xref: /linux/arch/x86/xen/enlighten.c (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec)
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/cpu.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/smp.h>
18 #include <linux/preempt.h>
19 #include <linux/hardirq.h>
20 #include <linux/percpu.h>
21 #include <linux/delay.h>
22 #include <linux/start_kernel.h>
23 #include <linux/sched.h>
24 #include <linux/kprobes.h>
25 #include <linux/bootmem.h>
26 #include <linux/module.h>
27 #include <linux/mm.h>
28 #include <linux/page-flags.h>
29 #include <linux/highmem.h>
30 #include <linux/console.h>
31 #include <linux/pci.h>
32 #include <linux/gfp.h>
33 #include <linux/memblock.h>
34 
35 #include <xen/xen.h>
36 #include <xen/interface/xen.h>
37 #include <xen/interface/version.h>
38 #include <xen/interface/physdev.h>
39 #include <xen/interface/vcpu.h>
40 #include <xen/interface/memory.h>
41 #include <xen/features.h>
42 #include <xen/page.h>
43 #include <xen/hvm.h>
44 #include <xen/hvc-console.h>
45 
46 #include <asm/paravirt.h>
47 #include <asm/apic.h>
48 #include <asm/page.h>
49 #include <asm/xen/pci.h>
50 #include <asm/xen/hypercall.h>
51 #include <asm/xen/hypervisor.h>
52 #include <asm/fixmap.h>
53 #include <asm/processor.h>
54 #include <asm/proto.h>
55 #include <asm/msr-index.h>
56 #include <asm/traps.h>
57 #include <asm/setup.h>
58 #include <asm/desc.h>
59 #include <asm/pgalloc.h>
60 #include <asm/pgtable.h>
61 #include <asm/tlbflush.h>
62 #include <asm/reboot.h>
63 #include <asm/stackprotector.h>
64 #include <asm/hypervisor.h>
65 
66 #include "xen-ops.h"
67 #include "mmu.h"
68 #include "multicalls.h"
69 
70 EXPORT_SYMBOL_GPL(hypercall_page);
71 
72 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
73 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
74 
75 enum xen_domain_type xen_domain_type = XEN_NATIVE;
76 EXPORT_SYMBOL_GPL(xen_domain_type);
77 
78 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
79 EXPORT_SYMBOL(machine_to_phys_mapping);
80 unsigned long  machine_to_phys_nr;
81 EXPORT_SYMBOL(machine_to_phys_nr);
82 
83 struct start_info *xen_start_info;
84 EXPORT_SYMBOL_GPL(xen_start_info);
85 
86 struct shared_info xen_dummy_shared_info;
87 
88 void *xen_initial_gdt;
89 
90 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
91 __read_mostly int xen_have_vector_callback;
92 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
93 
94 /*
95  * Point at some empty memory to start with. We map the real shared_info
96  * page as soon as fixmap is up and running.
97  */
98 struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
99 
100 /*
101  * Flag to determine whether vcpu info placement is available on all
102  * VCPUs.  We assume it is to start with, and then set it to zero on
103  * the first failure.  This is because it can succeed on some VCPUs
104  * and not others, since it can involve hypervisor memory allocation,
105  * or because the guest failed to guarantee all the appropriate
106  * constraints on all VCPUs (ie buffer can't cross a page boundary).
107  *
108  * Note that any particular CPU may be using a placed vcpu structure,
109  * but we can only optimise if the all are.
110  *
111  * 0: not available, 1: available
112  */
113 static int have_vcpu_info_placement = 1;
114 
115 static void clamp_max_cpus(void)
116 {
117 #ifdef CONFIG_SMP
118 	if (setup_max_cpus > MAX_VIRT_CPUS)
119 		setup_max_cpus = MAX_VIRT_CPUS;
120 #endif
121 }
122 
123 static void xen_vcpu_setup(int cpu)
124 {
125 	struct vcpu_register_vcpu_info info;
126 	int err;
127 	struct vcpu_info *vcpup;
128 
129 	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
130 
131 	if (cpu < MAX_VIRT_CPUS)
132 		per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
133 
134 	if (!have_vcpu_info_placement) {
135 		if (cpu >= MAX_VIRT_CPUS)
136 			clamp_max_cpus();
137 		return;
138 	}
139 
140 	vcpup = &per_cpu(xen_vcpu_info, cpu);
141 	info.mfn = arbitrary_virt_to_mfn(vcpup);
142 	info.offset = offset_in_page(vcpup);
143 
144 	/* Check to see if the hypervisor will put the vcpu_info
145 	   structure where we want it, which allows direct access via
146 	   a percpu-variable. */
147 	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
148 
149 	if (err) {
150 		printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
151 		have_vcpu_info_placement = 0;
152 		clamp_max_cpus();
153 	} else {
154 		/* This cpu is using the registered vcpu info, even if
155 		   later ones fail to. */
156 		per_cpu(xen_vcpu, cpu) = vcpup;
157 	}
158 }
159 
160 /*
161  * On restore, set the vcpu placement up again.
162  * If it fails, then we're in a bad state, since
163  * we can't back out from using it...
