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/bootmem.h> 24 #include <linux/module.h> 25 #include <linux/mm.h> 26 #include <linux/page-flags.h> 27 #include <linux/highmem.h> 28 29 #include <xen/interface/xen.h> 30 #include <xen/interface/physdev.h> 31 #include <xen/interface/vcpu.h> 32 #include <xen/interface/sched.h> 33 #include <xen/features.h> 34 #include <xen/page.h> 35 36 #include <asm/paravirt.h> 37 #include <asm/page.h> 38 #include <asm/xen/hypercall.h> 39 #include <asm/xen/hypervisor.h> 40 #include <asm/fixmap.h> 41 #include <asm/processor.h> 42 #include <asm/setup.h> 43 #include <asm/desc.h> 44 #include <asm/pgtable.h> 45 #include <asm/tlbflush.h> 46 #include <asm/reboot.h> 47 48 #include "xen-ops.h" 49 #include "mmu.h" 50 #include "multicalls.h" 51 52 EXPORT_SYMBOL_GPL(hypercall_page); 53 54 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 55 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 56 57 /* 58 * Note about cr3 (pagetable base) values: 59 * 60 * xen_cr3 contains the current logical cr3 value; it contains the 61 * last set cr3. This may not be the current effective cr3, because 62 * its update may be being lazily deferred. However, a vcpu looking 63 * at its own cr3 can use this value knowing that it everything will 64 * be self-consistent. 65 * 66 * xen_current_cr3 contains the actual vcpu cr3; it is set once the 67 * hypercall to set the vcpu cr3 is complete (so it may be a little 68 * out of date, but it will never be set early). If one vcpu is 69 * looking at another vcpu's cr3 value, it should use this variable. 70 */ 71 DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */ 72 DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */ 73 74 struct start_info *xen_start_info; 75 EXPORT_SYMBOL_GPL(xen_start_info); 76 77 static /* __initdata */ struct shared_info dummy_shared_info; 78 79 /* 80 * Point at some empty memory to start with. We map the real shared_info 81 * page as soon as fixmap is up and running. 82 */ 83 struct shared_info *HYPERVISOR_shared_info = (void *)&dummy_shared_info; 84 85 /* 86 * Flag to determine whether vcpu info placement is available on all 87 * VCPUs. We assume it is to start with, and then set it to zero on 88 * the first failure. This is because it can succeed on some VCPUs 89 * and not others, since it can involve hypervisor memory allocation, 90 * or because the guest failed to guarantee all the appropriate 91 * constraints on all VCPUs (ie buffer can't cross a page boundary). 92 * 93 * Note that any particular CPU may be using a placed vcpu structure, 94 * but we can only optimise if the all are. 95 * 96 * 0: not available, 1: available 97 */ 98 static int have_vcpu_info_placement = 0; 99 100 static void __init xen_vcpu_setup(int cpu) 101 { 102 struct vcpu_register_vcpu_info info; 103 int err; 104 struct vcpu_info *vcpup; 105 106 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 107 108 if (!have_vcpu_info_placement) 109 return; /* already tested, not available */ 110 111 vcpup = &per_cpu(xen_vcpu_info, cpu); 112 113 info.mfn = virt_to_mfn(vcpup); 114 info.offset = offset_in_page(vcpup); 115 116 printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %llx, offset %d\n", 117 cpu, vcpup, info.mfn, info.offset); 118 119 /* Check to see if the hypervisor will put the vcpu_info 120 structure where we want it, which allows direct access via 121 a percpu-variable. */ 122 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 123 124 if (err) { 125 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 126 have_vcpu_info_placement = 0; 127 } else { 128 /* This cpu is using the registered vcpu info, even if 129 later ones fail to. */ 130 per_cpu(xen_vcpu, cpu) = vcpup; 131 132 printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n", 133 cpu, vcpup); 134 } 135 } 136 137 static void __init xen_banner(void) 138 { 139 printk(KERN_INFO "Booting paravirtualized kernel on %s\n", 140 pv_info.name); 141 printk(KERN_INFO "Hypervisor signature: %s\n", xen_start_info->magic); 142 } 143 144 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 145 unsigned int *cx, unsigned int *dx) 146 { 147 unsigned maskedx = ~0; 148 149 /* 150 * Mask out inconvenient features, to try and disable as many 151 * unsupported kernel subsystems as possible. 