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 void xen_clts(void) 984 { 985 struct multicall_space mcs; 986 987 mcs = xen_mc_entry(0); 988 989 MULTI_fpu_taskswitch(mcs.mc, 0); 990 991 xen_mc_issue(PARAVIRT_LAZY_CPU); 992 } 993 994 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 995 996 static unsigned long xen_read_cr0(void) 997 { 998 unsigned long cr0 = this_cpu_read(xen_cr0_value); 999 1000 if (unlikely(cr0 == 0)) { 1001 cr0 = native_read_cr0(); 1002 this_cpu_write(xen_cr0_value, cr0); 1003 } 1004 1005 return cr0; 1006 } 1007 1008 static void xen_write_cr0(unsigned long cr0) 1009 { 1010 struct multicall_space mcs; 1011 1012 this_cpu_write(xen_cr0_value, cr0); 1013 1014 /* Only pay attention to cr0.TS; everything else is 1015 ignored. */ 1016 mcs = xen_mc_entry(0); 1017 1018 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 1019 1020 xen_mc_issue(PARAVIRT_LAZY_CPU); 1021 } 1022 1023 static void xen_write_cr4(unsigned long cr4) 1024 { 1025 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE); 1026 1027 native_write_cr4(cr4); 1028 } 1029 #ifdef CONFIG_X86_64 1030 static inline unsigned long xen_read_cr8(void) 1031 { 1032 return 0; 1033 } 1034 static inline void xen_write_cr8(unsigned long val) 1035 { 1036 BUG_ON(val); 1037 } 1038 #endif 1039 1040 static u64 xen_read_msr_safe(unsigned int msr, int *err) 1041 { 1042 u64 val; 1043 1044 if (pmu_msr_read(msr, &val, err)) 1045 return val; 1046 1047 val = native_read_msr_safe(msr, err); 1048 switch (msr) { 1049 case MSR_IA32_APICBASE: 1050 #ifdef CONFIG_X86_X2APIC 1051 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31)))) 1052 #endif 1053 val &= ~X2APIC_ENABLE; 1054 break; 1055 } 1056 return val; 1057 } 1058 1059 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 1060 { 1061 int ret; 1062 1063 ret = 0; 1064 1065 switch (msr) { 1066 #ifdef CONFIG_X86_64 1067 unsigned which; 1068 u64 base; 1069 1070 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 1071 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 1072 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 1073 1074 set: 1075 base = ((u64)high << 32) | low; 1076 if (HYPERVISOR_set_segment_base(which, base) != 0) 1077 ret = -EIO; 1078 break; 1079 #endif 1080 1081 case MSR_STAR: 1082 case MSR_CSTAR: 1083 case MSR_LSTAR: 1084 case MSR_SYSCALL_MASK: 1085 case MSR_IA32_SYSENTER_CS: 1086 case MSR_IA32_SYSENTER_ESP: 1087 case MSR_IA32_SYSENTER_EIP: 1088 /* Fast syscall setup is all done in hypercalls, so 1089 these are all ignored. Stub them out here to stop 1090 Xen console noise. */ 1091 break; 1092 1093 default: 1094 if (!pmu_msr_write(msr, low, high, &ret)) 1095 ret = native_write_msr_safe(msr, low, high); 1096 } 1097 1098 return ret; 1099 } 1100 1101 static u64 xen_read_msr(unsigned int msr) 1102 { 1103 /* 1104 * This will silently swallow a #GP from RDMSR. It may be worth 1105 * changing that. 1106 */ 1107 int err; 1108 1109 return xen_read_msr_safe(msr, &err); 1110 } 1111 1112 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high) 1113 { 1114 /* 1115 * This will silently swallow a #GP from WRMSR. It may be worth 1116 * changing that. 1117 */ 1118 xen_write_msr_safe(msr, low, high); 1119 } 1120 1121 void xen_setup_shared_info(void) 1122 { 1123 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1124 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1125 xen_start_info->shared_info); 1126 1127 HYPERVISOR_shared_info = 1128 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1129 } else 1130 HYPERVISOR_shared_info = 1131 (struct shared_info *)__va(xen_start_info->shared_info); 