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/export.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 #include <linux/frame.h> 36 37 #include <linux/kexec.h> 38 39 #include <xen/xen.h> 40 #include <xen/events.h> 41 #include <xen/interface/xen.h> 42 #include <xen/interface/version.h> 43 #include <xen/interface/physdev.h> 44 #include <xen/interface/vcpu.h> 45 #include <xen/interface/memory.h> 46 #include <xen/interface/nmi.h> 47 #include <xen/interface/xen-mca.h> 48 #include <xen/features.h> 49 #include <xen/page.h> 50 #include <xen/hvm.h> 51 #include <xen/hvc-console.h> 52 #include <xen/acpi.h> 53 54 #include <asm/paravirt.h> 55 #include <asm/apic.h> 56 #include <asm/page.h> 57 #include <asm/xen/pci.h> 58 #include <asm/xen/hypercall.h> 59 #include <asm/xen/hypervisor.h> 60 #include <asm/xen/cpuid.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/cpu.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 /* Linux <-> Xen vCPU id mapping */ 121 DEFINE_PER_CPU(uint32_t, xen_vcpu_id); 122 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); 123 124 enum xen_domain_type xen_domain_type = XEN_NATIVE; 125 EXPORT_SYMBOL_GPL(xen_domain_type); 126 127 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 128 EXPORT_SYMBOL(machine_to_phys_mapping); 129 unsigned long machine_to_phys_nr; 130 EXPORT_SYMBOL(machine_to_phys_nr); 131 132 struct start_info *xen_start_info; 133 EXPORT_SYMBOL_GPL(xen_start_info); 134 135 struct shared_info xen_dummy_shared_info; 136 137 void *xen_initial_gdt; 138 139 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 140 141 static int xen_cpu_up_prepare(unsigned int cpu); 142 static int xen_cpu_up_online(unsigned int cpu); 143 static int xen_cpu_dead(unsigned int cpu); 144 145 /* 146 * Point at some empty memory to start with. We map the real shared_info 147 * page as soon as fixmap is up and running. 148 */ 149 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 150 151 /* 152 * Flag to determine whether vcpu info placement is available on all 153 * VCPUs. We assume it is to start with, and then set it to zero on 154 * the first failure. This is because it can succeed on some VCPUs 155 * and not others, since it can involve hypervisor memory allocation, 156 * or because the guest failed to guarantee all the appropriate 157 * constraints on all VCPUs (ie buffer can't cross a page boundary). 158 * 159 * Note that any particular CPU may be using a placed vcpu structure, 160 * but we can only optimise if the all are. 161 * 162 * 0: not available, 1: available 163 */ 164 static int have_vcpu_info_placement = 1; 165 166 struct tls_descs { 167 struct desc_struct desc[3]; 168 }; 169 170 /* 171 * Updating the 3 TLS descriptors in the GDT on every task switch is 172 * surprisingly expensive so we avoid updating them if they haven't 173 * changed. Since Xen writes different descriptors than the one 174 * passed in the update_descriptor hypercall we keep shadow copies to 175 * compare against. 176 */ 177 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 178 179 static void clamp_max_cpus(void) 180 { 181 #ifdef CONFIG_SMP 182 if (setup_max_cpus > MAX_VIRT_CPUS) 183 setup_max_cpus = MAX_VIRT_CPUS; 184 #endif 185 } 186 187 void xen_vcpu_setup(int cpu) 188 { 189 struct vcpu_register_vcpu_info info; 190 int err; 191 struct vcpu_info *vcpup; 192 193 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 194 195 /* 196 * This path is called twice on PVHVM - first during bootup via 197 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 198 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 199 * As we can only do the VCPUOP_register_vcpu_info once lets 200 * not over-write its result. 201 * 202 * For PV it is called during restore (xen_vcpu_restore) and bootup 203 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 204 * use this function. 205 */ 206 if (xen_hvm_domain()) { 207 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 208 return; 209 } 210 if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) 211 per_cpu(xen_vcpu, cpu) = 212 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 213 214 if (!have_vcpu_info_placement) { 215 if (cpu >= MAX_VIRT_CPUS) 216 clamp_max_cpus(); 217 return; 218 } 219 220 vcpup = &per_cpu(xen_vcpu_info, cpu); 221 info.mfn = arbitrary_virt_to_mfn(vcpup); 222 info.offset = offset_in_page(vcpup); 223 224 /* Check to see if the hypervisor will put the vcpu_info 225 structure where we want it, which allows direct access via 226 a percpu-variable. 227 N.B. This hypercall can _only_ be called once per CPU. Subsequent 228 calls will error out with -EINVAL. This is due to the fact that 229 hypervisor has no unregister variant and this hypercall does not 230 allow to over-write info.mfn and info.offset. 231 */ 232 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu), 233 &info); 234 235 if (err) { 236 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 237 have_vcpu_info_placement = 0; 238 clamp_max_cpus(); 239 } else { 240 /* This cpu is using the registered vcpu info, even if 241 later ones fail to. */ 242 per_cpu(xen_vcpu, cpu) = vcpup; 243 } 244 } 245 246 /* 247 * On restore, set the vcpu placement up again. 248 * If it fails, then we're in a bad state, since 249 * we can't back out from using it... 250 */ 251 void xen_vcpu_restore(void) 252 { 253 int cpu; 254 255 for_each_possible_cpu(cpu) { 256 bool other_cpu = (cpu != smp_processor_id()); 257 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu), 258 NULL); 259 260 if (other_cpu && is_up && 261 HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL)) 262 BUG(); 263 264 xen_setup_runstate_info(cpu); 265 266 if (have_vcpu_info_placement) 267 xen_vcpu_setup(cpu); 268 269 if (other_cpu && is_up && 270 HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) 271 BUG(); 272 } 273 } 274 275 static void __init xen_banner(void) 276 { 277 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 278 struct xen_extraversion extra; 279 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 280 281 pr_info("Booting paravirtualized kernel %son %s\n", 282 xen_feature(XENFEAT_auto_translated_physmap) ? 