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/kernel.h> 15 #include <linux/init.h> 16 #include <linux/smp.h> 17 #include <linux/preempt.h> 18 #include <linux/hardirq.h> 19 #include <linux/percpu.h> 20 #include <linux/delay.h> 21 #include <linux/start_kernel.h> 22 #include <linux/sched.h> 23 #include <linux/kprobes.h> 24 #include <linux/bootmem.h> 25 #include <linux/module.h> 26 #include <linux/mm.h> 27 #include <linux/page-flags.h> 28 #include <linux/highmem.h> 29 #include <linux/console.h> 30 31 #include <xen/interface/xen.h> 32 #include <xen/interface/version.h> 33 #include <xen/interface/physdev.h> 34 #include <xen/interface/vcpu.h> 35 #include <xen/features.h> 36 #include <xen/page.h> 37 #include <xen/hvc-console.h> 38 39 #include <asm/paravirt.h> 40 #include <asm/apic.h> 41 #include <asm/page.h> 42 #include <asm/xen/hypercall.h> 43 #include <asm/xen/hypervisor.h> 44 #include <asm/fixmap.h> 45 #include <asm/processor.h> 46 #include <asm/proto.h> 47 #include <asm/msr-index.h> 48 #include <asm/traps.h> 49 #include <asm/setup.h> 50 #include <asm/desc.h> 51 #include <asm/pgtable.h> 52 #include <asm/tlbflush.h> 53 #include <asm/reboot.h> 54 55 #include "xen-ops.h" 56 #include "mmu.h" 57 #include "multicalls.h" 58 59 EXPORT_SYMBOL_GPL(hypercall_page); 60 61 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 62 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 63 64 enum xen_domain_type xen_domain_type = XEN_NATIVE; 65 EXPORT_SYMBOL_GPL(xen_domain_type); 66 67 struct start_info *xen_start_info; 68 EXPORT_SYMBOL_GPL(xen_start_info); 69 70 struct shared_info xen_dummy_shared_info; 71 72 void *xen_initial_gdt; 73 74 /* 75 * Point at some empty memory to start with. We map the real shared_info 76 * page as soon as fixmap is up and running. 77 */ 78 struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info; 79 80 /* 81 * Flag to determine whether vcpu info placement is available on all 82 * VCPUs. We assume it is to start with, and then set it to zero on 83 * the first failure. This is because it can succeed on some VCPUs 84 * and not others, since it can involve hypervisor memory allocation, 85 * or because the guest failed to guarantee all the appropriate 86 * constraints on all VCPUs (ie buffer can't cross a page boundary). 87 * 88 * Note that any particular CPU may be using a placed vcpu structure, 89 * but we can only optimise if the all are. 90 * 91 * 0: not available, 1: available 92 */ 93 static int have_vcpu_info_placement = 1; 94 95 static void xen_vcpu_setup(int cpu) 96 { 97 struct vcpu_register_vcpu_info info; 98 int err; 99 struct vcpu_info *vcpup; 100 101 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 102 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 103 104 if (!have_vcpu_info_placement) 105 return; /* already tested, not available */ 106 107 vcpup = &per_cpu(xen_vcpu_info, cpu); 108 109 info.mfn = arbitrary_virt_to_mfn(vcpup); 110 info.offset = offset_in_page(vcpup); 111 112 printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %llx, offset %d\n", 113 cpu, vcpup, info.mfn, info.offset); 114 115 /* Check to see if the hypervisor will put the vcpu_info 116 structure where we want it, which allows direct access via 117 a percpu-variable. */ 118 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 119 120 if (err) { 121 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 122 have_vcpu_info_placement = 0; 123 } else { 124 /* This cpu is using the registered vcpu info, even if 125 later ones fail to. */ 126 per_cpu(xen_vcpu, cpu) = vcpup; 127 128 printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n", 129 cpu, vcpup); 130 } 131 } 132 133 /* 134 * On restore, set the vcpu placement up again. 