1132 1133 #ifndef CONFIG_SMP 1134 /* In UP this is as good a place as any to set up shared info */ 1135 xen_setup_vcpu_info_placement(); 1136 #endif 1137 1138 xen_setup_mfn_list_list(); 1139 } 1140 1141 /* This is called once we have the cpu_possible_mask */ 1142 void xen_setup_vcpu_info_placement(void) 1143 { 1144 int cpu; 1145 1146 for_each_possible_cpu(cpu) { 1147 /* Set up direct vCPU id mapping for PV guests. */ 1148 per_cpu(xen_vcpu_id, cpu) = cpu; 1149 xen_vcpu_setup(cpu); 1150 } 1151 1152 /* xen_vcpu_setup managed to place the vcpu_info within the 1153 * percpu area for all cpus, so make use of it. Note that for 1154 * PVH we want to use native IRQ mechanism. */ 1155 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1156 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1157 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1158 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1159 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1160 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1161 } 1162 } 1163 1164 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1165 unsigned long addr, unsigned len) 1166 { 1167 char *start, *end, *reloc; 1168 unsigned ret; 1169 1170 start = end = reloc = NULL; 1171 1172 #define SITE(op, x) \ 1173 case PARAVIRT_PATCH(op.x): \ 1174 if (have_vcpu_info_placement) { \ 1175 start = (char *)xen_##x##_direct; \ 1176 end = xen_##x##_direct_end; \ 1177 reloc = xen_##x##_direct_reloc; \ 1178 } \ 1179 goto patch_site 1180 1181 switch (type) { 1182 SITE(pv_irq_ops, irq_enable); 1183 SITE(pv_irq_ops, irq_disable); 1184 SITE(pv_irq_ops, save_fl); 1185 SITE(pv_irq_ops, restore_fl); 1186 #undef SITE 1187 1188 patch_site: 1189 if (start == NULL || (end-start) > len) 1190 goto default_patch; 1191 1192 ret = paravirt_patch_insns(insnbuf, len, start, end); 1193 1194 /* Note: because reloc is assigned from something that 1195 appears to be an array, gcc assumes it's non-null, 1196 but doesn't know its relationship with start and 1197 end. */ 1198 if (reloc > start && reloc < end) { 1199 int reloc_off = reloc - start; 1200 long *relocp = (long *)(insnbuf + reloc_off); 1201 long delta = start - (char *)addr; 1202 1203 *relocp += delta; 1204 } 1205 break; 1206 1207 default_patch: 1208 default: 1209 ret = paravirt_patch_default(type, clobbers, insnbuf, 1210 addr, len); 1211 break; 1212 } 1213 1214 return ret; 1215 } 1216 1217 static const struct pv_info xen_info __initconst = { 1218 .shared_kernel_pmd = 0, 1219 1220 #ifdef CONFIG_X86_64 1221 .extra_user_64bit_cs = FLAT_USER_CS64, 1222 #endif 1223 .name = "Xen", 1224 }; 1225 1226 static const struct pv_init_ops xen_init_ops __initconst = { 1227 .patch = xen_patch, 1228 }; 1229 1230 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1231 .cpuid = xen_cpuid, 1232 1233 .set_debugreg = xen_set_debugreg, 1234 .get_debugreg = xen_get_debugreg, 1235 1236 .clts = xen_clts, 1237 1238 .read_cr0 = xen_read_cr0, 1239 .write_cr0 = xen_write_cr0, 1240 1241 .read_cr4 = native_read_cr4, 1242 .write_cr4 = xen_write_cr4, 1243 1244 #ifdef CONFIG_X86_64 1245 .read_cr8 = xen_read_cr8, 1246 .write_cr8 = xen_write_cr8, 1247 #endif 1248 1249 .wbinvd = native_wbinvd, 1250 1251 .read_msr = xen_read_msr, 1252 .write_msr = xen_write_msr, 1253 1254 .read_msr_safe = xen_read_msr_safe, 1255 .write_msr_safe = xen_write_msr_safe, 1256 1257 .read_pmc = xen_read_pmc, 1258 1259 .iret = xen_iret, 1260 #ifdef CONFIG_X86_64 1261 .usergs_sysret64 = xen_sysret64, 1262 #endif 1263 1264 .load_tr_desc = paravirt_nop, 1265 .set_ldt = xen_set_ldt, 