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the actual vcpu cr3; it is set once the 67 * hypercall to set the vcpu cr3 is complete (so it may be a little 68 * out of date, but it will never be set early).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 = 1; 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 *eax, unsigned int *ebx, 145 unsigned int *ecx, unsigned int *edx) 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 (*eax == 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" (*eax), 160 "=b" (*ebx), 161 "=c" (*ecx), 162 "=d" (*edx) 163 : "0" (*eax), "2" (*ecx)); 164 *edx &= 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 unsigned long linear_addr = (unsigned long)addr; 279 struct mmuext_op *op; 280 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 281 282 op = mcs.args; 283 op->cmd = MMUEXT_SET_LDT; 284 if (linear_addr) { 285 /* ldt my be vmalloced, use arbitrary_virt_to_machine */ 286 xmaddr_t maddr; 287 maddr = arbitrary_virt_to_machine((unsigned long)addr); 288 linear_addr = (unsigned long)maddr.maddr; 289 } 290 op->arg1.linear_addr = linear_addr; 291 op->arg2.nr_ents = entries; 292 293 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 294 295 xen_mc_issue(PARAVIRT_LAZY_CPU); 296 } 297 298 static void xen_load_gdt(const struct Xgt_desc_struct *dtr) 299 { 300 unsigned long *frames; 301 unsigned long va = dtr->address; 302 unsigned int size = dtr->size + 1; 303 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 304 int f; 305 struct multicall_space mcs; 306 307 /* A GDT can be up to 64k in size, which corresponds to 8192 308 8-byte entries, or 16 4k pages.. */ 309 310 BUG_ON(size > 65536); 311 BUG_ON(va & ~PAGE_MASK); 312 313 mcs = xen_mc_entry(sizeof(*frames) * pages); 314 frames = mcs.args; 315 316 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 317 frames[f] = virt_to_mfn(va); 318 make_lowmem_page_readonly((void *)va); 319 } 320 321 MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct)); 322 323 xen_mc_issue(PARAVIRT_LAZY_CPU); 324 } 325 326 static void load_TLS_descriptor(struct thread_struct *t, 327 unsigned int cpu, unsigned int i) 328 { 329 struct desc_struct *gdt = get_cpu_gdt_table(cpu); 330 xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 331 struct multicall_space mc = __xen_mc_entry(0); 332 333 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 334 } 335 336 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 337 { 338 xen_mc_batch(); 339 340 load_TLS_descriptor(t, cpu, 0); 341 load_TLS_descriptor(t, cpu, 1); 342 load_TLS_descriptor(t, cpu, 2); 343 344 xen_mc_issue(PARAVIRT_LAZY_CPU); 345 346 /* 347 * XXX sleazy hack: If we're being called in a lazy-cpu zone, 348 * it means we're in a context switch, and %gs has just been 349 * saved. This means we can zero it out to prevent faults on 350 * exit from the hypervisor if the next process has no %gs. 351 * Either way, it has been saved, and the new value will get 352 * loaded properly. This will go away as soon as Xen has been 353 * modified to not save/restore %gs for normal hypercalls. 354 */ 355 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) 356 loadsegment(gs, 0); 357 } 358 359 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 360 u32 low, u32 high) 361 { 362 unsigned long lp = (unsigned long)&dt[entrynum]; 363 xmaddr_t mach_lp = virt_to_machine(lp); 364 u64 entry = (u64)high << 32 | low; 365 366 preempt_disable(); 367 368 xen_mc_flush(); 369 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 370 BUG(); 371 372 preempt_enable(); 373 } 374 375 static int cvt_gate_to_trap(int vector, u32 low, u32 high, 376 struct trap_info *info) 377 { 378 u8 type, dpl; 379 380 type = (high >> 8) & 0x1f; 381 dpl = (high >> 13) & 3; 382 383 if (type != 0xf && type != 0xe) 384 return 0; 385 386 info->vector = vector; 387 info->address = (high & 0xffff0000) | (low & 0x0000ffff); 388 info->cs = low >> 16; 389 info->flags = dpl; 390 /* interrupt gates clear IF */ 391 if (type == 0xe) 392 info->flags |= 4; 393 394 return 1; 395 } 396 397 /* Locations of each CPU's IDT */ 398 static DEFINE_PER_CPU(struct Xgt_desc_struct, idt_desc); 399 400 /* Set an IDT entry. If the entry is part of the current IDT, then 401 also update Xen. */ 402 static void xen_write_idt_entry(struct desc_struct *dt, int entrynum, 403 u32 low, u32 high) 404 { 405 unsigned long p = (unsigned long)&dt[entrynum]; 406 unsigned long start, end; 407 408 preempt_disable(); 409 410 start = __get_cpu_var(idt_desc).address; 411 end = start + __get_cpu_var(idt_desc).size + 1; 412 413 xen_mc_flush(); 414 415 write_dt_entry(dt, entrynum, low, high); 416 417 if (p >= start && (p + 8) <= end) { 418 struct trap_info info[2]; 419 420 info[1].address = 0; 421 422 if (cvt_gate_to_trap(entrynum, low, high, &info[0])) 423 if (HYPERVISOR_set_trap_table(info)) 424 BUG(); 425 } 426 427 preempt_enable(); 428 } 429 430 static void xen_convert_trap_info(const struct Xgt_desc_struct *desc, 431 struct trap_info *traps) 432 { 433 unsigned in, out, count; 434 435 count = (desc->size+1) / 8; 436 BUG_ON(count > 256); 437 438 for (in = out = 0; in < count; in++) { 439 const u32 *entry = (u32 *)(desc->address + in * 8); 440 441 if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out])) 442 out++; 443 } 444 traps[out].address = 0; 445 } 446 447 void xen_copy_trap_info(struct trap_info *traps) 448 { 449 const struct Xgt_desc_struct *desc = &__get_cpu_var(idt_desc); 450 451 xen_convert_trap_info(desc, traps); 452 } 453 454 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 455 hold a spinlock to protect the static traps[] array (static because 456 it avoids allocation, and saves stack space). */ 457 static void xen_load_idt(const struct Xgt_desc_struct *desc) 458 { 459 static DEFINE_SPINLOCK(lock); 460 static struct trap_info traps[257]; 461 462 spin_lock(&lock); 463 464 __get_cpu_var(idt_desc) = *desc; 465 466 xen_convert_trap_info(desc, traps); 467 468 xen_mc_flush(); 469 if (HYPERVISOR_set_trap_table(traps)) 470 BUG(); 471 472 spin_unlock(&lock); 473 } 474 475 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 476 they're handled differently. */ 477 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 478 u32 low, u32 high) 479 { 480 preempt_disable(); 481 482 switch ((high >> 8) & 0xff) { 483 case DESCTYPE_LDT: 484 case DESCTYPE_TSS: 485 /* ignore */ 486 break; 487 488 default: { 489 xmaddr_t maddr = virt_to_machine(&dt[entry]); 490 u64 desc = (u64)high << 32 | low; 491 492 xen_mc_flush(); 493 if (HYPERVISOR_update_descriptor(maddr.maddr, desc)) 494 BUG(); 495 } 496 497 } 498 499 preempt_enable(); 500 } 501 502 static void xen_load_esp0(struct tss_struct *tss, 503 struct thread_struct *thread) 504 { 505 struct multicall_space mcs = xen_mc_entry(0); 506 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0); 507 xen_mc_issue(PARAVIRT_LAZY_CPU); 508 } 509 510 static void xen_set_iopl_mask(unsigned mask) 511 { 512 struct physdev_set_iopl set_iopl; 513 514 /* Force the change at ring 0. */ 515 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 516 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 517 } 518 519 static void xen_io_delay(void) 520 { 521 } 522 523 #ifdef CONFIG_X86_LOCAL_APIC 524 static unsigned long xen_apic_read(unsigned long reg) 525 { 526 return 0; 527 } 528 529 static void xen_apic_write(unsigned long reg, unsigned long val) 