135 * If it fails, then we're in a bad state, since 136 * we can't back out from using it... 137 */ 138 void xen_vcpu_restore(void) 139 { 140 if (have_vcpu_info_placement) { 141 int cpu; 142 143 for_each_online_cpu(cpu) { 144 bool other_cpu = (cpu != smp_processor_id()); 145 146 if (other_cpu && 147 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 148 BUG(); 149 150 xen_vcpu_setup(cpu); 151 152 if (other_cpu && 153 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 154 BUG(); 155 } 156 157 BUG_ON(!have_vcpu_info_placement); 158 } 159 } 160 161 static void __init xen_banner(void) 162 { 163 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 164 struct xen_extraversion extra; 165 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 166 167 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 168 pv_info.name); 169 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 170 version >> 16, version & 0xffff, extra.extraversion, 171 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 172 } 173 174 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 175 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 176 177 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 178 unsigned int *cx, unsigned int *dx) 179 { 180 unsigned maskecx = ~0; 181 unsigned maskedx = ~0; 182 183 /* 184 * Mask out inconvenient features, to try and disable as many 185 * unsupported kernel subsystems as possible. 186 */ 187 if (*ax == 1) { 188 maskecx = cpuid_leaf1_ecx_mask; 189 maskedx = cpuid_leaf1_edx_mask; 190 } 191 192 asm(XEN_EMULATE_PREFIX "cpuid" 193 : "=a" (*ax), 194 "=b" (*bx), 195 "=c" (*cx), 196 "=d" (*dx) 197 : "0" (*ax), "2" (*cx)); 198 199 *cx &= maskecx; 200 *dx &= maskedx; 201 } 202 203 static __init void xen_init_cpuid_mask(void) 204 { 205 unsigned int ax, bx, cx, dx; 206 207 cpuid_leaf1_edx_mask = 208 ~((1 << X86_FEATURE_MCE) | /* disable MCE */ 209 (1 << X86_FEATURE_MCA) | /* disable MCA */ 210 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 211 212 if (!xen_initial_domain()) 213 cpuid_leaf1_edx_mask &= 214 ~((1 << X86_FEATURE_APIC) | /* disable local APIC */ 215 (1 << X86_FEATURE_ACPI)); /* disable ACPI */ 216 217 ax = 1; 218 xen_cpuid(&ax, &bx, &cx, &dx); 219 220 /* cpuid claims we support xsave; try enabling it to see what happens */ 221 if (cx & (1 << (X86_FEATURE_XSAVE % 32))) { 222 unsigned long cr4; 223 224 set_in_cr4(X86_CR4_OSXSAVE); 225 226 cr4 = read_cr4(); 227 228 if ((cr4 & X86_CR4_OSXSAVE) == 0) 229 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32)); 230 231 clear_in_cr4(X86_CR4_OSXSAVE); 232 } 233 } 234 235 static void xen_set_debugreg(int reg, unsigned long val) 236 { 237 HYPERVISOR_set_debugreg(reg, val); 238 } 239 240 static unsigned long xen_get_debugreg(int reg) 241 { 242 return HYPERVISOR_get_debugreg(reg); 243 } 244 245 static void xen_end_context_switch(struct task_struct *next) 246 { 247 xen_mc_flush(); 248 paravirt_end_context_switch(next); 249 } 250 251 static unsigned long xen_store_tr(void) 252 { 253 return 0; 254 } 255 256 /* 257 * Set the page permissions for a particular virtual address. If the 258 * address is a vmalloc mapping (or other non-linear mapping), then 259 * find the linear mapping of the page and also set its protections to 260 * match. 