1 /* 2 * Core of Xen paravirt_ops implementation. 3 * 4 * This file contains the xen_paravirt_ops structure itself, and the 5 * implementations for: 6 * - privileged instructions 7 * - interrupt flags 8 * - segment operations 9 * - booting and setup 10 * 11 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 12 */ 13 14 #include <linux/cpu.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/smp.h> 18 #include <linux/preempt.h> 19 #include <linux/hardirq.h> 20 #include <linux/percpu.h> 21 #include <linux/delay.h> 22 #include <linux/start_kernel.h> 23 #include <linux/sched.h> 24 #include <linux/kprobes.h> 25 #include <linux/bootmem.h> 26 #include <linux/module.h> 27 #include <linux/mm.h> 28 #include <linux/page-flags.h> 29 #include <linux/highmem.h> 30 #include <linux/console.h> 31 #include <linux/pci.h> 32 #include <linux/gfp.h> 33 #include <linux/memblock.h> 34 35 #include <xen/xen.h> 36 #include <xen/interface/xen.h> 37 #include <xen/interface/version.h> 38 #include <xen/interface/physdev.h> 39 #include <xen/interface/vcpu.h> 40 #include <xen/interface/memory.h> 41 #include <xen/features.h> 42 #include <xen/page.h> 43 #include <xen/hvm.h> 44 #include <xen/hvc-console.h> 45 46 #include <asm/paravirt.h> 47 #include <asm/apic.h> 48 #include <asm/page.h> 49 #include <asm/xen/pci.h> 50 #include <asm/xen/hypercall.h> 51 #include <asm/xen/hypervisor.h> 52 #include <asm/fixmap.h> 53 #include <asm/processor.h> 54 #include <asm/proto.h> 55 #include <asm/msr-index.h> 56 #include <asm/traps.h> 57 #include <asm/setup.h> 58 #include <asm/desc.h> 59 #include <asm/pgalloc.h> 60 #include <asm/pgtable.h> 61 #include <asm/tlbflush.h> 62 #include <asm/reboot.h> 63 #include <asm/stackprotector.h> 64 #include <asm/hypervisor.h> 65 66 #include "xen-ops.h" 67 #include "mmu.h" 68 #include "multicalls.h" 69 70 EXPORT_SYMBOL_GPL(hypercall_page); 71 72 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 73 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 74 75 enum xen_domain_type xen_domain_type = XEN_NATIVE; 76 EXPORT_SYMBOL_GPL(xen_domain_type); 77 78 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 79 EXPORT_SYMBOL(machine_to_phys_mapping); 80 unsigned int machine_to_phys_order; 81 EXPORT_SYMBOL(machine_to_phys_order); 82 83 struct start_info *xen_start_info; 84 EXPORT_SYMBOL_GPL(xen_start_info); 85 86 struct shared_info xen_dummy_shared_info; 87 88 void *xen_initial_gdt; 89 90 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 91 __read_mostly int xen_have_vector_callback; 92 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 93 94 /* 95 * Point at some empty memory to start with. We map the real shared_info 96 * page as soon as fixmap is up and running. 97 */ 98 struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info; 99 100 /* 101 * Flag to determine whether vcpu info placement is available on all 102 * VCPUs. We assume it is to start with, and then set it to zero on 103 * the first failure. This is because it can succeed on some VCPUs 104 * and not others, since it can involve hypervisor memory allocation, 105 * or because the guest failed to guarantee all the appropriate 106 * constraints on all VCPUs (ie buffer can't cross a page boundary). 107 * 108 * Note that any particular CPU may be using a placed vcpu structure, 109 * but we can only optimise if the all are. 110 * 111 * 0: not available, 1: available 112 */ 113 static int have_vcpu_info_placement = 1; 114 115 static void clamp_max_cpus(void) 116 { 117 #ifdef CONFIG_SMP 118 if (setup_max_cpus > MAX_VIRT_CPUS) 119 setup_max_cpus = MAX_VIRT_CPUS; 120 #endif 121 } 122 123 static void xen_vcpu_setup(int cpu) 124 { 125 struct vcpu_register_vcpu_info info; 126 int err; 127 struct vcpu_info *vcpup; 128 129 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 130 131 if (cpu < MAX_VIRT_CPUS) 132 per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 133 134 if (!have_vcpu_info_placement) { 135 if (cpu >= MAX_VIRT_CPUS) 136 clamp_max_cpus(); 137 return; 138 } 139 140 vcpup = &per_cpu(xen_vcpu_info, cpu); 141 info.mfn = arbitrary_virt_to_mfn(vcpup); 142 info.offset = offset_in_page(vcpup); 143 144 /* Check to see if the hypervisor will put the vcpu_info 145 structure where we want it, which allows direct access via 146 a percpu-variable. */ 147 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 148 149 if (err) { 150 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 151 have_vcpu_info_placement = 0; 152 clamp_max_cpus(); 153 } else { 154 /* This cpu is using the registered vcpu info, even if 155 later ones fail to. */ 156 per_cpu(xen_vcpu, cpu) = vcpup; 157 } 158 } 159 160 /* 161 * On restore, set the vcpu placement up again. 