164  */
165 void xen_vcpu_restore(void)
166 {
167 	int cpu;
168 
169 	for_each_online_cpu(cpu) {
170 		bool other_cpu = (cpu != smp_processor_id());
171 
172 		if (other_cpu &&
173 		    HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL))
174 			BUG();
175 
176 		xen_setup_runstate_info(cpu);
177 
178 		if (have_vcpu_info_placement)
179 			xen_vcpu_setup(cpu);
180 
181 		if (other_cpu &&
182 		    HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
183 			BUG();
184 	}
185 }
186 
187 static void __init xen_banner(void)
188 {
189 	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
190 	struct xen_extraversion extra;
191 	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
192 
193 	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
194 	       pv_info.name);
195 	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
196 	       version >> 16, version & 0xffff, extra.extraversion,
197 	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
198 }
199 
200 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
201 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
202 
203 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
204 		      unsigned int *cx, unsigned int *dx)
205 {
206 	unsigned maskebx = ~0;
207 	unsigned maskecx = ~0;
208 	unsigned maskedx = ~0;
209 
210 	/*
211 	 * Mask out inconvenient features, to try and disable as many
212 	 * unsupported kernel subsystems as possible.
213 	 */
214 	switch (*ax) {
215 	case 1:
216 		maskecx = cpuid_leaf1_ecx_mask;
217 		maskedx = cpuid_leaf1_edx_mask;
218 		break;
219 
220 	case 0xb:
221 		/* Suppress extended topology stuff */
222 		maskebx = 0;
223 		break;
224 	}
225 
226 	asm(XEN_EMULATE_PREFIX "cpuid"
227 		: "=a" (*ax),
228 		  "=b" (*bx),
229 		  "=c" (*cx),
230 		  "=d" (*dx)
231 		: "0" (*ax), "2" (*cx));
232 
233 	*bx &= maskebx;
234 	*cx &= maskecx;
235 	*dx &= maskedx;
236 }
237 
238 static void __init xen_init_cpuid_mask(void)
239 {
240 	unsigned int ax, bx, cx, dx;
241 	unsigned int xsave_mask;
242 
243 	cpuid_leaf1_edx_mask =
244 		~((1 << X86_FEATURE_MCE)  |  /* disable MCE */
245 		  (1 << X86_FEATURE_MCA)  |  /* disable MCA */
246 		  (1 << X86_FEATURE_MTRR) |  /* disable MTRR */
247 		  (1 << X86_FEATURE_ACC));   /* thermal monitoring */
248 
249 	if (!xen_initial_domain())
250 		cpuid_leaf1_edx_mask &=
251 			~((1 << X86_FEATURE_APIC) |  /* disable local APIC */
252 			  (1 << X86_FEATURE_ACPI));  /* disable ACPI */
253 	ax = 1;
254 	xen_cpuid(&ax, &bx, &cx, &dx);
255 
256 	xsave_mask =
257 		(1 << (X86_FEATURE_XSAVE % 32)) |
258 		(1 << (X86_FEATURE_OSXSAVE % 32));
259 
260 	/* Xen will set CR4.OSXSAVE if supported and not disabled by force */
261 	if ((cx & xsave_mask) != xsave_mask)
262 		cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */
263 }
264 
265 static void xen_set_debugreg(int reg, unsigned long val)
266 {
267 	HYPERVISOR_set_debugreg(reg, val);
268 }
269 
270 static unsigned long xen_get_debugreg(int reg)
271 {
272 	return HYPERVISOR_get_debugreg(reg);
273 }
274 
275 static void xen_end_context_switch(struct task_struct *next)
276 {
277 	xen_mc_flush();
278 	paravirt_end_context_switch(next);
279 }
280 
281 static unsigned long xen_store_tr(void)
282 {
283 	return 0;
284 }
285 
286 /*
287  * Set the page permissions for a particular virtual address.  If the
288  * address is a vmalloc mapping (or other non-linear mapping), then
289  * find the linear mapping of the page and also set its protections to
290  * match.
291  */
292 static void set_aliased_prot(void *v, pgprot_t prot)
293 {
294 	int level;
295 	pte_t *ptep;
296 	pte_t pte;
297 	unsigned long pfn;
298 	struct page *page;
299 
300 	ptep = lookup_address((unsigned long)v, &level);
301 	BUG_ON(ptep == NULL);
302 
303 	pfn = pte_pfn(*ptep);
304 	page = pfn_to_page(pfn);
305 
306 	pte = pfn_pte(pfn, prot);
307 
308 	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
309 		BUG();
310 
311 	if (!PageHighMem(page)) {
312 		void *av = __va(PFN_PHYS(pfn));
313 
314 		if (av != v)
315 			if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
316 				BUG();
317 	} else
318 		kmap_flush_unused();
319 }
320 
321 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
322 {
323 	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
324 	int i;
325 
326 	for(i = 0; i < entries; i += entries_per_page)
327 		set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
328 }
329 
330 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
331 {
332 	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
333 	int i;
334 
335 	for(i = 0; i < entries; i += entries_per_page)
336 		set_aliased_prot(ldt + i, PAGE_KERNEL);
337 }
338 
339 static void xen_set_ldt(const void *addr, unsigned entries)
340 {
341 	struct mmuext_op *op;
342 	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
343 
344 	trace_xen_cpu_set_ldt(addr, entries);
345 
346 	op = mcs.args;
347 	op->cmd = MMUEXT_SET_LDT;
348 	op->arg1.linear_addr = (unsigned long)addr;
349 	op->arg2.nr_ents = entries;
350 
351 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
352 
353 	xen_mc_issue(PARAVIRT_LAZY_CPU);
354 }
355 
356 static void xen_load_gdt(const struct desc_ptr *dtr)
357 {
358 	unsigned long va = dtr->address;
359 	unsigned int size = dtr->size + 1;
360 	unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
361 	unsigned long frames[pages];
362 	int f;
363 
364 	/*
365 	 * A GDT can be up to 64k in size, which corresponds to 8192
366 	 * 8-byte entries, or 16 4k pages..
