS_descriptor(t, cpu, 0); 725 load_TLS_descriptor(t, cpu, 1); 726 load_TLS_descriptor(t, cpu, 2); 727 728 xen_mc_issue(PARAVIRT_LAZY_CPU); 729 } 730 731 #ifdef CONFIG_X86_64 732 static void xen_load_gs_index(unsigned int idx) 733 { 734 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 735 BUG(); 736 } 737 #endif 738 739 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 740 const void *ptr) 741 { 742 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 743 u64 entry = *(u64 *)ptr; 744 745 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 746 747 preempt_disable(); 748 749 xen_mc_flush(); 750 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 751 BUG(); 752 753 preempt_enable(); 754 } 755 756 static int cvt_gate_to_trap(int vector, const gate_desc *val, 757 struct trap_info *info) 758 { 759 unsigned long addr; 760 761 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 762 return 0; 763 764 info->vector = vector; 765 766 addr = gate_offset(*val); 767 #ifdef CONFIG_X86_64 768 /* 769 * Look for known traps using IST, and substitute them 770 * appropriately. The debugger ones are the only ones we care 771 * about. Xen will handle faults like double_fault, 772 * so we should never see them. Warn if 773 * there's an unexpected IST-using fault handler. 774 */ 775 if (addr == (unsigned long)debug) 776 addr = (unsigned long)xen_debug; 777 else if (addr == (unsigned long)int3) 778 addr = (unsigned long)xen_int3; 779 else if (addr == (unsigned long)stack_segment) 780 addr = (unsigned long)xen_stack_segment; 781 else if (addr == (unsigned long)double_fault) { 782 /* Don't need to handle these */ 783 return 0; 784 #ifdef CONFIG_X86_MCE 785 } else if (addr == (unsigned long)machine_check) { 786 /* 787 * when xen hypervisor inject vMCE to guest, 788 * use native mce handler to handle it 789 */ 790 ; 791 #endif 792 } else if (addr == (unsigned long)nmi) 793 /* 794 * Use the native version as well. 795 */ 796 ; 797 else { 798 /* Some other trap using IST? */ 799 if (WARN_ON(val->ist != 0)) 800 return 0; 801 } 802 #endif /* CONFIG_X86_64 */ 803 info->address = addr; 804 805 info->cs = gate_segment(*val); 806 info->flags = val->dpl; 807 /* interrupt gates clear IF */ 808 if (val->type == GATE_INTERRUPT) 809 info->flags |= 1 << 2; 810 811 return 1; 812 } 813 814 /* Locations of each CPU's IDT */ 815 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 816 817 /* Set an IDT entry. If the entry is part of the current IDT, then 818 also update Xen. */ 819 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 820 { 821 unsigned long p = (unsigned long)&dt[entrynum]; 822 unsigned long start, end; 823 824 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 825 826 preempt_disable(); 827 828 start = __this_cpu_read(idt_desc.address); 829 end = start + __this_cpu_read(idt_desc.size) + 1; 830 831 xen_mc_flush(); 832 833 native_write_idt_entry(dt, entrynum, g); 834 835 if (p >= start && (p + 8) <= end) { 836 struct trap_info info[2]; 837 838 info[1].address = 0; 839 840 if (cvt_gate_to_trap(entrynum, g, &info[0])) 841 if (HYPERVISOR_set_trap_table(info)) 842 BUG(); 843 } 844 845 preempt_enable(); 846 } 847 848 static void xen_convert_trap_info(const struct desc_ptr *desc, 849 struct trap_info *traps) 850 { 851 unsigned in, out, count; 852 853 count = (desc->size+1) / sizeof(gate_desc); 854 BUG_ON(count > 256); 855 856 for (in = out = 0; in < count; in++) { 857 gate_desc *entry = (gate_desc*)(desc->address) + in; 858 859 if (cvt_gate_to_trap(in, entry, &traps[out])) 860 out++; 861 } 862 traps[out].address = 0; 863 } 864 865 void xen_copy_trap_info(struct trap_info *traps) 866 { 867 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc); 868 869 xen_convert_trap_info(desc, traps); 870 } 871 872 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 873 hold a spinlock to protect the static traps[] array (static because 874 it avoids allocation, and saves stack space). */ 875 static void xen_load_idt(const struct desc_ptr *desc) 876 { 877 static DEFINE_SPINLOCK(lock); 878 static struct trap_info traps[257]; 879 880 trace_xen_cpu_load_idt(desc); 881 882 spin_lock(&lock); 883 884 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); 885 886 xen_convert_trap_info(desc, traps); 887 888 xen_mc_flush(); 889 if (HYPERVISOR_set_trap_table(traps)) 890 BUG(); 891 892 spin_unlock(&lock); 893 } 894 895 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 896 they're handled differently. */ 897 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 898 const void *desc, int type) 899 { 900 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 901 902 preempt_disable(); 903 904 switch (type) { 905 case DESC_LDT: 906 case DESC_TSS: 907 /* ignore */ 908 break; 909 910 default: { 911 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 912 913 xen_mc_flush(); 914 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 915 BUG(); 916 } 917 918 } 919 920 preempt_enable(); 921 } 922 923 /* 924 * Version of write_gdt_entry for use at early boot-time needed to 925 * update an entry as simply as possible. 926 */ 927 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 928 const void *desc, int type) 929 { 930 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 931 932 switch (type) { 933 case DESC_LDT: 934 case DESC_TSS: 935 /* ignore */ 936 break; 937 938 default: { 939 xmaddr_t maddr = virt_to_machine(&dt[entry]); 940 941 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 942 dt[entry] = *(struct desc_struct *)desc; 943 } 944 945 } 946 } 947 948 static void xen_load_sp0(struct tss_struct *tss, 949 struct thread_struct *thread) 950 { 951 struct multicall_space mcs; 952 953 mcs = xen_mc_entry(0); 954 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 955 xen_mc_issue(PARAVIRT_LAZY_CPU); 956 tss->x86_tss.sp0 = thread->sp0; 957 } 958 959 static void xen_set_iopl_mask(unsigned mask) 960 { 961 struct physdev_set_iopl set_iopl; 962 963 /* Force the change at ring 0. */ 964 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 965 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 966 } 967 968 static void xen_io_delay(void) 969 { 970 } 971 972 static void xen_clts(void) 973 { 974 struct multicall_space mcs; 975 976 mcs = xen_mc_entry(0); 977 978 MULTI_fpu_taskswitch(mcs.mc, 0); 979 980 xen_mc_issue(PARAVIRT_LAZY_CPU); 981 } 982 983 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 984 985 static unsigned long xen_read_cr0(void) 986 { 987 unsigned long cr0 = this_cpu_read(xen_cr0_value); 988 989 if (unlikely(cr0 == 0)) { 990 cr0 = native_read_cr0(); 991 this_cpu_write(xen_cr0_value, cr0); 992 } 993 994 return cr0; 995 } 996 997 static void xen_write_cr0(unsigned long cr0) 998 { 999 struct multicall_space mcs; 1000 1001 this_cpu_write(xen_cr0_value, cr0); 1002 1003 /* Only pay attention to cr0.TS; everything else is 1004 ignored. */ 1005 mcs = xen_mc_entry(0); 1006 1007 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 1008 1009 xen_mc_issue(PARAVIRT_LAZY_CPU); 1010 } 1011 1012 static void xen_write_cr4(unsigned long cr4) 1013 { 1014 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE); 1015 1016 native_write_cr4(cr4); 1017 } 1018 #ifdef CONFIG_X86_64 1019 static inline unsigned long xen_read_cr8(void) 1020 { 1021 return 0; 1022 } 1023 static inline void xen_write_cr8(unsigned long val) 1024 { 1025 BUG_ON(val); 1026 } 1027 #endif 1028 1029 static u64 xen_read_msr_safe(unsigned int msr, int *err) 1030 { 1031 u64 val; 1032 1033 if (pmu_msr_read(msr, &val, err)) 1034 return val; 1035 1036 val = native_read_msr_safe(msr, err); 1037 switch (msr) { 1038 case MSR_IA32_APICBASE: 1039 #ifdef CONFIG_X86_X2APIC 1040 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31)))) 1041 #endif 1042 val &= ~X2APIC_ENABLE; 