283 "with PVH extensions " : "", pv_info.name); 284 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 285 version >> 16, version & 0xffff, extra.extraversion, 286 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 287 } 288 /* Check if running on Xen version (major, minor) or later */ 289 bool 290 xen_running_on_version_or_later(unsigned int major, unsigned int minor) 291 { 292 unsigned int version; 293 294 if (!xen_domain()) 295 return false; 296 297 version = HYPERVISOR_xen_version(XENVER_version, NULL); 298 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 299 ((version >> 16) > major)) 300 return true; 301 return false; 302 } 303 304 #define CPUID_THERM_POWER_LEAF 6 305 #define APERFMPERF_PRESENT 0 306 307 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 308 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 309 310 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask; 311 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 312 static __read_mostly unsigned int cpuid_leaf5_edx_val; 313 314 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 315 unsigned int *cx, unsigned int *dx) 316 { 317 unsigned maskebx = ~0; 318 unsigned maskecx = ~0; 319 unsigned maskedx = ~0; 320 unsigned setecx = 0; 321 /* 322 * Mask out inconvenient features, to try and disable as many 323 * unsupported kernel subsystems as possible. 324 */ 325 switch (*ax) { 326 case 1: 327 maskecx = cpuid_leaf1_ecx_mask; 328 setecx = cpuid_leaf1_ecx_set_mask; 329 maskedx = cpuid_leaf1_edx_mask; 330 break; 331 332 case CPUID_MWAIT_LEAF: 333 /* Synthesize the values.. */ 334 *ax = 0; 335 *bx = 0; 336 *cx = cpuid_leaf5_ecx_val; 337 *dx = cpuid_leaf5_edx_val; 338 return; 339 340 case CPUID_THERM_POWER_LEAF: 341 /* Disabling APERFMPERF for kernel usage */ 342 maskecx = ~(1 << APERFMPERF_PRESENT); 343 break; 344 345 case 0xb: 346 /* Suppress extended topology stuff */ 347 maskebx = 0; 348 break; 349 } 350 351 asm(XEN_EMULATE_PREFIX "cpuid" 352 : "=a" (*ax), 353 "=b" (*bx), 354 "=c" (*cx), 355 "=d" (*dx) 356 : "0" (*ax), "2" (*cx)); 357 358 *bx &= maskebx; 359 *cx &= maskecx; 360 *cx |= setecx; 361 *dx &= maskedx; 362 } 363 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */ 364 365 static bool __init xen_check_mwait(void) 366 { 367 #ifdef CONFIG_ACPI 368 struct xen_platform_op op = { 369 .cmd = XENPF_set_processor_pminfo, 370 .u.set_pminfo.id = -1, 371 .u.set_pminfo.type = XEN_PM_PDC, 372 }; 373 uint32_t buf[3]; 374 unsigned int ax, bx, cx, dx; 375 unsigned int mwait_mask; 376 377 /* We need to determine whether it is OK to expose the MWAIT 378 * capability to the kernel to harvest deeper than C3 states from ACPI 379 * _CST using the processor_harvest_xen.c module. For this to work, we 380 * need to gather the MWAIT_LEAF values (which the cstate.c code 381 * checks against). The hypervisor won't expose the MWAIT flag because 382 * it would break backwards compatibility; so we will find out directly 383 * from the hardware and hypercall. 384 */ 385 if (!xen_initial_domain()) 386 return false; 387 388 /* 389 * When running under platform earlier than Xen4.2, do not expose 390 * mwait, to avoid the risk of loading native acpi pad driver 391 */ 392 if (!xen_running_on_version_or_later(4, 2)) 393 return false; 394 395 ax = 1; 396 cx = 0; 397 398 native_cpuid(&ax, &bx, &cx, &dx); 399 400 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 401 (1 << (X86_FEATURE_MWAIT % 32)); 402 403 if ((cx & mwait_mask) != mwait_mask) 404 return false; 405 406 /* We need to emulate the MWAIT_LEAF and for that we need both 407 * ecx and edx. The hypercall provides only partial information. 408 */ 409 410 ax = CPUID_MWAIT_LEAF; 411 bx = 0; 412 cx = 0; 413 dx = 0; 414 415 native_cpuid(&ax, &bx, &cx, &dx); 416 417 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so, 418 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 419 */ 420 buf[0] = ACPI_PDC_REVISION_ID; 421 buf[1] = 1; 422 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP); 423 424 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 425 426 if ((HYPERVISOR_platform_op(&op) == 0) && 427 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) { 428 cpuid_leaf5_ecx_val = cx; 429 cpuid_leaf5_edx_val = dx; 430 } 431 return true; 432 #else 433 return false; 434 #endif 435 } 436 static void __init xen_init_cpuid_mask(void) 437 { 438 unsigned int ax, bx, cx, dx; 439 unsigned int xsave_mask; 440 441 cpuid_leaf1_edx_mask = 442 ~((1 << X86_FEATURE_MTRR) | /* disable MTRR */ 443 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 444 445 if (!xen_initial_domain()) 446 cpuid_leaf1_edx_mask &= 447 ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ 448 449 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); 450 451 ax = 1; 452 cx = 0; 453 cpuid(1, &ax, &bx, &cx, &dx); 454 455 xsave_mask = 456 (1 << (X86_FEATURE_XSAVE % 32)) | 457 (1 << (X86_FEATURE_OSXSAVE % 32)); 458 459 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 460 if ((cx & xsave_mask) != xsave_mask) 461 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 462 if (xen_check_mwait()) 463 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); 464 } 465 466 static void xen_set_debugreg(int reg, unsigned long val) 467 { 468 HYPERVISOR_set_debugreg(reg, val); 469 } 470 471 static unsigned long xen_get_debugreg(int reg) 472 { 473 return HYPERVISOR_get_debugreg(reg); 474 } 475 476 static void xen_end_context_switch(struct task_struct *next) 477 { 478 xen_mc_flush(); 479 paravirt_end_context_switch(next); 480 } 481 482 static unsigned long xen_store_tr(void) 483 { 484 return 0; 485 } 486 487 /* 488 * Set the page permissions for a particular virtual address. If the 489 * address is a vmalloc mapping (or other non-linear mapping), then 490 * find the linear mapping of the page and also set its protections to 491 * match. 492 */ 493 static void set_aliased_prot(void *v, pgprot_t prot) 494 { 495 int level; 496 pte_t *ptep; 497 pte_t pte; 498 unsigned long pfn; 499 struct page *page; 500 unsigned char dummy; 501 502 ptep = lookup_address((unsigned long)v, &level); 503 BUG_ON(ptep == NULL); 504 505 pfn = pte_pfn(*ptep); 506 page = pfn_to_page(pfn); 507 508 pte = pfn_pte(pfn, prot); 509 510 /* 511 * Careful: update_va_mapping() will fail if the virtual address 512 * we're poking isn't populated in the page tables. We don't 513 * need to worry about the direct map (that's always in the page 514 * tables), but we need to be careful about vmap space. In 515 * particular, the top level page table can lazily propagate 516 * entries between processes, so if we've switched mms since we 517 * vmapped the target in the first place, we might not have the 518 * top-level page table entry populated. 