xref: /openbmc/linux/arch/x86/xen/enlighten.c (revision aac5987a)
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/export.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 #include <linux/edd.h>
35 #include <linux/frame.h>
36 
37 #include <linux/kexec.h>
38 
39 #include <xen/xen.h>
40 #include <xen/events.h>
41 #include <xen/interface/xen.h>
42 #include <xen/interface/version.h>
43 #include <xen/interface/physdev.h>
44 #include <xen/interface/vcpu.h>
45 #include <xen/interface/memory.h>
46 #include <xen/interface/nmi.h>
47 #include <xen/interface/xen-mca.h>
48 #include <xen/interface/hvm/start_info.h>
49 #include <xen/features.h>
50 #include <xen/page.h>
51 #include <xen/hvm.h>
52 #include <xen/hvc-console.h>
53 #include <xen/acpi.h>
54 
55 #include <asm/paravirt.h>
56 #include <asm/apic.h>
57 #include <asm/page.h>
58 #include <asm/xen/pci.h>
59 #include <asm/xen/hypercall.h>
60 #include <asm/xen/hypervisor.h>
61 #include <asm/xen/cpuid.h>
62 #include <asm/fixmap.h>
63 #include <asm/processor.h>
64 #include <asm/proto.h>
65 #include <asm/msr-index.h>
66 #include <asm/traps.h>
67 #include <asm/setup.h>
68 #include <asm/desc.h>
69 #include <asm/pgalloc.h>
70 #include <asm/pgtable.h>
71 #include <asm/tlbflush.h>
72 #include <asm/reboot.h>
73 #include <asm/stackprotector.h>
74 #include <asm/hypervisor.h>
75 #include <asm/mach_traps.h>
76 #include <asm/mwait.h>
77 #include <asm/pci_x86.h>
78 #include <asm/cpu.h>
79 
80 #ifdef CONFIG_ACPI
81 #include <linux/acpi.h>
82 #include <asm/acpi.h>
83 #include <acpi/pdc_intel.h>
84 #include <acpi/processor.h>
85 #include <xen/interface/platform.h>
86 #endif
87 
88 #include "xen-ops.h"
89 #include "mmu.h"
90 #include "smp.h"
91 #include "multicalls.h"
92 #include "pmu.h"
93 
94 EXPORT_SYMBOL_GPL(hypercall_page);
95 
96 /*
97  * Pointer to the xen_vcpu_info structure or
98  * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
99  * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
100  * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point
101  * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to
102  * acknowledge pending events.
103  * Also more subtly it is used by the patched version of irq enable/disable
104  * e.g. xen_irq_enable_direct and xen_iret in PV mode.
105  *
106  * The desire to be able to do those mask/unmask operations as a single
107  * instruction by using the per-cpu offset held in %gs is the real reason
108  * vcpu info is in a per-cpu pointer and the original reason for this
109  * hypercall.
110  *
111  */
112 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
113 
114 /*
115  * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info
116  * hypercall. This can be used both in PV and PVHVM mode. The structure
117  * overrides the default per_cpu(xen_vcpu, cpu) value.
118  */
119 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
120 
121 /* Linux <-> Xen vCPU id mapping */
122 DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
123 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
124 
125 enum xen_domain_type xen_domain_type = XEN_NATIVE;
126 EXPORT_SYMBOL_GPL(xen_domain_type);
127 
128 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
129 EXPORT_SYMBOL(machine_to_phys_mapping);
130 unsigned long  machine_to_phys_nr;
131 EXPORT_SYMBOL(machine_to_phys_nr);
132 
133 struct start_info *xen_start_info;
134 EXPORT_SYMBOL_GPL(xen_start_info);
135 
136 struct shared_info xen_dummy_shared_info;
137 
138 void *xen_initial_gdt;
139 
140 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
141 
142 static int xen_cpu_up_prepare(unsigned int cpu);
143 static int xen_cpu_up_online(unsigned int cpu);
144 static int xen_cpu_dead(unsigned int cpu);
145 
146 /*
147  * Point at some empty memory to start with. We map the real shared_info
148  * page as soon as fixmap is up and running.
149  */
150 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
151 
152 /*
153  * Flag to determine whether vcpu info placement is available on all
154  * VCPUs.  We assume it is to start with, and then set it to zero on
155  * the first failure.  This is because it can succeed on some VCPUs
156  * and not others, since it can involve hypervisor memory allocation,
157  * or because the guest failed to guarantee all the appropriate
158  * constraints on all VCPUs (ie buffer can't cross a page boundary).
159  *
160  * Note that any particular CPU may be using a placed vcpu structure,
161  * but we can only optimise if the all are.
162  *
163  * 0: not available, 1: available
164  */
165 static int have_vcpu_info_placement = 1;
166 
167 struct tls_descs {
168 	struct desc_struct desc[3];
169 };
170 
171 /*
172  * Updating the 3 TLS descriptors in the GDT on every task switch is
173  * surprisingly expensive so we avoid updating them if they haven't
174  * changed.  Since Xen writes different descriptors than the one
175  * passed in the update_descriptor hypercall we keep shadow copies to
176  * compare against.
177  */
178 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
179 
180 #ifdef CONFIG_XEN_PVH
181 /*
182  * PVH variables.
183  *
184  * xen_pvh and pvh_bootparams need to live in data segment since they
185  * are used after startup_{32|64}, which clear .bss, are invoked.
186  */
187 bool xen_pvh __attribute__((section(".data"))) = 0;
188 struct boot_params pvh_bootparams __attribute__((section(".data")));
189 
190 struct hvm_start_info pvh_start_info;
191 unsigned int pvh_start_info_sz = sizeof(pvh_start_info);
192 #endif
193 
194 static void clamp_max_cpus(void)
195 {
196 #ifdef CONFIG_SMP
197 	if (setup_max_cpus > MAX_VIRT_CPUS)
198 		setup_max_cpus = MAX_VIRT_CPUS;
199 #endif
200 }
201 
202 void xen_vcpu_setup(int cpu)
203 {
204 	struct vcpu_register_vcpu_info info;
205 	int err;
206 	struct vcpu_info *vcpup;
207 
208 	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
209 
210 	/*
211 	 * This path is called twice on PVHVM - first during bootup via
212 	 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being
213 	 * hotplugged: cpu_up -> xen_hvm_cpu_notify.
214 	 * As we can only do the VCPUOP_register_vcpu_info once lets
215 	 * not over-write its result.
216 	 *
217 	 * For PV it is called during restore (xen_vcpu_restore) and bootup
218 	 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
219 	 * use this function.
220 	 */
221 	if (xen_hvm_domain()) {
222 		if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
223 			return;
224 	}
225 	if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)
226 		per_cpu(xen_vcpu, cpu) =
227 			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
228 
229 	if (!have_vcpu_info_placement) {
230 		if (cpu >= MAX_VIRT_CPUS)
231 			clamp_max_cpus();
232 		return;
233 	}
234 
235 	vcpup = &per_cpu(xen_vcpu_info, cpu);
236 	info.mfn = arbitrary_virt_to_mfn(vcpup);
237 	info.offset = offset_in_page(vcpup);
238 
239 	/* Check to see if the hypervisor will put the vcpu_info
240 	   structure where we want it, which allows direct access via
241 	   a percpu-variable.
