Merge branch 'xen-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
[linux-2.6.git] / arch / x86 / xen / enlighten.c
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68  * out of date, but it will never be set early).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 }