530 { 531 /* Warn to see if there's any stray references */ 532 WARN_ON(1); 533 } 534 #endif 535 536 static void xen_flush_tlb(void) 537 { 538 struct mmuext_op *op; 539 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 540 541 op = mcs.args; 542 op->cmd = MMUEXT_TLB_FLUSH_LOCAL; 543 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 544 545 xen_mc_issue(PARAVIRT_LAZY_MMU); 546 } 547 548 static void xen_flush_tlb_single(unsigned long addr) 549 { 550 struct mmuext_op *op; 551 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 552 553 op = mcs.args; 554 op->cmd = MMUEXT_INVLPG_LOCAL; 555 op->arg1.linear_addr = addr & PAGE_MASK; 556 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 557 558 xen_mc_issue(PARAVIRT_LAZY_MMU); 559 } 560 561 static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm, 562 unsigned long va) 563 { 564 struct { 565 struct mmuext_op op; 566 cpumask_t mask; 567 } *args; 568 cpumask_t cpumask = *cpus; 569 struct multicall_space mcs; 570 571 /* 572 * A couple of (to be removed) sanity checks: 573 * 574 * - current CPU must not be in mask 575 * - mask must exist :) 576 */ 577 BUG_ON(cpus_empty(cpumask)); 578 BUG_ON(cpu_isset(smp_processor_id(), cpumask)); 579 BUG_ON(!mm); 580 581 /* If a CPU which we ran on has gone down, OK. */ 582 cpus_and(cpumask, cpumask, cpu_online_map); 583 if (cpus_empty(cpumask)) 584 return; 585 586 mcs = xen_mc_entry(sizeof(*args)); 587 args = mcs.args; 588 args->mask = cpumask; 589 args->op.arg2.vcpumask = &args->mask; 590 591 if (va == TLB_FLUSH_ALL) { 592 args->op.cmd = MMUEXT_TLB_FLUSH_MULTI; 593 } else { 594 args->op.cmd = MMUEXT_INVLPG_MULTI; 595 args->op.arg1.linear_addr = va; 596 } 597 598 MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF); 599 600 xen_mc_issue(PARAVIRT_LAZY_MMU); 601 } 602 603 static void xen_write_cr2(unsigned long cr2) 604 { 605 x86_read_percpu(xen_vcpu)->arch.cr2 = cr2; 606 } 607 608 static unsigned long xen_read_cr2(void) 609 { 610 return x86_read_percpu(xen_vcpu)->arch.cr2; 611 } 612 613 static unsigned long xen_read_cr2_direct(void) 614 { 615 return x86_read_percpu(xen_vcpu_info.arch.cr2); 616 } 617 618 static void xen_write_cr4(unsigned long cr4) 619 { 620 /* Just ignore cr4 changes; Xen doesn't allow us to do 621 anything anyway. */ 622 } 623 624 static unsigned long xen_read_cr3(void) 625 { 626 return x86_read_percpu(xen_cr3); 627 } 628 629 static void set_current_cr3(void *v) 630 { 631 x86_write_percpu(xen_current_cr3, (unsigned long)v); 632 } 633 634 static void xen_write_cr3(unsigned long cr3) 635 { 636 struct mmuext_op *op; 637 struct multicall_space mcs; 638 unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3)); 639 640 BUG_ON(preemptible()); 641 642 mcs = xen_mc_entry(sizeof(*op)); /* disables interrupts */ 643 644 /* Update while interrupts are disabled, so its atomic with 645 respect to ipis */ 646 x86_write_percpu(xen_cr3, cr3); 647 648 op = mcs.args; 649 op->cmd = MMUEXT_NEW_BASEPTR; 650 op->arg1.mfn = mfn; 651 652 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 653 654 /* Update xen_update_cr3 once the batch has actually 655 been submitted. */ 656 xen_mc_callback(set_current_cr3, (void *)cr3); 657 658 xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */ 659 } 660 661 /* Early in boot, while setting up the initial pagetable, assume 662 everything is pinned. */ 663 static __init void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn) 664 { 665 BUG_ON(mem_map); /* should only be used early */ 666 make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); 667 } 668 669 static void pin_pagetable_pfn(unsigned level, unsigned long pfn) 670 { 671 struct mmuext_op op; 672 op.cmd = level; 