1266 .load_gdt = xen_load_gdt, 1267 .load_idt = xen_load_idt, 1268 .load_tls = xen_load_tls, 1269 #ifdef CONFIG_X86_64 1270 .load_gs_index = xen_load_gs_index, 1271 #endif 1272 1273 .alloc_ldt = xen_alloc_ldt, 1274 .free_ldt = xen_free_ldt, 1275 1276 .store_idt = native_store_idt, 1277 .store_tr = xen_store_tr, 1278 1279 .write_ldt_entry = xen_write_ldt_entry, 1280 .write_gdt_entry = xen_write_gdt_entry, 1281 .write_idt_entry = xen_write_idt_entry, 1282 .load_sp0 = xen_load_sp0, 1283 1284 .set_iopl_mask = xen_set_iopl_mask, 1285 .io_delay = xen_io_delay, 1286 1287 /* Xen takes care of %gs when switching to usermode for us */ 1288 .swapgs = paravirt_nop, 1289 1290 .start_context_switch = paravirt_start_context_switch, 1291 .end_context_switch = xen_end_context_switch, 1292 }; 1293 1294 static void xen_reboot(int reason) 1295 { 1296 struct sched_shutdown r = { .reason = reason }; 1297 int cpu; 1298 1299 for_each_online_cpu(cpu) 1300 xen_pmu_finish(cpu); 1301 1302 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1303 BUG(); 1304 } 1305 1306 static void xen_restart(char *msg) 1307 { 1308 xen_reboot(SHUTDOWN_reboot); 1309 } 1310 1311 static void xen_emergency_restart(void) 1312 { 1313 xen_reboot(SHUTDOWN_reboot); 1314 } 1315 1316 static void xen_machine_halt(void) 1317 { 1318 xen_reboot(SHUTDOWN_poweroff); 1319 } 1320 1321 static void xen_machine_power_off(void) 1322 { 1323 if (pm_power_off) 1324 pm_power_off(); 1325 xen_reboot(SHUTDOWN_poweroff); 1326 } 1327 1328 static void xen_crash_shutdown(struct pt_regs *regs) 1329 { 1330 xen_reboot(SHUTDOWN_crash); 1331 } 1332 1333 static int 1334 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1335 { 1336 if (!kexec_crash_loaded()) 1337 xen_reboot(SHUTDOWN_crash); 1338 return NOTIFY_DONE; 1339 } 1340 1341 static struct notifier_block xen_panic_block = { 1342 .notifier_call= xen_panic_event, 1343 .priority = INT_MIN 1344 }; 1345 1346 int xen_panic_handler_init(void) 1347 { 1348 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1349 return 0; 1350 } 1351 1352 static const struct machine_ops xen_machine_ops __initconst = { 1353 .restart = xen_restart, 1354 .halt = xen_machine_halt, 1355 .power_off = xen_machine_power_off, 1356 .shutdown = xen_machine_halt, 1357 .crash_shutdown = xen_crash_shutdown, 1358 .emergency_restart = xen_emergency_restart, 1359 }; 1360 1361 static unsigned char xen_get_nmi_reason(void) 1362 { 1363 unsigned char reason = 0; 1364 1365 /* Construct a value which looks like it came from port 0x61. */ 1366 if (test_bit(_XEN_NMIREASON_io_error, 1367 &HYPERVISOR_shared_info->arch.nmi_reason)) 1368 reason |= NMI_REASON_IOCHK; 1369 if (test_bit(_XEN_NMIREASON_pci_serr, 1370 &HYPERVISOR_shared_info->arch.nmi_reason)) 1371 reason |= NMI_REASON_SERR; 1372 1373 return reason; 1374 } 1375 1376 static void __init xen_boot_params_init_edd(void) 1377 { 1378 #if IS_ENABLED(CONFIG_EDD) 1379 struct xen_platform_op op; 1380 struct edd_info *edd_info; 1381 u32 *mbr_signature; 1382 unsigned nr; 1383 int ret; 1384 1385 edd_info = boot_params.eddbuf; 1386 mbr_signature = boot_params.edd_mbr_sig_buffer; 1387 1388 op.cmd = XENPF_firmware_info; 1389 1390 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1391 for (nr = 0; nr < EDDMAXNR; nr++) { 1392 struct edd_info *info = edd_info + nr; 1393 1394 op.u.firmware_info.index = nr; 1395 info->params.length = sizeof(info->params); 1396 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1397 &info->params); 1398 ret = HYPERVISOR_platform_op(&op); 1399 if (ret) 1400 break; 1401 1402 