261 */ 262 static void set_aliased_prot(void *v, pgprot_t prot) 263 { 264 int level; 265 pte_t *ptep; 266 pte_t pte; 267 unsigned long pfn; 268 struct page *page; 269 270 ptep = lookup_address((unsigned long)v, &level); 271 BUG_ON(ptep == NULL); 272 273 pfn = pte_pfn(*ptep); 274 page = pfn_to_page(pfn); 275 276 pte = pfn_pte(pfn, prot); 277 278 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 279 BUG(); 280 281 if (!PageHighMem(page)) { 282 void *av = __va(PFN_PHYS(pfn)); 283 284 if (av != v) 285 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 286 BUG(); 287 } else 288 kmap_flush_unused(); 289 } 290 291 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 292 { 293 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 294 int i; 295 296 for(i = 0; i < entries; i += entries_per_page) 297 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 298 } 299 300 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 301 { 302 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 303 int i; 304 305 for(i = 0; i < entries; i += entries_per_page) 306 set_aliased_prot(ldt + i, PAGE_KERNEL); 307 } 308 309 static void xen_set_ldt(const void *addr, unsigned entries) 310 { 311 struct mmuext_op *op; 312 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 313 314 op = mcs.args; 315 op->cmd = MMUEXT_SET_LDT; 316 op->arg1.linear_addr = (unsigned long)addr; 317 op->arg2.nr_ents = entries; 318 319 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 320 321 xen_mc_issue(PARAVIRT_LAZY_CPU); 322 } 323 324 static void xen_load_gdt(const struct desc_ptr *dtr) 325 { 326 unsigned long va = dtr->address; 327 unsigned int size = dtr->size + 1; 328 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 329 unsigned long frames[pages]; 330 int f; 331 332 /* A GDT can be up to 64k in size, which corresponds to 8192 333 8-byte entries, or 16 4k pages.. */ 334 335 BUG_ON(size > 65536); 336 BUG_ON(va & ~PAGE_MASK); 337 338 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 339 int level; 340 pte_t *ptep = lookup_address(va, &level); 341 unsigned long pfn, mfn; 342 void *virt; 343 344 BUG_ON(ptep == NULL); 345 346 pfn = pte_pfn(*ptep); 347 mfn = pfn_to_mfn(pfn); 348 virt = __va(PFN_PHYS(pfn)); 349 350 frames[f] = mfn; 351 352 make_lowmem_page_readonly((void *)va); 353 make_lowmem_page_readonly(virt); 354 } 355 356 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 357 BUG(); 358 } 359 360 static void load_TLS_descriptor(struct thread_struct *t, 361 unsigned int cpu, unsigned int i) 362 { 363 struct desc_struct *gdt = get_cpu_gdt_table(cpu); 364 xmaddr_t maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 365 struct multicall_space mc = __xen_mc_entry(0); 366 367 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 368 } 369 370 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 371 { 372 /* 373 * XXX sleazy hack: If we're being called in a lazy-cpu zone 374 * and lazy gs handling is enabled, it means we're in a 375 * context switch, and %gs has just been saved. This means we 376 * can zero it out to prevent faults on exit from the 377 * hypervisor if the next process has no %gs. Either way, it 378 * has been saved, and the new value will get loaded properly. 379 * This will go away as soon as Xen has been modified to not 380 * save/restore %gs for normal hypercalls. 381 * 382 * On x86_64, this hack is not used for %gs, because gs points 383 * to KERNEL_GS_BASE (and uses it for PDA references), so we 384 * must not zero %gs on x86_64 385 * 386 * For x86_64, we need to zero %fs, otherwise we may get an 387 * exception between the new %fs descriptor being loaded and 388 * %fs being effectively cleared at __switch_to(). 