367 	 */
368 
369 	BUG_ON(size > 65536);
370 	BUG_ON(va & ~PAGE_MASK);
371 
372 	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
373 		int level;
374 		pte_t *ptep;
375 		unsigned long pfn, mfn;
376 		void *virt;
377 
378 		/*
379 		 * The GDT is per-cpu and is in the percpu data area.
380 		 * That can be virtually mapped, so we need to do a
381 		 * page-walk to get the underlying MFN for the
382 		 * hypercall.  The page can also be in the kernel's
383 		 * linear range, so we need to RO that mapping too.
384 		 */
385 		ptep = lookup_address(va, &level);
386 		BUG_ON(ptep == NULL);
387 
388 		pfn = pte_pfn(*ptep);
389 		mfn = pfn_to_mfn(pfn);
390 		virt = __va(PFN_PHYS(pfn));
391 
392 		frames[f] = mfn;
393 
394 		make_lowmem_page_readonly((void *)va);
395 		make_lowmem_page_readonly(virt);
396 	}
397 
398 	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
399 		BUG();
400 }
401 
402 /*
403  * load_gdt for early boot, when the gdt is only mapped once
404  */
405 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
406 {
407 	unsigned long va = dtr->address;
408 	unsigned int size = dtr->size + 1;
409 	unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
410 	unsigned long frames[pages];
411 	int f;
412 
413 	/*
414 	 * A GDT can be up to 64k in size, which corresponds to 8192
415 	 * 8-byte entries, or 16 4k pages..
416 	 */
417 
418 	BUG_ON(size > 65536);
419 	BUG_ON(va & ~PAGE_MASK);
420 
421 	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
422 		pte_t pte;
423 		unsigned long pfn, mfn;
424 
425 		pfn = virt_to_pfn(va);
426 		mfn = pfn_to_mfn(pfn);
427 
428 		pte = pfn_pte(pfn, PAGE_KERNEL_RO);
429 
430 		if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
431 			BUG();
432 
433 		frames[f] = mfn;
434 	}
435 
436 	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
437 		BUG();
438 }
439 
440 static void load_TLS_descriptor(struct thread_struct *t,
441 				unsigned int cpu, unsigned int i)
442 {
443 	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
444 	xmaddr_t maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
445 	struct multicall_space mc = __xen_mc_entry(0);
446 
447 	MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
448 }
449 
450 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
451 {
452 	/*
453 	 * XXX sleazy hack: If we're being called in a lazy-cpu zone
454 	 * and lazy gs handling is enabled, it means we're in a
455 	 * context switch, and %gs has just been saved.  This means we
456 	 * can zero it out to prevent faults on exit from the
457 	 * hypervisor if the next process has no %gs.  Either way, it
458 	 * has been saved, and the new value will get loaded properly.
459 	 * This will go away as soon as Xen has been modified to not
460 	 * save/restore %gs for normal hypercalls.
461 	 *
462 	 * On x86_64, this hack is not used for %gs, because gs points
463 	 * to KERNEL_GS_BASE (and uses it for PDA references), so we
464 	 * must not zero %gs on x86_64
465 	 *
466 	 * For x86_64, we need to zero %fs, otherwise we may get an
467 	 * exception between the new %fs descriptor being loaded and
468 	 * %fs being effectively cleared at __switch_to().
469 	 */
470 	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
471 #ifdef CONFIG_X86_32
472 		lazy_load_gs(0);
473 #else
474 		loadsegment(fs, 0);
475 #endif
476 	}
477 
478 	xen_mc_batch();
479 
480 	load_TLS_descriptor(t, cpu, 0);
481 	load_TLS_descriptor(t, cpu, 1);
482 	load_TLS_descriptor(t, cpu, 2);
483 
484 	xen_mc_issue(PARAVIRT_LAZY_CPU);
485 }
486 
487 #ifdef CONFIG_X86_64
488 static void xen_load_gs_index(unsigned int idx)
489 {
490 	if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
491 		BUG();
492 }
493 #endif
494 
495 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
496 				const void *ptr)
497 {
498 	xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
499 	u64 entry = *(u64 *)ptr;
500 
501 	trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
502 
503 	preempt_disable();
504 
505 	xen_mc_flush();
506 	if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
507 		BUG();
508 
509 	preempt_enable();
510 }
511 
512 static int cvt_gate_to_trap(int vector, const gate_desc *val,
513 			    struct trap_info *info)
514 {
515 	unsigned long addr;
516 
517 	if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
518 		return 0;
519 
520 	info->vector = vector;
521 
522 	addr = gate_offset(*val);
523 #ifdef CONFIG_X86_64
524 	/*
525 	 * Look for known traps using IST, and substitute them
526 	 * appropriately.  The debugger ones are the only ones we care
527 	 * about.  Xen will handle faults like double_fault and
528 	 * machine_check, so we should never see them.  Warn if
529 	 * there's an unexpected IST-using fault handler.