519 * 520 * We disable preemption because we want the same mm active when 521 * we probe the target and when we issue the hypercall. We'll 522 * have the same nominal mm, but if we're a kernel thread, lazy 523 * mm dropping could change our pgd. 524 * 525 * Out of an abundance of caution, this uses __get_user() to fault 526 * in the target address just in case there's some obscure case 527 * in which the target address isn't readable. 528 */ 529 530 preempt_disable(); 531 532 probe_kernel_read(&dummy, v, 1); 533 534 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 535 BUG(); 536 537 if (!PageHighMem(page)) { 538 void *av = __va(PFN_PHYS(pfn)); 539 540 if (av != v) 541 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 542 BUG(); 543 } else 544 kmap_flush_unused(); 545 546 preempt_enable(); 547 } 548 549 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 550 { 551 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 552 int i; 553 554 /* 555 * We need to mark the all aliases of the LDT pages RO. We 556 * don't need to call vm_flush_aliases(), though, since that's 557 * only responsible for flushing aliases out the TLBs, not the 558 * page tables, and Xen will flush the TLB for us if needed. 559 * 560 * To avoid confusing future readers: none of this is necessary 561 * to load the LDT. The hypervisor only checks this when the 562 * LDT is faulted in due to subsequent descriptor access. 563 */ 564 565 for(i = 0; i < entries; i += entries_per_page) 566 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 567 } 568 569 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 570 { 571 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 572 int i; 573 574 for(i = 0; i < entries; i += entries_per_page) 575 set_aliased_prot(ldt + i, PAGE_KERNEL); 576 } 577 578 static void xen_set_ldt(const void *addr, unsigned entries) 579 { 580 struct mmuext_op *op; 581 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 582 583 trace_xen_cpu_set_ldt(addr, entries); 584 585 op = mcs.args; 586 op->cmd = MMUEXT_SET_LDT; 587 op->arg1.linear_addr = (unsigned long)addr; 588 op->arg2.nr_ents = entries; 589 590 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 591 592 xen_mc_issue(PARAVIRT_LAZY_CPU); 593 } 594 595 static void xen_load_gdt(const struct desc_ptr *dtr) 596 { 597 unsigned long va = dtr->address; 598 unsigned int size = dtr->size + 1; 599 unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); 600 unsigned long frames[pages]; 601 int f; 602 603 /* 604 * A GDT can be up to 64k in size, which corresponds to 8192 605 * 8-byte entries, or 16 4k pages.. 606 */ 607 608 BUG_ON(size > 65536); 609 BUG_ON(va & ~PAGE_MASK); 610 611 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 612 int level; 613 pte_t *ptep; 614 unsigned long pfn, mfn; 615 void *virt; 616 617 /* 618 * The GDT is per-cpu and is in the percpu data area. 619 * That can be virtually mapped, so we need to do a 620 * page-walk to get the underlying MFN for the 621 * hypercall. The page can also be in the kernel's 622 * linear range, so we need to RO that mapping too. 623 */ 624 ptep = lookup_address(va, &level); 625 BUG_ON(ptep == NULL); 626 627 pfn = pte_pfn(*ptep); 628 mfn = pfn_to_mfn(pfn); 629 virt = __va(PFN_PHYS(pfn)); 630 631 frames[f] = mfn; 632 633 make_lowmem_page_readonly((void *)va); 634 make_lowmem_page_readonly(virt); 635 } 636 637 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 638 BUG(); 639 } 640 641 /* 642 * load_gdt for early boot, when the gdt is only mapped once 643 */ 644 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 645 { 646 unsigned long va = dtr->address; 647 unsigned int size = dtr->size + 1; 648 unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); 649 unsigned long frames[pages]; 650 int f; 651 652 /* 653 * A GDT can be up to 64k in size, which corresponds to 8192 654 * 8-byte entries, or 16 4k pages.. 655 */ 656 657 BUG_ON(size > 65536); 658 BUG_ON(va & ~PAGE_MASK); 659 660 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 661 pte_t pte; 662 unsigned long pfn, mfn; 663 664 pfn = virt_to_pfn(va); 665 mfn = pfn_to_mfn(pfn); 666 667 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 668 669 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 670 BUG(); 671 672 frames[f] = mfn; 673 } 674 675 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 676 BUG(); 677 } 678 679 static inline bool desc_equal(const struct desc_struct *d1, 680 const struct desc_struct *d2) 681 { 682 return d1->a == d2->a && d1->b == d2->b; 683 } 684 685 static void load_TLS_descriptor(struct thread_struct *t, 686 unsigned int cpu, unsigned int i) 687 { 688 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 689 struct desc_struct *gdt; 690 xmaddr_t maddr; 691 struct multicall_space mc; 692 693 if (desc_equal(shadow, &t->tls_array[i])) 694 return; 695 696 *shadow = t->tls_array[i]; 697 698 gdt = get_cpu_gdt_table(cpu); 699 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 700 mc = __xen_mc_entry(0); 701 702 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 703 } 704 705 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 706 { 707 /* 708 * XXX sleazy hack: If we're being called in a lazy-cpu zone 709 * and lazy gs handling is enabled, it means we're in a 710 * context switch, and %gs has just been saved. This means we 711 * can zero it out to prevent faults on exit from the 712 * hypervisor if the next process has no %gs. Either way, it 713 * has been saved, and the new value will get loaded properly. 714 * This will go away as soon as Xen has been modified to not 715 * save/restore %gs for normal hypercalls. 716 * 717 * On x86_64, this hack is not used for %gs, because gs points 718 * to KERNEL_GS_BASE (and uses it for PDA references), so we 719 * must not zero %gs on x86_64 720 * 721 * For x86_64, we need to zero %fs, otherwise we may get an 722 * exception between the new %fs descriptor being loaded and 723 * %fs being effectively cleared at __switch_to(). 