389 */ 390 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 391 #ifdef CONFIG_X86_32 392 lazy_load_gs(0); 393 #else 394 loadsegment(fs, 0); 395 #endif 396 } 397 398 xen_mc_batch(); 399 400 load_TLS_descriptor(t, cpu, 0); 401 load_TLS_descriptor(t, cpu, 1); 402 load_TLS_descriptor(t, cpu, 2); 403 404 xen_mc_issue(PARAVIRT_LAZY_CPU); 405 } 406 407 #ifdef CONFIG_X86_64 408 static void xen_load_gs_index(unsigned int idx) 409 { 410 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 411 BUG(); 412 } 413 #endif 414 415 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 416 const void *ptr) 417 { 418 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 419 u64 entry = *(u64 *)ptr; 420 421 preempt_disable(); 422 423 xen_mc_flush(); 424 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 425 BUG(); 426 427 preempt_enable(); 428 } 429 430 static int cvt_gate_to_trap(int vector, const gate_desc *val, 431 struct trap_info *info) 432 { 433 unsigned long addr; 434 435 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 436 return 0; 437 438 info->vector = vector; 439 440 addr = gate_offset(*val); 441 #ifdef CONFIG_X86_64 442 /* 443 * Look for known traps using IST, and substitute them 444 * appropriately. The debugger ones are the only ones we care 445 * about. Xen will handle faults like double_fault and 446 * machine_check, so we should never see them. Warn if 447 * there's an unexpected IST-using fault handler. 448 */ 449 if (addr == (unsigned long)debug) 450 addr = (unsigned long)xen_debug; 451 else if (addr == (unsigned long)int3) 452 addr = (unsigned long)xen_int3; 453 else if (addr == (unsigned long)stack_segment) 454 addr = (unsigned long)xen_stack_segment; 455 else if (addr == (unsigned long)double_fault || 456 addr == (unsigned long)nmi) { 457 /* Don't need to handle these */ 458 return 0; 459 #ifdef CONFIG_X86_MCE 460 } else if (addr == (unsigned long)machine_check) { 461 return 0; 462 #endif 463 } else { 464 /* Some other trap using IST? */ 465 if (WARN_ON(val->ist != 0)) 466 return 0; 467 } 468 #endif /* CONFIG_X86_64 */ 469 info->address = addr; 470 471 info->cs = gate_segment(*val); 472 info->flags = val->dpl; 473 /* interrupt gates clear IF */ 474 if (val->type == GATE_INTERRUPT) 475 info->flags |= 1 << 2; 476 477 return 1; 478 } 479 480 /* Locations of each CPU's IDT */ 481 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 482 483 /* Set an IDT entry. If the entry is part of the current IDT, then 484 also update Xen. */ 485 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 486 { 487 unsigned long p = (unsigned long)&dt[entrynum]; 488 unsigned long start, end; 489 490 preempt_disable(); 491 492 start = __get_cpu_var(idt_desc).address; 493 end = start + __get_cpu_var(idt_desc).size + 1; 494 495 xen_mc_flush(); 496 497 native_write_idt_entry(dt, entrynum, g); 498 499 if (p >= start && (p + 8) <= end) { 500 struct trap_info info[2]; 501 502 info[1].address = 0; 503 504 if (cvt_gate_to_trap(entrynum, g, &info[0])) 505 if (HYPERVISOR_set_trap_table(info)) 506 BUG(); 507 } 508 509 preempt_enable(); 510 } 511 512 static void xen_convert_trap_info(const struct desc_ptr *desc, 513 struct trap_info *traps) 514 { 515 unsigned in, out, count; 516 517 count = (desc->size+1) / sizeof(gate_desc); 518 BUG_ON(count > 256); 519 520 for (in = out = 0; in < count; in++) { 521 gate_desc *entry = (gate_desc*)(desc->address) + in; 522 523 if (cvt_gate_to_trap(in, entry, &traps[out])) 524 out++; 525 } 526 traps[out].address = 0; 527 } 528 