152 */ 153 if (*ax == 1) 154 maskedx = ~((1 << X86_FEATURE_APIC) | /* disable APIC */ 155 (1 << X86_FEATURE_ACPI) | /* disable ACPI */ 156 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 157 158 asm(XEN_EMULATE_PREFIX "cpuid" 159 : "=a" (*ax), 160 "=b" (*bx), 161 "=c" (*cx), 162 "=d" (*dx) 163 : "0" (*ax), "2" (*cx)); 164 *dx &= maskedx; 165 } 166 167 static void xen_set_debugreg(int reg, unsigned long val) 168 { 169 HYPERVISOR_set_debugreg(reg, val); 170 } 171 172 static unsigned long xen_get_debugreg(int reg) 173 { 174 return HYPERVISOR_get_debugreg(reg); 175 } 176 177 static unsigned long xen_save_fl(void) 178 { 179 struct vcpu_info *vcpu; 180 unsigned long flags; 181 182 vcpu = x86_read_percpu(xen_vcpu); 183 184 /* flag has opposite sense of mask */ 185 flags = !vcpu->evtchn_upcall_mask; 186 187 /* convert to IF type flag 188 -0 -> 0x00000000 189 -1 -> 0xffffffff 190 */ 191 return (-flags) & X86_EFLAGS_IF; 192 } 193 194 static void xen_restore_fl(unsigned long flags) 195 { 196 struct vcpu_info *vcpu; 197 198 /* convert from IF type flag */ 199 flags = !(flags & X86_EFLAGS_IF); 200 201 /* There's a one instruction preempt window here. We need to 202 make sure we're don't switch CPUs between getting the vcpu 203 pointer and updating the mask. */ 204 preempt_disable(); 205 vcpu = x86_read_percpu(xen_vcpu); 206 vcpu->evtchn_upcall_mask = flags; 207 preempt_enable_no_resched(); 208 209 /* Doesn't matter if we get preempted here, because any 210 pending event will get dealt with anyway. */ 211 212 if (flags == 0) { 213 preempt_check_resched(); 214 barrier(); /* unmask then check (avoid races) */ 215 if (unlikely(vcpu->evtchn_upcall_pending)) 216 force_evtchn_callback(); 217 } 218 } 219 220 static void xen_irq_disable(void) 221 { 222 /* There's a one instruction preempt window here. We need to 223 make sure we're don't switch CPUs between getting the vcpu 224 pointer and updating the mask. */ 225 preempt_disable(); 226 x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1; 227 preempt_enable_no_resched(); 228 } 229 230 static void xen_irq_enable(void) 231 { 232 struct vcpu_info *vcpu; 233 234 /* There's a one instruction preempt window here. We need to 235 make sure we're don't switch CPUs between getting the vcpu 236 pointer and updating the mask. */ 237 preempt_disable(); 238 vcpu = x86_read_percpu(xen_vcpu); 239 vcpu->evtchn_upcall_mask = 0; 240 preempt_enable_no_resched(); 241 242 /* Doesn't matter if we get preempted here, because any 243 pending event will get dealt with anyway. */ 244 245 barrier(); /* unmask then check (avoid races) */ 246 if (unlikely(vcpu->evtchn_upcall_pending)) 247 force_evtchn_callback(); 248 } 249 250 static void xen_safe_halt(void) 251 { 252 /* Blocking includes an implicit local_irq_enable(). */ 253 if (HYPERVISOR_sched_op(SCHEDOP_block, 0) != 0) 254 BUG(); 255 } 256 257 static void xen_halt(void) 258 { 259 if (irqs_disabled()) 260 HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL); 261 else 262 xen_safe_halt(); 263 } 264 265 static void xen_leave_lazy(void) 266 { 267 paravirt_leave_lazy(paravirt_get_lazy_mode()); 268 xen_mc_flush(); 269 } 270 271 static unsigned long xen_store_tr(void) 272 { 273 return 0; 274 } 275 276 static void xen_set_ldt(const void *addr, unsigned entries) 277 { 278 struct mmuext_op *op; 279 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 280 281 op = mcs.args; 282 op->cmd = MMUEXT_SET_LDT; 283 op->arg1.linear_addr = (unsigned long)addr; 284 op->arg2.nr_ents = entries; 285 286 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 287 288 xen_mc_issue(PARAVIRT_LAZY_CPU); 289 } 290 291 static void xen_load_gdt(const struct desc_ptr *dtr) 292 { 293 unsigned long *frames; 294 unsigned long va = dtr->address; 295 unsigned int size = dtr->size + 1; 296 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 297 int f; 298 struct multicall_space mcs; 299 300 /* A GDT can be up to 64k in size, which corresponds to 8192 301 