530 	 */
531 	if (addr == (unsigned long)debug)
532 		addr = (unsigned long)xen_debug;
533 	else if (addr == (unsigned long)int3)
534 		addr = (unsigned long)xen_int3;
535 	else if (addr == (unsigned long)stack_segment)
536 		addr = (unsigned long)xen_stack_segment;
537 	else if (addr == (unsigned long)double_fault ||
538 		 addr == (unsigned long)nmi) {
539 		/* Don't need to handle these */
540 		return 0;
541 #ifdef CONFIG_X86_MCE
542 	} else if (addr == (unsigned long)machine_check) {
543 		return 0;
544 #endif
545 	} else {
546 		/* Some other trap using IST? */
547 		if (WARN_ON(val->ist != 0))
548 			return 0;
549 	}
550 #endif	/* CONFIG_X86_64 */
551 	info->address = addr;
552 
553 	info->cs = gate_segment(*val);
554 	info->flags = val->dpl;
555 	/* interrupt gates clear IF */
556 	if (val->type == GATE_INTERRUPT)
557 		info->flags |= 1 << 2;
558 
559 	return 1;
560 }
561 
562 /* Locations of each CPU's IDT */
563 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
564 
565 /* Set an IDT entry.  If the entry is part of the current IDT, then
566    also update Xen. */
567 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
568 {
569 	unsigned long p = (unsigned long)&dt[entrynum];
570 	unsigned long start, end;
571 
572 	trace_xen_cpu_write_idt_entry(dt, entrynum, g);
573 
574 	preempt_disable();
575 
576 	start = __this_cpu_read(idt_desc.address);
577 	end = start + __this_cpu_read(idt_desc.size) + 1;
578 
579 	xen_mc_flush();
580 
581 	native_write_idt_entry(dt, entrynum, g);
582 
583 	if (p >= start && (p + 8) <= end) {
584 		struct trap_info info[2];
585 
586 		info[1].address = 0;
587 
588 		if (cvt_gate_to_trap(entrynum, g, &info[0]))
589 			if (HYPERVISOR_set_trap_table(info))
590 				BUG();
591 	}
592 
593 	preempt_enable();
594 }
595 
596 static void xen_convert_trap_info(const struct desc_ptr *desc,
597 				  struct trap_info *traps)
598 {
599 	unsigned in, out, count;
600 
601 	count = (desc->size+1) / sizeof(gate_desc);
602 	BUG_ON(count > 256);
603 
604 	for (in = out = 0; in < count; in++) {
605 		gate_desc *entry = (gate_desc*)(desc->address) + in;
606 
607 		if (cvt_gate_to_trap(in, entry, &traps[out]))
608 			out++;
609 	}
610 	traps[out].address = 0;
611 }
612 
613 void xen_copy_trap_info(struct trap_info *traps)
614 {
615 	const struct desc_ptr *desc = &__get_cpu_var(idt_desc);
616 
617 	xen_convert_trap_info(desc, traps);
618 }
619 
620 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
621    hold a spinlock to protect the static traps[] array (static because
622    it avoids allocation, and saves stack space). */
623 static void xen_load_idt(const struct desc_ptr *desc)
624 {
625 	static DEFINE_SPINLOCK(lock);
626 	static struct trap_info traps[257];
627 
628 	trace_xen_cpu_load_idt(desc);
629 
630 	spin_lock(&lock);
631 
632 	__get_cpu_var(idt_desc) = *desc;
633 
634 	xen_convert_trap_info(desc, traps);
635 
636 	xen_mc_flush();
637 	if (HYPERVISOR_set_trap_table(traps))
638 		BUG();
639 
640 	spin_unlock(&lock);
641 }
642 
643 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
644    they're handled differently. */
645 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
646 				const void *desc, int type)
647 {
648 	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
649 
650 	preempt_disable();
651 
652 	switch (type) {
653 	case DESC_LDT:
654 	case DESC_TSS:
655 		/* ignore */
656 		break;
657 
658 	default: {
659 		xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
660 
661 		xen_mc_flush();
662 		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
663 			BUG();
664 	}
665 
666 	}
667 
668 	preempt_enable();
669 }
670 
671 /*
672  * Version of write_gdt_entry for use at early boot-time needed to
673  * update an entry as simply as possible.
674  */
675 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
676 					    const void *desc, int type)
677 {
678 	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
679 
680 	switch (type) {
681 	case DESC_LDT:
682 	case DESC_TSS:
683 		/* ignore */
684 		break;
685 
686 	default: {
687 		xmaddr_t maddr = virt_to_machine(&dt[entry]);
688 
689 		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
690 			dt[entry] = *(struct desc_struct *)desc;
691 	}
692 
693 	}
694 }
695 
696 static void xen_load_sp0(struct tss_struct *tss,
697 			 struct thread_struct *thread)
698 {
699 	struct multicall_space mcs;
700 
701 	mcs = xen_mc_entry(0);
702 	MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
703 	xen_mc_issue(PARAVIRT_LAZY_CPU);
704 }
705 
706 static void xen_set_iopl_mask(unsigned mask)
707 {
708 	struct physdev_set_iopl set_iopl;
709 
710 	/* Force the change at ring 0. */
711 	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
712 	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
713 }
714 
715 static void xen_io_delay(void)