724 */ 725 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 726 #ifdef CONFIG_X86_32 727 lazy_load_gs(0); 728 #else 729 loadsegment(fs, 0); 730 #endif 731 } 732 733 xen_mc_batch(); 734 735 load_TLS_descriptor(t, cpu, 0); 736 load_TLS_descriptor(t, cpu, 1); 737 load_TLS_descriptor(t, cpu, 2); 738 739 xen_mc_issue(PARAVIRT_LAZY_CPU); 740 } 741 742 #ifdef CONFIG_X86_64 743 static void xen_load_gs_index(unsigned int idx) 744 { 745 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 746 BUG(); 747 } 748 #endif 749 750 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 751 const void *ptr) 752 { 753 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 754 u64 entry = *(u64 *)ptr; 755 756 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 757 758 preempt_disable(); 759 760 xen_mc_flush(); 761 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 762 BUG(); 763 764 preempt_enable(); 765 } 766 767 static int cvt_gate_to_trap(int vector, const gate_desc *val, 768 struct trap_info *info) 769 { 770 unsigned long addr; 771 772 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 773 return 0; 774 775 info->vector = vector; 776 777 addr = gate_offset(*val); 778 #ifdef CONFIG_X86_64 779 /* 780 * Look for known traps using IST, and substitute them 781 * appropriately. The debugger ones are the only ones we care 782 * about. Xen will handle faults like double_fault, 783 * so we should never see them. Warn if 784 * there's an unexpected IST-using fault handler. 785 */ 786 if (addr == (unsigned long)debug) 787 addr = (unsigned long)xen_debug; 788 else if (addr == (unsigned long)int3) 789 addr = (unsigned long)xen_int3; 790 else if (addr == (unsigned long)stack_segment) 791 addr = (unsigned long)xen_stack_segment; 792 else if (addr == (unsigned long)double_fault) { 793 /* Don't need to handle these */ 794 return 0; 795 #ifdef CONFIG_X86_MCE 796 } else if (addr == (unsigned long)machine_check) { 797 /* 798 * when xen hypervisor inject vMCE to guest, 799 * use native mce handler to handle it 800 */ 801 ; 802 #endif 803 } else if (addr == (unsigned long)nmi) 804 /* 805 * Use the native version as well. 806 */ 807 ; 808 else { 809 /* Some other trap using IST? */ 810 if (WARN_ON(val->ist != 0)) 811 return 0; 812 } 813 #endif /* CONFIG_X86_64 */ 814 info->address = addr; 815 816 info->cs = gate_segment(*val); 817 info->flags = val->dpl; 818 /* interrupt gates clear IF */ 819 if (val->type == GATE_INTERRUPT) 820 info->flags |= 1 << 2; 821 822 return 1; 823 } 824 825 /* Locations of each CPU's IDT */ 826 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 827 828 /* Set an IDT entry. If the entry is part of the current IDT, then 829 also update Xen. */ 830 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 831 { 832 unsigned long p = (unsigned long)&dt[entrynum]; 833 unsigned long start, end; 834 835 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 836 837 preempt_disable(); 838 839 start = __this_cpu_read(idt_desc.address); 840 end = start + __this_cpu_read(idt_desc.size) + 1; 841 842 xen_mc_flush(); 843 844 native_write_idt_entry(dt, entrynum, g); 845 846 if (p >= start && (p + 8) <= end) { 847 struct trap_info info[2]; 848 849 info[1].address = 0; 850 851 if (cvt_gate_to_trap(entrynum, g, &info[0])) 852 if (HYPERVISOR_set_trap_table(info)) 853 BUG(); 854 } 855 856 preempt_enable(); 857 } 858 859 static void xen_convert_trap_info(const struct desc_ptr *desc, 860 struct trap_info *traps) 861 { 862 unsigned in, out, count; 863 864 count = (desc->size+1) / sizeof(gate_desc); 865 BUG_ON(count > 256); 866 867 for (in = out = 0; in < count; in++) { 868 gate_desc *entry = (gate_desc*)(desc->address) + in; 869 870 if (cvt_gate_to_trap(in, entry, &traps[out])) 871 out++; 872 } 873 traps[out].address = 0; 874 } 875 876 void xen_copy_trap_info(struct trap_info *traps) 877 { 878 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc); 879 880 xen_convert_trap_info(desc, traps); 881 } 882 883 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 884 hold a spinlock to protect the static traps[] array (static because 885 it avoids allocation, and saves stack space). */ 886 static void xen_load_idt(const struct desc_ptr *desc) 887 { 888 static DEFINE_SPINLOCK(lock); 889 static struct trap_info traps[257]; 890 891 trace_xen_cpu_load_idt(desc); 892 893 spin_lock(&lock); 894 895 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); 896 897 xen_convert_trap_info(desc, traps); 898 899 xen_mc_flush(); 900 if (HYPERVISOR_set_trap_table(traps)) 901 BUG(); 902 903 spin_unlock(&lock); 904 } 905 906 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 907 they're handled differently. */ 908 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 909 const void *desc, int type) 910 { 911 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 912 913 preempt_disable(); 914 915 switch (type) { 916 case DESC_LDT: 917 case DESC_TSS: 918 /* ignore */ 919 break; 920 921 default: { 922 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 923 924 xen_mc_flush(); 925 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 926 BUG(); 927 } 928 929 } 930 931 preempt_enable(); 932 } 933 934 /* 935 * Version of write_gdt_entry for use at early boot-time needed to 936 * update an entry as simply as possible. 937 */ 938 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 939 const void *desc, int type) 940 { 941 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 942 943 switch (type) { 944 case DESC_LDT: 945 case DESC_TSS: 946 /* ignore */ 947 break; 948 949 default: { 950 xmaddr_t maddr = virt_to_machine(&dt[entry]); 951 952 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 953 dt[entry] = *(struct desc_struct *)desc; 954 } 955 956 } 957 } 958 959 static void xen_load_sp0(struct tss_struct *tss, 960 struct thread_struct *thread) 961 { 962 struct multicall_space mcs; 963 964 mcs = xen_mc_entry(0); 965 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 966 xen_mc_issue(PARAVIRT_LAZY_CPU); 967 tss->x86_tss.sp0 = thread->sp0; 968 } 969 970 void xen_set_iopl_mask(unsigned mask) 971 { 972 struct physdev_set_iopl set_iopl; 973 974 /* Force the change at ring 0. */ 975 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 976 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 977 } 978 979 static void xen_io_delay(void) 980 { 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 break; 1081 1082 default: 1083 if (!pmu_msr_write(msr, low, high, &ret)) 1084 ret = native_write_msr_safe(msr, low, high); 1085 } 1086 1087 return ret; 1088 } 1089 1090 static u64 xen_read_msr(unsigned int msr) 1091 { 1092 /* 1093 * This will silently swallow a #GP from RDMSR. It may be worth 1094 * changing that. 1095 */ 1096 int err; 1097 1098 return xen_read_msr_safe(msr, &err); 