242 	   N.B. This hypercall can _only_ be called once per CPU. Subsequent
243 	   calls will error out with -EINVAL. This is due to the fact that
244 	   hypervisor has no unregister variant and this hypercall does not
245 	   allow to over-write info.mfn and info.offset.
246 	 */
247 	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
248 				 &info);
249 
250 	if (err) {
251 		printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
252 		have_vcpu_info_placement = 0;
253 		clamp_max_cpus();
254 	} else {
255 		/* This cpu is using the registered vcpu info, even if
256 		   later ones fail to. */
257 		per_cpu(xen_vcpu, cpu) = vcpup;
258 	}
259 }
260 
261 /*
262  * On restore, set the vcpu placement up again.
263  * If it fails, then we're in a bad state, since
264  * we can't back out from using it...
265  */
266 void xen_vcpu_restore(void)
267 {
268 	int cpu;
269 
270 	for_each_possible_cpu(cpu) {
271 		bool other_cpu = (cpu != smp_processor_id());
272 		bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu),
273 						NULL);
274 
275 		if (other_cpu && is_up &&
276 		    HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
277 			BUG();
278 
279 		xen_setup_runstate_info(cpu);
280 
281 		if (have_vcpu_info_placement)
282 			xen_vcpu_setup(cpu);
283 
284 		if (other_cpu && is_up &&
285 		    HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
286 			BUG();
287 	}
288 }
289 
290 static void __init xen_banner(void)
291 {
292 	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
293 	struct xen_extraversion extra;
294 	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
295 
296 	pr_info("Booting paravirtualized kernel %son %s\n",
297 		xen_feature(XENFEAT_auto_translated_physmap) ?
298 			"with PVH extensions " : "", pv_info.name);
299 	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
300 	       version >> 16, version & 0xffff, extra.extraversion,
301 	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
302 }
303 /* Check if running on Xen version (major, minor) or later */
304 bool
305 xen_running_on_version_or_later(unsigned int major, unsigned int minor)
306 {
307 	unsigned int version;
308 
309 	if (!xen_domain())
310 		return false;
311 
312 	version = HYPERVISOR_xen_version(XENVER_version, NULL);
313 	if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
314 		((version >> 16) > major))
315 		return true;
316 	return false;
317 }
318 
319 #define CPUID_THERM_POWER_LEAF 6
320 #define APERFMPERF_PRESENT 0
321 
322 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
323 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
324 
325 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask;
326 static __read_mostly unsigned int cpuid_leaf5_ecx_val;
327 static __read_mostly unsigned int cpuid_leaf5_edx_val;
328 
329 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
330 		      unsigned int *cx, unsigned int *dx)
331 {
332 	unsigned maskebx = ~0;
333 	unsigned maskecx = ~0;
334 	unsigned maskedx = ~0;
335 	unsigned setecx = 0;
336 	/*
337 	 * Mask out inconvenient features, to try and disable as many
338 	 * unsupported kernel subsystems as possible.
339 	 */
340 	switch (*ax) {
341 	case 1:
342 		maskecx = cpuid_leaf1_ecx_mask;
343 		setecx = cpuid_leaf1_ecx_set_mask;
344 		maskedx = cpuid_leaf1_edx_mask;
345 		break;
346 
347 	case CPUID_MWAIT_LEAF:
348 		/* Synthesize the values.. */
349 		*ax = 0;
350 		*bx = 0;
351 		*cx = cpuid_leaf5_ecx_val;
352 		*dx = cpuid_leaf5_edx_val;
353 		return;
354 
355 	case CPUID_THERM_POWER_LEAF:
356 		/* Disabling APERFMPERF for kernel usage */
357 		maskecx = ~(1 << APERFMPERF_PRESENT);
358 		break;
359 
360 	case 0xb:
361 		/* Suppress extended topology stuff */
362 		maskebx = 0;
363 		break;
364 	}
365 
366 	asm(XEN_EMULATE_PREFIX "cpuid"
367 		: "=a" (*ax),
368 		  "=b" (*bx),
369 		  "=c" (*cx),
370 		  "=d" (*dx)
371 		: "0" (*ax), "2" (*cx));
372 
373 	*bx &= maskebx;
374 	*cx &= maskecx;
375 	*cx |= setecx;
376 	*dx &= maskedx;
377 }
378 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
379 
380 static bool __init xen_check_mwait(void)
381 {
382 #ifdef CONFIG_ACPI
383 	struct xen_platform_op op = {
384 		.cmd			= XENPF_set_processor_pminfo,
385 		.u.set_pminfo.id	= -1,
386 		.u.set_pminfo.type	= XEN_PM_PDC,
387 	};
388 	uint32_t buf[3];
389 	unsigned int ax, bx, cx, dx;
390 	unsigned int mwait_mask;
391 
392 	/* We need to determine whether it is OK to expose the MWAIT
393 	 * capability to the kernel to harvest deeper than C3 states from ACPI
394 	 * _CST using the processor_harvest_xen.c module. For this to work, we
395 	 * need to gather the MWAIT_LEAF values (which the cstate.c code
396 	 * checks against). The hypervisor won't expose the MWAIT flag because
397 	 * it would break backwards compatibility; so we will find out directly
398 	 * from the hardware and hypercall.
399 	 */
400 	if (!xen_initial_domain())
401 		return false;
402 
403 	/*
404 	 * When running under platform earlier than Xen4.2, do not expose
405 	 * mwait, to avoid the risk of loading native acpi pad driver
406 	 */
407 	if (!xen_running_on_version_or_later(4, 2))
408 		return false;
409 
410 	ax = 1;
411 	cx = 0;
412 
413 	native_cpuid(&ax, &bx, &cx, &dx);
414 
415 	mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
416 		     (1 << (X86_FEATURE_MWAIT % 32));
417 
418 	if ((cx & mwait_mask) != mwait_mask)
419 		return false;
420 
421 	/* We need to emulate the MWAIT_LEAF and for that we need both
422 	 * ecx and edx. The hypercall provides only partial information.