1043 break; 1044 } 1045 return val; 1046 } 1047 1048 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 1049 { 1050 int ret; 1051 1052 ret = 0; 1053 1054 switch (msr) { 1055 #ifdef CONFIG_X86_64 1056 unsigned which; 1057 u64 base; 1058 1059 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 1060 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 1061 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 1062 1063 set: 1064 base = ((u64)high << 32) | low; 1065 if (HYPERVISOR_set_segment_base(which, base) != 0) 1066 ret = -EIO; 1067 break; 1068 #endif 1069 1070 case MSR_STAR: 1071 case MSR_CSTAR: 1072 case MSR_LSTAR: 1073 case MSR_SYSCALL_MASK: 1074 case MSR_IA32_SYSENTER_CS: 1075 case MSR_IA32_SYSENTER_ESP: 1076 case MSR_IA32_SYSENTER_EIP: 1077 /* Fast syscall setup is all done in hypercalls, so 1078 these are all ignored. Stub them out here to stop 1079 Xen console noise. */ 1080 1081 default: 1082 if (!pmu_msr_write(msr, low, high, &ret)) 1083 ret = native_write_msr_safe(msr, low, high); 1084 } 1085 1086 return ret; 1087 } 1088 1089 void xen_setup_shared_info(void) 1090 { 1091 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1092 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1093 xen_start_info->shared_info); 1094 1095 HYPERVISOR_shared_info = 1096 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1097 } else 1098 HYPERVISOR_shared_info = 1099 (struct shared_info *)__va(xen_start_info->shared_info); 1100 1101 #ifndef CONFIG_SMP 1102 /* In UP this is as good a place as any to set up shared info */ 1103 xen_setup_vcpu_info_placement(); 1104 #endif 1105 1106 xen_setup_mfn_list_list(); 1107 } 1108 1109 /* This is called once we have the cpu_possible_mask */ 1110 void xen_setup_vcpu_info_placement(void) 1111 { 1112 int cpu; 1113 1114 for_each_possible_cpu(cpu) 1115 xen_vcpu_setup(cpu); 1116 1117 /* xen_vcpu_setup managed to place the vcpu_info within the 1118 * percpu area for all cpus, so make use of it. Note that for 1119 * PVH we want to use native IRQ mechanism. */ 1120 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1121 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1122 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1123 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1124 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1125 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1126 } 1127 } 1128 1129 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1130 unsigned long addr, unsigned len) 1131 { 1132 char *start, *end, *reloc; 1133 unsigned ret; 1134 1135 start = end = reloc = NULL; 1136 1137 #define SITE(op, x) \ 1138 case PARAVIRT_PATCH(op.x): \ 1139 if (have_vcpu_info_placement) { \ 1140 start = (char *)xen_##x##_direct; \ 1141 end = xen_##x##_direct_end; \ 1142 reloc = xen_##x##_direct_reloc; \ 1143 } \ 1144 goto patch_site 1145 1146 switch (type) { 1147 SITE(pv_irq_ops, irq_enable); 1148 SITE(pv_irq_ops, irq_disable); 1149 SITE(pv_irq_ops, save_fl); 1150 SITE(pv_irq_ops, restore_fl); 1151 #undef SITE 1152 1153 patch_site: 1154 if (start == NULL || (end-start) > len) 1155 goto default_patch; 1156 1157 ret = paravirt_patch_insns(insnbuf, len, start, end); 1158 1159 /* Note: because reloc is assigned from something that 1160 appears to be an array, gcc assumes it's non-null, 1161 but doesn't know its relationship with start and 1162 end. */ 1163 if (reloc > start && reloc < end) { 1164 int reloc_off = reloc - start; 1165 long *relocp = (long *)(insnbuf + reloc_off); 1166 long delta = start - (char *)addr; 1167 1168 *relocp += delta; 1169 } 1170 break; 1171 1172 default_patch: 1173 default: 1174 ret = paravirt_patch_default(type, clobbers, insnbuf, 1175 addr, len); 1176 break; 1177 } 1178 1179 return ret; 1180 } 1181 1182 static const struct pv_info xen_info __initconst = { 1183 .paravirt_enabled = 1, 1184 .shared_kernel_pmd = 0, 1185 