529 void xen_copy_trap_info(struct trap_info *traps) 530 { 531 const struct desc_ptr *desc = &__get_cpu_var(idt_desc); 532 533 xen_convert_trap_info(desc, traps); 534 } 535 536 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 537 hold a spinlock to protect the static traps[] array (static because 538 it avoids allocation, and saves stack space). */ 539 static void xen_load_idt(const struct desc_ptr *desc) 540 { 541 static DEFINE_SPINLOCK(lock); 542 static struct trap_info traps[257]; 543 544 spin_lock(&lock); 545 546 __get_cpu_var(idt_desc) = *desc; 547 548 xen_convert_trap_info(desc, traps); 549 550 xen_mc_flush(); 551 if (HYPERVISOR_set_trap_table(traps)) 552 BUG(); 553 554 spin_unlock(&lock); 555 } 556 557 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 558 they're handled differently. */ 559 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 560 const void *desc, int type) 561 { 562 preempt_disable(); 563 564 switch (type) { 565 case DESC_LDT: 566 case DESC_TSS: 567 /* ignore */ 568 break; 569 570 default: { 571 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 572 573 xen_mc_flush(); 574 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 575 BUG(); 576 } 577 578 } 579 580 preempt_enable(); 581 } 582 583 static void xen_load_sp0(struct tss_struct *tss, 584 struct thread_struct *thread) 585 { 586 struct multicall_space mcs = xen_mc_entry(0); 587 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 588 xen_mc_issue(PARAVIRT_LAZY_CPU); 589 } 590 591 static void xen_set_iopl_mask(unsigned mask) 592 { 593 struct physdev_set_iopl set_iopl; 594 595 /* Force the change at ring 0. */ 596 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 597 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 598 } 599 600 static void xen_io_delay(void) 601 { 602 } 603 604 #ifdef CONFIG_X86_LOCAL_APIC 605 static u32 xen_apic_read(u32 reg) 606 { 607 return 0; 608 } 609 610 static void xen_apic_write(u32 reg, u32 val) 611 { 612 /* Warn to see if there's any stray references */ 613 WARN_ON(1); 614 } 615 616 static u64 xen_apic_icr_read(void) 617 { 618 return 0; 619 } 620 621 static void xen_apic_icr_write(u32 low, u32 id) 622 { 623 /* Warn to see if there's any stray references */ 624 WARN_ON(1); 625 } 626 627 static void xen_apic_wait_icr_idle(void) 628 { 629 return; 630 } 631 632 static u32 xen_safe_apic_wait_icr_idle(void) 633 { 634 return 0; 635 } 636 637 static void set_xen_basic_apic_ops(void) 638 { 639 apic->read = xen_apic_read; 640 apic->write = xen_apic_write; 641 apic->icr_read = xen_apic_icr_read; 642 apic->icr_write = xen_apic_icr_write; 643 apic->wait_icr_idle = xen_apic_wait_icr_idle; 644 apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle; 645 } 646 647 #endif 648 649 650 static void xen_clts(void) 651 { 652 struct multicall_space mcs; 653 654 mcs = xen_mc_entry(0); 655 656 MULTI_fpu_taskswitch(mcs.mc, 0); 657 658 xen_mc_issue(PARAVIRT_LAZY_CPU); 659 } 660 661 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 662 663 static unsigned long xen_read_cr0(void) 664 { 665 unsigned long cr0 = percpu_read(xen_cr0_value); 666 667 if (unlikely(cr0 == 0)) { 668 cr0 = native_read_cr0(); 669 percpu_write(xen_cr0_value, cr0); 670 } 671 672 return cr0; 673 } 674 675 static void xen_write_cr0(unsigned long cr0) 676 { 677 struct multicall_space mcs; 678 679 percpu_write(xen_cr0_value, cr0); 680 681 /* Only pay attention to cr0.TS; everything else is 682 ignored. */ 683 mcs = xen_mc_entry(0); 684 685 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 686 687 