423 	 */
424 
425 	ax = CPUID_MWAIT_LEAF;
426 	bx = 0;
427 	cx = 0;
428 	dx = 0;
429 
430 	native_cpuid(&ax, &bx, &cx, &dx);
431 
432 	/* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
433 	 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
434 	 */
435 	buf[0] = ACPI_PDC_REVISION_ID;
436 	buf[1] = 1;
437 	buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
438 
439 	set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
440 
441 	if ((HYPERVISOR_platform_op(&op) == 0) &&
442 	    (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
443 		cpuid_leaf5_ecx_val = cx;
444 		cpuid_leaf5_edx_val = dx;
445 	}
446 	return true;
447 #else
448 	return false;
449 #endif
450 }
451 static void __init xen_init_cpuid_mask(void)
452 {
453 	unsigned int ax, bx, cx, dx;
454 	unsigned int xsave_mask;
455 
456 	cpuid_leaf1_edx_mask =
457 		~((1 << X86_FEATURE_MTRR) |  /* disable MTRR */
458 		  (1 << X86_FEATURE_ACC));   /* thermal monitoring */
459 
460 	if (!xen_initial_domain())
461 		cpuid_leaf1_edx_mask &=
462 			~((1 << X86_FEATURE_ACPI));  /* disable ACPI */
463 
464 	cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32));
465 
466 	ax = 1;
467 	cx = 0;
468 	cpuid(1, &ax, &bx, &cx, &dx);
469 
470 	xsave_mask =
471 		(1 << (X86_FEATURE_XSAVE % 32)) |
472 		(1 << (X86_FEATURE_OSXSAVE % 32));
473 
474 	/* Xen will set CR4.OSXSAVE if supported and not disabled by force */
475 	if ((cx & xsave_mask) != xsave_mask)
476 		cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */
477 	if (xen_check_mwait())
478 		cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32));
479 }
480 
481 static void xen_set_debugreg(int reg, unsigned long val)
482 {
483 	HYPERVISOR_set_debugreg(reg, val);
484 }
485 
486 static unsigned long xen_get_debugreg(int reg)
487 {
488 	return HYPERVISOR_get_debugreg(reg);
489 }
490 
491 static void xen_end_context_switch(struct task_struct *next)
492 {
493 	xen_mc_flush();
494 	paravirt_end_context_switch(next);
495 }
496 
497 static unsigned long xen_store_tr(void)
498 {
499 	return 0;
500 }
501 
502 /*
503  * Set the page permissions for a particular virtual address.  If the
504  * address is a vmalloc mapping (or other non-linear mapping), then
505  * find the linear mapping of the page and also set its protections to
506  * match.
507  */
508 static void set_aliased_prot(void *v, pgprot_t prot)
509 {
510 	int level;
511 	pte_t *ptep;
512 	pte_t pte;
513 	unsigned long pfn;
514 	struct page *page;
515 	unsigned char dummy;
516 
517 	ptep = lookup_address((unsigned long)v, &level);
518 	BUG_ON(ptep == NULL);
519 
520 	pfn = pte_pfn(*ptep);
521 	page = pfn_to_page(pfn);
522 
523 	pte = pfn_pte(pfn, prot);
524 
525 	/*
526 	 * Careful: update_va_mapping() will fail if the virtual address
527 	 * we're poking isn't populated in the page tables.  We don't
528 	 * need to worry about the direct map (that's always in the page
529 	 * tables), but we need to be careful about vmap space.  In
530 	 * particular, the top level page table can lazily propagate
531 	 * entries between processes, so if we've switched mms since we
532 	 * vmapped the target in the first place, we might not have the
533 	 * top-level page table entry populated.
534 	 *
535 	 * We disable preemption because we want the same mm active when
536 	 * we probe the target and when we issue the hypercall.  We'll
537 	 * have the same nominal mm, but if we're a kernel thread, lazy
538 	 * mm dropping could change our pgd.
539 	 *
540 	 * Out of an abundance of caution, this uses __get_user() to fault
541 	 * in the target address just in case there's some obscure case
542 	 * in which the target address isn't readable.
543 	 */
544 
545 	preempt_disable();
546 
547 	probe_kernel_read(&dummy, v, 1);
548 
549 	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
550 		BUG();
551 
552 	if (!PageHighMem(page)) {
553 		void *av = __va(PFN_PHYS(pfn));
554 
555 		if (av != v)
556 			if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
557 				BUG();
558 	} else
559 		kmap_flush_unused();
560 
561 	preempt_enable();
562 }
563 
564 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
565 {
566 	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
567 	int i;
568 
569 	/*
570 	 * We need to mark the all aliases of the LDT pages RO.  We
571 	 * don't need to call vm_flush_aliases(), though, since that's
572 	 * only responsible for flushing aliases out the TLBs, not the
573 	 * page tables, and Xen will flush the TLB for us if needed.
574 	 *
575 	 * To avoid confusing future readers: none of this is necessary
576 	 * to load the LDT.  The hypervisor only checks this when the
577 	 * LDT is faulted in due to subsequent descriptor access.
578 	 */
579 
580 	for(i = 0; i < entries; i += entries_per_page)
581 		set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
582 }
583 
584 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
585 {
586 	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
587 	int i;
588 
589 	for(i = 0; i < entries; i += entries_per_page)
590 		set_aliased_prot(ldt + i, PAGE_KERNEL);
591 }
592 
593 static void xen_set_ldt(const void *addr, unsigned entries)
594 {
595 	struct mmuext_op *op;
596 	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
597 
598 	trace_xen_cpu_set_ldt(addr, entries);
599 
600 	op = mcs.args;
601 	op->cmd = MMUEXT_SET_LDT;
602 	op->arg1.linear_addr = (unsigned long)addr;
603 	op->arg2.nr_ents = entries;
604 
605 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
606 
607 	xen_mc_issue(PARAVIRT_LAZY_CPU);
608 }
609 
610 static void xen_load_gdt(const struct desc_ptr *dtr)
611 {
612 	unsigned long va = dtr->address;
613 	unsigned int size = dtr->size + 1;
614 	unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
615 	unsigned long frames[pages];
616 	int f;
617 
618 	/*
619 	 * A GDT can be up to 64k in size, which corresponds to 8192
620 	 * 8-byte entries, or 16 4k pages..
621 	 */
622 
623 	BUG_ON(size > 65536);
624 	BUG_ON(va & ~PAGE_MASK);
625 
626 	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
627 		int level;
628 		pte_t *ptep;
629 		unsigned long pfn, mfn;
630 		void *virt;
631 
632 		/*
633 		 * The GDT is per-cpu and is in the percpu data area.
634 		 * That can be virtually mapped, so we need to do a
635 		 * page-walk to get the underlying MFN for the
636 		 * hypercall.  The page can also be in the kernel's
637 		 * linear range, so we need to RO that mapping too.
638 		 */
639 		ptep = lookup_address(va, &level);
640 		BUG_ON(ptep == NULL);
641 
642 		pfn = pte_pfn(*ptep);
643 		mfn = pfn_to_mfn(pfn);
644 		virt = __va(PFN_PHYS(pfn));
645 
646 		frames[f] = mfn;
647 
648 		make_lowmem_page_readonly((void *)va);
649 		make_lowmem_page_readonly(virt);
650 	}
651 
652 	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
653 		BUG();
654 }
655 
656 /*
657  * load_gdt for early boot, when the gdt is only mapped once
658  */
659 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
660 {
661 	unsigned long va = dtr->address;
662 	unsigned int size = dtr->size + 1;
663 	unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
664 	unsigned long frames[pages];
665 	int f;
666 
667 	/*
668 	 * A GDT can be up to 64k in size, which corresponds to 8192
669 	 * 8-byte entries, or 16 4k pages..