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1403 C(device); 1404 C(version); 1405 C(interface_support); 1406 C(legacy_max_cylinder); 1407 C(legacy_max_head); 1408 C(legacy_sectors_per_track); 1409 #undef C 1410 } 1411 boot_params.eddbuf_entries = nr; 1412 1413 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1414 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1415 op.u.firmware_info.index = nr; 1416 ret = HYPERVISOR_platform_op(&op); 1417 if (ret) 1418 break; 1419 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1420 } 1421 boot_params.edd_mbr_sig_buf_entries = nr; 1422 #endif 1423 } 1424 1425 /* 1426 * Set up the GDT and segment registers for -fstack-protector. Until 1427 * we do this, we have to be careful not to call any stack-protected 1428 * function, which is most of the kernel. 1429 * 1430 * Note, that it is __ref because the only caller of this after init 1431 * is PVH which is not going to use xen_load_gdt_boot or other 1432 * __init functions. 1433 */ 1434 static void __ref xen_setup_gdt(int cpu) 1435 { 1436 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1437 #ifdef CONFIG_X86_64 1438 unsigned long dummy; 1439 1440 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1441 switch_to_new_gdt(cpu); /* GDT and GS set */ 1442 1443 /* We are switching of the Xen provided GDT to our HVM mode 1444 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1445 * and we are jumping to reload it. 1446 */ 1447 asm volatile ("pushq %0\n" 1448 "leaq 1f(%%rip),%0\n" 1449 "pushq %0\n" 1450 "lretq\n" 1451 "1:\n" 1452 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1453 1454 /* 1455 * While not needed, we also set the %es, %ds, and %fs 1456 * to zero. We don't care about %ss as it is NULL. 1457 * Strictly speaking this is not needed as Xen zeros those 1458 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1459 * 1460 * Linux zeros them in cpu_init() and in secondary_startup_64 1461 * (for BSP). 1462 */ 1463 loadsegment(es, 0); 1464 loadsegment(ds, 0); 1465 loadsegment(fs, 0); 1466 #else 1467 /* PVH: TODO Implement. */ 1468 BUG(); 1469 #endif 1470 return; /* PVH does not need any PV GDT ops. */ 1471 } 1472 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1473 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1474 1475 setup_stack_canary_segment(0); 1476 switch_to_new_gdt(0); 1477 1478 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1479 pv_cpu_ops.load_gdt = xen_load_gdt; 1480 } 1481 1482 #ifdef CONFIG_XEN_PVH 1483 /* 1484 * A PV guest starts with default flags that are not set for PVH, set them 1485 * here asap. 1486 */ 1487 static void xen_pvh_set_cr_flags(int cpu) 1488 { 1489 1490 /* Some of these are setup in 'secondary_startup_64'. The others: 1491 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1492 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1493 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1494 1495 if (!cpu) 1496 return; 1497 /* 1498 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1499 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu(). 1500 */ 1501 if (boot_cpu_has(X86_FEATURE_PSE)) 1502 cr4_set_bits_and_update_boot(X86_CR4_PSE); 1503 1504 if (boot_cpu_has(X86_FEATURE_PGE)) 1505 cr4_set_bits_and_update_boot(X86_CR4_PGE); 1506 } 1507 1508 /* 1509 * Note, that it is ref - because the only caller of this after init 1510 * is PVH which is not going to use xen_load_gdt_boot or other 1511 * __init functions. 