716 {
717 }
718 
719 #ifdef CONFIG_X86_LOCAL_APIC
720 static u32 xen_apic_read(u32 reg)
721 {
722 	return 0;
723 }
724 
725 static void xen_apic_write(u32 reg, u32 val)
726 {
727 	/* Warn to see if there's any stray references */
728 	WARN_ON(1);
729 }
730 
731 static u64 xen_apic_icr_read(void)
732 {
733 	return 0;
734 }
735 
736 static void xen_apic_icr_write(u32 low, u32 id)
737 {
738 	/* Warn to see if there's any stray references */
739 	WARN_ON(1);
740 }
741 
742 static void xen_apic_wait_icr_idle(void)
743 {
744         return;
745 }
746 
747 static u32 xen_safe_apic_wait_icr_idle(void)
748 {
749         return 0;
750 }
751 
752 static void set_xen_basic_apic_ops(void)
753 {
754 	apic->read = xen_apic_read;
755 	apic->write = xen_apic_write;
756 	apic->icr_read = xen_apic_icr_read;
757 	apic->icr_write = xen_apic_icr_write;
758 	apic->wait_icr_idle = xen_apic_wait_icr_idle;
759 	apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle;
760 }
761 
762 #endif
763 
764 static void xen_clts(void)
765 {
766 	struct multicall_space mcs;
767 
768 	mcs = xen_mc_entry(0);
769 
770 	MULTI_fpu_taskswitch(mcs.mc, 0);
771 
772 	xen_mc_issue(PARAVIRT_LAZY_CPU);
773 }
774 
775 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
776 
777 static unsigned long xen_read_cr0(void)
778 {
779 	unsigned long cr0 = percpu_read(xen_cr0_value);
780 
781 	if (unlikely(cr0 == 0)) {
782 		cr0 = native_read_cr0();
783 		percpu_write(xen_cr0_value, cr0);
784 	}
785 
786 	return cr0;
787 }
788 
789 static void xen_write_cr0(unsigned long cr0)
790 {
791 	struct multicall_space mcs;
792 
793 	percpu_write(xen_cr0_value, cr0);
794 
795 	/* Only pay attention to cr0.TS; everything else is
796 	   ignored. */
797 	mcs = xen_mc_entry(0);
798 
799 	MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
800 
801 	xen_mc_issue(PARAVIRT_LAZY_CPU);
802 }
803 
804 static void xen_write_cr4(unsigned long cr4)
805 {
806 	cr4 &= ~X86_CR4_PGE;
807 	cr4 &= ~X86_CR4_PSE;
808 
809 	native_write_cr4(cr4);
810 }
811 
812 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
813 {
814 	int ret;
815 
816 	ret = 0;
817 
818 	switch (msr) {
819 #ifdef CONFIG_X86_64
820 		unsigned which;
821 		u64 base;
822 
823 	case MSR_FS_BASE:		which = SEGBASE_FS; goto set;
824 	case MSR_KERNEL_GS_BASE:	which = SEGBASE_GS_USER; goto set;
825 	case MSR_GS_BASE:		which = SEGBASE_GS_KERNEL; goto set;
826 
827 	set:
828 		base = ((u64)high << 32) | low;
829 		if (HYPERVISOR_set_segment_base(which, base) != 0)
830 			ret = -EIO;
831 		break;
832 #endif
833 
834 	case MSR_STAR:
835 	case MSR_CSTAR:
836 	case MSR_LSTAR:
837 	case MSR_SYSCALL_MASK:
838 	case MSR_IA32_SYSENTER_CS:
839 	case MSR_IA32_SYSENTER_ESP:
840 	case MSR_IA32_SYSENTER_EIP:
841 		/* Fast syscall setup is all done in hypercalls, so
842 		   these are all ignored.  Stub them out here to stop
843 		   Xen console noise. */
844 		break;
845 
846 	case MSR_IA32_CR_PAT:
847 		if (smp_processor_id() == 0)
848 			xen_set_pat(((u64)high << 32) | low);
849 		break;
850 
851 	default:
852 		ret = native_write_msr_safe(msr, low, high);
853 	}
854 
855 	return ret;
856 }
857 
858 void xen_setup_shared_info(void)
859 {
860 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
861 		set_fixmap(FIX_PARAVIRT_BOOTMAP,
862 			   xen_start_info->shared_info);
863 
864 		HYPERVISOR_shared_info =
865 			(struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
866 	} else
867 		HYPERVISOR_shared_info =
868 			(struct shared_info *)__va(xen_start_info->shared_info);
869 
870 #ifndef CONFIG_SMP
871 	/* In UP this is as good a place as any to set up shared info */
872 	xen_setup_vcpu_info_placement();
873 #endif
874 
875 	xen_setup_mfn_list_list();
876 }
877 
878 /* This is called once we have the cpu_possible_map */
879 void xen_setup_vcpu_info_placement(void)
880 {
881 	int cpu;
882 
883 	for_each_possible_cpu(cpu)
884 		xen_vcpu_setup(cpu);
885 
886 	/* xen_vcpu_setup managed to place the vcpu_info within the
887 	   percpu area for all cpus, so make use of it */
888 	if (have_vcpu_info_placement) {
889 		pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
890 		pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
891 		pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
892 		pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
893 		pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
894 	}
895 }
896 
897 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
898 			  unsigned long addr, unsigned len)
899 {
900 	char *start, *end, *reloc;
901 	unsigned ret;
902 
903 	start = end = reloc = NULL;
904 
905 #define SITE(op, x)							\
906 	case PARAVIRT_PATCH(op.x):					\
907 	if (have_vcpu_info_placement) {					\
908 		start = (char *)xen_##x##_direct;			\
909 		end = xen_##x##_direct_end;				\
910 		reloc = xen_##x##_direct_reloc;				\