670 	 */
671 
672 	BUG_ON(size > 65536);
673 	BUG_ON(va & ~PAGE_MASK);
674 
675 	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
676 		pte_t pte;
677 		unsigned long pfn, mfn;
678 
679 		pfn = virt_to_pfn(va);
680 		mfn = pfn_to_mfn(pfn);
681 
682 		pte = pfn_pte(pfn, PAGE_KERNEL_RO);
683 
684 		if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
685 			BUG();
686 
687 		frames[f] = mfn;
688 	}
689 
690 	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
691 		BUG();
692 }
693 
694 static inline bool desc_equal(const struct desc_struct *d1,
695 			      const struct desc_struct *d2)
696 {
697 	return d1->a == d2->a && d1->b == d2->b;
698 }
699 
700 static void load_TLS_descriptor(struct thread_struct *t,
701 				unsigned int cpu, unsigned int i)
702 {
703 	struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
704 	struct desc_struct *gdt;
705 	xmaddr_t maddr;
706 	struct multicall_space mc;
707 
708 	if (desc_equal(shadow, &t->tls_array[i]))
709 		return;
710 
711 	*shadow = t->tls_array[i];
712 
713 	gdt = get_cpu_gdt_table(cpu);
714 	maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
715 	mc = __xen_mc_entry(0);
716 
717 	MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
718 }
719 
720 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
721 {
722 	/*
723 	 * XXX sleazy hack: If we're being called in a lazy-cpu zone
724 	 * and lazy gs handling is enabled, it means we're in a
725 	 * context switch, and %gs has just been saved.  This means we
726 	 * can zero it out to prevent faults on exit from the
727 	 * hypervisor if the next process has no %gs.  Either way, it
728 	 * has been saved, and the new value will get loaded properly.
729 	 * This will go away as soon as Xen has been modified to not
730 	 * save/restore %gs for normal hypercalls.
731 	 *
732 	 * On x86_64, this hack is not used for %gs, because gs points
733 	 * to KERNEL_GS_BASE (and uses it for PDA references), so we
734 	 * must not zero %gs on x86_64
735 	 *
736 	 * For x86_64, we need to zero %fs, otherwise we may get an
737 	 * exception between the new %fs descriptor being loaded and
738 	 * %fs being effectively cleared at __switch_to().
739 	 */
740 	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
741 #ifdef CONFIG_X86_32
742 		lazy_load_gs(0);
743 #else
744 		loadsegment(fs, 0);
745 #endif
746 	}
747 
748 	xen_mc_batch();
749 
750 	load_TLS_descriptor(t, cpu, 0);
751 	load_TLS_descriptor(t, cpu, 1);
752 	load_TLS_descriptor(t, cpu, 2);
753 
754 	xen_mc_issue(PARAVIRT_LAZY_CPU);
755 }
756 
757 #ifdef CONFIG_X86_64
758 static void xen_load_gs_index(unsigned int idx)
759 {
760 	if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
761 		BUG();
762 }
763 #endif
764 
765 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
766 				const void *ptr)
767 {
768 	xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
769 	u64 entry = *(u64 *)ptr;
770 
771 	trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
772 
773 	preempt_disable();
774 
775 	xen_mc_flush();
776 	if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
777 		BUG();
778 
779 	preempt_enable();
780 }
781 
782 static int cvt_gate_to_trap(int vector, const gate_desc *val,
783 			    struct trap_info *info)
784 {
785 	unsigned long addr;
786 
787 	if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
788 		return 0;
789 
790 	info->vector = vector;
791 
792 	addr = gate_offset(*val);
793 #ifdef CONFIG_X86_64
794 	/*
795 	 * Look for known traps using IST, and substitute them
796 	 * appropriately.  The debugger ones are the only ones we care
797 	 * about.  Xen will handle faults like double_fault,
798 	 * so we should never see them.  Warn if
799 	 * there's an unexpected IST-using fault handler.
800 	 */
801 	if (addr == (unsigned long)debug)
802 		addr = (unsigned long)xen_debug;
803 	else if (addr == (unsigned long)int3)
804 		addr = (unsigned long)xen_int3;
805 	else if (addr == (unsigned long)stack_segment)
806 		addr = (unsigned long)xen_stack_segment;
807 	else if (addr == (unsigned long)double_fault) {
808 		/* Don't need to handle these */
809 		return 0;
810 #ifdef CONFIG_X86_MCE
811 	} else if (addr == (unsigned long)machine_check) {
812 		/*
813 		 * when xen hypervisor inject vMCE to guest,
814 		 * use native mce handler to handle it
815 		 */
816 		;
817 #endif
818 	} else if (addr == (unsigned long)nmi)
819 		/*
820 		 * Use the native version as well.
821 		 */
822 		;
823 	else {
824 		/* Some other trap using IST? */
825 		if (WARN_ON(val->ist != 0))
826 			return 0;
827 	}
828 #endif	/* CONFIG_X86_64 */
829 	info->address = addr;
830 
831 	info->cs = gate_segment(*val);
832 	info->flags = val->dpl;
833 	/* interrupt gates clear IF */
834 	if (val->type == GATE_INTERRUPT)
835 		info->flags |= 1 << 2;
836 
837 	return 1;
838 }
839 
840 /* Locations of each CPU's IDT */
841 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
842 
843 /* Set an IDT entry.  If the entry is part of the current IDT, then
844    also update Xen. */
845 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
846 {
847 	unsigned long p = (unsigned long)&dt[entrynum];
848 	unsigned long start, end;
849 
850 	trace_xen_cpu_write_idt_entry(dt, entrynum, g);
851 
852 	preempt_disable();
853 
854 	start = __this_cpu_read(idt_desc.address);
855 	end = start + __this_cpu_read(idt_desc.size) + 1;
856 
857 	xen_mc_flush();
858 
859 	native_write_idt_entry(dt, entrynum, g);
860 
861 	if (p >= start && (p + 8) <= end) {
862 		struct trap_info info[2];
863 
864 		info[1].address = 0;
865 
866 		if (cvt_gate_to_trap(entrynum, g, &info[0]))
867 			if (HYPERVISOR_set_trap_table(info))
868 				BUG();
869 	}
870 
871 	preempt_enable();
872 }
873 
874 static void xen_convert_trap_info(const struct desc_ptr *desc,
875 				  struct trap_info *traps)
876 {
877 	unsigned in, out, count;
878 
879 	count = (desc->size+1) / sizeof(gate_desc);
880 	BUG_ON(count > 256);
881 
882 	for (in = out = 0; in < count; in++) {
883 		gate_desc *entry = (gate_desc*)(desc->address) + in;
884 
885 		if (cvt_gate_to_trap(in, entry, &traps[out]))
886 			out++;
887 	}
888 	traps[out].address = 0;
889 }
890 
891 void xen_copy_trap_info(struct trap_info *traps)
892 {
893 	const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
894 
895 	xen_convert_trap_info(desc, traps);
896 }
897 
898 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
899    hold a spinlock to protect the static traps[] array (static because
900    it avoids allocation, and saves stack space). */
901 static void xen_load_idt(const struct desc_ptr *desc)
902 {
903 	static DEFINE_SPINLOCK(lock);
904 	static struct trap_info traps[257];
905 
906 	trace_xen_cpu_load_idt(desc);
907 
908 	spin_lock(&lock);
909 
910 	memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
911 
912 	xen_convert_trap_info(desc, traps);
913 
914 	xen_mc_flush();
915 	if (HYPERVISOR_set_trap_table(traps))
916 		BUG();
917 
918 	spin_unlock(&lock);
919 }
920 
921 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
922    they're handled differently. */
923 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
924 				const void *desc, int type)
925 {
926 	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
927 
928 	preempt_disable();
929 
930 	switch (type) {
931 	case DESC_LDT:
932 	case DESC_TSS:
933 		/* ignore */
934 		break;
935 
936 	default: {
937 		xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
938 
939 		xen_mc_flush();
940 		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
941 			BUG();
942 	}
943 
944 	}
945 
946 	preempt_enable();
947 }
948 
949 /*
950  * Version of write_gdt_entry for use at early boot-time needed to
951  * update an entry as simply as possible.