xen_mc_issue(PARAVIRT_LAZY_CPU); 688 } 689 690 static void xen_write_cr4(unsigned long cr4) 691 { 692 cr4 &= ~X86_CR4_PGE; 693 cr4 &= ~X86_CR4_PSE; 694 695 native_write_cr4(cr4); 696 } 697 698 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 699 { 700 int ret; 701 702 ret = 0; 703 704 switch (msr) { 705 #ifdef CONFIG_X86_64 706 unsigned which; 707 u64 base; 708 709 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 710 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 711 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 712 713 set: 714 base = ((u64)high << 32) | low; 715 if (HYPERVISOR_set_segment_base(which, base) != 0) 716 ret = -EFAULT; 717 break; 718 #endif 719 720 case MSR_STAR: 721 case MSR_CSTAR: 722 case MSR_LSTAR: 723 case MSR_SYSCALL_MASK: 724 case MSR_IA32_SYSENTER_CS: 725 case MSR_IA32_SYSENTER_ESP: 726 case MSR_IA32_SYSENTER_EIP: 727 /* Fast syscall setup is all done in hypercalls, so 728 these are all ignored. Stub them out here to stop 729 Xen console noise. */ 730 break; 731 732 default: 733 ret = native_write_msr_safe(msr, low, high); 734 } 735 736 return ret; 737 } 738 739 void xen_setup_shared_info(void) 740 { 741 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 742 set_fixmap(FIX_PARAVIRT_BOOTMAP, 743 xen_start_info->shared_info); 744 745 HYPERVISOR_shared_info = 746 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 747 } else 748 HYPERVISOR_shared_info = 749 (struct shared_info *)__va(xen_start_info->shared_info); 750 751 #ifndef CONFIG_SMP 752 /* In UP this is as good a place as any to set up shared info */ 753 xen_setup_vcpu_info_placement(); 754 #endif 755 756 xen_setup_mfn_list_list(); 757 } 758 759 /* This is called once we have the cpu_possible_map */ 760 void xen_setup_vcpu_info_placement(void) 761 { 762 int cpu; 763 764 for_each_possible_cpu(cpu) 765 xen_vcpu_setup(cpu); 766 767 /* xen_vcpu_setup managed to place the vcpu_info within the 768 percpu area for all cpus, so make use of it */ 769 if (have_vcpu_info_placement) { 770 printk(KERN_INFO "Xen: using vcpu_info placement\n"); 771 772 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 773 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 774 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 775 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 776 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 777 } 778 } 779 780 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 781 unsigned long addr, unsigned len) 782 { 783 char *start, *end, *reloc; 784 unsigned ret; 785 786 start = end = reloc = NULL; 787 788 #define SITE(op, x) \ 789 case PARAVIRT_PATCH(op.x): \ 790 if (have_vcpu_info_placement) { \ 791 start = (char *)xen_##x##_direct; \ 792 end = xen_##x##_direct_end; \ 793 reloc = xen_##x##_direct_reloc; \ 794 } \ 795 goto patch_site 796 797 switch (type) { 798 SITE(pv_irq_ops, irq_enable); 799 SITE(pv_irq_ops, irq_disable); 800 SITE(pv_irq_ops, save_fl); 801 SITE(pv_irq_ops, restore_fl); 802 #undef SITE 803 804 patch_site: 805 if (start == NULL || (end-start) > len) 806 goto default_patch; 807 808 ret = paravirt_patch_insns(insnbuf, len, start, end); 809 810 /* Note: because reloc is assigned from something that 811 appears to be an array, gcc assumes it's non-null, 812 but doesn't know its relationship with start and 813 end. */ 814 if (reloc > start && reloc < end) { 815 int reloc_off = reloc - start; 816 long *relocp = (long *)(insnbuf + reloc_off); 817 long delta = start - (char *)addr; 818 819 *relocp += delta; 820 } 821 break; 822 823 