911 	}								\
912 	goto patch_site
913 
914 	switch (type) {
915 		SITE(pv_irq_ops, irq_enable);
916 		SITE(pv_irq_ops, irq_disable);
917 		SITE(pv_irq_ops, save_fl);
918 		SITE(pv_irq_ops, restore_fl);
919 #undef SITE
920 
921 	patch_site:
922 		if (start == NULL || (end-start) > len)
923 			goto default_patch;
924 
925 		ret = paravirt_patch_insns(insnbuf, len, start, end);
926 
927 		/* Note: because reloc is assigned from something that
928 		   appears to be an array, gcc assumes it's non-null,
929 		   but doesn't know its relationship with start and
930 		   end. */
931 		if (reloc > start && reloc < end) {
932 			int reloc_off = reloc - start;
933 			long *relocp = (long *)(insnbuf + reloc_off);
934 			long delta = start - (char *)addr;
935 
936 			*relocp += delta;
937 		}
938 		break;
939 
940 	default_patch:
941 	default:
942 		ret = paravirt_patch_default(type, clobbers, insnbuf,
943 					     addr, len);
944 		break;
945 	}
946 
947 	return ret;
948 }
949 
950 static const struct pv_info xen_info __initconst = {
951 	.paravirt_enabled = 1,
952 	.shared_kernel_pmd = 0,
953 
954 #ifdef CONFIG_X86_64
955 	.extra_user_64bit_cs = FLAT_USER_CS64,
956 #endif
957 
958 	.name = "Xen",
959 };
960 
961 static const struct pv_init_ops xen_init_ops __initconst = {
962 	.patch = xen_patch,
963 };
964 
965 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
966 	.cpuid = xen_cpuid,
967 
968 	.set_debugreg = xen_set_debugreg,
969 	.get_debugreg = xen_get_debugreg,
970 
971 	.clts = xen_clts,
972 
973 	.read_cr0 = xen_read_cr0,
974 	.write_cr0 = xen_write_cr0,
975 
976 	.read_cr4 = native_read_cr4,
977 	.read_cr4_safe = native_read_cr4_safe,
978 	.write_cr4 = xen_write_cr4,
979 
980 	.wbinvd = native_wbinvd,
981 
982 	.read_msr = native_read_msr_safe,
983 	.write_msr = xen_write_msr_safe,
984 	.read_tsc = native_read_tsc,
985 	.read_pmc = native_read_pmc,
986 
987 	.iret = xen_iret,
988 	.irq_enable_sysexit = xen_sysexit,
989 #ifdef CONFIG_X86_64
990 	.usergs_sysret32 = xen_sysret32,
991 	.usergs_sysret64 = xen_sysret64,
992 #endif
993 
994 	.load_tr_desc = paravirt_nop,
995 	.set_ldt = xen_set_ldt,
996 	.load_gdt = xen_load_gdt,
997 	.load_idt = xen_load_idt,
998 	.load_tls = xen_load_tls,
999 #ifdef CONFIG_X86_64
1000 	.load_gs_index = xen_load_gs_index,
1001 #endif
1002 
1003 	.alloc_ldt = xen_alloc_ldt,
1004 	.free_ldt = xen_free_ldt,
1005 
1006 	.store_gdt = native_store_gdt,
1007 	.store_idt = native_store_idt,
1008 	.store_tr = xen_store_tr,
1009 
1010 	.write_ldt_entry = xen_write_ldt_entry,
1011 	.write_gdt_entry = xen_write_gdt_entry,
1012 	.write_idt_entry = xen_write_idt_entry,
1013 	.load_sp0 = xen_load_sp0,
1014 
1015 	.set_iopl_mask = xen_set_iopl_mask,
1016 	.io_delay = xen_io_delay,
1017 
1018 	/* Xen takes care of %gs when switching to usermode for us */
1019 	.swapgs = paravirt_nop,
1020 
1021 	.start_context_switch = paravirt_start_context_switch,
1022 	.end_context_switch = xen_end_context_switch,
1023 };
1024 
1025 static const struct pv_apic_ops xen_apic_ops __initconst = {
1026 #ifdef CONFIG_X86_LOCAL_APIC
1027 	.startup_ipi_hook = paravirt_nop,
1028 #endif
1029 };
1030 
1031 static void xen_reboot(int reason)
1032 {
1033 	struct sched_shutdown r = { .reason = reason };
1034 
1035 	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
1036 		BUG();
1037 }
1038 
1039 static void xen_restart(char *msg)
1040 {
1041 	xen_reboot(SHUTDOWN_reboot);
1042 }
1043 
1044 static void xen_emergency_restart(void)
1045 {
1046 	xen_reboot(SHUTDOWN_reboot);
1047 }
1048 
1049 static void xen_machine_halt(void)
1050 {
1051 	xen_reboot(SHUTDOWN_poweroff);
1052 }
1053 
1054 static void xen_machine_power_off(void)
1055 {
1056 	if (pm_power_off)
1057 		pm_power_off();
1058 	xen_reboot(SHUTDOWN_poweroff);
1059 }
1060 
1061 static void xen_crash_shutdown(struct pt_regs *regs)
1062 {
1063 	xen_reboot(SHUTDOWN_crash);
1064 }
1065 
1066 static int
1067 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
1068 {
1069 	xen_reboot(SHUTDOWN_crash);
1070 	return NOTIFY_DONE;
1071 }
1072 
1073 static struct notifier_block xen_panic_block = {
1074 	.notifier_call= xen_panic_event,
1075 };
1076 
1077 int xen_panic_handler_init(void)
1078 {
1079 	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
1080 	return 0;
1081 }
1082 
1083 static const struct machine_ops xen_machine_ops __initconst = {
1084 	.restart = xen_restart,
1085 	.halt = xen_machine_halt,
1086 	.power_off = xen_machine_power_off,
1087 	.shutdown = xen_machine_halt,
1088 	.crash_shutdown = xen_crash_shutdown,
1089 	.emergency_restart = xen_emergency_restart,
1090 };
1091 
1092 /*
1093  * Set up the GDT and segment registers for -fstack-protector.  Until
1094  * we do this, we have to be careful not to call any stack-protected
1095  * function, which is most of the kernel.