673 op.arg1.mfn = pfn_to_mfn(pfn); 674 if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF)) 675 BUG(); 676 } 677 678 /* This needs to make sure the new pte page is pinned iff its being 679 attached to a pinned pagetable. */ 680 static void xen_alloc_pt(struct mm_struct *mm, u32 pfn) 681 { 682 struct page *page = pfn_to_page(pfn); 683 684 if (PagePinned(virt_to_page(mm->pgd))) { 685 SetPagePinned(page); 686 687 if (!PageHighMem(page)) { 688 make_lowmem_page_readonly(__va(PFN_PHYS(pfn))); 689 pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn); 690 } else 691 /* make sure there are no stray mappings of 692 this page */ 693 kmap_flush_unused(); 694 } 695 } 696 697 /* This should never happen until we're OK to use struct page */ 698 static void xen_release_pt(u32 pfn) 699 { 700 struct page *page = pfn_to_page(pfn); 701 702 if (PagePinned(page)) { 703 if (!PageHighMem(page)) { 704 pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn); 705 make_lowmem_page_readwrite(__va(PFN_PHYS(pfn))); 706 } 707 } 708 } 709 710 #ifdef CONFIG_HIGHPTE 711 static void *xen_kmap_atomic_pte(struct page *page, enum km_type type) 712 { 713 pgprot_t prot = PAGE_KERNEL; 714 715 if (PagePinned(page)) 716 prot = PAGE_KERNEL_RO; 717 718 if (0 && PageHighMem(page)) 719 printk("mapping highpte %lx type %d prot %s\n", 720 page_to_pfn(page), type, 721 (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ"); 722 723 return kmap_atomic_prot(page, type, prot); 724 } 725 #endif 726 727 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte) 728 { 729 /* If there's an existing pte, then don't allow _PAGE_RW to be set */ 730 if (pte_val_ma(*ptep) & _PAGE_PRESENT) 731 pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & 732 pte_val_ma(pte)); 733 734 return pte; 735 } 736 737 /* Init-time set_pte while constructing initial pagetables, which 738 doesn't allow RO pagetable pages to be remapped RW */ 739 static __init void xen_set_pte_init(pte_t *ptep, pte_t pte) 740 { 741 pte = mask_rw_pte(ptep, pte); 742 743 xen_set_pte(ptep, pte); 744 } 745 746 static __init void xen_pagetable_setup_start(pgd_t *base) 747 { 748 pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base; 749 750 /* special set_pte for pagetable initialization */ 751 pv_mmu_ops.set_pte = xen_set_pte_init; 752 753 init_mm.pgd = base; 754 /* 755 * copy top-level of Xen-supplied pagetable into place. For 756 * !PAE we can use this as-is, but for PAE it is a stand-in 757 * while we copy the pmd pages. 758 */ 759 memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t)); 760 761 if (PTRS_PER_PMD > 1) { 762 int i; 763 /* 764 * For PAE, need to allocate new pmds, rather than 765 * share Xen's, since Xen doesn't like pmd's being 766 * shared between address spaces. 767 */ 768 for (i = 0; i < PTRS_PER_PGD; i++) { 769 if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) { 770 pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE); 771 772 memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]), 773 PAGE_SIZE); 774 775 make_lowmem_page_readonly(pmd); 776 777 set_pgd(&base[i], __pgd(1 + __pa(pmd))); 778 } else 779 pgd_clear(&base[i]); 780 } 781 } 782 783 /* make sure zero_page is mapped RO so we can use it in pagetables */ 784 make_lowmem_page_readonly(empty_zero_page); 785 make_lowmem_page_readonly(base); 786 /* 787 * Switch to new pagetable. This is done before 788 * pagetable_init has done anything so that the new pages 789 * added to the table can be prepared properly for Xen. 790 */ 791 xen_write_cr3(__pa(base)); 792 } 793 794 static __init void xen_pagetable_setup_done(pgd_t *base) 795 { 796 /* This will work as long as patching hasn't happened yet 797 (which it hasn't) */ 798 pv_mmu_ops.alloc_pt = xen_alloc_pt; 799 pv_mmu_ops.set_pte = xen_set_pte; 800 801 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 802 /* 803 * Create a mapping for the shared info page. 804 * Should be set_fixmap(), but shared_info is a machine 805 * address with no corresponding pseudo-phys address. 