1186 #ifdef CONFIG_X86_64 1187 .extra_user_64bit_cs = FLAT_USER_CS64, 1188 #endif 1189 1190 .name = "Xen", 1191 }; 1192 1193 static const struct pv_init_ops xen_init_ops __initconst = { 1194 .patch = xen_patch, 1195 }; 1196 1197 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1198 .cpuid = xen_cpuid, 1199 1200 .set_debugreg = xen_set_debugreg, 1201 .get_debugreg = xen_get_debugreg, 1202 1203 .clts = xen_clts, 1204 1205 .read_cr0 = xen_read_cr0, 1206 .write_cr0 = xen_write_cr0, 1207 1208 .read_cr4 = native_read_cr4, 1209 .read_cr4_safe = native_read_cr4_safe, 1210 .write_cr4 = xen_write_cr4, 1211 1212 #ifdef CONFIG_X86_64 1213 .read_cr8 = xen_read_cr8, 1214 .write_cr8 = xen_write_cr8, 1215 #endif 1216 1217 .wbinvd = native_wbinvd, 1218 1219 .read_msr = xen_read_msr_safe, 1220 .write_msr = xen_write_msr_safe, 1221 1222 .read_pmc = xen_read_pmc, 1223 1224 .iret = xen_iret, 1225 #ifdef CONFIG_X86_64 1226 .usergs_sysret32 = xen_sysret32, 1227 .usergs_sysret64 = xen_sysret64, 1228 #else 1229 .irq_enable_sysexit = xen_sysexit, 1230 #endif 1231 1232 .load_tr_desc = paravirt_nop, 1233 .set_ldt = xen_set_ldt, 1234 .load_gdt = xen_load_gdt, 1235 .load_idt = xen_load_idt, 1236 .load_tls = xen_load_tls, 1237 #ifdef CONFIG_X86_64 1238 .load_gs_index = xen_load_gs_index, 1239 #endif 1240 1241 .alloc_ldt = xen_alloc_ldt, 1242 .free_ldt = xen_free_ldt, 1243 1244 .store_idt = native_store_idt, 1245 .store_tr = xen_store_tr, 1246 1247 .write_ldt_entry = xen_write_ldt_entry, 1248 .write_gdt_entry = xen_write_gdt_entry, 1249 .write_idt_entry = xen_write_idt_entry, 1250 .load_sp0 = xen_load_sp0, 1251 1252 .set_iopl_mask = xen_set_iopl_mask, 1253 .io_delay = xen_io_delay, 1254 1255 /* Xen takes care of %gs when switching to usermode for us */ 1256 .swapgs = paravirt_nop, 1257 1258 .start_context_switch = paravirt_start_context_switch, 1259 .end_context_switch = xen_end_context_switch, 1260 }; 1261 1262 static const struct pv_apic_ops xen_apic_ops __initconst = { 1263 #ifdef CONFIG_X86_LOCAL_APIC 1264 .startup_ipi_hook = paravirt_nop, 1265 #endif 1266 }; 1267 1268 static void xen_reboot(int reason) 1269 { 1270 struct sched_shutdown r = { .reason = reason }; 1271 int cpu; 1272 1273 for_each_online_cpu(cpu) 1274 xen_pmu_finish(cpu); 1275 1276 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1277 BUG(); 1278 } 1279 1280 static void xen_restart(char *msg) 1281 { 1282 xen_reboot(SHUTDOWN_reboot); 1283 } 1284 1285 static void xen_emergency_restart(void) 1286 { 1287 xen_reboot(SHUTDOWN_reboot); 1288 } 1289 1290 static void xen_machine_halt(void) 1291 { 1292 xen_reboot(SHUTDOWN_poweroff); 1293 } 1294 1295 static void xen_machine_power_off(void) 1296 { 1297 if (pm_power_off) 1298 pm_power_off(); 1299 xen_reboot(SHUTDOWN_poweroff); 1300 } 1301 1302 static void xen_crash_shutdown(struct pt_regs *regs) 1303 { 1304 xen_reboot(SHUTDOWN_crash); 1305 } 1306 1307 static int 1308 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1309 { 1310 xen_reboot(SHUTDOWN_crash); 1311 return NOTIFY_DONE; 1312 } 1313 1314 static struct notifier_block xen_panic_block = { 1315 .notifier_call= xen_panic_event, 1316 .priority = INT_MIN 1317 }; 1318 1319 int xen_panic_handler_init(void) 1320 { 1321 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1322 return 0; 1323 } 1324 1325 static const struct machine_ops xen_machine_ops __initconst = { 1326 .restart = xen_restart, 1327 .halt = xen_machine_halt, 1328 .power_off = xen_machine_power_off, 1329 .shutdown = xen_machine_halt, 1330 .crash_shutdown = xen_crash_shutdown, 1331 .emergency_restart = xen_emergency_restart, 1332 }; 1333 1334 static unsigned char xen_get_nmi_reason(void) 1335 { 1336 unsigned char reason = 0; 1337 1338 /* Construct a value which looks like it came from port 0x61. */ 1339 if (test_bit(_XEN_NMIREASON_io_error, 1340 &HYPERVISOR_shared_info->arch.nmi_reason)) 1341 