1099 } 1100 1101 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high) 1102 { 1103 /* 1104 * This will silently swallow a #GP from WRMSR. It may be worth 1105 * changing that. 1106 */ 1107 xen_write_msr_safe(msr, low, high); 1108 } 1109 1110 void xen_setup_shared_info(void) 1111 { 1112 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1113 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1114 xen_start_info->shared_info); 1115 1116 HYPERVISOR_shared_info = 1117 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1118 } else 1119 HYPERVISOR_shared_info = 1120 (struct shared_info *)__va(xen_start_info->shared_info); 1121 1122 #ifndef CONFIG_SMP 1123 /* In UP this is as good a place as any to set up shared info */ 1124 xen_setup_vcpu_info_placement(); 1125 #endif 1126 1127 xen_setup_mfn_list_list(); 1128 } 1129 1130 /* This is called once we have the cpu_possible_mask */ 1131 void xen_setup_vcpu_info_placement(void) 1132 { 1133 int cpu; 1134 1135 for_each_possible_cpu(cpu) { 1136 /* Set up direct vCPU id mapping for PV guests. */ 1137 per_cpu(xen_vcpu_id, cpu) = cpu; 1138 xen_vcpu_setup(cpu); 1139 } 1140 1141 /* xen_vcpu_setup managed to place the vcpu_info within the 1142 * percpu area for all cpus, so make use of it. Note that for 1143 * PVH we want to use native IRQ mechanism. */ 1144 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1145 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1146 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1147 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1148 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1149 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1150 } 1151 } 1152 1153 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1154 unsigned long addr, unsigned len) 1155 { 1156 char *start, *end, *reloc; 1157 unsigned ret; 1158 1159 start = end = reloc = NULL; 1160 1161 #define SITE(op, x) \ 1162 case PARAVIRT_PATCH(op.x): \ 1163 if (have_vcpu_info_placement) { \ 1164 start = (char *)xen_##x##_direct; \ 1165 end = xen_##x##_direct_end; \ 1166 reloc = xen_##x##_direct_reloc; \ 1167 } \ 1168 goto patch_site 1169 1170 switch (type) { 1171 SITE(pv_irq_ops, irq_enable); 1172 SITE(pv_irq_ops, irq_disable); 1173 SITE(pv_irq_ops, save_fl); 1174 SITE(pv_irq_ops, restore_fl); 1175 #undef SITE 1176 1177 patch_site: 1178 if (start == NULL || (end-start) > len) 1179 goto default_patch; 1180 1181 ret = paravirt_patch_insns(insnbuf, len, start, end); 1182 1183 /* Note: because reloc is assigned from something that 1184 appears to be an array, gcc assumes it's non-null, 1185 but doesn't know its relationship with start and 1186 end. */ 1187 if (reloc > start && reloc < end) { 1188 int reloc_off = reloc - start; 1189 long *relocp = (long *)(insnbuf + reloc_off); 1190 long delta = start - (char *)addr; 1191 1192 *relocp += delta; 1193 } 1194 break; 1195 1196 default_patch: 1197 default: 1198 ret = paravirt_patch_default(type, clobbers, insnbuf, 1199 addr, len); 1200 break; 1201 } 1202 1203 return ret; 1204 } 1205 1206 static const struct pv_info xen_info __initconst = { 1207 .shared_kernel_pmd = 0, 1208 1209 #ifdef CONFIG_X86_64 1210 .extra_user_64bit_cs = FLAT_USER_CS64, 1211 #endif 1212 .name = "Xen", 1213 }; 1214 1215 static const struct pv_init_ops xen_init_ops __initconst = { 1216 .patch = xen_patch, 1217 }; 1218 1219 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1220 .cpuid = xen_cpuid, 1221 1222 .set_debugreg = xen_set_debugreg, 1223 .get_debugreg = xen_get_debugreg, 1224 1225 .read_cr0 = xen_read_cr0, 1226 .write_cr0 = xen_write_cr0, 1227 1228 .read_cr4 = native_read_cr4, 1229 .write_cr4 = xen_write_cr4, 1230 1231 #ifdef CONFIG_X86_64 1232 .read_cr8 = xen_read_cr8, 1233 .write_cr8 = xen_write_cr8, 1234 #endif 1235 1236 .wbinvd = native_wbinvd, 1237 1238 .read_msr = xen_read_msr, 1239 .write_msr = xen_write_msr, 1240 1241 .read_msr_safe = xen_read_msr_safe, 1242 .write_msr_safe = xen_write_msr_safe, 1243 1244 .read_pmc = xen_read_pmc, 1245 1246 .iret = xen_iret, 1247 #ifdef CONFIG_X86_64 1248 .usergs_sysret64 = xen_sysret64, 1249 #endif 1250 1251 .load_tr_desc = paravirt_nop, 1252 .set_ldt = xen_set_ldt, 1253 .load_gdt = xen_load_gdt, 1254 .load_idt = xen_load_idt, 1255 .load_tls = xen_load_tls, 1256 #ifdef CONFIG_X86_64 1257 .load_gs_index = xen_load_gs_index, 1258 #endif 1259 1260 .alloc_ldt = xen_alloc_ldt, 1261 .free_ldt = xen_free_ldt, 1262 1263 .store_idt = native_store_idt, 1264 .store_tr = xen_store_tr, 1265 1266 .write_ldt_entry = xen_write_ldt_entry, 1267 .write_gdt_entry = xen_write_gdt_entry, 1268 .write_idt_entry = xen_write_idt_entry, 1269 .load_sp0 = xen_load_sp0, 1270 1271 .set_iopl_mask = xen_set_iopl_mask, 1272 .io_delay = xen_io_delay, 1273 1274 /* Xen takes care of %gs when switching to usermode for us */ 1275 .swapgs = paravirt_nop, 1276 1277 .start_context_switch = paravirt_start_context_switch, 1278 .end_context_switch = xen_end_context_switch, 1279 }; 1280 1281 static void xen_reboot(int reason) 1282 { 1283 struct sched_shutdown r = { .reason = reason }; 1284 int cpu; 1285 1286 for_each_online_cpu(cpu) 1287 xen_pmu_finish(cpu); 1288 1289 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1290 BUG(); 1291 } 1292 1293 static void xen_restart(char *msg) 1294 { 1295 xen_reboot(SHUTDOWN_reboot); 1296 } 1297 1298 static void xen_emergency_restart(void) 1299 { 1300 xen_reboot(SHUTDOWN_reboot); 1301 } 1302 1303 static void xen_machine_halt(void) 1304 { 1305 xen_reboot(SHUTDOWN_poweroff); 1306 } 1307 1308 static void xen_machine_power_off(void) 1309 { 1310 if (pm_power_off) 1311 pm_power_off(); 1312 xen_reboot(SHUTDOWN_poweroff); 1313 } 1314 1315 static void xen_crash_shutdown(struct pt_regs *regs) 1316 { 1317 xen_reboot(SHUTDOWN_crash); 1318 } 1319 1320 static int 1321 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1322 { 1323 if (!kexec_crash_loaded()) 1324 xen_reboot(SHUTDOWN_crash); 1325 return NOTIFY_DONE; 1326 } 1327 1328 static struct notifier_block xen_panic_block = { 1329 .notifier_call= xen_panic_event, 1330 .priority = INT_MIN 1331 }; 1332 1333 int xen_panic_handler_init(void) 1334 { 1335 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1336 return 0; 1337 } 1338 1339 static const struct machine_ops xen_machine_ops __initconst = { 1340 .restart = xen_restart, 1341 .halt = xen_machine_halt, 1342 .power_off = xen_machine_power_off, 1343 .shutdown = xen_machine_halt, 1344 .crash_shutdown = xen_crash_shutdown, 1345 .emergency_restart = xen_emergency_restart, 1346 }; 1347 1348 static unsigned char xen_get_nmi_reason(void) 1349 { 1350 unsigned char reason = 0; 1351 1352 /* Construct a value which looks like it came from port 0x61. */ 1353 if (test_bit(_XEN_NMIREASON_io_error, 1354 &HYPERVISOR_shared_info->arch.nmi_reason)) 1355 reason |= NMI_REASON_IOCHK; 1356 if (test_bit(_XEN_NMIREASON_pci_serr, 1357 &HYPERVISOR_shared_info->arch.nmi_reason)) 1358 reason |= NMI_REASON_SERR; 1359 1360 return reason; 1361 } 1362 1363 static void __init xen_boot_params_init_edd(void) 1364 { 1365 #if IS_ENABLED(CONFIG_EDD) 1366 struct xen_platform_op op; 1367 struct edd_info *edd_info; 1368 u32 *mbr_signature; 1369 unsigned nr; 1370 int ret; 1371 1372 edd_info = boot_params.eddbuf; 1373 mbr_signature = boot_params.edd_mbr_sig_buffer; 1374 1375 op.cmd = XENPF_firmware_info; 1376 1377 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1378 for (nr = 0; nr < EDDMAXNR; nr++) { 1379 struct edd_info *info = edd_info + nr; 1380 1381 op.u.firmware_info.index = nr; 1382 info->params.length = sizeof(info->params); 1383 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1384 &info->params); 1385 ret = HYPERVISOR_platform_op(&op); 1386 if (ret) 1387 break; 1388 1389 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1390 C(device); 1391 C(version); 1392 C(interface_support); 1393 C(legacy_max_cylinder); 1394 C(legacy_max_head); 1395 C(legacy_sectors_per_track); 1396 #undef C 1397 } 1398 boot_params.eddbuf_entries = nr; 1399 1400 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1401 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1402 op.u.firmware_info.index = nr; 1403 ret = HYPERVISOR_platform_op(&op); 1404 if (ret) 1405 break; 1406 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1407 } 1408 boot_params.edd_mbr_sig_buf_entries = nr; 1409 #endif 1410 } 1411 1412 /* 1413 * Set up the GDT and segment registers for -fstack-protector. Until 1414 * we do this, we have to be careful not to call any stack-protected 1415 * function, which is most of the kernel. 1416 * 1417 * Note, that it is __ref because the only caller of this after init 1418 * is PVH which is not going to use xen_load_gdt_boot or other 1419 * __init functions. 1420 */ 1421 static void __ref xen_setup_gdt(int cpu) 1422 { 1423 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1424 #ifdef CONFIG_X86_64 1425 unsigned long dummy; 1426 1427 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1428 switch_to_new_gdt(cpu); /* GDT and GS set */ 1429 1430 /* We are switching of the Xen provided GDT to our HVM mode 1431 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1432 * and we are jumping to reload it. 1433 */ 1434 asm volatile ("pushq %0\n" 1435 "leaq 1f(%%rip),%0\n" 1436 "pushq %0\n" 1437 "lretq\n" 1438 "1:\n" 1439 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1440 1441 /* 1442 * While not needed, we also set the %es, %ds, and %fs 1443 * to zero. We don't care about %ss as it is NULL. 1444 * Strictly speaking this is not needed as Xen zeros those 1445 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1446 * 1447 * Linux zeros them in cpu_init() and in secondary_startup_64 1448 * (for BSP). 1449 */ 1450 loadsegment(es, 0); 1451 loadsegment(ds, 0); 1452 loadsegment(fs, 0); 1453 #else 1454 /* PVH: TODO Implement. */ 1455 BUG(); 1456 #endif 1457 return; /* PVH does not need any PV GDT ops. */ 1458 } 1459 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1460 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1461 1462 setup_stack_canary_segment(0); 1463 switch_to_new_gdt(0); 1464 1465 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1466 pv_cpu_ops.load_gdt = xen_load_gdt; 1467 } 1468 1469 #ifdef CONFIG_XEN_PVH 1470 /* 1471 * A PV guest starts with default flags that are not set for PVH, set them 1472 * here asap. 1473 */ 1474 static void xen_pvh_set_cr_flags(int cpu) 1475 { 1476 1477 /* Some of these are setup in 'secondary_startup_64'. The others: 1478 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1479 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1480 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1481 1482 if (!cpu) 1483 return; 1484 /* 1485 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1486 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu(). 1487 */ 1488 if (boot_cpu_has(X86_FEATURE_PSE)) 1489 cr4_set_bits_and_update_boot(X86_CR4_PSE); 1490 1491 if (boot_cpu_has(X86_FEATURE_PGE)) 1492 cr4_set_bits_and_update_boot(X86_CR4_PGE); 1493 } 1494 1495 /* 1496 * Note, that it is ref - because the only caller of this after init 1497 * is PVH which is not going to use xen_load_gdt_boot or other 1498 * __init functions. 1499 */ 1500 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1501 { 1502 xen_setup_gdt(cpu); 1503 xen_pvh_set_cr_flags(cpu); 1504 } 1505 1506 static void __init xen_pvh_early_guest_init(void) 1507 { 1508 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1509 return; 1510 1511 BUG_ON(!xen_feature(XENFEAT_hvm_callback_vector)); 1512 1513 xen_pvh_early_cpu_init(0, false); 1514 xen_pvh_set_cr_flags(0); 1515 1516 #ifdef CONFIG_X86_32 1517 BUG(); /* PVH: Implement proper support. */ 1518 #endif 1519 } 1520 #endif /* CONFIG_XEN_PVH */ 1521 1522 static void __init xen_dom0_set_legacy_features(void) 1523 { 1524 x86_platform.legacy.rtc = 1; 1525 } 1526 1527 static int xen_cpuhp_setup(void) 1528 { 1529 int rc; 1530 1531 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 1532 "x86/xen/hvm_guest:prepare", 1533 xen_cpu_up_prepare, xen_cpu_dead); 1534 if (rc >= 0) { 1535 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 1536 "x86/xen/hvm_guest:online", 1537 xen_cpu_up_online, NULL); 1538 if (rc < 0) 1539 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 1540 } 1541 1542 return rc >= 0 ? 