1512 */ 1513 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1514 { 1515 xen_setup_gdt(cpu); 1516 xen_pvh_set_cr_flags(cpu); 1517 } 1518 1519 static void __init xen_pvh_early_guest_init(void) 1520 { 1521 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1522 return; 1523 1524 BUG_ON(!xen_feature(XENFEAT_hvm_callback_vector)); 1525 1526 xen_pvh_early_cpu_init(0, false); 1527 xen_pvh_set_cr_flags(0); 1528 1529 #ifdef CONFIG_X86_32 1530 BUG(); /* PVH: Implement proper support. */ 1531 #endif 1532 } 1533 #endif /* CONFIG_XEN_PVH */ 1534 1535 static void __init xen_dom0_set_legacy_features(void) 1536 { 1537 x86_platform.legacy.rtc = 1; 1538 } 1539 1540 static int xen_cpuhp_setup(void) 1541 { 1542 int rc; 1543 1544 rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE, 1545 "XEN_HVM_GUEST_PREPARE", 1546 xen_cpu_up_prepare, xen_cpu_dead); 1547 if (rc >= 0) { 1548 rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, 1549 "XEN_HVM_GUEST_ONLINE", 1550 xen_cpu_up_online, NULL); 1551 if (rc < 0) 1552 cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE); 1553 } 1554 1555 return rc >= 0 ? 0 : rc; 1556 } 1557 1558 /* First C function to be called on Xen boot */ 1559 asmlinkage __visible void __init xen_start_kernel(void) 1560 { 1561 struct physdev_set_iopl set_iopl; 1562 unsigned long initrd_start = 0; 1563 int rc; 1564 1565 if (!xen_start_info) 1566 return; 1567 1568 xen_domain_type = XEN_PV_DOMAIN; 1569 1570 xen_setup_features(); 1571 #ifdef CONFIG_XEN_PVH 1572 xen_pvh_early_guest_init(); 1573 #endif 1574 xen_setup_machphys_mapping(); 1575 1576 /* Install Xen paravirt ops */ 1577 pv_info = xen_info; 1578 pv_init_ops = xen_init_ops; 1579 if (!xen_pvh_domain()) { 1580 pv_cpu_ops = xen_cpu_ops; 1581 1582 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1583 } 1584 1585 if (xen_feature(XENFEAT_auto_translated_physmap)) 1586 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup; 1587 else 1588 x86_init.resources.memory_setup = xen_memory_setup; 1589 x86_init.oem.arch_setup = xen_arch_setup; 1590 x86_init.oem.banner = xen_banner; 1591 1592 xen_init_time_ops(); 1593 1594 /* 1595 * Set up some pagetable state before starting to set any ptes. 1596 */ 1597 1598 xen_init_mmu_ops(); 1599 1600 /* Prevent unwanted bits from being set in PTEs. */ 1601 __supported_pte_mask &= ~_PAGE_GLOBAL; 1602 1603 /* 1604 * Prevent page tables from being allocated in highmem, even 1605 * if CONFIG_HIGHPTE is enabled. 1606 */ 1607 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1608 1609 /* Work out if we support NX */ 1610 x86_configure_nx(); 1611 1612 /* Get mfn list */ 1613 xen_build_dynamic_phys_to_machine(); 1614 1615 /* 1616 * Set up kernel GDT and segment registers, mainly so that 1617 * -fstack-protector code can be executed. 1618 */ 1619 xen_setup_gdt(0); 1620 1621 xen_init_irq_ops(); 1622 xen_init_cpuid_mask(); 1623 1624 #ifdef CONFIG_X86_LOCAL_APIC 1625 /* 1626 * set up the basic apic ops. 1627 */ 1628 xen_init_apic(); 1629 #endif 1630 1631 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1632 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1633 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1634 } 1635 1636 machine_ops = xen_machine_ops; 1637 1638 /* 1639 * The only reliable way to retain the initial address of the 1640 * percpu gdt_page is to remember it here, so we can go and 1641 * mark it RW later, when the initial percpu area is freed. 1642 */ 1643 xen_initial_gdt = &per_cpu(gdt_page, 0); 1644 1645 xen_smp_init(); 1646 1647 #ifdef CONFIG_ACPI_NUMA 1648 /* 1649 * The pages we from Xen are not related to machine pages, so 1650 * any NUMA information the kernel tries to get from ACPI will 1651 * be meaningless. Prevent it from trying. 