reason |= NMI_REASON_IOCHK; 1342 if (test_bit(_XEN_NMIREASON_pci_serr, 1343 &HYPERVISOR_shared_info->arch.nmi_reason)) 1344 reason |= NMI_REASON_SERR; 1345 1346 return reason; 1347 } 1348 1349 static void __init xen_boot_params_init_edd(void) 1350 { 1351 #if IS_ENABLED(CONFIG_EDD) 1352 struct xen_platform_op op; 1353 struct edd_info *edd_info; 1354 u32 *mbr_signature; 1355 unsigned nr; 1356 int ret; 1357 1358 edd_info = boot_params.eddbuf; 1359 mbr_signature = boot_params.edd_mbr_sig_buffer; 1360 1361 op.cmd = XENPF_firmware_info; 1362 1363 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1364 for (nr = 0; nr < EDDMAXNR; nr++) { 1365 struct edd_info *info = edd_info + nr; 1366 1367 op.u.firmware_info.index = nr; 1368 info->params.length = sizeof(info->params); 1369 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1370 &info->params); 1371 ret = HYPERVISOR_dom0_op(&op); 1372 if (ret) 1373 break; 1374 1375 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1376 C(device); 1377 C(version); 1378 C(interface_support); 1379 C(legacy_max_cylinder); 1380 C(legacy_max_head); 1381 C(legacy_sectors_per_track); 1382 #undef C 1383 } 1384 boot_params.eddbuf_entries = nr; 1385 1386 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1387 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1388 op.u.firmware_info.index = nr; 1389 ret = HYPERVISOR_dom0_op(&op); 1390 if (ret) 1391 break; 1392 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1393 } 1394 boot_params.edd_mbr_sig_buf_entries = nr; 1395 #endif 1396 } 1397 1398 /* 1399 * Set up the GDT and segment registers for -fstack-protector. Until 1400 * we do this, we have to be careful not to call any stack-protected 1401 * function, which is most of the kernel. 1402 * 1403 * Note, that it is __ref because the only caller of this after init 1404 * is PVH which is not going to use xen_load_gdt_boot or other 1405 * __init functions. 1406 */ 1407 static void __ref xen_setup_gdt(int cpu) 1408 { 1409 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1410 #ifdef CONFIG_X86_64 1411 unsigned long dummy; 1412 1413 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1414 switch_to_new_gdt(cpu); /* GDT and GS set */ 1415 1416 /* We are switching of the Xen provided GDT to our HVM mode 1417 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1418 * and we are jumping to reload it. 1419 */ 1420 asm volatile ("pushq %0\n" 1421 "leaq 1f(%%rip),%0\n" 1422 "pushq %0\n" 1423 "lretq\n" 1424 "1:\n" 1425 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1426 1427 /* 1428 * While not needed, we also set the %es, %ds, and %fs 1429 * to zero. We don't care about %ss as it is NULL. 1430 * Strictly speaking this is not needed as Xen zeros those 1431 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1432 * 1433 * Linux zeros them in cpu_init() and in secondary_startup_64 1434 * (for BSP). 1435 */ 1436 loadsegment(es, 0); 1437 loadsegment(ds, 0); 1438 loadsegment(fs, 0); 1439 #else 1440 /* PVH: TODO Implement. */ 1441 BUG(); 1442 #endif 1443 return; /* PVH does not need any PV GDT ops. */ 1444 } 1445 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1446 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1447 1448 setup_stack_canary_segment(0); 1449 switch_to_new_gdt(0); 1450 1451 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1452 pv_cpu_ops.load_gdt = xen_load_gdt; 1453 } 1454 1455 #ifdef CONFIG_XEN_PVH 1456 /* 1457 * A PV guest starts with default flags that are not set for PVH, set them 1458 * here asap. 1459 */ 1460 static void xen_pvh_set_cr_flags(int cpu) 1461 { 1462 1463 /* Some of these are setup in 'secondary_startup_64'. The others: 1464 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1465 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1466 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1467 1468 if (!cpu) 1469 return; 1470 /* 1471 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1472 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu(). 