1096  */
1097 static void __init xen_setup_stackprotector(void)
1098 {
1099 	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
1100 	pv_cpu_ops.load_gdt = xen_load_gdt_boot;
1101 
1102 	setup_stack_canary_segment(0);
1103 	switch_to_new_gdt(0);
1104 
1105 	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
1106 	pv_cpu_ops.load_gdt = xen_load_gdt;
1107 }
1108 
1109 /* First C function to be called on Xen boot */
1110 asmlinkage void __init xen_start_kernel(void)
1111 {
1112 	struct physdev_set_iopl set_iopl;
1113 	int rc;
1114 	pgd_t *pgd;
1115 
1116 	if (!xen_start_info)
1117 		return;
1118 
1119 	xen_domain_type = XEN_PV_DOMAIN;
1120 
1121 	xen_setup_machphys_mapping();
1122 
1123 	/* Install Xen paravirt ops */
1124 	pv_info = xen_info;
1125 	pv_init_ops = xen_init_ops;
1126 	pv_cpu_ops = xen_cpu_ops;
1127 	pv_apic_ops = xen_apic_ops;
1128 
1129 	x86_init.resources.memory_setup = xen_memory_setup;
1130 	x86_init.oem.arch_setup = xen_arch_setup;
1131 	x86_init.oem.banner = xen_banner;
1132 
1133 	xen_init_time_ops();
1134 
1135 	/*
1136 	 * Set up some pagetable state before starting to set any ptes.
1137 	 */
1138 
1139 	xen_init_mmu_ops();
1140 
1141 	/* Prevent unwanted bits from being set in PTEs. */
1142 	__supported_pte_mask &= ~_PAGE_GLOBAL;
1143 	if (!xen_initial_domain())
1144 		__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
1145 
1146 	__supported_pte_mask |= _PAGE_IOMAP;
1147 
1148 	/*
1149 	 * Prevent page tables from being allocated in highmem, even
1150 	 * if CONFIG_HIGHPTE is enabled.
1151 	 */
1152 	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1153 
1154 	/* Work out if we support NX */
1155 	x86_configure_nx();
1156 
1157 	xen_setup_features();
1158 
1159 	/* Get mfn list */
1160 	if (!xen_feature(XENFEAT_auto_translated_physmap))
1161 		xen_build_dynamic_phys_to_machine();
1162 
1163 	/*
1164 	 * Set up kernel GDT and segment registers, mainly so that
1165 	 * -fstack-protector code can be executed.
1166 	 */
1167 	xen_setup_stackprotector();
1168 
1169 	xen_init_irq_ops();
1170 	xen_init_cpuid_mask();
1171 
1172 #ifdef CONFIG_X86_LOCAL_APIC
1173 	/*
1174 	 * set up the basic apic ops.
1175 	 */
1176 	set_xen_basic_apic_ops();
1177 #endif
1178 
1179 	if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1180 		pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1181 		pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1182 	}
1183 
1184 	machine_ops = xen_machine_ops;
1185 
1186 	/*
1187 	 * The only reliable way to retain the initial address of the
1188 	 * percpu gdt_page is to remember it here, so we can go and
1189 	 * mark it RW later, when the initial percpu area is freed.
1190 	 */
1191 	xen_initial_gdt = &per_cpu(gdt_page, 0);
1192 
1193 	xen_smp_init();
1194 
1195 #ifdef CONFIG_ACPI_NUMA
1196 	/*
1197 	 * The pages we from Xen are not related to machine pages, so
1198 	 * any NUMA information the kernel tries to get from ACPI will
1199 	 * be meaningless.  Prevent it from trying.
1200 	 */
1201 	acpi_numa = -1;
1202 #endif
1203 
1204 	pgd = (pgd_t *)xen_start_info->pt_base;
1205 
1206 	if (!xen_initial_domain())
1207 		__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
1208 
1209 	__supported_pte_mask |= _PAGE_IOMAP;
1210 	/* Don't do the full vcpu_info placement stuff until we have a
1211 	   possible map and a non-dummy shared_info. */
1212 	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
1213 
1214 	local_irq_disable();
1215 	early_boot_irqs_disabled = true;
1216 
1217 	memblock_init();
1218 
1219 	xen_raw_console_write("mapping kernel into physical memory\n");
1220 	pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
1221 	xen_ident_map_ISA();
1222 
1223 	/* Allocate and initialize top and mid mfn levels for p2m structure */
1224 	xen_build_mfn_list_list();
1225 
1226 	/* keep using Xen gdt for now; no urgent need to change it */
1227 
1228 #ifdef CONFIG_X86_32
1229 	pv_info.kernel_rpl = 1;
1230 	if (xen_feature(XENFEAT_supervisor_mode_kernel))
1231 		pv_info.kernel_rpl = 0;
1232 #else
1233 	pv_info.kernel_rpl = 0;
1234 #endif
1235 	/* set the limit of our address space */
1236 	xen_reserve_top();
1237 
1238 	/* We used to do this in xen_arch_setup, but that is too late on AMD
1239 	 * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
1240 	 * which pokes 0xcf8 port.