8-byte entries, or 16 4k pages.. */ 302 303 BUG_ON(size > 65536); 304 BUG_ON(va & ~PAGE_MASK); 305 306 mcs = xen_mc_entry(sizeof(*frames) * pages); 307 frames = mcs.args; 308 309 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 310 frames[f] = virt_to_mfn(va); 311 make_lowmem_page_readonly((void *)va); 312 } 313 314 MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct)); 315 316 xen_mc_issue(PARAVIRT_LAZY_CPU); 317 } 318 319 static void load_TLS_descriptor(struct thread_struct *t, 320 unsigned int cpu, unsigned int i) 321 { 322 struct desc_struct *gdt = get_cpu_gdt_table(cpu); 323 xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 324 struct multicall_space mc = __xen_mc_entry(0); 325 326 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 327 } 328 329 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 330 { 331 xen_mc_batch(); 332 333 load_TLS_descriptor(t, cpu, 0); 334 load_TLS_descriptor(t, cpu, 1); 335 load_TLS_descriptor(t, cpu, 2); 336 337 xen_mc_issue(PARAVIRT_LAZY_CPU); 338 339 /* 340 * XXX sleazy hack: If we're being called in a lazy-cpu zone, 341 * it means we're in a context switch, and %gs has just been 342 * saved. This means we can zero it out to prevent faults on 343 * exit from the hypervisor if the next process has no %gs. 344 * Either way, it has been saved, and the new value will get 345 * loaded properly. This will go away as soon as Xen has been 346 * modified to not save/restore %gs for normal hypercalls. 347 */ 348 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) 349 loadsegment(gs, 0); 350 } 351 352 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 353 const void *ptr) 354 { 355 unsigned long lp = (unsigned long)&dt[entrynum]; 356 xmaddr_t mach_lp = virt_to_machine(lp); 357 u64 entry = *(u64 *)ptr; 358 359 preempt_disable(); 360 361 xen_mc_flush(); 362 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 363 BUG(); 364 365 preempt_enable(); 366 } 367 368 static int cvt_gate_to_trap(int vector, u32 low, u32 high, 369 struct trap_info *info) 370 { 371 u8 type, dpl; 372 373 type = (high >> 8) & 0x1f; 374 dpl = (high >> 13) & 3; 375 376 if (type != 0xf && type != 0xe) 377 return 0; 378 379 info->vector = vector; 380 info->address = (high & 0xffff0000) | (low & 0x0000ffff); 381 info->cs = low >> 16; 382 info->flags = dpl; 383 /* interrupt gates clear IF */ 384 if (type == 0xe) 385 info->flags |= 4; 386 387 return 1; 388 } 389 390 /* Locations of each CPU's IDT */ 391 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 392 393 /* Set an IDT entry. If the entry is part of the current IDT, then 394 also update Xen. */ 395 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 396 { 397 unsigned long p = (unsigned long)&dt[entrynum]; 398 unsigned long start, end; 399 400 preempt_disable(); 401 402 start = __get_cpu_var(idt_desc).address; 403 end = start + __get_cpu_var(idt_desc).size + 1; 404 405 xen_mc_flush(); 406 407 native_write_idt_entry(dt, entrynum, g); 408 409 if (p >= start && (p + 8) <= end) { 410 struct trap_info info[2]; 411 u32 *desc = (u32 *)g; 412 413 info[1].address = 0; 414 415 if (cvt_gate_to_trap(entrynum, desc[0], desc[1], &info[0])) 416 if (HYPERVISOR_set_trap_table(info)) 417 BUG(); 418 } 419 420 preempt_enable(); 421 } 422 423 static void xen_convert_trap_info(const struct desc_ptr *desc, 424 struct trap_info *traps) 425 { 426 unsigned in, out, count; 427 428 count = (desc->size+1) / 8; 429 BUG_ON(count > 256); 430 431 for (in = out = 0; in < count; in++) { 432 const u32 *entry = (u32 *)(desc->address + in * 8); 433 434 if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out])) 435 out++; 436 } 437 traps[out].address = 0; 438 } 439 440 void xen_copy_trap_info(struct trap_info *traps) 441 { 442 const struct desc_ptr *desc = &__get_cpu_var(idt_desc); 443 444 xen_convert_trap_info(desc, traps); 445 } 446 447 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 448 hold a spinlock to protect the static traps[] array (static because 449 it avoids allocation, and saves stack space). */ 450 static void xen_load_idt(const struct desc_ptr *desc) 451 { 452 static DEFINE_SPINLOCK(lock); 