1473 */ 1474 if (cpu_has_pse) 1475 cr4_set_bits_and_update_boot(X86_CR4_PSE); 1476 1477 if (cpu_has_pge) 1478 cr4_set_bits_and_update_boot(X86_CR4_PGE); 1479 } 1480 1481 /* 1482 * Note, that it is ref - because the only caller of this after init 1483 * is PVH which is not going to use xen_load_gdt_boot or other 1484 * __init functions. 1485 */ 1486 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1487 { 1488 xen_setup_gdt(cpu); 1489 xen_pvh_set_cr_flags(cpu); 1490 } 1491 1492 static void __init xen_pvh_early_guest_init(void) 1493 { 1494 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1495 return; 1496 1497 if (!xen_feature(XENFEAT_hvm_callback_vector)) 1498 return; 1499 1500 xen_have_vector_callback = 1; 1501 1502 xen_pvh_early_cpu_init(0, false); 1503 xen_pvh_set_cr_flags(0); 1504 1505 #ifdef CONFIG_X86_32 1506 BUG(); /* PVH: Implement proper support. */ 1507 #endif 1508 } 1509 #endif /* CONFIG_XEN_PVH */ 1510 1511 /* First C function to be called on Xen boot */ 1512 asmlinkage __visible void __init xen_start_kernel(void) 1513 { 1514 struct physdev_set_iopl set_iopl; 1515 unsigned long initrd_start = 0; 1516 u64 pat; 1517 int rc; 1518 1519 if (!xen_start_info) 1520 return; 1521 1522 xen_domain_type = XEN_PV_DOMAIN; 1523 1524 xen_setup_features(); 1525 #ifdef CONFIG_XEN_PVH 1526 xen_pvh_early_guest_init(); 1527 #endif 1528 xen_setup_machphys_mapping(); 1529 1530 /* Install Xen paravirt ops */ 1531 pv_info = xen_info; 1532 pv_init_ops = xen_init_ops; 1533 pv_apic_ops = xen_apic_ops; 1534 if (!xen_pvh_domain()) { 1535 pv_cpu_ops = xen_cpu_ops; 1536 1537 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1538 } 1539 1540 if (xen_feature(XENFEAT_auto_translated_physmap)) 1541 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup; 1542 else 1543 x86_init.resources.memory_setup = xen_memory_setup; 1544 x86_init.oem.arch_setup = xen_arch_setup; 1545 x86_init.oem.banner = xen_banner; 1546 1547 xen_init_time_ops(); 1548 1549 /* 1550 * Set up some pagetable state before starting to set any ptes. 1551 */ 1552 1553 xen_init_mmu_ops(); 1554 1555 /* Prevent unwanted bits from being set in PTEs. */ 1556 __supported_pte_mask &= ~_PAGE_GLOBAL; 1557 1558 /* 1559 * Prevent page tables from being allocated in highmem, even 1560 * if CONFIG_HIGHPTE is enabled. 1561 */ 1562 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1563 1564 /* Work out if we support NX */ 1565 x86_configure_nx(); 1566 1567 /* Get mfn list */ 1568 xen_build_dynamic_phys_to_machine(); 1569 1570 /* 1571 * Set up kernel GDT and segment registers, mainly so that 1572 * -fstack-protector code can be executed. 1573 */ 1574 xen_setup_gdt(0); 1575 1576 xen_init_irq_ops(); 1577 xen_init_cpuid_mask(); 1578 1579 #ifdef CONFIG_X86_LOCAL_APIC 1580 /* 1581 * set up the basic apic ops. 1582 */ 1583 xen_init_apic(); 1584 #endif 1585 1586 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1587 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1588 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1589 } 1590 1591 machine_ops = xen_machine_ops; 1592 1593 /* 1594 * The only reliable way to retain the initial address of the 1595 * percpu gdt_page is to remember it here, so we can go and 1596 * mark it RW later, when the initial percpu area is freed. 1597 */ 1598 xen_initial_gdt = &per_cpu(gdt_page, 0); 1599 1600 xen_smp_init(); 1601 1602 #ifdef CONFIG_ACPI_NUMA 1603 /* 1604 * The pages we from Xen are not related to machine pages, so 1605 * any NUMA information the kernel tries to get from ACPI will 1606 * be meaningless. Prevent it from trying. 