1241 	 */
1242 	set_iopl.iopl = 1;
1243 	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1244 	if (rc != 0)
1245 		xen_raw_printk("physdev_op failed %d\n", rc);
1246 
1247 #ifdef CONFIG_X86_32
1248 	/* set up basic CPUID stuff */
1249 	cpu_detect(&new_cpu_data);
1250 	new_cpu_data.hard_math = 1;
1251 	new_cpu_data.wp_works_ok = 1;
1252 	new_cpu_data.x86_capability[0] = cpuid_edx(1);
1253 #endif
1254 
1255 	/* Poke various useful things into boot_params */
1256 	boot_params.hdr.type_of_loader = (9 << 4) | 0;
1257 	boot_params.hdr.ramdisk_image = xen_start_info->mod_start
1258 		? __pa(xen_start_info->mod_start) : 0;
1259 	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1260 	boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1261 
1262 	if (!xen_initial_domain()) {
1263 		add_preferred_console("xenboot", 0, NULL);
1264 		add_preferred_console("tty", 0, NULL);
1265 		add_preferred_console("hvc", 0, NULL);
1266 		if (pci_xen)
1267 			x86_init.pci.arch_init = pci_xen_init;
1268 	} else {
1269 		const struct dom0_vga_console_info *info =
1270 			(void *)((char *)xen_start_info +
1271 				 xen_start_info->console.dom0.info_off);
1272 
1273 		xen_init_vga(info, xen_start_info->console.dom0.info_size);
1274 		xen_start_info->console.domU.mfn = 0;
1275 		xen_start_info->console.domU.evtchn = 0;
1276 
1277 		/* Make sure ACS will be enabled */
1278 		pci_request_acs();
1279 	}
1280 
1281 
1282 	xen_raw_console_write("about to get started...\n");
1283 
1284 	xen_setup_runstate_info(0);
1285 
1286 	/* Start the world */
1287 #ifdef CONFIG_X86_32
1288 	i386_start_kernel();
1289 #else
1290 	x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1291 #endif
1292 }
1293 
1294 static int init_hvm_pv_info(int *major, int *minor)
1295 {
1296 	uint32_t eax, ebx, ecx, edx, pages, msr, base;
1297 	u64 pfn;
1298 
1299 	base = xen_cpuid_base();
1300 	cpuid(base + 1, &eax, &ebx, &ecx, &edx);
1301 
1302 	*major = eax >> 16;
1303 	*minor = eax & 0xffff;
1304 	printk(KERN_INFO "Xen version %d.%d.\n", *major, *minor);
1305 
1306 	cpuid(base + 2, &pages, &msr, &ecx, &edx);
1307 
1308 	pfn = __pa(hypercall_page);
1309 	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
1310 
1311 	xen_setup_features();
1312 
1313 	pv_info.name = "Xen HVM";
1314 
1315 	xen_domain_type = XEN_HVM_DOMAIN;
1316 
1317 	return 0;
1318 }
1319 
1320 void __ref xen_hvm_init_shared_info(void)
1321 {
1322 	int cpu;
1323 	struct xen_add_to_physmap xatp;
1324 	static struct shared_info *shared_info_page = 0;
1325 
1326 	if (!shared_info_page)
1327 		shared_info_page = (struct shared_info *)
1328 			extend_brk(PAGE_SIZE, PAGE_SIZE);
1329 	xatp.domid = DOMID_SELF;
1330 	xatp.idx = 0;
1331 	xatp.space = XENMAPSPACE_shared_info;
1332 	xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
1333 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
1334 		BUG();
1335 
1336 	HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
1337 
1338 	/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
1339 	 * page, we use it in the event channel upcall and in some pvclock
1340 	 * related functions. We don't need the vcpu_info placement
1341 	 * optimizations because we don't use any pv_mmu or pv_irq op on
1342 	 * HVM.
1343 	 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
1344 	 * online but xen_hvm_init_shared_info is run at resume time too and
1345 	 * in that case multiple vcpus might be online. */
1346 	for_each_online_cpu(cpu) {
1347 		per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
1348 	}
1349 }
1350 
1351 #ifdef CONFIG_XEN_PVHVM
1352 static int __cpuinit xen_hvm_cpu_notify(struct notifier_block *self,
1353 				    unsigned long action, void *hcpu)
1354 {
1355 	int cpu = (long)hcpu;
1356 	switch (action) {
1357 	case CPU_UP_PREPARE:
1358 		per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
1359 		if (xen_have_vector_callback)
1360 			xen_init_lock_cpu(cpu);
1361 		break;
1362 	default:
1363 		break;
1364 	}
1365 	return NOTIFY_OK;
1366 }
1367 
1368 static struct notifier_block xen_hvm_cpu_notifier __cpuinitdata = {
1369 	.notifier_call	= xen_hvm_cpu_notify,
1370 };
1371 
1372 static void __init xen_hvm_guest_init(void)
1373 {
1374 	int r;
1375 	int major, minor;
1376 
1377 	r = init_hvm_pv_info(&major, &minor);
1378 	if (r < 0)
1379 		return;
1380 
1381 	xen_hvm_init_shared_info();
1382 
1383 	if (xen_feature(XENFEAT_hvm_callback_vector))
1384 		xen_have_vector_callback = 1;
1385 	xen_hvm_smp_init();
1386 	register_cpu_notifier(&xen_hvm_cpu_notifier);
1387 	xen_unplug_emulated_devices();
1388 	have_vcpu_info_placement = 0;
1389 	x86_init.irqs.intr_init = xen_init_IRQ;
1390 	xen_hvm_init_time_ops();
1391 	xen_hvm_init_mmu_ops();
1392 }
1393 
1394 static bool __init xen_hvm_platform(void)
1395 {
1396 	if (xen_pv_domain())
1397 		return false;
1398 
1399 	if (!xen_cpuid_base())
1400 		return false;
1401 
1402 	return true;
1403 }
1404 
1405 bool xen_hvm_need_lapic(void)
1406 {
1407 	if (xen_pv_domain())
1408 		return false;
1409 	if (!xen_hvm_domain())
1410 		return false;
1411 	if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
1412 		return false;
1413 	return true;
1414 }
1415 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
1416 
1417 const struct hypervisor_x86 x86_hyper_xen_hvm __refconst = {
1418 	.name			= "Xen HVM",
1419 	.detect			= xen_hvm_platform,
1420 	.init_platform		= xen_hvm_guest_init,
1421 };
1422 EXPORT_SYMBOL(x86_hyper_xen_hvm);
1423 #endif
1424