453 static struct trap_info traps[257]; 454 455 spin_lock(&lock); 456 457 __get_cpu_var(idt_desc) = *desc; 458 459 xen_convert_trap_info(desc, traps); 460 461 xen_mc_flush(); 462 if (HYPERVISOR_set_trap_table(traps)) 463 BUG(); 464 465 spin_unlock(&lock); 466 } 467 468 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 469 they're handled differently. */ 470 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 471 const void *desc, int type) 472 { 473 preempt_disable(); 474 475 switch (type) { 476 case DESC_LDT: 477 case DESC_TSS: 478 /* ignore */ 479 break; 480 481 default: { 482 xmaddr_t maddr = virt_to_machine(&dt[entry]); 483 484 xen_mc_flush(); 485 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 486 BUG(); 487 } 488 489 } 490 491 preempt_enable(); 492 } 493 494 static void xen_load_sp0(struct tss_struct *tss, 495 struct thread_struct *thread) 496 { 497 struct multicall_space mcs = xen_mc_entry(0); 498 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 499 xen_mc_issue(PARAVIRT_LAZY_CPU); 500 } 501 502 static void xen_set_iopl_mask(unsigned mask) 503 { 504 struct physdev_set_iopl set_iopl; 505 506 /* Force the change at ring 0. */ 507 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 508 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 509 } 510 511 static void xen_io_delay(void) 512 { 513 } 514 515 #ifdef CONFIG_X86_LOCAL_APIC 516 static u32 xen_apic_read(unsigned long reg) 517 { 518 return 0; 519 } 520 521 static void xen_apic_write(unsigned long reg, u32 val) 522 { 523 /* Warn to see if there's any stray references */ 524 WARN_ON(1); 525 } 526 #endif 527 528 static void xen_flush_tlb(void) 529 { 530 struct mmuext_op *op; 531 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 532 533 op = mcs.args; 534 op->cmd = MMUEXT_TLB_FLUSH_LOCAL; 535 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 536 537 xen_mc_issue(PARAVIRT_LAZY_MMU); 538 } 539 540 static void xen_flush_tlb_single(unsigned long addr) 541 { 542 struct mmuext_op *op; 543 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 544 545 op = mcs.args; 546 op->cmd = MMUEXT_INVLPG_LOCAL; 547 op->arg1.linear_addr = addr & PAGE_MASK; 548 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 549 550 xen_mc_issue(PARAVIRT_LAZY_MMU); 551 } 552 553 static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm, 554 unsigned long va) 555 { 556 struct { 557 struct mmuext_op op; 558 cpumask_t mask; 559 } *args; 560 cpumask_t cpumask = *cpus; 561 struct multicall_space mcs; 562 563 /* 564 * A couple of (to be removed) sanity checks: 565 * 566 * - current CPU must not be in mask 567 * - mask must exist :) 568 */ 569 BUG_ON(cpus_empty(cpumask)); 570 BUG_ON(cpu_isset(smp_processor_id(), cpumask)); 571 BUG_ON(!mm); 572 573 /* If a CPU which we ran on has gone down, OK. */ 574 cpus_and(cpumask, cpumask, cpu_online_map); 575 if (cpus_empty(cpumask)) 576 return; 577 578 mcs = xen_mc_entry(sizeof(*args)); 579 args = mcs.args; 580 args->mask = cpumask; 581 args->op.arg2.vcpumask = &args->mask; 582 583 if (va == TLB_FLUSH_ALL) { 584 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; 585 } else { 586 args->op.cmd = MMUEXT_INVLPG_MULTI; 587 args->op.arg1.linear_addr = va; 588 } 589 590 MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF); 591 592 xen_mc_issue(PARAVIRT_LAZY_MMU); 593 } 594 595 static void xen_write_cr2(unsigned long cr2) 596 { 597 x86_read_percpu(xen_vcpu)->arch.cr2 = cr2; 598 } 599 600 static unsigned long xen_read_cr2(void) 601 { 602 return x86_read_percpu(xen_vcpu)->arch.cr2; 603 } 604 605 static unsigned long xen_read_cr2_direct(void) 606 { 607 return x86_read_percpu(xen_vcpu_info.arch.cr2); 608 } 609 610 static void xen_write_cr4(unsigned long cr4) 611 { 612 /* Just ignore cr4 changes; Xen doesn't allow us to do 613 anything anyway. */ 614 } 615 616 static unsigned long xen_read_cr3(void) 617 { 618 return x86_read_percpu(xen_cr3); 619 } 620 621 static void set_current_cr3(void *v) 622 { 623 x86_write_percpu(xen_current_cr3, (unsigned long)v); 624 } 625 626 static void xen_write_cr3(unsigned long cr3) 627 { 628 struct mmuext_op *op; 629 struct