952  */
953 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
954 					    const void *desc, int type)
955 {
956 	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
957 
958 	switch (type) {
959 	case DESC_LDT:
960 	case DESC_TSS:
961 		/* ignore */
962 		break;
963 
964 	default: {
965 		xmaddr_t maddr = virt_to_machine(&dt[entry]);
966 
967 		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
968 			dt[entry] = *(struct desc_struct *)desc;
969 	}
970 
971 	}
972 }
973 
974 static void xen_load_sp0(struct tss_struct *tss,
975 			 struct thread_struct *thread)
976 {
977 	struct multicall_space mcs;
978 
979 	mcs = xen_mc_entry(0);
980 	MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
981 	xen_mc_issue(PARAVIRT_LAZY_CPU);
982 	tss->x86_tss.sp0 = thread->sp0;
983 }
984 
985 void xen_set_iopl_mask(unsigned mask)
986 {
987 	struct physdev_set_iopl set_iopl;
988 
989 	/* Force the change at ring 0. */
990 	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
991 	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
992 }
993 
994 static void xen_io_delay(void)
995 {
996 }
997 
998 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
999 
1000 static unsigned long xen_read_cr0(void)
1001 {
1002 	unsigned long cr0 = this_cpu_read(xen_cr0_value);
1003 
1004 	if (unlikely(cr0 == 0)) {
1005 		cr0 = native_read_cr0();
1006 		this_cpu_write(xen_cr0_value, cr0);
1007 	}
1008 
1009 	return cr0;
1010 }
1011 
1012 static void xen_write_cr0(unsigned long cr0)
1013 {
1014 	struct multicall_space mcs;
1015 
1016 	this_cpu_write(xen_cr0_value, cr0);
1017 
1018 	/* Only pay attention to cr0.TS; everything else is
1019 	   ignored. */
1020 	mcs = xen_mc_entry(0);
1021 
1022 	MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
1023 
1024 	xen_mc_issue(PARAVIRT_LAZY_CPU);
1025 }
1026 
1027 static void xen_write_cr4(unsigned long cr4)
1028 {
1029 	cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
1030 
1031 	native_write_cr4(cr4);
1032 }
1033 #ifdef CONFIG_X86_64
1034 static inline unsigned long xen_read_cr8(void)
1035 {
1036 	return 0;
1037 }
1038 static inline void xen_write_cr8(unsigned long val)
1039 {
1040 	BUG_ON(val);
1041 }
1042 #endif
1043 
1044 static u64 xen_read_msr_safe(unsigned int msr, int *err)
1045 {
1046 	u64 val;
1047 
1048 	if (pmu_msr_read(msr, &val, err))
1049 		return val;
1050 
1051 	val = native_read_msr_safe(msr, err);
1052 	switch (msr) {
1053 	case MSR_IA32_APICBASE:
1054 #ifdef CONFIG_X86_X2APIC
1055 		if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31))))
1056 #endif
1057 			val &= ~X2APIC_ENABLE;
1058 		break;
1059 	}
1060 	return val;
1061 }
1062 
1063 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
1064 {
1065 	int ret;
1066 
1067 	ret = 0;
1068 
1069 	switch (msr) {
1070 #ifdef CONFIG_X86_64
1071 		unsigned which;
1072 		u64 base;
1073 
1074 	case MSR_FS_BASE:		which = SEGBASE_FS; goto set;
1075 	case MSR_KERNEL_GS_BASE:	which = SEGBASE_GS_USER; goto set;
1076 	case MSR_GS_BASE:		which = SEGBASE_GS_KERNEL; goto set;
1077 
1078 	set:
1079 		base = ((u64)high << 32) | low;
1080 		if (HYPERVISOR_set_segment_base(which, base) != 0)
1081 			ret = -EIO;
1082 		break;
1083 #endif
1084 
1085 	case MSR_STAR:
1086 	case MSR_CSTAR:
1087 	case MSR_LSTAR:
1088 	case MSR_SYSCALL_MASK:
1089 	case MSR_IA32_SYSENTER_CS:
1090 	case MSR_IA32_SYSENTER_ESP:
1091 	case MSR_IA32_SYSENTER_EIP:
1092 		/* Fast syscall setup is all done in hypercalls, so
1093 		   these are all ignored.  Stub them out here to stop
1094 		   Xen console noise. */
1095 		break;
1096 
1097 	default:
1098 		if (!pmu_msr_write(msr, low, high, &ret))
1099 			ret = native_write_msr_safe(msr, low, high);
1100 	}
1101 
1102 	return ret;
1103 }
1104 
1105 static u64 xen_read_msr(unsigned int msr)
1106 {
1107 	/*
1108 	 * This will silently swallow a #GP from RDMSR.  It may be worth
1109 	 * changing that.
1110 	 */
1111 	int err;
1112 
1113 	return xen_read_msr_safe(msr, &err);
1114 }
1115 
1116 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
1117 {
1118 	/*
1119 	 * This will silently swallow a #GP from WRMSR.  It may be worth
1120 	 * changing that.
1121 	 */
1122 	xen_write_msr_safe(msr, low, high);
1123 }
1124 
1125 void xen_setup_shared_info(void)
1126 {
1127 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1128 		set_fixmap(FIX_PARAVIRT_BOOTMAP,
1129 			   xen_start_info->shared_info);
1130 
1131 		HYPERVISOR_shared_info =
1132 			(struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
1133 	} else
1134 		HYPERVISOR_shared_info =
1135 			(struct shared_info *)__va(xen_start_info->shared_info);
1136 
1137 #ifndef CONFIG_SMP
1138 	/* In UP this is as good a place as any to set up shared info */
1139 	xen_setup_vcpu_info_placement();
1140 #endif
1141 
1142 	xen_setup_mfn_list_list();
1143 }
1144 
1145 /* This is called once we have the cpu_possible_mask */
1146 void xen_setup_vcpu_info_placement(void)
1147 {
1148 	int cpu;
1149 
1150 	for_each_possible_cpu(cpu) {
1151 		/* Set up direct vCPU id mapping for PV guests. */
1152 		per_cpu(xen_vcpu_id, cpu) = cpu;
1153 		xen_vcpu_setup(cpu);
1154 	}
1155 
1156 	/*
1157 	 * xen_vcpu_setup managed to place the vcpu_info within the
1158 	 * percpu area for all cpus, so make use of it.