1652 */ 1653 acpi_numa = -1; 1654 #endif 1655 /* Don't do the full vcpu_info placement stuff until we have a 1656 possible map and a non-dummy shared_info. */ 1657 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1658 1659 WARN_ON(xen_cpuhp_setup()); 1660 1661 local_irq_disable(); 1662 early_boot_irqs_disabled = true; 1663 1664 xen_raw_console_write("mapping kernel into physical memory\n"); 1665 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, 1666 xen_start_info->nr_pages); 1667 xen_reserve_special_pages(); 1668 1669 /* keep using Xen gdt for now; no urgent need to change it */ 1670 1671 #ifdef CONFIG_X86_32 1672 pv_info.kernel_rpl = 1; 1673 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1674 pv_info.kernel_rpl = 0; 1675 #else 1676 pv_info.kernel_rpl = 0; 1677 #endif 1678 /* set the limit of our address space */ 1679 xen_reserve_top(); 1680 1681 /* PVH: runs at default kernel iopl of 0 */ 1682 if (!xen_pvh_domain()) { 1683 /* 1684 * We used to do this in xen_arch_setup, but that is too late 1685 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1686 * early_amd_init which pokes 0xcf8 port. 1687 */ 1688 set_iopl.iopl = 1; 1689 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1690 if (rc != 0) 1691 xen_raw_printk("physdev_op failed %d\n", rc); 1692 } 1693 1694 #ifdef CONFIG_X86_32 1695 /* set up basic CPUID stuff */ 1696 cpu_detect(&new_cpu_data); 1697 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); 1698 new_cpu_data.wp_works_ok = 1; 1699 new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1); 1700 #endif 1701 1702 if (xen_start_info->mod_start) { 1703 if (xen_start_info->flags & SIF_MOD_START_PFN) 1704 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1705 else 1706 initrd_start = __pa(xen_start_info->mod_start); 1707 } 1708 1709 /* Poke various useful things into boot_params */ 1710 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1711 boot_params.hdr.ramdisk_image = initrd_start; 1712 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1713 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1714 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN; 1715 1716 if (!xen_initial_domain()) { 1717 add_preferred_console("xenboot", 0, NULL); 1718 add_preferred_console("tty", 0, NULL); 1719 add_preferred_console("hvc", 0, NULL); 1720 if (pci_xen) 1721 x86_init.pci.arch_init = pci_xen_init; 1722 } else { 1723 const struct dom0_vga_console_info *info = 1724 (void *)((char *)xen_start_info + 1725 xen_start_info->console.dom0.info_off); 1726 struct xen_platform_op op = { 1727 .cmd = XENPF_firmware_info, 1728 .interface_version = XENPF_INTERFACE_VERSION, 1729 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1730 }; 1731 1732 x86_platform.set_legacy_features = 1733 xen_dom0_set_legacy_features; 1734 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1735 xen_start_info->console.domU.mfn = 0; 1736 xen_start_info->console.domU.evtchn = 0; 1737 1738 if (HYPERVISOR_platform_op(&op) == 0) 1739 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1740 1741 /* Make sure ACS will be enabled */ 1742 pci_request_acs(); 1743 1744 xen_acpi_sleep_register(); 1745 1746 /* Avoid searching for BIOS MP tables */ 1747 x86_init.mpparse.find_smp_config = x86_init_noop; 1748 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1749 1750 xen_boot_params_init_edd(); 1751 } 1752 #ifdef CONFIG_PCI 1753 /* PCI BIOS service won't work from a PV guest. */ 1754 pci_probe &= ~PCI_PROBE_BIOS; 1755 #endif 1756 xen_raw_console_write("about to get started...