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