1607 */ 1608 acpi_numa = -1; 1609 #endif 1610 /* Don't do the full vcpu_info placement stuff until we have a 1611 possible map and a non-dummy shared_info. */ 1612 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1613 1614 local_irq_disable(); 1615 early_boot_irqs_disabled = true; 1616 1617 xen_raw_console_write("mapping kernel into physical memory\n"); 1618 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, 1619 xen_start_info->nr_pages); 1620 xen_reserve_special_pages(); 1621 1622 /* 1623 * Modify the cache mode translation tables to match Xen's PAT 1624 * configuration. 1625 */ 1626 rdmsrl(MSR_IA32_CR_PAT, pat); 1627 pat_init_cache_modes(pat); 1628 1629 /* keep using Xen gdt for now; no urgent need to change it */ 1630 1631 #ifdef CONFIG_X86_32 1632 pv_info.kernel_rpl = 1; 1633 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1634 pv_info.kernel_rpl = 0; 1635 #else 1636 pv_info.kernel_rpl = 0; 1637 #endif 1638 /* set the limit of our address space */ 1639 xen_reserve_top(); 1640 1641 /* PVH: runs at default kernel iopl of 0 */ 1642 if (!xen_pvh_domain()) { 1643 /* 1644 * We used to do this in xen_arch_setup, but that is too late 1645 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1646 * early_amd_init which pokes 0xcf8 port. 1647 */ 1648 set_iopl.iopl = 1; 1649 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1650 if (rc != 0) 1651 xen_raw_printk("physdev_op failed %d\n", rc); 1652 } 1653 1654 #ifdef CONFIG_X86_32 1655 /* set up basic CPUID stuff */ 1656 cpu_detect(&new_cpu_data); 1657 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); 1658 new_cpu_data.wp_works_ok = 1; 1659 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1660 #endif 1661 1662 if (xen_start_info->mod_start) { 1663 if (xen_start_info->flags & SIF_MOD_START_PFN) 1664 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1665 else 1666 initrd_start = __pa(xen_start_info->mod_start); 1667 } 1668 1669 /* Poke various useful things into boot_params */ 1670 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1671 boot_params.hdr.ramdisk_image = initrd_start; 1672 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1673 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1674 1675 if (!xen_initial_domain()) { 1676 add_preferred_console("xenboot", 0, NULL); 1677 add_preferred_console("tty", 0, NULL); 1678 add_preferred_console("hvc", 0, NULL); 1679 if (pci_xen) 1680 x86_init.pci.arch_init = pci_xen_init; 1681 } else { 1682 const struct dom0_vga_console_info *info = 1683 (void *)((char *)xen_start_info + 1684 xen_start_info->console.dom0.info_off); 1685 struct xen_platform_op op = { 1686 .cmd = XENPF_firmware_info, 1687 .interface_version = XENPF_INTERFACE_VERSION, 1688 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1689 }; 1690 1691 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1692 xen_start_info->console.domU.mfn = 0; 1693 xen_start_info->console.domU.evtchn = 0; 1694 1695 if (HYPERVISOR_dom0_op(&op) == 0) 1696 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1697 1698 /* Make sure ACS will be enabled */ 1699 pci_request_acs(); 1700 1701 xen_acpi_sleep_register(); 1702 1703 /* Avoid searching for BIOS MP tables */ 1704 x86_init.mpparse.find_smp_config = x86_init_noop; 1705 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1706 1707 xen_boot_params_init_edd(); 1708 } 1709 #ifdef CONFIG_PCI 1710 /* PCI BIOS service won't work from a PV guest. */ 1711 pci_probe &= ~PCI_PROBE_BIOS; 1712 #endif 1713 xen_raw_console_write("about to get started...