0 : rc; 1543 } 1544 1545 /* First C function to be called on Xen boot */ 1546 asmlinkage __visible void __init xen_start_kernel(void) 1547 { 1548 struct physdev_set_iopl set_iopl; 1549 unsigned long initrd_start = 0; 1550 int rc; 1551 1552 if (!xen_start_info) 1553 return; 1554 1555 xen_domain_type = XEN_PV_DOMAIN; 1556 1557 xen_setup_features(); 1558 #ifdef CONFIG_XEN_PVH 1559 xen_pvh_early_guest_init(); 1560 #endif 1561 xen_setup_machphys_mapping(); 1562 1563 /* Install Xen paravirt ops */ 1564 pv_info = xen_info; 1565 pv_init_ops = xen_init_ops; 1566 if (!xen_pvh_domain()) { 1567 pv_cpu_ops = xen_cpu_ops; 1568 1569 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1570 } 1571 1572 if (xen_feature(XENFEAT_auto_translated_physmap)) 1573 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup; 1574 else 1575 x86_init.resources.memory_setup = xen_memory_setup; 1576 x86_init.oem.arch_setup = xen_arch_setup; 1577 x86_init.oem.banner = xen_banner; 1578 1579 xen_init_time_ops(); 1580 1581 /* 1582 * Set up some pagetable state before starting to set any ptes. 1583 */ 1584 1585 xen_init_mmu_ops(); 1586 1587 /* Prevent unwanted bits from being set in PTEs. */ 1588 __supported_pte_mask &= ~_PAGE_GLOBAL; 1589 1590 /* 1591 * Prevent page tables from being allocated in highmem, even 1592 * if CONFIG_HIGHPTE is enabled. 1593 */ 1594 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1595 1596 /* Work out if we support NX */ 1597 x86_configure_nx(); 1598 1599 /* Get mfn list */ 1600 xen_build_dynamic_phys_to_machine(); 1601 1602 /* 1603 * Set up kernel GDT and segment registers, mainly so that 1604 * -fstack-protector code can be executed. 1605 */ 1606 xen_setup_gdt(0); 1607 1608 xen_init_irq_ops(); 1609 xen_init_cpuid_mask(); 1610 1611 #ifdef CONFIG_X86_LOCAL_APIC 1612 /* 1613 * set up the basic apic ops. 1614 */ 1615 xen_init_apic(); 1616 #endif 1617 1618 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1619 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1620 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1621 } 1622 1623 machine_ops = xen_machine_ops; 1624 1625 /* 1626 * The only reliable way to retain the initial address of the 1627 * percpu gdt_page is to remember it here, so we can go and 1628 * mark it RW later, when the initial percpu area is freed. 1629 */ 1630 xen_initial_gdt = &per_cpu(gdt_page, 0); 1631 1632 xen_smp_init(); 1633 1634 #ifdef CONFIG_ACPI_NUMA 1635 /* 1636 * The pages we from Xen are not related to machine pages, so 1637 * any NUMA information the kernel tries to get from ACPI will 1638 * be meaningless. Prevent it from trying. 1639 */ 1640 acpi_numa = -1; 1641 #endif 1642 /* Don't do the full vcpu_info placement stuff until we have a 1643 possible map and a non-dummy shared_info. */ 1644 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1645 1646 WARN_ON(xen_cpuhp_setup()); 1647 1648 local_irq_disable(); 1649 early_boot_irqs_disabled = true; 1650 1651 xen_raw_console_write("mapping kernel into physical memory\n"); 1652 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, 1653 xen_start_info->nr_pages); 1654 xen_reserve_special_pages(); 1655 1656 /* keep using Xen gdt for now; no urgent need to change it */ 1657 1658 #ifdef CONFIG_X86_32 1659 pv_info.kernel_rpl = 1; 1660 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1661 pv_info.kernel_rpl = 0; 1662 #else 1663 pv_info.kernel_rpl = 0; 1664 #endif 1665 /* set the limit of our address space */ 1666 xen_reserve_top(); 1667 1668 /* PVH: runs at default kernel iopl of 0 */ 1669 if (!xen_pvh_domain()) { 1670 /* 1671 * We used to do this in xen_arch_setup, but that is too late 1672 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1673 * early_amd_init which pokes 0xcf8 port. 1674 */ 1675 set_iopl.iopl = 1; 1676 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1677 if (rc != 0) 1678 xen_raw_printk("physdev_op failed %d\n", rc); 1679 } 1680 1681 #ifdef CONFIG_X86_32 1682 /* set up basic CPUID stuff */ 1683 cpu_detect(&new_cpu_data); 1684 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); 1685 new_cpu_data.wp_works_ok = 1; 1686 new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1); 1687 #endif 1688 1689 if (xen_start_info->mod_start) { 1690 if (xen_start_info->flags & SIF_MOD_START_PFN) 1691 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1692 else 1693 initrd_start = __pa(xen_start_info->mod_start); 1694 } 1695 1696 /* Poke various useful things into boot_params */ 1697 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1698 boot_params.hdr.ramdisk_image = initrd_start; 1699 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1700 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1701 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN; 1702 1703 if (!xen_initial_domain()) { 1704 add_preferred_console("xenboot", 0, NULL); 1705 add_preferred_console("tty", 0, NULL); 1706 add_preferred_console("hvc", 0, NULL); 1707 if (pci_xen) 1708 x86_init.pci.arch_init = pci_xen_init; 1709 } else { 1710 const struct dom0_vga_console_info *info = 1711 (void *)((char *)xen_start_info + 1712 xen_start_info->console.dom0.info_off); 1713 struct xen_platform_op op = { 1714 .cmd = XENPF_firmware_info, 1715 .interface_version = XENPF_INTERFACE_VERSION, 1716 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1717 }; 1718 1719 x86_platform.set_legacy_features = 1720 xen_dom0_set_legacy_features; 1721 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1722 xen_start_info->console.domU.mfn = 0; 1723 xen_start_info->console.domU.evtchn = 0; 1724 1725 if (HYPERVISOR_platform_op(&op) == 0) 1726 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1727 1728 /* Make sure ACS will be enabled */ 1729 pci_request_acs(); 1730 1731 xen_acpi_sleep_register(); 1732 1733 /* Avoid searching for BIOS MP tables */ 1734 x86_init.mpparse.find_smp_config = x86_init_noop; 1735 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1736 1737 xen_boot_params_init_edd(); 1738 } 1739 #ifdef CONFIG_PCI 1740 /* PCI BIOS service won't work from a PV guest. */ 1741 pci_probe &= ~PCI_PROBE_BIOS; 1742 #endif 1743 xen_raw_console_write("about to get started...