multicall_space mcs; 630 unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3)); 631 632 BUG_ON(preemptible()); 633 634 mcs = xen_mc_entry(sizeof(*op)); /* disables interrupts */ 635 636 /* Update while interrupts are disabled, so its atomic with 637 respect to ipis */ 638 x86_write_percpu(xen_cr3, cr3); 639 640 op = mcs.args; 641 op->cmd = MMUEXT_NEW_BASEPTR; 642 op->arg1.mfn = mfn; 643 644 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 645 646 /* Update xen_update_cr3 once the batch has actually 647 been submitted. */ 648 xen_mc_callback(set_current_cr3, (void *)cr3); 649 650 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */ 651 } 652 653 /* Early in boot, while setting up the initial pagetable, assume 654 everything is pinned. */ 655 static __init void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn) 656 { 657 BUG_ON(mem_map); /* should only be used early */ 658 make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); 659 } 660 661 /* Early release_pt assumes that all pts are pinned, since there's 662 only init_mm and anything attached to that is pinned. */ 663 static void xen_release_pt_init(u32 pfn) 664 { 665 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); 666 } 667 668 static void pin_pagetable_pfn(unsigned level, unsigned long pfn) 669 { 670 struct mmuext_op op; 671 op.cmd = level; 672 op.arg1.mfn = pfn_to_mfn(pfn); 673 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) 674 BUG(); 675 } 676 677 /* This needs to make sure the new pte page is pinned iff its being 678 attached to a pinned pagetable. */ 679 static void xen_alloc_ptpage(struct mm_struct *mm, u32 pfn, unsigned level) 680 { 681 struct page *page = pfn_to_page(pfn); 682 683 if (PagePinned(virt_to_page(mm->pgd))) { 684 SetPagePinned(page); 685 686 if (!PageHighMem(page)) { 687 make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); 688 pin_pagetable_pfn(level, pfn); 689 } else 690 /* make sure there are no stray mappings of 691 this page */ 692 kmap_flush_unused(); 693 } 694 } 695 696 static void xen_alloc_pt(struct mm_struct *mm, u32 pfn) 697 { 698 xen_alloc_ptpage(mm, pfn, MMUEXT_PIN_L1_TABLE); 699 } 700 701 static void xen_alloc_pd(struct mm_struct *mm, u32 pfn) 702 { 703 xen_alloc_ptpage(mm, pfn, MMUEXT_PIN_L2_TABLE); 704 } 705 706 /* This should never happen until we're OK to use struct page */ 707 static void xen_release_pt(u32 pfn) 708 { 709 struct page *page = pfn_to_page(pfn); 710 711 if (PagePinned(page)) { 712 if (!PageHighMem(page)) { 713 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn); 714 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); 715 } 716 } 717 } 718 719 #ifdef CONFIG_HIGHPTE 720 static void *xen_kmap_atomic_pte(struct page *page, enum km_type type) 721 { 722 pgprot_t prot = PAGE_KERNEL; 723 724 if (PagePinned(page)) 725 prot = PAGE_KERNEL_RO; 726 727 if (0 && PageHighMem(page)) 728 printk("mapping highpte %lx type %d prot %s\n", 729 page_to_pfn(page), type, 730 (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ"); 731 732 return kmap_atomic_prot(page, type, prot); 733 } 734 #endif 735 736 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte) 737 { 738 /* If there's an existing pte, then don't allow _PAGE_RW to be set */ 739 if (pte_val_ma(*ptep) & _PAGE_PRESENT) 740 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & 741 pte_val_ma(pte)); 742 743 return pte; 744 } 745 746 /* Init-time set_pte while constructing initial pagetables, which 747 doesn't allow RO pagetable pages to be remapped RW */ 748 static __init void xen_set_pte_init(pte_t *ptep, pte_t pte) 749 { 750 pte = mask_rw_pte(ptep, pte); 751 752 xen_set_pte(ptep, pte); 753 } 754 755 static __init void xen_pagetable_setup_start(pgd_t *base) 756 { 757 pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base; 758 759 /* special set_pte for pagetable initialization */ 760 pv_mmu_ops.set_pte = xen_set_pte_init; 761 762 init_mm.pgd = base; 763 /* 764 * copy top-level of Xen-supplied pagetable into place. For 765 * !PAE we can use this as-is, but for PAE it is a stand-in 766 * while we copy the pmd pages. 