1159 	 */
1160 	if (have_vcpu_info_placement) {
1161 		pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
1162 		pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
1163 		pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
1164 		pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
1165 		pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
1166 	}
1167 }
1168 
1169 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
1170 			  unsigned long addr, unsigned len)
1171 {
1172 	char *start, *end, *reloc;
1173 	unsigned ret;
1174 
1175 	start = end = reloc = NULL;
1176 
1177 #define SITE(op, x)							\
1178 	case PARAVIRT_PATCH(op.x):					\
1179 	if (have_vcpu_info_placement) {					\
1180 		start = (char *)xen_##x##_direct;			\
1181 		end = xen_##x##_direct_end;				\
1182 		reloc = xen_##x##_direct_reloc;				\
1183 	}								\
1184 	goto patch_site
1185 
1186 	switch (type) {
1187 		SITE(pv_irq_ops, irq_enable);
1188 		SITE(pv_irq_ops, irq_disable);
1189 		SITE(pv_irq_ops, save_fl);
1190 		SITE(pv_irq_ops, restore_fl);
1191 #undef SITE
1192 
1193 	patch_site:
1194 		if (start == NULL || (end-start) > len)
1195 			goto default_patch;
1196 
1197 		ret = paravirt_patch_insns(insnbuf, len, start, end);
1198 
1199 		/* Note: because reloc is assigned from something that
1200 		   appears to be an array, gcc assumes it's non-null,
1201 		   but doesn't know its relationship with start and
1202 		   end. */
1203 		if (reloc > start && reloc < end) {
1204 			int reloc_off = reloc - start;
1205 			long *relocp = (long *)(insnbuf + reloc_off);
1206 			long delta = start - (char *)addr;
1207 
1208 			*relocp += delta;
1209 		}
1210 		break;
1211 
1212 	default_patch:
1213 	default:
1214 		ret = paravirt_patch_default(type, clobbers, insnbuf,
1215 					     addr, len);
1216 		break;
1217 	}
1218 
1219 	return ret;
1220 }
1221 
1222 static const struct pv_info xen_info __initconst = {
1223 	.shared_kernel_pmd = 0,
1224 
1225 #ifdef CONFIG_X86_64
1226 	.extra_user_64bit_cs = FLAT_USER_CS64,
1227 #endif
1228 	.name = "Xen",
1229 };
1230 
1231 static const struct pv_init_ops xen_init_ops __initconst = {
1232 	.patch = xen_patch,
1233 };
1234 
1235 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
1236 	.cpuid = xen_cpuid,
1237 
1238 	.set_debugreg = xen_set_debugreg,
1239 	.get_debugreg = xen_get_debugreg,
1240 
1241 	.read_cr0 = xen_read_cr0,
1242 	.write_cr0 = xen_write_cr0,
1243 
1244 	.read_cr4 = native_read_cr4,
1245 	.write_cr4 = xen_write_cr4,
1246 
1247 #ifdef CONFIG_X86_64
1248 	.read_cr8 = xen_read_cr8,
1249 	.write_cr8 = xen_write_cr8,
1250 #endif
1251 
1252 	.wbinvd = native_wbinvd,
1253 
1254 	.read_msr = xen_read_msr,
1255 	.write_msr = xen_write_msr,
1256 
1257 	.read_msr_safe = xen_read_msr_safe,
1258 	.write_msr_safe = xen_write_msr_safe,
1259 
1260 	.read_pmc = xen_read_pmc,
1261 
1262 	.iret = xen_iret,
1263 #ifdef CONFIG_X86_64
1264 	.usergs_sysret64 = xen_sysret64,
1265 #endif
1266 
1267 	.load_tr_desc = paravirt_nop,
1268 	.set_ldt = xen_set_ldt,
1269 	.load_gdt = xen_load_gdt,
1270 	.load_idt = xen_load_idt,
1271 	.load_tls = xen_load_tls,
1272 #ifdef CONFIG_X86_64
1273 	.load_gs_index = xen_load_gs_index,
1274 #endif
1275 
1276 	.alloc_ldt = xen_alloc_ldt,
1277 	.free_ldt = xen_free_ldt,
1278 
1279 	.store_idt = native_store_idt,
1280 	.store_tr = xen_store_tr,
1281 
1282 	.write_ldt_entry = xen_write_ldt_entry,
1283 	.write_gdt_entry = xen_write_gdt_entry,
1284 	.write_idt_entry = xen_write_idt_entry,
1285 	.load_sp0 = xen_load_sp0,
1286 
1287 	.set_iopl_mask = xen_set_iopl_mask,
1288 	.io_delay = xen_io_delay,
1289 
1290 	/* Xen takes care of %gs when switching to usermode for us */
1291 	.swapgs = paravirt_nop,
1292 
1293 	.start_context_switch = paravirt_start_context_switch,
1294 	.end_context_switch = xen_end_context_switch,
1295 };
1296 
1297 static void xen_reboot(int reason)
1298 {
1299 	struct sched_shutdown r = { .reason = reason };
1300 	int cpu;
1301 
1302 	for_each_online_cpu(cpu)
1303 		xen_pmu_finish(cpu);
1304 
1305 	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
1306 		BUG();
1307 }
1308 
1309 static void xen_restart(char *msg)
1310 {
1311 	xen_reboot(SHUTDOWN_reboot);
1312 }
1313 
1314 static void xen_emergency_restart(void)
1315 {
1316 	xen_reboot(SHUTDOWN_reboot);
1317 }
1318 
1319 static void xen_machine_halt(void)
1320 {
1321 	xen_reboot(SHUTDOWN_poweroff);
1322 }
1323 
1324 static void xen_machine_power_off(void)
1325 {
1326 	if (pm_power_off)
1327 		pm_power_off();
1328 	xen_reboot(SHUTDOWN_poweroff);
1329 }
1330 
1331 static void xen_crash_shutdown(struct pt_regs *regs)
1332 {
1333 	xen_reboot(SHUTDOWN_crash);
1334 }
1335 
1336 static int
1337 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
1338 {
1339 	if (!kexec_crash_loaded())
1340 		xen_reboot(SHUTDOWN_crash);
1341 	return NOTIFY_DONE;
1342 }
1343 
1344 static struct notifier_block xen_panic_block = {
1345 	.notifier_call= xen_panic_event,
1346 	.priority = INT_MIN
1347 };
1348 
1349 int xen_panic_handler_init(void)
1350 {
1351 	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
1352 	return 0;
1353 }
1354 
1355 static const struct machine_ops xen_machine_ops __initconst = {
1356 	.restart = xen_restart,
1357 	.halt = xen_machine_halt,
1358 	.power_off = xen_machine_power_off,
1359 	.shutdown = xen_machine_halt,
1360 	.crash_shutdown = xen_crash_shutdown,
1361 	.emergency_restart = xen_emergency_restart,
1362 };
1363 
1364 static unsigned char xen_get_nmi_reason(void)
1365 {
1366 	unsigned char reason = 0;
1367 
1368 	/* Construct a value which looks like it came from port 0x61. */
1369 	if (test_bit(_XEN_NMIREASON_io_error,
1370 		     &HYPERVISOR_shared_info->arch.nmi_reason))
1371 		reason |= NMI_REASON_IOCHK;
1372 	if (test_bit(_XEN_NMIREASON_pci_serr,
1373 		     &HYPERVISOR_shared_info->arch.nmi_reason))
1374 		reason |= NMI_REASON_SERR;
1375 
1376 	return reason;
1377 }
1378 
1379 static void __init xen_boot_params_init_edd(void)
1380 {
1381 #if IS_ENABLED(CONFIG_EDD)
1382 	struct xen_platform_op op;
1383 	struct edd_info *edd_info;
1384 	u32 *mbr_signature;
1385 	unsigned nr;
1386 	int ret;
1387 
1388 	edd_info = boot_params.eddbuf;
1389 	mbr_signature = boot_params.edd_mbr_sig_buffer;
1390 
1391 	op.cmd = XENPF_firmware_info;
1392 
1393 	op.u.firmware_info.type = XEN_FW_DISK_INFO;
1394 	for (nr = 0; nr < EDDMAXNR; nr++) {
1395 		struct edd_info *info = edd_info + nr;
1396 
1397 		op.u.firmware_info.index = nr;
1398 		info->params.length = sizeof(info->params);
1399 		set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
1400 				     &info->params);
1401 		ret = HYPERVISOR_platform_op(&op);
1402 		if (ret)
1403 			break;
1404 
1405 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1406 		C(device);
1407 		C(version);
1408 		C(interface_support);
1409 		C(legacy_max_cylinder);
1410 		C(legacy_max_head);
1411 		C(legacy_sectors_per_track);
1412 #undef C
1413 	}
1414 	boot_params.eddbuf_entries = nr;
1415 
1416 	op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
1417 	for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
1418 		op.u.firmware_info.index = nr;
1419 		ret = HYPERVISOR_platform_op(&op);
1420 		if (ret)
1421 			break;
1422 		mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
1423 	}
1424 	boot_params.edd_mbr_sig_buf_entries = nr;
1425 #endif
1426 }
1427 
1428 /*
1429  * Set up the GDT and segment registers for -fstack-protector.  Until
1430  * we do this, we have to be careful not to call any stack-protected
1431  * function, which is most of the kernel.