162 * If it fails, then we're in a bad state, since 163 * we can't back out from using it... 164 */ 165 void xen_vcpu_restore(void) 166 { 167 int cpu; 168 169 for_each_online_cpu(cpu) { 170 bool other_cpu = (cpu != smp_processor_id()); 171 172 if (other_cpu && 173 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 174 BUG(); 175 176 xen_setup_runstate_info(cpu); 177 178 if (have_vcpu_info_placement) 179 xen_vcpu_setup(cpu); 180 181 if (other_cpu && 182 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 183 BUG(); 184 } 185 } 186 187 static void __init xen_banner(void) 188 { 189 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 190 struct xen_extraversion extra; 191 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 192 193 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 194 pv_info.name); 195 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 196 version >> 16, version & 0xffff, extra.extraversion, 197 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 198 } 199 200 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 201 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 202 203 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 204 unsigned int *cx, unsigned int *dx) 205 { 206 unsigned maskebx = ~0; 207 unsigned maskecx = ~0; 208 unsigned maskedx = ~0; 209 210 /* 211 * Mask out inconvenient features, to try and disable as many 212 * unsupported kernel subsystems as possible. 213 */ 214 switch (*ax) { 215 case 1: 216 maskecx = cpuid_leaf1_ecx_mask; 217 maskedx = cpuid_leaf1_edx_mask; 218 break; 219 220 case 0xb: 221 /* Suppress extended topology stuff */ 222 maskebx = 0; 223 break; 224 } 225 226 asm(XEN_EMULATE_PREFIX "cpuid" 227 : "=a" (*ax), 228 "=b" (*bx), 229 "=c" (*cx), 230 "=d" (*dx) 231 : "0" (*ax), "2" (*cx)); 232 233 *bx &= maskebx; 234 *cx &= maskecx; 235 *dx &= maskedx; 236 } 237 238 static void __init xen_init_cpuid_mask(void) 239 { 240 unsigned int ax, bx, cx, dx; 241 unsigned int xsave_mask; 242 243 cpuid_leaf1_edx_mask = 244 ~((1 << X86_FEATURE_MCE) | /* disable MCE */ 245 (1 << X86_FEATURE_MCA) | /* disable MCA */ 246 (1 << X86_FEATURE_MTRR) | /* disable MTRR */ 247 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 248 249 if (!xen_initial_domain()) 250 cpuid_leaf1_edx_mask &= 251 ~((1 << X86_FEATURE_APIC) | /* disable local APIC */ 252 (1 << X86_FEATURE_ACPI)); /* disable ACPI */ 253 ax = 1; 254 xen_cpuid(&ax, &bx, &cx, &dx); 255 256 xsave_mask = 257 (1 << (X86_FEATURE_XSAVE % 32)) | 258 (1 << (X86_FEATURE_OSXSAVE % 32)); 259 260 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 261 if ((cx & xsave_mask) != xsave_mask) 262 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 263 } 264 265 static void xen_set_debugreg(int reg, unsigned long val) 266 { 267 HYPERVISOR_set_debugreg(reg, val); 268 } 269 270 static unsigned long xen_get_debugreg(int reg) 271 { 272 return HYPERVISOR_get_debugreg(reg); 273 } 274 275 static void xen_end_context_switch(struct task_struct *next) 276 { 277 xen_mc_flush(); 278 paravirt_end_context_switch(next); 279 } 280 281 static unsigned long xen_store_tr(void) 282 { 283 return 0; 284 } 285 286 /* 287 * Set the page permissions for a particular virtual address. If the 288 * address is a vmalloc mapping (or other non-linear mapping), then 289 * find the linear mapping of the page and also set its protections to 290 * match. 291 */ 292 static void set_aliased_prot(void *v, pgprot_t prot) 293 { 294 int level; 295 pte_t *ptep; 296 pte_t pte; 297 unsigned long pfn; 298 struct page *page; 299 300 ptep = lookup_address((unsigned long)v, &level); 301 BUG_ON(ptep == NULL); 302 303 pfn = pte_pfn(*ptep); 304 page = pfn_to_page(pfn); 305 306 pte = pfn_pte(pfn, prot); 307 308 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 309 BUG(); 310 311 if (!PageHighMem(page)) { 312 void *av = __va(PFN_PHYS(pfn)); 313 314 if (av != v) 315 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 316 BUG(); 317 } else 318 kmap_flush_unused(); 319 } 320 321 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 322 { 323 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 324 int i; 325 326 for(i = 0; i < entries; i += entries_per_page) 327 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 328 } 329 330 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 331 { 332 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 333 int i; 334 335 for(i = 0; i < entries; i += entries_per_page) 336 set_aliased_prot(ldt + i, PAGE_KERNEL); 337 } 338 339 static void xen_set_ldt(const void *addr, unsigned entries) 340 { 341 struct mmuext_op *op; 342 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 343 344 op = mcs.args; 345 op->cmd = MMUEXT_SET_LDT; 346 op->arg1.linear_addr = (unsigned long)addr; 347 op->arg2.nr_ents = entries; 348 349 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 350 351 xen_mc_issue(PARAVIRT_LAZY_CPU); 352 } 353 354 static void xen_load_gdt(const struct desc_ptr *dtr) 355 { 356 unsigned long va = dtr->address; 357 unsigned int size = dtr->size + 1; 358 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 359 unsigned long frames[pages]; 360 int f; 361 362 /* 363 * A GDT can be up to 64k in size, which corresponds to 8192 364 * 8-byte entries, or 16 4k pages.. 