806 */ 807 set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP), 808 PFN_DOWN(xen_start_info->shared_info), 809 PAGE_KERNEL); 810 811 HYPERVISOR_shared_info = 812 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 813 814 } else 815 HYPERVISOR_shared_info = 816 (struct shared_info *)__va(xen_start_info->shared_info); 817 818 /* Actually pin the pagetable down, but we can't set PG_pinned 819 yet because the page structures don't exist yet. */ 820 { 821 unsigned level; 822 823 #ifdef CONFIG_X86_PAE 824 level = MMUEXT_PIN_L3_TABLE; 825 #else 826 level = MMUEXT_PIN_L2_TABLE; 827 #endif 828 829 pin_pagetable_pfn(level, PFN_DOWN(__pa(base))); 830 } 831 } 832 833 /* This is called once we have the cpu_possible_map */ 834 void __init xen_setup_vcpu_info_placement(void) 835 { 836 int cpu; 837 838 for_each_possible_cpu(cpu) 839 xen_vcpu_setup(cpu); 840 841 /* xen_vcpu_setup managed to place the vcpu_info within the 842 percpu area for all cpus, so make use of it */ 843 if (have_vcpu_info_placement) { 844 printk(KERN_INFO "Xen: using vcpu_info placement\n"); 845 846 pv_irq_ops.save_fl = xen_save_fl_direct; 847 pv_irq_ops.restore_fl = xen_restore_fl_direct; 848 pv_irq_ops.irq_disable = xen_irq_disable_direct; 849 pv_irq_ops.irq_enable = xen_irq_enable_direct; 850 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 851 pv_cpu_ops.iret = xen_iret_direct; 852 } 853 } 854 855 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 856 unsigned long addr, unsigned len) 857 { 858 char *start, *end, *reloc; 859 unsigned ret; 860 861 start = end = reloc = NULL; 862 863 #define SITE(op, x) \ 864 case PARAVIRT_PATCH(op.x): \ 865 if (have_vcpu_info_placement) { \ 866 start = (char *)xen_##x##_direct; \ 867 end = xen_##x##_direct_end; \ 868 reloc = xen_##x##_direct_reloc; \ 869 } \ 870 goto patch_site 871 872 switch (type) { 873 SITE(pv_irq_ops, irq_enable); 874 SITE(pv_irq_ops, irq_disable); 875 SITE(pv_irq_ops, save_fl); 876 SITE(pv_irq_ops, restore_fl); 877 #undef SITE 878 879 patch_site: 880 if (start == NULL || (end-start) > len) 881 goto default_patch; 882 883 ret = paravirt_patch_insns(insnbuf, len, start, end); 884 885 /* Note: because reloc is assigned from something that 886 appears to be an array, gcc assumes it's non-null, 887 but doesn't know its relationship with start and 888 end. */ 889 if (reloc > start && reloc < end) { 890 int reloc_off = reloc - start; 891 long *relocp = (long *)(insnbuf + reloc_off); 892 long delta = start - (char *)addr; 893 894 *relocp += delta; 895 } 896 break; 897 898 default_patch: 899 default: 900 ret = paravirt_patch_default(type, clobbers, insnbuf, 901 addr, len); 902 break; 903 } 904 905 return ret; 906 } 907 908 static const struct pv_info xen_info __initdata = { 909 .paravirt_enabled = 1, 910 .shared_kernel_pmd = 0, 911 912 .name = "Xen", 913 }; 914 915 static const struct pv_init_ops xen_init_ops __initdata = { 916 .patch = xen_patch, 917 918 .banner = xen_banner, 919 .memory_setup = xen_memory_setup, 920 .arch_setup = xen_arch_setup, 921 .post_allocator_init = xen_mark_init_mm_pinned, 922 }; 923 924 static const struct pv_time_ops xen_time_ops __initdata = { 925 .time_init = xen_time_init, 926 927 .set_wallclock = xen_set_wallclock, 928 .get_wallclock = xen_get_wallclock, 929 .get_cpu_khz = xen_cpu_khz, 930 .sched_clock = xen_sched_clock, 931 }; 932 933 static