default_patch: 824 default: 825 ret = paravirt_patch_default(type, clobbers, insnbuf, 826 addr, len); 827 break; 828 } 829 830 return ret; 831 } 832 833 static const struct pv_info xen_info __initdata = { 834 .paravirt_enabled = 1, 835 .shared_kernel_pmd = 0, 836 837 .name = "Xen", 838 }; 839 840 static const struct pv_init_ops xen_init_ops __initdata = { 841 .patch = xen_patch, 842 843 .banner = xen_banner, 844 .memory_setup = xen_memory_setup, 845 .arch_setup = xen_arch_setup, 846 .post_allocator_init = xen_post_allocator_init, 847 }; 848 849 static const struct pv_time_ops xen_time_ops __initdata = { 850 .time_init = xen_time_init, 851 852 .set_wallclock = xen_set_wallclock, 853 .get_wallclock = xen_get_wallclock, 854 .get_tsc_khz = xen_tsc_khz, 855 .sched_clock = xen_sched_clock, 856 }; 857 858 static const struct pv_cpu_ops xen_cpu_ops __initdata = { 859 .cpuid = xen_cpuid, 860 861 .set_debugreg = xen_set_debugreg, 862 .get_debugreg = xen_get_debugreg, 863 864 .clts = xen_clts, 865 866 .read_cr0 = xen_read_cr0, 867 .write_cr0 = xen_write_cr0, 868 869 .read_cr4 = native_read_cr4, 870 .read_cr4_safe = native_read_cr4_safe, 871 .write_cr4 = xen_write_cr4, 872 873 .wbinvd = native_wbinvd, 874 875 .read_msr = native_read_msr_safe, 876 .write_msr = xen_write_msr_safe, 877 .read_tsc = native_read_tsc, 878 .read_pmc = native_read_pmc, 879 880 .iret = xen_iret, 881 .irq_enable_sysexit = xen_sysexit, 882 #ifdef CONFIG_X86_64 883 .usergs_sysret32 = xen_sysret32, 884 .usergs_sysret64 = xen_sysret64, 885 #endif 886 887 .load_tr_desc = paravirt_nop, 888 .set_ldt = xen_set_ldt, 889 .load_gdt = xen_load_gdt, 890 .load_idt = xen_load_idt, 891 .load_tls = xen_load_tls, 892 #ifdef CONFIG_X86_64 893 .load_gs_index = xen_load_gs_index, 894 #endif 895 896 .alloc_ldt = xen_alloc_ldt, 897 .free_ldt = xen_free_ldt, 898 899 .store_gdt = native_store_gdt, 900 .store_idt = native_store_idt, 901 .store_tr = xen_store_tr, 902 903 .write_ldt_entry = xen_write_ldt_entry, 904 .write_gdt_entry = xen_write_gdt_entry, 905 .write_idt_entry = xen_write_idt_entry, 906 .load_sp0 = xen_load_sp0, 907 908 .set_iopl_mask = xen_set_iopl_mask, 909 .io_delay = xen_io_delay, 910 911 /* Xen takes care of %gs when switching to usermode for us */ 912 .swapgs = paravirt_nop, 913 914 .start_context_switch = paravirt_start_context_switch, 915 .end_context_switch = xen_end_context_switch, 916 }; 917 918 static const struct pv_apic_ops xen_apic_ops __initdata = { 919 #ifdef CONFIG_X86_LOCAL_APIC 920 .setup_boot_clock = paravirt_nop, 921 .setup_secondary_clock = paravirt_nop, 922 .startup_ipi_hook = paravirt_nop, 923 #endif 924 }; 925 926 static void xen_reboot(int reason) 927 { 928 struct sched_shutdown r = { .reason = reason }; 929 930 #ifdef CONFIG_SMP 931 smp_send_stop(); 932 #endif 933 934 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 935 BUG(); 936 } 937 938 static void xen_restart(char *msg) 939 { 940 xen_reboot(SHUTDOWN_reboot); 941 } 942 943 static void xen_emergency_restart(void) 944 { 945 xen_reboot(SHUTDOWN_reboot); 946 } 947 948 static void xen_machine_halt(void) 949 { 950 xen_reboot(SHUTDOWN_poweroff); 951 } 952 953 static void xen_crash_shutdown(struct pt_regs *regs) 954 { 955 xen_reboot(SHUTDOWN_crash); 956 } 957 958 static const struct machine_ops __initdata xen_machine_ops = { 959 .restart = xen_restart, 960 .halt = xen_machine_halt, 961 .power_off = xen_machine_halt, 962 .shutdown = xen_machine_halt, 963 .crash_shutdown = xen_crash_shutdown, 964 .emergency_restart = xen_emergency_restart, 965 }; 966 