365 */ 366 367 BUG_ON(size > 65536); 368 BUG_ON(va & ~PAGE_MASK); 369 370 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 371 int level; 372 pte_t *ptep; 373 unsigned long pfn, mfn; 374 void *virt; 375 376 /* 377 * The GDT is per-cpu and is in the percpu data area. 378 * That can be virtually mapped, so we need to do a 379 * page-walk to get the underlying MFN for the 380 * hypercall. The page can also be in the kernel's 381 * linear range, so we need to RO that mapping too. 382 */ 383 ptep = lookup_address(va, &level); 384 BUG_ON(ptep == NULL); 385 386 pfn = pte_pfn(*ptep); 387 mfn = pfn_to_mfn(pfn); 388 virt = __va(PFN_PHYS(pfn)); 389 390 frames[f] = mfn; 391 392 make_lowmem_page_readonly((void *)va); 393 make_lowmem_page_readonly(virt); 394 } 395 396 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 397 BUG(); 398 } 399 400 /* 401 * load_gdt for early boot, when the gdt is only mapped once 402 */ 403 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 404 { 405 unsigned long va = dtr->address; 406 unsigned int size = dtr->size + 1; 407 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 408 unsigned long frames[pages]; 409 int f; 410 411 /* 412 * A GDT can be up to 64k in size, which corresponds to 8192 413 * 8-byte entries, or 16 4k pages.. 414 */ 415 416 BUG_ON(size > 65536); 417 BUG_ON(va & ~PAGE_MASK); 418 419 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 420 pte_t pte; 421 unsigned long pfn, mfn; 422 423 pfn = virt_to_pfn(va); 424 mfn = pfn_to_mfn(pfn); 425 426 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 427 428 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 429 BUG(); 430 431 frames[f] = mfn; 432 } 433 434 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 435 BUG(); 436 } 437 438 static void load_TLS_descriptor(struct thread_struct *t, 439 unsigned int cpu, unsigned int i) 440 { 441 struct desc_struct *gdt = get_cpu_gdt_table(cpu); 442 xmaddr_t maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 443 struct multicall_space mc = __xen_mc_entry(0); 444 445 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 446 } 447 448 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 449 { 450 /* 451 * XXX sleazy hack: If we're being called in a lazy-cpu zone 452 * and lazy gs handling is enabled, it means we're in a 453 * context switch, and %gs has just been saved. This means we 454 * can zero it out to prevent faults on exit from the 455 * hypervisor if the next process has no %gs. Either way, it 456 * has been saved, and the new value will get loaded properly. 457 * This will go away as soon as Xen has been modified to not 458 * save/restore %gs for normal hypercalls. 459 * 460 * On x86_64, this hack is not used for %gs, because gs points 461 * to KERNEL_GS_BASE (and uses it for PDA references), so we 462 * must not zero %gs on x86_64 463 * 464 * For x86_64, we need to zero %fs, otherwise we may get an 465 * exception between the new %fs descriptor being loaded and 466 * %fs being effectively cleared at __switch_to(). 467 */ 468 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 469 #ifdef CONFIG_X86_32 470 lazy_load_gs(0); 471 #else 472 loadsegment(fs, 0); 473 #endif 474 } 475 476 xen_mc_batch(); 477 478 load_TLS_descriptor(t, cpu, 0); 479 load_TLS_descriptor(t, cpu, 1); 480 load_TLS_descriptor(t, cpu, 2); 481 482 xen_mc_issue(PARAVIRT_LAZY_CPU); 483 } 484 485 #ifdef CONFIG_X86_64 486 static void xen_load_gs_index(unsigned int idx) 487 { 488 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 489 BUG(); 490 } 491 #endif 492 493 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 494 const void *ptr) 495 { 496 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 497 u64 entry = *(u64 *)ptr; 498 499 preempt_disable(); 500 501 xen_mc_flush(); 502 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 503 BUG(); 504 505 preempt_enable(); 506 } 507 508 static int cvt_gate_to_trap(int vector, const gate_desc *val, 509 struct trap_info *info) 510 { 511 unsigned long addr; 512 513 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 514 return 0; 515 516 info->vector = vector; 517 518 addr = gate_offset(*val); 519 #ifdef CONFIG_X86_64 520 /* 521 * Look for known traps using IST, and substitute them 522 * appropriately. The debugger ones are the only ones we care 523 * about. Xen will handle faults like double_fault and 524 * machine_check, so we should never see them. Warn if 525 * there's an unexpected IST-using fault handler. 