1432  */
1433 static void xen_setup_gdt(int cpu)
1434 {
1435 	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
1436 	pv_cpu_ops.load_gdt = xen_load_gdt_boot;
1437 
1438 	setup_stack_canary_segment(0);
1439 	switch_to_new_gdt(0);
1440 
1441 	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
1442 	pv_cpu_ops.load_gdt = xen_load_gdt;
1443 }
1444 
1445 static void __init xen_dom0_set_legacy_features(void)
1446 {
1447 	x86_platform.legacy.rtc = 1;
1448 }
1449 
1450 static int xen_cpuhp_setup(void)
1451 {
1452 	int rc;
1453 
1454 	rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
1455 				       "x86/xen/hvm_guest:prepare",
1456 				       xen_cpu_up_prepare, xen_cpu_dead);
1457 	if (rc >= 0) {
1458 		rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
1459 					       "x86/xen/hvm_guest:online",
1460 					       xen_cpu_up_online, NULL);
1461 		if (rc < 0)
1462 			cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
1463 	}
1464 
1465 	return rc >= 0 ? 0 : rc;
1466 }
1467 
1468 /* First C function to be called on Xen boot */
1469 asmlinkage __visible void __init xen_start_kernel(void)
1470 {
1471 	struct physdev_set_iopl set_iopl;
1472 	unsigned long initrd_start = 0;
1473 	int rc;
1474 
1475 	if (!xen_start_info)
1476 		return;
1477 
1478 	xen_domain_type = XEN_PV_DOMAIN;
1479 
1480 	xen_setup_features();
1481 
1482 	xen_setup_machphys_mapping();
1483 
1484 	/* Install Xen paravirt ops */
1485 	pv_info = xen_info;
1486 	pv_init_ops = xen_init_ops;
1487 	pv_cpu_ops = xen_cpu_ops;
1488 
1489 	x86_platform.get_nmi_reason = xen_get_nmi_reason;
1490 
1491 	x86_init.resources.memory_setup = xen_memory_setup;
1492 	x86_init.oem.arch_setup = xen_arch_setup;
1493 	x86_init.oem.banner = xen_banner;
1494 
1495 	xen_init_time_ops();
1496 
1497 	/*
1498 	 * Set up some pagetable state before starting to set any ptes.
1499 	 */
1500 
1501 	xen_init_mmu_ops();
1502 
1503 	/* Prevent unwanted bits from being set in PTEs. */
1504 	__supported_pte_mask &= ~_PAGE_GLOBAL;
1505 
1506 	/*
1507 	 * Prevent page tables from being allocated in highmem, even
1508 	 * if CONFIG_HIGHPTE is enabled.
1509 	 */
1510 	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1511 
1512 	/* Work out if we support NX */
1513 	x86_configure_nx();
1514 
1515 	/* Get mfn list */
1516 	xen_build_dynamic_phys_to_machine();
1517 
1518 	/*
1519 	 * Set up kernel GDT and segment registers, mainly so that
1520 	 * -fstack-protector code can be executed.
1521 	 */
1522 	xen_setup_gdt(0);
1523 
1524 	xen_init_irq_ops();
1525 	xen_init_cpuid_mask();
1526 
1527 #ifdef CONFIG_X86_LOCAL_APIC
1528 	/*
1529 	 * set up the basic apic ops.
1530 	 */
1531 	xen_init_apic();
1532 #endif
1533 
1534 	if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1535 		pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1536 		pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1537 	}
1538 
1539 	machine_ops = xen_machine_ops;
1540 
1541 	/*
1542 	 * The only reliable way to retain the initial address of the
1543 	 * percpu gdt_page is to remember it here, so we can go and
1544 	 * mark it RW later, when the initial percpu area is freed.
1545 	 */
1546 	xen_initial_gdt = &per_cpu(gdt_page, 0);
1547 
1548 	xen_smp_init();
1549 
1550 #ifdef CONFIG_ACPI_NUMA
1551 	/*
1552 	 * The pages we from Xen are not related to machine pages, so
1553 	 * any NUMA information the kernel tries to get from ACPI will
1554 	 * be meaningless.  Prevent it from trying.
1555 	 */
1556 	acpi_numa = -1;
1557 #endif
1558 	/* Don't do the full vcpu_info placement stuff until we have a
1559 	   possible map and a non-dummy shared_info. */
1560 	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
1561 
1562 	WARN_ON(xen_cpuhp_setup());
1563 
1564 	local_irq_disable();
1565 	early_boot_irqs_disabled = true;
1566 
1567 	xen_raw_console_write("mapping kernel into physical memory\n");
1568 	xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
1569 				   xen_start_info->nr_pages);
1570 	xen_reserve_special_pages();
1571 
1572 	/* keep using Xen gdt for now; no urgent need to change it */
1573 
1574 #ifdef CONFIG_X86_32
1575 	pv_info.kernel_rpl = 1;
1576 	if (xen_feature(XENFEAT_supervisor_mode_kernel))
1577 		pv_info.kernel_rpl = 0;
1578 #else
1579 	pv_info.kernel_rpl = 0;
1580 #endif
1581 	/* set the limit of our address space */
1582 	xen_reserve_top();
1583 
1584 	/*
1585 	 * We used to do this in xen_arch_setup, but that is too late
1586 	 * on AMD were early_cpu_init (run before ->arch_setup()) calls
1587 	 * early_amd_init which pokes 0xcf8 port.