967 /* First C function to be called on Xen boot */ 968 asmlinkage void __init xen_start_kernel(void) 969 { 970 pgd_t *pgd; 971 972 if (!xen_start_info) 973 return; 974 975 xen_domain_type = XEN_PV_DOMAIN; 976 977 BUG_ON(memcmp(xen_start_info->magic, "xen-3", 5) != 0); 978 979 xen_setup_features(); 980 981 /* Install Xen paravirt ops */ 982 pv_info = xen_info; 983 pv_init_ops = xen_init_ops; 984 pv_time_ops = xen_time_ops; 985 pv_cpu_ops = xen_cpu_ops; 986 pv_apic_ops = xen_apic_ops; 987 pv_mmu_ops = xen_mmu_ops; 988 989 xen_init_irq_ops(); 990 991 xen_init_cpuid_mask(); 992 993 #ifdef CONFIG_X86_LOCAL_APIC 994 /* 995 * set up the basic apic ops. 996 */ 997 set_xen_basic_apic_ops(); 998 #endif 999 1000 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1001 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1002 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1003 } 1004 1005 machine_ops = xen_machine_ops; 1006 1007 #ifdef CONFIG_X86_64 1008 /* 1009 * Setup percpu state. We only need to do this for 64-bit 1010 * because 32-bit already has %fs set properly. 1011 */ 1012 load_percpu_segment(0); 1013 #endif 1014 /* 1015 * The only reliable way to retain the initial address of the 1016 * percpu gdt_page is to remember it here, so we can go and 1017 * mark it RW later, when the initial percpu area is freed. 1018 */ 1019 xen_initial_gdt = &per_cpu(gdt_page, 0); 1020 1021 xen_smp_init(); 1022 1023 /* Get mfn list */ 1024 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1025 xen_build_dynamic_phys_to_machine(); 1026 1027 pgd = (pgd_t *)xen_start_info->pt_base; 1028 1029 /* Prevent unwanted bits from being set in PTEs. */ 1030 __supported_pte_mask &= ~_PAGE_GLOBAL; 1031 if (!xen_initial_domain()) 1032 __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD); 1033 1034 #ifdef CONFIG_X86_64 1035 /* Work out if we support NX */ 1036 check_efer(); 1037 #endif 1038 1039 /* Don't do the full vcpu_info placement stuff until we have a 1040 possible map and a non-dummy shared_info. */ 1041 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1042 1043 local_irq_disable(); 1044 early_boot_irqs_off(); 1045 1046 xen_raw_console_write("mapping kernel into physical memory\n"); 1047 pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages); 1048 1049 init_mm.pgd = pgd; 1050 1051 /* keep using Xen gdt for now; no urgent need to change it */ 1052 1053 pv_info.kernel_rpl = 1; 1054 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1055 pv_info.kernel_rpl = 0; 1056 1057 /* set the limit of our address space */ 1058 xen_reserve_top(); 1059 1060 #ifdef CONFIG_X86_32 1061 /* set up basic CPUID stuff */ 1062 cpu_detect(&new_cpu_data); 1063 new_cpu_data.hard_math = 1; 1064 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1065 #endif 1066 1067 /* Poke various useful things into boot_params */ 1068 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1069 boot_params.hdr.ramdisk_image = xen_start_info->mod_start 1070 ? __pa(xen_start_info->mod_start) : 0; 1071 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1072 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1073 1074 if (!xen_initial_domain()) { 1075 add_preferred_console("xenboot", 0, NULL); 1076 add_preferred_console("tty", 0, NULL); 1077 add_preferred_console("hvc", 0, NULL); 1078 } 1079 1080 xen_raw_console_write("about to get started...\n"); 1081 1082 /* Start the world */ 1083 #ifdef CONFIG_X86_32 1084 i386_start_kernel(); 1085 #else 1086 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1087 #endif 1088 } 1089