526 */ 527 if (addr == (unsigned long)debug) 528 addr = (unsigned long)xen_debug; 529 else if (addr == (unsigned long)int3) 530 addr = (unsigned long)xen_int3; 531 else if (addr == (unsigned long)stack_segment) 532 addr = (unsigned long)xen_stack_segment; 533 else if (addr == (unsigned long)double_fault || 534 addr == (unsigned long)nmi) { 535 /* Don't need to handle these */ 536 return 0; 537 #ifdef CONFIG_X86_MCE 538 } else if (addr == (unsigned long)machine_check) { 539 return 0; 540 #endif 541 } else { 542 /* Some other trap using IST? */ 543 if (WARN_ON(val->ist != 0)) 544 return 0; 545 } 546 #endif /* CONFIG_X86_64 */ 547 info->address = addr; 548 549 info->cs = gate_segment(*val); 550 info->flags = val->dpl; 551 /* interrupt gates clear IF */ 552 if (val->type == GATE_INTERRUPT) 553 info->flags |= 1 << 2; 554 555 return 1; 556 } 557 558 /* Locations of each CPU's IDT */ 559 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 560 561 /* Set an IDT entry. If the entry is part of the current IDT, then 562 also update Xen. */ 563 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 564 { 565 unsigned long p = (unsigned long)&dt[entrynum]; 566 unsigned long start, end; 567 568 preempt_disable(); 569 570 start = __this_cpu_read(idt_desc.address); 571 end = start + __this_cpu_read(idt_desc.size) + 1; 572 573 xen_mc_flush(); 574 575 native_write_idt_entry(dt, entrynum, g); 576 577 if (p >= start && (p + 8) <= end) { 578 struct trap_info info[2]; 579 580 info[1].address = 0; 581 582 if (cvt_gate_to_trap(entrynum, g, &info[0])) 583 if (HYPERVISOR_set_trap_table(info)) 584 BUG(); 585 } 586 587 preempt_enable(); 588 } 589 590 static void xen_convert_trap_info(const struct desc_ptr *desc, 591 struct trap_info *traps) 592 { 593 unsigned in, out, count; 594 595 count = (desc->size+1) / sizeof(gate_desc); 596 BUG_ON(count > 256); 597 598 for (in = out = 0; in < count; in++) { 599 gate_desc *entry = (gate_desc*)(desc->address) + in; 600 601 if (cvt_gate_to_trap(in, entry, &traps[out])) 602 out++; 603 } 604 traps[out].address = 0; 605 } 606 607 void xen_copy_trap_info(struct trap_info *traps) 608 { 609 const struct desc_ptr *desc = &__get_cpu_var(idt_desc); 610 611 xen_convert_trap_info(desc, traps); 612 } 613 614 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 615 hold a spinlock to protect the static traps[] array (static because 616 it avoids allocation, and saves stack space). */ 617 static void xen_load_idt(const struct desc_ptr *desc) 618 { 619 static DEFINE_SPINLOCK(lock); 620 static struct trap_info traps[257]; 621 622 spin_lock(&lock); 623 624 __get_cpu_var(idt_desc) = *desc; 625 626 xen_convert_trap_info(desc, traps); 627 628 xen_mc_flush(); 629 if (HYPERVISOR_set_trap_table(traps)) 630 BUG(); 631 632 spin_unlock(&lock); 633 } 634 635 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 636 they're handled differently. */ 637 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 638 const void *desc, int type) 639 { 640 preempt_disable(); 641 642 switch (type) { 643 case DESC_LDT: 644 case DESC_TSS: 645 /* ignore */ 646 break; 647 648 default: { 649 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 650 651 xen_mc_flush(); 652 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 653 BUG(); 654 } 655 656 } 657 658 preempt_enable(); 659 } 660 661 /* 662 * Version of write_gdt_entry for use at early boot-time needed to 663 * update an entry as simply as possible. 