\n"); 1744 1745 /* Let's presume PV guests always boot on vCPU with id 0. */ 1746 per_cpu(xen_vcpu_id, 0) = 0; 1747 1748 xen_setup_runstate_info(0); 1749 1750 xen_efi_init(); 1751 1752 /* Start the world */ 1753 #ifdef CONFIG_X86_32 1754 i386_start_kernel(); 1755 #else 1756 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1757 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1758 #endif 1759 } 1760 1761 void __ref xen_hvm_init_shared_info(void) 1762 { 1763 int cpu; 1764 struct xen_add_to_physmap xatp; 1765 static struct shared_info *shared_info_page = 0; 1766 1767 if (!shared_info_page) 1768 shared_info_page = (struct shared_info *) 1769 extend_brk(PAGE_SIZE, PAGE_SIZE); 1770 xatp.domid = DOMID_SELF; 1771 xatp.idx = 0; 1772 xatp.space = XENMAPSPACE_shared_info; 1773 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1774 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1775 BUG(); 1776 1777 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1778 1779 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1780 * page, we use it in the event channel upcall and in some pvclock 1781 * related functions. We don't need the vcpu_info placement 1782 * optimizations because we don't use any pv_mmu or pv_irq op on 1783 * HVM. 1784 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1785 * online but xen_hvm_init_shared_info is run at resume time too and 1786 * in that case multiple vcpus might be online. */ 1787 for_each_online_cpu(cpu) { 1788 /* Leave it to be NULL. */ 1789 if (xen_vcpu_nr(cpu) >= MAX_VIRT_CPUS) 1790 continue; 1791 per_cpu(xen_vcpu, cpu) = 1792 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 1793 } 1794 } 1795 1796 #ifdef CONFIG_XEN_PVHVM 1797 static void __init init_hvm_pv_info(void) 1798 { 1799 int major, minor; 1800 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1801 u64 pfn; 1802 1803 base = xen_cpuid_base(); 1804 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1805 1806 major = eax >> 16; 1807 minor = eax & 0xffff; 1808 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1809 1810 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1811 1812 pfn = __pa(hypercall_page); 1813 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1814 1815 xen_setup_features(); 1816 1817 cpuid(base + 4, &eax, &ebx, &ecx, &edx); 1818 if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT) 1819 this_cpu_write(xen_vcpu_id, ebx); 1820 else 1821 this_cpu_write(xen_vcpu_id, smp_processor_id()); 1822 1823 pv_info.name = "Xen HVM"; 1824 1825 xen_domain_type = XEN_HVM_DOMAIN; 1826 } 1827 #endif 1828 1829 static int xen_cpu_up_prepare(unsigned int cpu) 1830 { 1831 int rc; 1832 1833 if (xen_hvm_domain()) { 1834 /* 1835 * This can happen if CPU was offlined earlier and 1836 * offlining timed out in common_cpu_die(). 1837 */ 1838 if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) { 1839 xen_smp_intr_free(cpu); 1840 xen_uninit_lock_cpu(cpu); 1841 } 1842 1843 if (cpu_acpi_id(cpu) != U32_MAX) 1844 per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu); 1845 else 1846 per_cpu(xen_vcpu_id, cpu) = cpu; 1847 xen_vcpu_setup(cpu); 1848 } 1849 1850 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 1851 xen_setup_timer(cpu); 1852 1853 rc = xen_smp_intr_init(cpu); 1854 if (rc) { 1855 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n", 1856 cpu, rc); 1857 return rc; 1858 } 1859 return 0; 1860 } 1861 1862 static int xen_cpu_dead(unsigned int cpu) 1863 { 1864 xen_smp_intr_free(cpu); 1865 1866 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 1867 xen_teardown_timer(cpu); 1868 1869 return 0; 1870 } 1871 1872 static int xen_cpu_up_online(unsigned int cpu) 1873 { 1874 xen_init_lock_cpu(cpu); 1875 return 0; 1876 } 1877 1878 #ifdef CONFIG_XEN_PVHVM 1879 #ifdef CONFIG_KEXEC_CORE 1880 static void xen_hvm_shutdown(void) 1881 { 1882 native_machine_shutdown(); 1883 if (kexec_in_progress) 1884 xen_reboot(SHUTDOWN_soft_reset); 1885 } 1886 1887 static void xen_hvm_crash_shutdown(struct pt_regs *regs) 1888 { 1889 native_machine_crash_shutdown(regs); 1890 xen_reboot(SHUTDOWN_soft_reset); 1891 } 1892 #endif 1893 1894 static void __init xen_hvm_guest_init(void) 1895 { 1896 if (xen_pv_domain()) 1897 return; 1898 1899 init_hvm_pv_info(); 1900 1901 xen_hvm_init_shared_info(); 1902 1903 xen_panic_handler_init(); 1904 1905 BUG_ON(!xen_feature(XENFEAT_hvm_callback_vector)); 1906 1907 xen_hvm_smp_init(); 1908 WARN_ON(xen_cpuhp_setup()); 1909 xen_unplug_emulated_devices(); 1910 x86_init.irqs.intr_init = xen_init_IRQ; 1911 xen_hvm_init_time_ops(); 1912 xen_hvm_init_mmu_ops(); 1913 #ifdef CONFIG_KEXEC_CORE 1914 machine_ops.shutdown = xen_hvm_shutdown; 1915 machine_ops.crash_shutdown = xen_hvm_crash_shutdown; 1916 #endif 1917 } 1918 #endif 1919 1920 static bool xen_nopv = false; 1921 static __init int xen_parse_nopv(char *arg) 1922 { 1923 xen_nopv = true; 1924 return 0; 1925 } 1926 early_param("xen_nopv", xen_parse_nopv); 1927 1928 static uint32_t __init xen_platform(void) 1929 { 1930 if (xen_nopv) 1931 return 0; 1932 1933 return xen_cpuid_base(); 1934 } 1935 1936 bool xen_hvm_need_lapic(void) 1937 { 1938 if (xen_nopv) 1939 return false; 1940 if (xen_pv_domain()) 1941 return false; 1942 if (!xen_hvm_domain()) 1943 return false; 1944 if (xen_feature(XENFEAT_hvm_pirqs)) 1945 return false; 1946 return true; 1947 } 1948 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1949 1950 static void xen_set_cpu_features(struct cpuinfo_x86 *c) 1951 { 1952 if (xen_pv_domain()) { 1953 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); 1954 set_cpu_cap(c, X86_FEATURE_XENPV); 1955 } 1956 } 1957 1958 static void xen_pin_vcpu(int cpu) 1959 { 1960 static bool disable_pinning; 1961 struct sched_pin_override pin_override; 1962 int ret; 1963 1964 if (disable_pinning) 1965 return; 1966 1967 pin_override.pcpu = cpu; 1968 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 1969 1970 /* Ignore errors when removing override. */ 1971 if (cpu < 0) 1972 return; 1973 1974 switch (ret) { 1975 case -ENOSYS: 1976 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 1977 cpu); 1978 disable_pinning = true; 1979 break; 1980 case -EPERM: 1981 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 1982 disable_pinning = true; 1983 break; 1984 case -EINVAL: 1985 case -EBUSY: 1986 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 1987 cpu); 1988 break; 1989 case 0: 1990 break; 1991 default: 1992 WARN(1, "rc %d while trying to pin vcpu\n", ret); 1993 disable_pinning = true; 1994 } 1995 } 1996 1997 const struct hypervisor_x86 x86_hyper_xen = { 1998 .name = "Xen", 1999 .detect = xen_platform, 2000 #ifdef CONFIG_XEN_PVHVM 2001 .init_platform = xen_hvm_guest_init, 2002 #endif 2003 .x2apic_available = xen_x2apic_para_available, 2004 .set_cpu_features = xen_set_cpu_features, 2005 .pin_vcpu = xen_pin_vcpu, 2006 }; 2007 EXPORT_SYMBOL(x86_hyper_xen); 2008 2009 #ifdef CONFIG_HOTPLUG_CPU 2010 void xen_arch_register_cpu(int num) 2011 { 2012 arch_register_cpu(num); 2013 } 2014 EXPORT_SYMBOL(xen_arch_register_cpu); 2015 2016 void xen_arch_unregister_cpu(int num) 2017 { 2018 arch_unregister_cpu(num); 2019 } 2020 EXPORT_SYMBOL(xen_arch_unregister_cpu); 2021 #endif 2022