767 */ 768 memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t)); 769 770 if (PTRS_PER_PMD > 1) { 771 int i; 772 /* 773 * For PAE, need to allocate new pmds, rather than 774 * share Xen's, since Xen doesn't like pmd's being 775 * shared between address spaces. 776 */ 777 for (i = 0; i < PTRS_PER_PGD; i++) { 778 if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) { 779 pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE); 780 781 memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]), 782 PAGE_SIZE); 783 784 make_lowmem_page_readonly(pmd); 785 786 set_pgd(&base[i], __pgd(1 + __pa(pmd))); 787 } else 788 pgd_clear(&base[i]); 789 } 790 } 791 792 /* make sure zero_page is mapped RO so we can use it in pagetables */ 793 make_lowmem_page_readonly(empty_zero_page); 794 make_lowmem_page_readonly(base); 795 /* 796 * Switch to new pagetable. This is done before 797 * pagetable_init has done anything so that the new pages 798 * added to the table can be prepared properly for Xen. 799 */ 800 xen_write_cr3(__pa(base)); 801 } 802 803 static __init void xen_pagetable_setup_done(pgd_t *base) 804 { 805 /* This will work as long as patching hasn't happened yet 806 (which it hasn't) */ 807 pv_mmu_ops.alloc_pt = xen_alloc_pt; 808 pv_mmu_ops.alloc_pd = xen_alloc_pd; 809 pv_mmu_ops.release_pt = xen_release_pt; 810 pv_mmu_ops.release_pd = xen_release_pt; 811 pv_mmu_ops.set_pte = xen_set_pte; 812 813 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 814 /* 815 * Create a mapping for the shared info page. 816 * Should be set_fixmap(), but shared_info is a machine 817 * address with no corresponding pseudo-phys address. 818 */ 819 set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP), 820 PFN_DOWN(xen_start_info->shared_info), 821 PAGE_KERNEL); 822 823 HYPERVISOR_shared_info = 824 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 825 826 } else 827 HYPERVISOR_shared_info = 828 (struct shared_info *)__va(xen_start_info->shared_info); 829 830 /* Actually pin the pagetable down, but we can't set PG_pinned 831 yet because the page structures don't exist yet. */ 832 { 833 unsigned level; 834 835 #ifdef CONFIG_X86_PAE 836 level = MMUEXT_PIN_L3_TABLE; 837 #else 838 level = MMUEXT_PIN_L2_TABLE; 839 #endif 840 841 pin_pagetable_pfn(level, PFN_DOWN(__pa(base))); 842 } 843 } 844 845 /* This is called once we have the cpu_possible_map */ 846 void __init xen_setup_vcpu_info_placement(void) 847 { 848 int cpu; 849 850 for_each_possible_cpu(cpu) 851 xen_vcpu_setup(cpu); 852 853 /* xen_vcpu_setup managed to place the vcpu_info within the 854 percpu area for all cpus, so make use of it */ 855 if (have_vcpu_info_placement) { 856 printk(KERN_INFO "Xen: using vcpu_info placement\n"); 857 858 pv_irq_ops.save_fl = xen_save_fl_direct; 859 pv_irq_ops.restore_fl = xen_restore_fl_direct; 860 pv_irq_ops.irq_disable = xen_irq_disable_direct; 861 pv_irq_ops.irq_enable = xen_irq_enable_direct; 862 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 863 pv_cpu_ops.iret = xen_iret_direct; 864 } 865 } 866 867 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 868 unsigned long addr, unsigned len) 869 { 870 char *start, *end, *reloc; 871 unsigned ret; 872 873 start = end = reloc = NULL; 874 875 #define SITE(op, x) \ 876 case PARAVIRT_PATCH(op.x): \ 877 if (have_vcpu_info_placement) { \ 878 start = (char *)xen_##x##_direct; \ 879 end = xen_##x##_direct_end; \ 880 reloc = xen_##x##_direct_reloc; \ 881 } \ 882 goto patch_site 883 884 switch (type) { 885 SITE(pv_irq_ops, irq_enable); 886 SITE(pv_irq_ops, irq_disable); 887 SITE(pv_irq_ops, save_fl); 888 SITE(pv_irq_ops, restore_fl); 889 #undef SITE 890 891 patch_site: 892 if (start == NULL || (end-start) > len) 893 goto default_patch; 894 895 ret = paravirt_patch_insns(insnbuf, len, start, end); 896 897 /* Note: because reloc is assigned from something that 898 appears to be an array, gcc assumes it's non-null, 899 but doesn't know its relationship with start and 900 end. */ 901 if (reloc > start && reloc < end) { 902 int reloc_off = reloc - start; 903 long *relocp = (long *)(insnbuf + reloc_off); 904 long delta = start - (char *)addr; 905 906 *relocp += delta; 907 } 908 break; 909 910 default_patch: 911 default: 912 ret = paravirt_patch_default(type, clobbers, insnbuf, 913 addr, len); 914 break; 915 } 916 917 return ret; 918 } 919 920 static const struct pv_info xen_info __initdata = { 921 .paravirt_enabled = 1, 922 .shared_kernel_pmd = 0, 923 924 .name = "Xen", 925 }; 926 927 static const struct pv_init_ops xen_init_ops __initdata = { 928 .patch = xen_patch, 929 930 .banner = xen_banner, 931 .memory_setup = xen_memory_setup, 932 .arch_setup = xen_arch_setup, 933 .post_allocator_init = xen_mark_init_mm_pinned, 934 }; 935 936 static const struct pv_time_ops xen_time_ops __initdata = { 937 .time_init = xen_time_init, 938 939 .set_wallclock = xen_set_wallclock, 940 .get_wallclock = xen_get_wallclock, 941 .get_cpu_khz = xen_cpu_khz, 942 .sched_clock = xen_sched_clock, 943 }; 944 945 static const struct pv_cpu_ops xen_cpu_ops __initdata = { 946 .cpuid = xen_cpuid, 947 948 .set_debugreg = xen_set_debugreg, 949 .get_debugreg = xen_get_debugreg, 950 951 .clts = native_clts, 952 953 .read_cr0 = native_read_cr0, 954 .write_cr0 = native_write_cr0, 955 956 .read_cr4 = native_read_cr4, 957 .read_cr4_safe = native_read_cr4_safe, 958 .write_cr4 = xen_write_cr4, 959 960 .wbinvd = native_wbinvd, 961 962 .read_msr = native_read_msr_safe, 963 .write_msr = native_write_msr_safe, 964 .read_tsc = native_read_tsc, 965 .read_pmc = native_read_pmc, 966 967 .iret = (void *)&hypercall_page[__HYPERVISOR_iret], 968 .irq_enable_syscall_ret = NULL, /* never called */ 969 970 .load_tr_desc = paravirt_nop, 971 .set_ldt = xen_set_ldt, 972 .load_gdt = xen_load_gdt, 973 .load_idt = xen_load_idt, 974 .load_tls = xen_load_tls, 975 976 .store_gdt = native_store_gdt, 977 .store_idt = native_store_idt, 978 .store_tr = xen_store_tr, 979 980 .write_ldt_entry = xen_write_ldt_entry, 981 .write_gdt_entry = xen_write_gdt_entry, 982 .write_idt_entry = xen_write_idt_entry, 983 .load_sp0 = xen_load_sp0, 984 985 .set_iopl_mask = xen_set_iopl_mask, 986 .io_delay = xen_io_delay, 987 988 .lazy_mode = { 989 .enter = paravirt_enter_lazy_cpu, 990 .leave = xen_leave_lazy, 991 }, 992 }; 993 994 static const struct pv_irq_ops xen_irq_ops __initdata = { 995 .init_IRQ = xen_init_IRQ, 996 .save_fl = xen_save_fl, 997 .restore_fl = xen_restore_fl, 998 .irq_disable = xen_irq_disable, 999 .irq_enable = xen_irq_enable, 1000 .safe_halt = xen_safe_halt, 1001 .halt = xen_halt, 1002 }; 1003 1004 static const struct pv_apic_ops xen_apic_ops __initdata = { 1005 #ifdef CONFIG_X86_LOCAL_APIC 1006 .apic_write = xen_apic_write, 1007 .apic_write_atomic = xen_apic_write, 1008 .apic_read = xen_apic_read, 1009 .setup_boot_clock = paravirt_nop, 1010 .setup_secondary_clock = paravirt_nop, 1011 .startup_ipi_hook = paravirt_nop, 1012 #endif 1013 }; 1014 1015 static const struct pv_mmu_ops xen_mmu_ops __initdata = { 1016 .pagetable_setup_start = xen_pagetable_setup_start, 1017 .pagetable_setup_done = xen_pagetable_setup_done, 1018 1019 .read_cr2 = xen_read_cr2, 1020 .write_cr2 = xen_write_cr2, 1021 1022 .read_cr3 = xen_read_cr3, 1023 .write_cr3 = xen_write_cr3, 1024 1025 .flush_tlb_user = xen_flush_tlb, 1026 .flush_tlb_kernel = xen_flush_tlb, 1027 .flush_tlb_single = xen_flush_tlb_single, 1028 .flush_tlb_others = xen_flush_tlb_others, 1029 1030 .pte_update = paravirt_nop, 1031 .pte_update_defer = paravirt_nop, 1032 1033 .alloc_pt = xen_alloc_pt_init, 1034 .release_pt = xen_release_pt_init, 1035 .alloc_pd = xen_alloc_pt_init, 1036 .alloc_pd_clone = paravirt_nop, 1037 .release_pd = xen_release_pt_init, 1038 1039 #ifdef CONFIG_HIGHPTE 1040 .kmap_atomic_pte = xen_kmap_atomic_pte, 1041 #endif 1042 1043 .set_pte = NULL, /* see xen_pagetable_setup_* */ 1044 .set_pte_at = xen_set_pte_at, 1045 .set_pmd = xen_set_pmd, 1046 1047 .pte_val = xen_pte_val, 1048 .pgd_val = xen_pgd_val, 1049 1050 .make_pte = xen_make_pte, 1051 .make_pgd = xen_make_pgd, 1052 1053 #ifdef CONFIG_X86_PAE 1054 .set_pte_atomic = xen_set_pte_atomic, 1055 .set_pte_present = xen_set_pte_at, 1056 .set_pud = xen_set_pud, 1057 .pte_clear = xen_pte_clear, 1058 .pmd_clear = xen_pmd_clear, 1059 1060 .make_pmd = xen_make_pmd, 1061 .pmd_val = xen_pmd_val, 1062 #endif /* PAE */ 1063 1064 .activate_mm = xen_activate_mm, 1065 .dup_mmap = xen_dup_mmap, 1066 .exit_mmap = xen_exit_mmap, 1067 1068 .lazy_mode = { 1069 .enter = paravirt_enter_lazy_mmu, 1070 .leave = xen_leave_lazy, 1071 }, 1072 }; 1073 1074 #ifdef CONFIG_SMP 1075 static const struct smp_ops xen_smp_ops __initdata = { 1076 .