664 */ 665 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 666 const void *desc, int type) 667 { 668 switch (type) { 669 case DESC_LDT: 670 case DESC_TSS: 671 /* ignore */ 672 break; 673 674 default: { 675 xmaddr_t maddr = virt_to_machine(&dt[entry]); 676 677 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 678 dt[entry] = *(struct desc_struct *)desc; 679 } 680 681 } 682 } 683 684 static void xen_load_sp0(struct tss_struct *tss, 685 struct thread_struct *thread) 686 { 687 struct multicall_space mcs = xen_mc_entry(0); 688 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 689 xen_mc_issue(PARAVIRT_LAZY_CPU); 690 } 691 692 static void xen_set_iopl_mask(unsigned mask) 693 { 694 struct physdev_set_iopl set_iopl; 695 696 /* Force the change at ring 0. */ 697 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 698 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 699 } 700 701 static void xen_io_delay(void) 702 { 703 } 704 705 #ifdef CONFIG_X86_LOCAL_APIC 706 static u32 xen_apic_read(u32 reg) 707 { 708 return 0; 709 } 710 711 static void xen_apic_write(u32 reg, u32 val) 712 { 713 /* Warn to see if there's any stray references */ 714 WARN_ON(1); 715 } 716 717 static u64 xen_apic_icr_read(void) 718 { 719 return 0; 720 } 721 722 static void xen_apic_icr_write(u32 low, u32 id) 723 { 724 /* Warn to see if there's any stray references */ 725 WARN_ON(1); 726 } 727 728 static void xen_apic_wait_icr_idle(void) 729 { 730 return; 731 } 732 733 static u32 xen_safe_apic_wait_icr_idle(void) 734 { 735 return 0; 736 } 737 738 static void set_xen_basic_apic_ops(void) 739 { 740 apic->read = xen_apic_read; 741 apic->write = xen_apic_write; 742 apic->icr_read = xen_apic_icr_read; 743 apic->icr_write = xen_apic_icr_write; 744 apic->wait_icr_idle = xen_apic_wait_icr_idle; 745 apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle; 746 } 747 748 #endif 749 750 static void xen_clts(void) 751 { 752 struct multicall_space mcs; 753 754 mcs = xen_mc_entry(0); 755 756 MULTI_fpu_taskswitch(mcs.mc, 0); 757 758 xen_mc_issue(PARAVIRT_LAZY_CPU); 759 } 760 761 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 762 763 static unsigned long xen_read_cr0(void) 764 { 765 unsigned long cr0 = percpu_read(xen_cr0_value); 766 767 if (unlikely(cr0 == 0)) { 768 cr0 = native_read_cr0(); 769 percpu_write(xen_cr0_value, cr0); 770 } 771 772 return cr0; 773 } 774 775 static void xen_write_cr0(unsigned long cr0) 776 { 777 struct multicall_space mcs; 778 779 percpu_write(xen_cr0_value, cr0); 780 781 /* Only pay attention to cr0.TS; everything else is 782 ignored. */ 783 mcs = xen_mc_entry(0); 784 785 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 786 787 xen_mc_issue(PARAVIRT_LAZY_CPU); 788 } 789 790 static void xen_write_cr4(unsigned long cr4) 791 { 792 cr4 &= ~X86_CR4_PGE; 793 cr4 &= ~X86_CR4_PSE; 794 795 native_write_cr4(cr4); 796 } 797 798 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 799 { 800 int ret; 801 802 ret = 0; 803 804 switch (msr) { 805 #ifdef CONFIG_X86_64 806 unsigned which; 807 u64 base; 808 809 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 810 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 811 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 812 813 set: 814 base = ((u64)high << 32) | low; 815 if (HYPERVISOR_set_segment_base(which, base) != 0) 816 ret = -EIO; 817 break; 818 #endif 819 820 case MSR_STAR: 821 case MSR_CSTAR: 822 case MSR_LSTAR: 823 case MSR_SYSCALL_MASK: 824 case MSR_IA32_SYSENTER_CS: 825 case MSR_IA32_SYSENTER_ESP: 826 case MSR_IA32_SYSENTER_EIP: 827 /* Fast syscall setup is all done in hypercalls, so 828 these are all ignored. Stub them out here to stop 829 Xen console noise. */ 830 break; 831 832 case MSR_IA32_CR_PAT: 833 if (smp_processor_id() == 0) 834 xen_set_pat(((u64)high << 32) | low); 835 break; 836 837 default: 838 ret = native_write_msr_safe(msr, low, high); 839 } 840 841 return ret; 842 } 843 844 void xen_setup_shared_info(void) 845 { 846 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 847 set_fixmap(FIX_PARAVIRT_BOOTMAP, 848 xen_start_info->shared_info); 849 850 HYPERVISOR_shared_info = 851 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 852 } else 853 HYPERVISOR_shared_info = 854 (struct shared_info *)__va(xen_start_info->shared_info); 855 856 #ifndef CONFIG_SMP 857 /* In UP this is as good a place as any to set up shared info */ 858 xen_setup_vcpu_info_placement(); 859 #endif 860 861 xen_setup_mfn_list_list(); 862 } 863 864 /* This is called once we have the cpu_possible_map */ 865 void xen_setup_vcpu_info_placement(void) 866 { 867 int cpu; 868 869 for_each_possible_cpu(cpu) 870 xen_vcpu_setup(cpu); 871 872 /* xen_vcpu_setup managed to place the vcpu_info within the 873 percpu area for all cpus, so make use of it */ 874 if (have_vcpu_info_placement) { 875 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 876 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 877 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 878 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 879 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 880 } 881 } 882 883 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 884 unsigned long addr, unsigned len) 885 { 886 char *start, *end, *reloc; 887 unsigned ret; 888 889 start = end = reloc = NULL; 890 891 #define