const struct pv_cpu_ops xen_cpu_ops __initdata = { 934 .cpuid = xen_cpuid, 935 936 .set_debugreg = xen_set_debugreg, 937 .get_debugreg = xen_get_debugreg, 938 939 .clts = native_clts, 940 941 .read_cr0 = native_read_cr0, 942 .write_cr0 = native_write_cr0, 943 944 .read_cr4 = native_read_cr4, 945 .read_cr4_safe = native_read_cr4_safe, 946 .write_cr4 = xen_write_cr4, 947 948 .wbinvd = native_wbinvd, 949 950 .read_msr = native_read_msr_safe, 951 .write_msr = native_write_msr_safe, 952 .read_tsc = native_read_tsc, 953 .read_pmc = native_read_pmc, 954 955 .iret = (void *)&hypercall_page[__HYPERVISOR_iret], 956 .irq_enable_sysexit = NULL, /* never called */ 957 958 .load_tr_desc = paravirt_nop, 959 .set_ldt = xen_set_ldt, 960 .load_gdt = xen_load_gdt, 961 .load_idt = xen_load_idt, 962 .load_tls = xen_load_tls, 963 964 .store_gdt = native_store_gdt, 965 .store_idt = native_store_idt, 966 .store_tr = xen_store_tr, 967 968 .write_ldt_entry = xen_write_ldt_entry, 969 .write_gdt_entry = xen_write_gdt_entry, 970 .write_idt_entry = xen_write_idt_entry, 971 .load_esp0 = xen_load_esp0, 972 973 .set_iopl_mask = xen_set_iopl_mask, 974 .io_delay = xen_io_delay, 975 976 .lazy_mode = { 977 .enter = paravirt_enter_lazy_cpu, 978 .leave = xen_leave_lazy, 979 }, 980 }; 981 982 static const struct pv_irq_ops xen_irq_ops __initdata = { 983 .init_IRQ = xen_init_IRQ, 984 .save_fl = xen_save_fl, 985 .restore_fl = xen_restore_fl, 986 .irq_disable = xen_irq_disable, 987 .irq_enable = xen_irq_enable, 988 .safe_halt = xen_safe_halt, 989 .halt = xen_halt, 990 }; 991 992 static const struct pv_apic_ops xen_apic_ops __initdata = { 993 #ifdef CONFIG_X86_LOCAL_APIC 994 .apic_write = xen_apic_write, 995 .apic_write_atomic = xen_apic_write, 996 .apic_read = xen_apic_read, 997 .setup_boot_clock = paravirt_nop, 998 .setup_secondary_clock = paravirt_nop, 999 .startup_ipi_hook = paravirt_nop, 1000 #endif 1001 }; 1002 1003 static const struct pv_mmu_ops xen_mmu_ops __initdata = { 1004 .pagetable_setup_start = xen_pagetable_setup_start, 1005 .pagetable_setup_done = xen_pagetable_setup_done, 1006 1007 .read_cr2 = xen_read_cr2, 1008 .write_cr2 = xen_write_cr2, 1009 1010 .read_cr3 = xen_read_cr3, 1011 .write_cr3 = xen_write_cr3, 1012 1013 .flush_tlb_user = xen_flush_tlb, 1014 .flush_tlb_kernel = xen_flush_tlb, 1015 .flush_tlb_single = xen_flush_tlb_single, 1016 .flush_tlb_others = xen_flush_tlb_others, 1017 1018 .pte_update = paravirt_nop, 1019 .pte_update_defer = paravirt_nop, 1020 1021 .alloc_pt = xen_alloc_pt_init, 1022 .release_pt = xen_release_pt, 1023 .alloc_pd = paravirt_nop, 1024 .alloc_pd_clone = paravirt_nop, 1025 .release_pd = paravirt_nop, 1026 1027 #ifdef CONFIG_HIGHPTE 1028 .kmap_atomic_pte = xen_kmap_atomic_pte, 1029 #endif 1030 1031 .set_pte = NULL, /* see xen_pagetable_setup_* */ 1032 .set_pte_at = xen_set_pte_at, 1033 .set_pmd = xen_set_pmd, 1034 1035 .pte_val = xen_pte_val, 1036 .pgd_val = xen_pgd_val, 1037 1038 .make_pte = xen_make_pte, 1039 .make_pgd = xen_make_pgd, 1040 1041 #ifdef CONFIG_X86_PAE 1042 .set_pte_atomic = xen_set_pte_atomic, 1043 .set_pte_present = xen_set_pte_at, 1044 .set_pud = xen_set_pud, 1045 .pte_clear = xen_pte_clear, 1046 .pmd_clear = xen_pmd_clear, 1047 1048 .make_pmd = xen_make_pmd, 1049 .pmd_val = xen_pmd_val, 1050 #endif /* PAE */ 1051 1052 .activate_mm = xen_activate_mm, 1053 .dup_mmap = xen_dup_mmap, 1054 .exit_mmap = xen_exit_mmap, 1055 1056 .lazy_mode = { 1057 .enter = paravirt_enter_lazy_mmu, 1058 .leave = xen_leave_lazy, 1059 }, 1060 }; 1061 1062 #ifdef CONFIG_SMP 1063 static const struct smp_ops xen_smp_ops __initdata = { 1064 .