\n"); 1757 1758 /* Let's presume PV guests always boot on vCPU with id 0. */ 1759 per_cpu(xen_vcpu_id, 0) = 0; 1760 1761 xen_setup_runstate_info(0); 1762 1763 xen_efi_init(); 1764 1765 /* Start the world */ 1766 #ifdef CONFIG_X86_32 1767 i386_start_kernel(); 1768 #else 1769 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1770 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1771 #endif 1772 } 1773 1774 void __ref xen_hvm_init_shared_info(void) 1775 { 1776 int cpu; 1777 struct xen_add_to_physmap xatp; 1778 static struct shared_info *shared_info_page = 0; 1779 1780 if (!shared_info_page) 1781 shared_info_page = (struct shared_info *) 1782 extend_brk(PAGE_SIZE, PAGE_SIZE); 1783 xatp.domid = DOMID_SELF; 1784 xatp.idx = 0; 1785 xatp.space = XENMAPSPACE_shared_info; 1786 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1787 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1788 BUG(); 1789 1790 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1791 1792 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1793 * page, we use it in the event channel upcall and in some pvclock 1794 * related functions. We don't need the vcpu_info placement 1795 * optimizations because we don't use any pv_mmu or pv_irq op on 1796 * HVM. 1797 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1798 * online but xen_hvm_init_shared_info is run at resume time too and 1799 * in that case multiple vcpus might be online. */ 1800 for_each_online_cpu(cpu) { 1801 /* Leave it to be NULL. */ 1802 if (xen_vcpu_nr(cpu) >= MAX_VIRT_CPUS) 1803 continue; 1804 per_cpu(xen_vcpu, cpu) = 1805 &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)]; 1806 } 1807 } 1808 1809 #ifdef CONFIG_XEN_PVHVM 1810 static void __init init_hvm_pv_info(void) 1811 { 1812 int major, minor; 1813 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1814 u64 pfn; 1815 1816 base = xen_cpuid_base(); 1817 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1818 1819 major = eax >> 16; 1820 minor = eax & 0xffff; 1821 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1822 1823 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1824 1825 pfn = __pa(hypercall_page); 1826 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1827 1828 xen_setup_features(); 1829 1830 cpuid(base + 4, &eax, &ebx, &ecx, &edx); 1831 if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT) 1832 this_cpu_write(xen_vcpu_id, ebx); 1833 else 1834 this_cpu_write(xen_vcpu_id, smp_processor_id()); 1835 1836 pv_info.name = "Xen HVM"; 1837 1838 xen_domain_type = XEN_HVM_DOMAIN; 1839 } 1840 1841 static int xen_cpu_up_prepare(unsigned int cpu) 1842 { 1843 int rc; 1844 1845 if (xen_hvm_domain()) { 1846 /* 1847 * This can happen if CPU was offlined earlier and 1848 * offlining timed out in common_cpu_die(). 1849 */ 1850 if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) { 1851 xen_smp_intr_free(cpu); 1852 xen_uninit_lock_cpu(cpu); 1853 } 1854 1855 if (cpu_acpi_id(cpu) != U32_MAX) 1856 per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu); 1857 else 1858 per_cpu(xen_vcpu_id, cpu) = cpu; 1859 xen_vcpu_setup(cpu); 1860 } 1861 1862 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 1863 xen_setup_timer(cpu); 1864 1865 rc = xen_smp_intr_init(cpu); 1866 if (rc) { 1867 WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n", 1868 cpu, rc); 1869 return rc; 1870 } 1871 return 0; 1872 } 1873 1874 static int xen_cpu_dead(unsigned int cpu) 1875 { 1876 xen_smp_intr_free(cpu); 1877 1878 if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) 1879 xen_teardown_timer(cpu); 1880 1881 return 0; 1882 } 1883 