SITE(op, x) \ 892 case PARAVIRT_PATCH(op.x): \ 893 if (have_vcpu_info_placement) { \ 894 start = (char *)xen_##x##_direct; \ 895 end = xen_##x##_direct_end; \ 896 reloc = xen_##x##_direct_reloc; \ 897 } \ 898 goto patch_site 899 900 switch (type) { 901 SITE(pv_irq_ops, irq_enable); 902 SITE(pv_irq_ops, irq_disable); 903 SITE(pv_irq_ops, save_fl); 904 SITE(pv_irq_ops, restore_fl); 905 #undef SITE 906 907 patch_site: 908 if (start == NULL || (end-start) > len) 909 goto default_patch; 910 911 ret = paravirt_patch_insns(insnbuf, len, start, end); 912 913 /* Note: because reloc is assigned from something that 914 appears to be an array, gcc assumes it's non-null, 915 but doesn't know its relationship with start and 916 end. */ 917 if (reloc > start && reloc < end) { 918 int reloc_off = reloc - start; 919 long *relocp = (long *)(insnbuf + reloc_off); 920 long delta = start - (char *)addr; 921 922 *relocp += delta; 923 } 924 break; 925 926 default_patch: 927 default: 928 ret = paravirt_patch_default(type, clobbers, insnbuf, 929 addr, len); 930 break; 931 } 932 933 return ret; 934 } 935 936 static const struct pv_info xen_info __initconst = { 937 .paravirt_enabled = 1, 938 .shared_kernel_pmd = 0, 939 940 .name = "Xen", 941 }; 942 943 static const struct pv_init_ops xen_init_ops __initconst = { 944 .patch = xen_patch, 945 }; 946 947 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 948 .cpuid = xen_cpuid, 949 950 .set_debugreg = xen_set_debugreg, 951 .get_debugreg = xen_get_debugreg, 952 953 .clts = xen_clts, 954 955 .read_cr0 = xen_read_cr0, 956 .write_cr0 = xen_write_cr0, 957 958 .read_cr4 = native_read_cr4, 959 .read_cr4_safe = native_read_cr4_safe, 960 .write_cr4 = xen_write_cr4, 961 962 .wbinvd = native_wbinvd, 963 964 .read_msr = native_read_msr_safe, 965 .write_msr = xen_write_msr_safe, 966 .read_tsc = native_read_tsc, 967 .read_pmc = native_read_pmc, 968 969 .iret = xen_iret, 970 .irq_enable_sysexit = xen_sysexit, 971 #ifdef CONFIG_X86_64 972 .usergs_sysret32 = xen_sysret32, 973 .usergs_sysret64 = xen_sysret64, 974 #endif 975 976 .load_tr_desc = paravirt_nop, 977 .set_ldt = xen_set_ldt, 978 .load_gdt = xen_load_gdt, 979 .load_idt = xen_load_idt, 980 .load_tls = xen_load_tls, 981 #ifdef CONFIG_X86_64 982 .load_gs_index = xen_load_gs_index, 983 #endif 984 985 .alloc_ldt = xen_alloc_ldt, 986 .free_ldt = xen_free_ldt, 987 988 .store_gdt = native_store_gdt, 989 .store_idt = native_store_idt, 990 .store_tr = xen_store_tr, 991 992 .write_ldt_entry = xen_write_ldt_entry, 993 .write_gdt_entry = xen_write_gdt_entry, 994 .write_idt_entry = xen_write_idt_entry, 995 .load_sp0 = xen_load_sp0, 996 997 .set_iopl_mask = xen_set_iopl_mask, 998 .io_delay = xen_io_delay, 999 1000 /* Xen takes care of %gs when switching to usermode for us */ 1001 .swapgs = paravirt_nop, 1002 1003 .start_context_switch = paravirt_start_context_switch, 1004 .end_context_switch = xen_end_context_switch, 1005 }; 1006 1007 static const struct pv_apic_ops xen_apic_ops __initconst = { 1008 #ifdef CONFIG_X86_LOCAL_APIC 1009 .startup_ipi_hook = paravirt_nop, 1010 #endif 1011 }; 1012 1013 static void xen_reboot(int reason) 1014 { 1015 struct sched_shutdown r = { .reason = reason }; 1016 1017 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1018 BUG(); 1019 } 1020 1021 static void xen_restart(char *msg) 1022 { 1023 xen_reboot(SHUTDOWN_reboot); 1024 } 1025 1026 static void xen_emergency_restart(void) 1027 { 1028 xen_reboot(SHUTDOWN_reboot); 1029 } 1030 1031 static void xen_machine_halt(void) 1032 { 1033 xen_reboot(SHUTDOWN_poweroff); 1034 } 1035 1036 static void xen_machine_power_off(void) 1037 { 1038 if (pm_power_off) 1039 pm_power_off(); 1040 xen_reboot(SHUTDOWN_poweroff); 1041 } 1042 1043 static void xen_crash_shutdown(struct pt_regs *regs) 1044 { 1045 xen_reboot(SHUTDOWN_crash); 1046 } 1047 1048 static int 1049 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1050 { 1051 xen_reboot(SHUTDOWN_crash); 1052 return NOTIFY_DONE; 1053 } 1054 1055 static struct notifier_block xen_panic_block = { 1056 .notifier_call= xen_panic_event, 1057 }; 1058 1059 int xen_panic_handler_init(void) 1060 { 1061 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1062 return 0; 1063 } 1064 1065 static const struct machine_ops xen_machine_ops __initconst = { 1066 .restart = xen_restart, 1067 .halt = xen_machine_halt, 1068 .power_off = xen_machine_power_off, 1069 .shutdown = xen_machine_halt, 1070 .crash_shutdown = xen_crash_shutdown, 1071 .emergency_restart = xen_emergency_restart, 1072 }; 1073 1074 /* 1075 * Set up the GDT and segment registers for -fstack-protector. Until 1076 * we do this, we have to be careful not to call any stack-protected 1077 * function, which is most of the kernel. 