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu, 1077 .smp_prepare_cpus = xen_smp_prepare_cpus, 1078 .cpu_up = xen_cpu_up, 1079 .smp_cpus_done = xen_smp_cpus_done, 1080 1081 .smp_send_stop = xen_smp_send_stop, 1082 .smp_send_reschedule = xen_smp_send_reschedule, 1083 .smp_call_function_mask = xen_smp_call_function_mask, 1084 }; 1085 #endif /* CONFIG_SMP */ 1086 1087 static void xen_reboot(int reason) 1088 { 1089 #ifdef CONFIG_SMP 1090 smp_send_stop(); 1091 #endif 1092 1093 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason)) 1094 BUG(); 1095 } 1096 1097 static void xen_restart(char *msg) 1098 { 1099 xen_reboot(SHUTDOWN_reboot); 1100 } 1101 1102 static void xen_emergency_restart(void) 1103 { 1104 xen_reboot(SHUTDOWN_reboot); 1105 } 1106 1107 static void xen_machine_halt(void) 1108 { 1109 xen_reboot(SHUTDOWN_poweroff); 1110 } 1111 1112 static void xen_crash_shutdown(struct pt_regs *regs) 1113 { 1114 xen_reboot(SHUTDOWN_crash); 1115 } 1116 1117 static const struct machine_ops __initdata xen_machine_ops = { 1118 .restart = xen_restart, 1119 .halt = xen_machine_halt, 1120 .power_off = xen_machine_halt, 1121 .shutdown = xen_machine_halt, 1122 .crash_shutdown = xen_crash_shutdown, 1123 .emergency_restart = xen_emergency_restart, 1124 }; 1125 1126 1127 static void __init xen_reserve_top(void) 1128 { 1129 unsigned long top = HYPERVISOR_VIRT_START; 1130 struct xen_platform_parameters pp; 1131 1132 if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0) 1133 top = pp.virt_start; 1134 1135 reserve_top_address(-top + 2 * PAGE_SIZE); 1136 } 1137 1138 /* First C function to be called on Xen boot */ 1139 asmlinkage void __init xen_start_kernel(void) 1140 { 1141 pgd_t *pgd; 1142 1143 if (!xen_start_info) 1144 return; 1145 1146 BUG_ON(memcmp(xen_start_info->magic, "xen-3", 5) != 0); 1147 1148 /* Install Xen paravirt ops */ 1149 pv_info = xen_info; 1150 pv_init_ops = xen_init_ops; 1151 pv_time_ops = xen_time_ops; 1152 pv_cpu_ops = xen_cpu_ops; 1153 pv_irq_ops = xen_irq_ops; 1154 pv_apic_ops = xen_apic_ops; 1155 pv_mmu_ops = xen_mmu_ops; 1156 1157 machine_ops = xen_machine_ops; 1158 1159 #ifdef CONFIG_SMP 1160 smp_ops = xen_smp_ops; 1161 #endif 1162 1163 xen_setup_features(); 1164 1165 /* Get mfn list */ 1166 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1167 phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list; 1168 1169 pgd = (pgd_t *)xen_start_info->pt_base; 1170 1171 init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE; 1172 1173 init_mm.pgd = pgd; /* use the Xen pagetables to start */ 1174 1175 /* keep using Xen gdt for now; no urgent need to change it */ 1176 1177 x86_write_percpu(xen_cr3, __pa(pgd)); 1178 x86_write_percpu(xen_current_cr3, __pa(pgd)); 1179 1180 #ifdef CONFIG_SMP 1181 /* Don't do the full vcpu_info placement stuff until we have a 1182 possible map. */ 1183 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1184 #else 1185 /* May as well do it now, since there's no good time to call 1186 it later on UP. */ 1187 xen_setup_vcpu_info_placement(); 1188 #endif 1189 1190 pv_info.kernel_rpl = 1; 1191 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1192 pv_info.kernel_rpl = 0; 1193 1194 /* set the limit of our address space */ 1195 xen_reserve_top(); 1196 1197 /* set up basic CPUID stuff */ 1198 cpu_detect(&new_cpu_data); 1199 new_cpu_data.hard_math = 1; 1200 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1201 1202 /* Poke various useful things into boot_params */ 1203 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1204 boot_params.hdr.ramdisk_image = xen_start_info->mod_start 1205 ? __pa(xen_start_info->mod_start) : 0; 1206 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1207 1208 /* Start the world */ 1209 start_kernel(); 1210 } 1211