1884 static int xen_cpu_up_online(unsigned int cpu) 1885 { 1886 xen_init_lock_cpu(cpu); 1887 return 0; 1888 } 1889 1890 #ifdef CONFIG_KEXEC_CORE 1891 static void xen_hvm_shutdown(void) 1892 { 1893 native_machine_shutdown(); 1894 if (kexec_in_progress) 1895 xen_reboot(SHUTDOWN_soft_reset); 1896 } 1897 1898 static void xen_hvm_crash_shutdown(struct pt_regs *regs) 1899 { 1900 native_machine_crash_shutdown(regs); 1901 xen_reboot(SHUTDOWN_soft_reset); 1902 } 1903 #endif 1904 1905 static void __init xen_hvm_guest_init(void) 1906 { 1907 if (xen_pv_domain()) 1908 return; 1909 1910 init_hvm_pv_info(); 1911 1912 xen_hvm_init_shared_info(); 1913 1914 xen_panic_handler_init(); 1915 1916 BUG_ON(!xen_feature(XENFEAT_hvm_callback_vector)); 1917 1918 xen_hvm_smp_init(); 1919 WARN_ON(xen_cpuhp_setup()); 1920 xen_unplug_emulated_devices(); 1921 x86_init.irqs.intr_init = xen_init_IRQ; 1922 xen_hvm_init_time_ops(); 1923 xen_hvm_init_mmu_ops(); 1924 #ifdef CONFIG_KEXEC_CORE 1925 machine_ops.shutdown = xen_hvm_shutdown; 1926 machine_ops.crash_shutdown = xen_hvm_crash_shutdown; 1927 #endif 1928 } 1929 #endif 1930 1931 static bool xen_nopv = false; 1932 static __init int xen_parse_nopv(char *arg) 1933 { 1934 xen_nopv = true; 1935 return 0; 1936 } 1937 early_param("xen_nopv", xen_parse_nopv); 1938 1939 static uint32_t __init xen_platform(void) 1940 { 1941 if (xen_nopv) 1942 return 0; 1943 1944 return xen_cpuid_base(); 1945 } 1946 1947 bool xen_hvm_need_lapic(void) 1948 { 1949 if (xen_nopv) 1950 return false; 1951 if (xen_pv_domain()) 1952 return false; 1953 if (!xen_hvm_domain()) 1954 return false; 1955 if (xen_feature(XENFEAT_hvm_pirqs)) 1956 return false; 1957 return true; 1958 } 1959 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1960 1961 static void xen_set_cpu_features(struct cpuinfo_x86 *c) 1962 { 1963 if (xen_pv_domain()) { 1964 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); 1965 set_cpu_cap(c, X86_FEATURE_XENPV); 1966 } 1967 } 1968 1969 static void xen_pin_vcpu(int cpu) 1970 { 1971 static bool disable_pinning; 1972 struct sched_pin_override pin_override; 1973 int ret; 1974 1975 if (disable_pinning) 1976 return; 1977 1978 pin_override.pcpu = cpu; 1979 ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override); 1980 1981 /* Ignore errors when removing override. */ 1982 if (cpu < 0) 1983 return; 1984 1985 switch (ret) { 1986 case -ENOSYS: 1987 pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n", 1988 cpu); 1989 disable_pinning = true; 1990 break; 1991 case -EPERM: 1992 WARN(1, "Trying to pin vcpu without having privilege to do so\n"); 1993 disable_pinning = true; 1994 break; 1995 case -EINVAL: 1996 case -EBUSY: 1997 pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n", 1998 cpu); 1999 break; 2000 case 0: 2001 break; 2002 default: 2003 WARN(1, "rc %d while trying to pin vcpu\n", ret); 2004 disable_pinning = true; 2005 } 2006 } 2007 2008 const struct hypervisor_x86 x86_hyper_xen = { 2009 .name = "Xen", 2010 .detect = xen_platform, 2011 #ifdef CONFIG_XEN_PVHVM 2012 .init_platform = xen_hvm_guest_init, 2013 #endif 2014 .x2apic_available = xen_x2apic_para_available, 2015 .set_cpu_features = xen_set_cpu_features, 2016 .pin_vcpu = xen_pin_vcpu, 2017 }; 2018 EXPORT_SYMBOL(x86_hyper_xen); 2019 2020 #ifdef CONFIG_HOTPLUG_CPU 2021 void xen_arch_register_cpu(int num) 2022 { 2023 arch_register_cpu(num); 2024 } 2025 EXPORT_SYMBOL(xen_arch_register_cpu); 2026 2027 void xen_arch_unregister_cpu(int num) 2028 { 2029 arch_unregister_cpu(num); 2030 } 2031 EXPORT_SYMBOL(xen_arch_unregister_cpu); 2032 #endif 2033