1078 */ 1079 static void __init xen_setup_stackprotector(void) 1080 { 1081 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1082 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1083 1084 setup_stack_canary_segment(0); 1085 switch_to_new_gdt(0); 1086 1087 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1088 pv_cpu_ops.load_gdt = xen_load_gdt; 1089 } 1090 1091 /* First C function to be called on Xen boot */ 1092 asmlinkage void __init xen_start_kernel(void) 1093 { 1094 struct physdev_set_iopl set_iopl; 1095 int rc; 1096 pgd_t *pgd; 1097 1098 if (!xen_start_info) 1099 return; 1100 1101 xen_domain_type = XEN_PV_DOMAIN; 1102 1103 xen_setup_machphys_mapping(); 1104 1105 /* Install Xen paravirt ops */ 1106 pv_info = xen_info; 1107 pv_init_ops = xen_init_ops; 1108 pv_cpu_ops = xen_cpu_ops; 1109 pv_apic_ops = xen_apic_ops; 1110 1111 x86_init.resources.memory_setup = xen_memory_setup; 1112 x86_init.oem.arch_setup = xen_arch_setup; 1113 x86_init.oem.banner = xen_banner; 1114 1115 xen_init_time_ops(); 1116 1117 /* 1118 * Set up some pagetable state before starting to set any ptes. 1119 */ 1120 1121 xen_init_mmu_ops(); 1122 1123 /* Prevent unwanted bits from being set in PTEs. */ 1124 __supported_pte_mask &= ~_PAGE_GLOBAL; 1125 if (!xen_initial_domain()) 1126 __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); 1127 1128 __supported_pte_mask |= _PAGE_IOMAP; 1129 1130 /* 1131 * Prevent page tables from being allocated in highmem, even 1132 * if CONFIG_HIGHPTE is enabled. 1133 */ 1134 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1135 1136 /* Work out if we support NX */ 1137 x86_configure_nx(); 1138 1139 xen_setup_features(); 1140 1141 /* Get mfn list */ 1142 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1143 xen_build_dynamic_phys_to_machine(); 1144 1145 /* 1146 * Set up kernel GDT and segment registers, mainly so that 1147 * -fstack-protector code can be executed. 1148 */ 1149 xen_setup_stackprotector(); 1150 1151 xen_init_irq_ops(); 1152 xen_init_cpuid_mask(); 1153 1154 #ifdef CONFIG_X86_LOCAL_APIC 1155 /* 1156 * set up the basic apic ops. 1157 */ 1158 set_xen_basic_apic_ops(); 1159 #endif 1160 1161 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1162 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1163 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1164 } 1165 1166 machine_ops = xen_machine_ops; 1167 1168 /* 1169 * The only reliable way to retain the initial address of the 1170 * percpu gdt_page is to remember it here, so we can go and 1171 * mark it RW later, when the initial percpu area is freed. 1172 */ 1173 xen_initial_gdt = &per_cpu(gdt_page, 0); 1174 1175 xen_smp_init(); 1176 1177 #ifdef CONFIG_ACPI_NUMA 1178 /* 1179 * The pages we from Xen are not related to machine pages, so 1180 * any NUMA information the kernel tries to get from ACPI will 1181 * be meaningless. Prevent it from trying. 1182 */ 1183 acpi_numa = -1; 1184 #endif 1185 1186 pgd = (pgd_t *)xen_start_info->pt_base; 1187 1188 if (!xen_initial_domain()) 1189 __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); 1190 1191 __supported_pte_mask |= _PAGE_IOMAP; 1192 /* Don't do the full vcpu_info placement stuff until we have a 1193 possible map and a non-dummy shared_info. */ 1194 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1195 1196 local_irq_disable(); 1197 early_boot_irqs_disabled = true; 1198 1199 memblock_init(); 1200 1201 xen_raw_console_write("mapping kernel into physical memory\n"); 1202 pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages); 1203 xen_ident_map_ISA(); 1204 1205 /* Allocate and initialize top and mid mfn levels for p2m structure */ 1206 xen_build_mfn_list_list(); 1207 1208 /* keep using Xen gdt for now; no urgent need to change it */ 1209 1210 #ifdef CONFIG_X86_32 1211 pv_info.kernel_rpl = 1; 1212 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1213 pv_info.kernel_rpl = 0; 1214 #else 1215 pv_info.kernel_rpl = 0; 1216 #endif 1217 /* set the limit of our address space */ 1218 xen_reserve_top(); 1219 1220 /* We used to do this in xen_arch_setup, but that is too late on AMD 1221 * were early_cpu_init (run before ->arch_setup()) calls early_amd_init 1222 * which pokes 0xcf8 port. 1223 */ 1224 set_iopl.iopl = 1; 1225 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1226 if (rc != 0) 1227 xen_raw_printk("physdev_op failed %d\n", rc); 1228 1229 #ifdef CONFIG_X86_32 1230 /* set up basic CPUID stuff */ 1231 cpu_detect(&new_cpu_data); 1232 new_cpu_data.hard_math = 1; 1233 new_cpu_data.wp_works_ok = 1; 1234 