\n"); 1714 1715 xen_setup_runstate_info(0); 1716 1717 xen_efi_init(); 1718 1719 /* Start the world */ 1720 #ifdef CONFIG_X86_32 1721 i386_start_kernel(); 1722 #else 1723 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1724 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1725 #endif 1726 } 1727 1728 void __ref xen_hvm_init_shared_info(void) 1729 { 1730 int cpu; 1731 struct xen_add_to_physmap xatp; 1732 static struct shared_info *shared_info_page = 0; 1733 1734 if (!shared_info_page) 1735 shared_info_page = (struct shared_info *) 1736 extend_brk(PAGE_SIZE, PAGE_SIZE); 1737 xatp.domid = DOMID_SELF; 1738 xatp.idx = 0; 1739 xatp.space = XENMAPSPACE_shared_info; 1740 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1741 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1742 BUG(); 1743 1744 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1745 1746 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1747 * page, we use it in the event channel upcall and in some pvclock 1748 * related functions. We don't need the vcpu_info placement 1749 * optimizations because we don't use any pv_mmu or pv_irq op on 1750 * HVM. 1751 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1752 * online but xen_hvm_init_shared_info is run at resume time too and 1753 * in that case multiple vcpus might be online. */ 1754 for_each_online_cpu(cpu) { 1755 /* Leave it to be NULL. */ 1756 if (cpu >= MAX_VIRT_CPUS) 1757 continue; 1758 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1759 } 1760 } 1761 1762 #ifdef CONFIG_XEN_PVHVM 1763 static void __init init_hvm_pv_info(void) 1764 { 1765 int major, minor; 1766 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1767 u64 pfn; 1768 1769 base = xen_cpuid_base(); 1770 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1771 1772 major = eax >> 16; 1773 minor = eax & 0xffff; 1774 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1775 1776 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1777 1778 pfn = __pa(hypercall_page); 1779 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1780 1781 xen_setup_features(); 1782 1783 pv_info.name = "Xen HVM"; 1784 1785 xen_domain_type = XEN_HVM_DOMAIN; 1786 } 1787 1788 static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, 1789 void *hcpu) 1790 { 1791 int cpu = (long)hcpu; 1792 switch (action) { 1793 case CPU_UP_PREPARE: 1794 xen_vcpu_setup(cpu); 1795 if (xen_have_vector_callback) { 1796 if (xen_feature(XENFEAT_hvm_safe_pvclock)) 1797 xen_setup_timer(cpu); 1798 } 1799 break; 1800 default: 1801 break; 1802 } 1803 return NOTIFY_OK; 1804 } 1805 1806 static struct notifier_block xen_hvm_cpu_notifier = { 1807 .notifier_call = xen_hvm_cpu_notify, 1808 }; 1809 1810 static void __init xen_hvm_guest_init(void) 1811 { 1812 if (xen_pv_domain()) 1813 return; 1814 1815 init_hvm_pv_info(); 1816 1817 xen_hvm_init_shared_info(); 1818 1819 xen_panic_handler_init(); 1820 1821 if (xen_feature(XENFEAT_hvm_callback_vector)) 1822 xen_have_vector_callback = 1; 1823 xen_hvm_smp_init(); 1824 register_cpu_notifier(&xen_hvm_cpu_notifier); 1825 xen_unplug_emulated_devices(); 1826 x86_init.irqs.intr_init = xen_init_IRQ; 1827 xen_hvm_init_time_ops(); 1828 xen_hvm_init_mmu_ops(); 1829 } 1830 #endif 1831 1832 static bool xen_nopv = false; 1833 static __init int xen_parse_nopv(char *arg) 1834 { 1835 xen_nopv = true; 1836 return 0; 1837 } 1838 early_param("xen_nopv", xen_parse_nopv); 1839 1840 static uint32_t __init xen_platform(void) 1841 { 1842 if (xen_nopv) 1843 return 0; 1844 1845 return xen_cpuid_base(); 1846 } 1847 1848 bool xen_hvm_need_lapic(void) 1849 { 1850 if (xen_nopv) 1851 return false; 1852 if (xen_pv_domain()) 1853 return false; 1854 if (!xen_hvm_domain()) 1855 return false; 1856 if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) 1857 return false; 1858 return true; 1859 } 1860 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1861 1862 static void xen_set_cpu_features(struct cpuinfo_x86 *c) 1863 { 1864 if (xen_pv_domain()) 1865 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); 1866 } 1867 1868 const struct hypervisor_x86 x86_hyper_xen = { 1869 .name = "Xen", 1870 .detect = xen_platform, 1871 #ifdef CONFIG_XEN_PVHVM 1872 .init_platform = xen_hvm_guest_init, 1873 #endif 1874 .x2apic_available = xen_x2apic_para_available, 1875 .set_cpu_features = xen_set_cpu_features, 1876 }; 1877 EXPORT_SYMBOL(x86_hyper_xen); 1878