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu, 1065 .smp_prepare_cpus = xen_smp_prepare_cpus, 1066 .cpu_up = xen_cpu_up, 1067 .smp_cpus_done = xen_smp_cpus_done, 1068 1069 .smp_send_stop = xen_smp_send_stop, 1070 .smp_send_reschedule = xen_smp_send_reschedule, 1071 .smp_call_function_mask = xen_smp_call_function_mask, 1072 }; 1073 #endif /* CONFIG_SMP */ 1074 1075 static void xen_reboot(int reason) 1076 { 1077 #ifdef CONFIG_SMP 1078 smp_send_stop(); 1079 #endif 1080 1081 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason)) 1082 BUG(); 1083 } 1084 1085 static void xen_restart(char *msg) 1086 { 1087 xen_reboot(SHUTDOWN_reboot); 1088 } 1089 1090 static void xen_emergency_restart(void) 1091 { 1092 xen_reboot(SHUTDOWN_reboot); 1093 } 1094 1095 static void xen_machine_halt(void) 1096 { 1097 xen_reboot(SHUTDOWN_poweroff); 1098 } 1099 1100 static void xen_crash_shutdown(struct pt_regs *regs) 1101 { 1102 xen_reboot(SHUTDOWN_crash); 1103 } 1104 1105 static const struct machine_ops __initdata xen_machine_ops = { 1106 .restart = xen_restart, 1107 .halt = xen_machine_halt, 1108 .power_off = xen_machine_halt, 1109 .shutdown = xen_machine_halt, 1110 .crash_shutdown = xen_crash_shutdown, 1111 .emergency_restart = xen_emergency_restart, 1112 }; 1113 1114 1115 static void __init xen_reserve_top(void) 1116 { 1117 unsigned long top = HYPERVISOR_VIRT_START; 1118 struct xen_platform_parameters pp; 1119 1120 if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0) 1121 top = pp.virt_start; 1122 1123 reserve_top_address(-top + 2 * PAGE_SIZE); 1124 } 1125 1126 /* First C function to be called on Xen boot */ 1127 asmlinkage void __init xen_start_kernel(void) 1128 { 1129 pgd_t *pgd; 1130 1131 if (!xen_start_info) 1132 return; 1133 1134 BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0); 1135 1136 /* Install Xen paravirt ops */ 1137 pv_info = xen_info; 1138 pv_init_ops = xen_init_ops; 1139 pv_time_ops = xen_time_ops; 1140 pv_cpu_ops = xen_cpu_ops; 1141 pv_irq_ops = xen_irq_ops; 1142 pv_apic_ops = xen_apic_ops; 1143 pv_mmu_ops = xen_mmu_ops; 1144 1145 machine_ops = xen_machine_ops; 1146 1147 #ifdef CONFIG_SMP 1148 smp_ops = xen_smp_ops; 1149 #endif 1150 1151 xen_setup_features(); 1152 1153 /* Get mfn list */ 1154 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1155 phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list; 1156 1157 pgd = (pgd_t *)xen_start_info->pt_base; 1158 1159 init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE; 1160 1161 init_mm.pgd = pgd; /* use the Xen pagetables to start */ 1162 1163 /* keep using Xen gdt for now; no urgent need to change it */ 1164 1165 x86_write_percpu(xen_cr3, __pa(pgd)); 1166 x86_write_percpu(xen_current_cr3, __pa(pgd)); 1167 1168 #ifdef CONFIG_SMP 1169 /* Don't do the full vcpu_info placement stuff until we have a 1170 possible map. */ 1171 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1172 #else 1173 /* May as well do it now, since there's no good time to call 1174 it later on UP. */ 1175 xen_setup_vcpu_info_placement(); 1176 #endif 1177 1178 pv_info.kernel_rpl = 1; 1179 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1180 pv_info.kernel_rpl = 0; 1181 1182 /* set the limit of our address space */ 1183 xen_reserve_top(); 1184 1185 /* set up basic CPUID stuff */ 1186 cpu_detect(&new_cpu_data); 1187 new_cpu_data.hard_math = 1; 1188 new_cpu_data.x86_capability[0] = cpuid_edx(1); 1189 1190 /* Poke various useful things into boot_params */ 1191 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1192 boot_params.hdr.ramdisk_image = xen_start_info->mod_start 1193 ? __pa(xen_start_info->mod_start) : 0; 1194 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1195 1196 /* Start the world */ 1197 start_kernel(); 1198 } 1199