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1235 #endif 1236 1237 /* Poke various useful things into boot_params */ 1238 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1239 boot_params.hdr.ramdisk_image = xen_start_info->mod_start 1240 ? __pa(xen_start_info->mod_start) : 0; 1241 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1242 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1243 1244 if (!xen_initial_domain()) { 1245 add_preferred_console("xenboot", 0, NULL); 1246 add_preferred_console("tty", 0, NULL); 1247 add_preferred_console("hvc", 0, NULL); 1248 if (pci_xen) 1249 x86_init.pci.arch_init = pci_xen_init; 1250 } else { 1251 /* Make sure ACS will be enabled */ 1252 pci_request_acs(); 1253 } 1254 1255 1256 xen_raw_console_write("about to get started...\n"); 1257 1258 xen_setup_runstate_info(0); 1259 1260 /* Start the world */ 1261 #ifdef CONFIG_X86_32 1262 i386_start_kernel(); 1263 #else 1264 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1265 #endif 1266 } 1267 1268 static int init_hvm_pv_info(int *major, int *minor) 1269 { 1270 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1271 u64 pfn; 1272 1273 base = xen_cpuid_base(); 1274 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1275 1276 *major = eax >> 16; 1277 *minor = eax & 0xffff; 1278 printk(KERN_INFO "Xen version %d.%d.\n", *major, *minor); 1279 1280 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1281 1282 pfn = __pa(hypercall_page); 1283 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1284 1285 xen_setup_features(); 1286 1287 pv_info.name = "Xen HVM"; 1288 1289 xen_domain_type = XEN_HVM_DOMAIN; 1290 1291 return 0; 1292 } 1293 1294 void __ref xen_hvm_init_shared_info(void) 1295 { 1296 int cpu; 1297 struct xen_add_to_physmap xatp; 1298 static struct shared_info *shared_info_page = 0; 1299 1300 if (!shared_info_page) 1301 shared_info_page = (struct shared_info *) 1302 extend_brk(PAGE_SIZE, PAGE_SIZE); 1303 xatp.domid = DOMID_SELF; 1304 xatp.idx = 0; 1305 xatp.space = XENMAPSPACE_shared_info; 1306 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1307 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1308 BUG(); 1309 1310 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1311 1312 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1313 * page, we use it in the event channel upcall and in some pvclock 1314 * related functions. We don't need the vcpu_info placement 1315 * optimizations because we don't use any pv_mmu or pv_irq op on 1316 * HVM. 1317 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1318 * online but xen_hvm_init_shared_info is run at resume time too and 1319 * in that case multiple vcpus might be online. */ 1320 for_each_online_cpu(cpu) { 1321 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1322 } 1323 } 1324 1325 #ifdef CONFIG_XEN_PVHVM 1326 static int __cpuinit xen_hvm_cpu_notify(struct notifier_block *self, 1327 unsigned long action, void *hcpu) 1328 { 1329 int cpu = (long)hcpu; 1330 switch (action) { 1331 case CPU_UP_PREPARE: 1332 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1333 if (xen_have_vector_callback) 1334 xen_init_lock_cpu(cpu); 1335 break; 1336 default: 1337 break; 1338 } 1339 return NOTIFY_OK; 1340 } 1341 1342 static struct notifier_block xen_hvm_cpu_notifier __cpuinitdata = { 1343 .notifier_call = xen_hvm_cpu_notify, 1344 }; 1345 1346 static void __init xen_hvm_guest_init(void) 1347 { 1348 int r; 1349 int major, minor; 1350 1351 r = init_hvm_pv_info(&major, &minor); 1352 if (r < 0) 1353 return; 1354 1355 xen_hvm_init_shared_info(); 1356 1357 if (xen_feature(XENFEAT_hvm_callback_vector)) 1358 xen_have_vector_callback = 1; 1359 xen_hvm_smp_init(); 1360 register_cpu_notifier(&xen_hvm_cpu_notifier); 1361 xen_unplug_emulated_devices(); 1362 have_vcpu_info_placement = 0; 1363 x86_init.irqs.intr_init = xen_init_IRQ; 1364 xen_hvm_init_time_ops(); 1365 xen_hvm_init_mmu_ops(); 1366 } 1367 1368 static bool __init xen_hvm_platform(void) 1369 { 1370 if (xen_pv_domain()) 1371 return false; 1372 1373 if (!xen_cpuid_base()) 1374 return false; 1375 1376 return true; 1377 } 1378 1379 bool xen_hvm_need_lapic(void) 1380 { 1381 if (xen_pv_domain()) 1382 return false; 1383 if (!xen_hvm_domain()) 1384 return false; 1385 if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) 1386 return false; 1387 return true; 1388 } 1389 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1390 1391 const struct hypervisor_x86 x86_hyper_xen_hvm __refconst = { 1392 .name = "Xen HVM", 1393 .detect = xen_hvm_platform, 1394 .init_platform = xen_hvm_guest_init, 1395 }; 1396 EXPORT_SYMBOL(x86_hyper_xen_hvm); 1397 #endif 1398