1588 	 */
1589 	set_iopl.iopl = 1;
1590 	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1591 	if (rc != 0)
1592 		xen_raw_printk("physdev_op failed %d\n", rc);
1593 
1594 #ifdef CONFIG_X86_32
1595 	/* set up basic CPUID stuff */
1596 	cpu_detect(&new_cpu_data);
1597 	set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
1598 	new_cpu_data.wp_works_ok = 1;
1599 	new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
1600 #endif
1601 
1602 	if (xen_start_info->mod_start) {
1603 	    if (xen_start_info->flags & SIF_MOD_START_PFN)
1604 		initrd_start = PFN_PHYS(xen_start_info->mod_start);
1605 	    else
1606 		initrd_start = __pa(xen_start_info->mod_start);
1607 	}
1608 
1609 	/* Poke various useful things into boot_params */
1610 	boot_params.hdr.type_of_loader = (9 << 4) | 0;
1611 	boot_params.hdr.ramdisk_image = initrd_start;
1612 	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1613 	boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1614 	boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
1615 
1616 	if (!xen_initial_domain()) {
1617 		add_preferred_console("xenboot", 0, NULL);
1618 		add_preferred_console("tty", 0, NULL);
1619 		add_preferred_console("hvc", 0, NULL);
1620 		if (pci_xen)
1621 			x86_init.pci.arch_init = pci_xen_init;
1622 	} else {
1623 		const struct dom0_vga_console_info *info =
1624 			(void *)((char *)xen_start_info +
1625 				 xen_start_info->console.dom0.info_off);
1626 		struct xen_platform_op op = {
1627 			.cmd = XENPF_firmware_info,
1628 			.interface_version = XENPF_INTERFACE_VERSION,
1629 			.u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
1630 		};
1631 
1632 		x86_platform.set_legacy_features =
1633 				xen_dom0_set_legacy_features;
1634 		xen_init_vga(info, xen_start_info->console.dom0.info_size);
1635 		xen_start_info->console.domU.mfn = 0;
1636 		xen_start_info->console.domU.evtchn = 0;
1637 
1638 		if (HYPERVISOR_platform_op(&op) == 0)
1639 			boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
1640 
1641 		/* Make sure ACS will be enabled */
1642 		pci_request_acs();
1643 
1644 		xen_acpi_sleep_register();
1645 
1646 		/* Avoid searching for BIOS MP tables */
1647 		x86_init.mpparse.find_smp_config = x86_init_noop;
1648 		x86_init.mpparse.get_smp_config = x86_init_uint_noop;
1649 
1650 		xen_boot_params_init_edd();
1651 	}
1652 #ifdef CONFIG_PCI
1653 	/* PCI BIOS service won't work from a PV guest. */
1654 	pci_probe &= ~PCI_PROBE_BIOS;
1655 #endif
1656 	xen_raw_console_write("about to get started...\n");
1657 
1658 	/* Let's presume PV guests always boot on vCPU with id 0. */
1659 	per_cpu(xen_vcpu_id, 0) = 0;
1660 
1661 	xen_setup_runstate_info(0);
1662 
1663 	xen_efi_init();
1664 
1665 	/* Start the world */
1666 #ifdef CONFIG_X86_32
1667 	i386_start_kernel();
1668 #else
1669 	cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1670 	x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1671 #endif
1672 }
1673 
1674 #ifdef CONFIG_XEN_PVH
1675 
1676 static void xen_pvh_arch_setup(void)
1677 {
1678 #ifdef CONFIG_ACPI
1679 	/* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
1680 	if (nr_ioapics == 0)
1681 		acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
1682 #endif
1683 }
1684 
1685 static void __init init_pvh_bootparams(void)
1686 {
1687 	struct xen_memory_map memmap;
1688 	unsigned int i;
1689 	int rc;
1690 
1691 	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
1692 
1693 	memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_map);
1694 	set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_map);
1695 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
1696 	if (rc) {
1697 		xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
1698 		BUG();
1699 	}
1700 
1701 	if (memmap.nr_entries < E820MAX - 1) {
1702 		pvh_bootparams.e820_map[memmap.nr_entries].addr =
1703 			ISA_START_ADDRESS;
1704 		pvh_bootparams.e820_map[memmap.nr_entries].size =
1705 			ISA_END_ADDRESS - ISA_START_ADDRESS;
1706 		pvh_bootparams.e820_map[memmap.nr_entries].type =
1707 			E820_RESERVED;
1708 		memmap.nr_entries++;
1709 	} else
1710 		xen_raw_printk("Warning: Can fit ISA range into e820\n");
1711 
1712 	sanitize_e820_map(pvh_bootparams.e820_map,
1713 			  ARRAY_SIZE(pvh_bootparams.e820_map),
1714 			  &memmap.nr_entries);
1715 
1716 	pvh_bootparams.e820_entries = memmap.nr_entries;
1717 	for (i = 0; i < pvh_bootparams.e820_entries; i++)
1718 		e820_add_region(pvh_bootparams.e820_map[i].addr,
1719 				pvh_bootparams.e820_map[i].size,
1720 				pvh_bootparams.e820_map[i].type);
1721 
1722 	pvh_bootparams.hdr.cmd_line_ptr =
1723 		pvh_start_info.cmdline_paddr;
1724 
1725 	/* The first module is always ramdisk. */
1726 	if (pvh_start_info.nr_modules) {
1727 		struct hvm_modlist_entry *modaddr =
1728 			__va(pvh_start_info.modlist_paddr);
1729 		pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
1730 		pvh_bootparams.hdr.ramdisk_size = modaddr->size;
1731 	}
1732 
1733 	/*
1734 	 * See Documentation/x86/boot.txt.
1735 	 *
1736 	 * Version 2.12 supports Xen entry point but we will use default x86/PC
1737 	 * environment (i.e. hardware_subarch 0).
1738 	 */
1739 	pvh_bootparams.hdr.version = 0x212;
1740 	pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */
1741 }
1742 
1743 /*
1744  * This routine (and those that it might call) should not use
1745  * anything that lives in .bss since that segment will be cleared later.
1746  */
1747 void __init xen_prepare_pvh(void)
1748 {
1749 	u32 msr;
1750 	u64 pfn;
1751 
1752 	if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
1753 		xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
1754 				pvh_start_info.magic);
1755 		BUG();
1756 	}
1757 
1758 	xen_pvh = 1;
1759 
1760 	msr = cpuid_ebx(xen_cpuid_base() + 2);
1761 	pfn = __pa(hypercall_page);
1762 	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
1763 
1764 	init_pvh_bootparams();
1765 
1766 	x86_init.oem.arch_setup = xen_pvh_arch_setup;
1767 }
1768 #endif
1769 
1770 void __ref xen_hvm_init_shared_info(void)
1771 {
1772 	int cpu;
1773 	struct xen_add_to_physmap xatp;
1774 	static struct shared_info *shared_info_page = 0;
1775 
1776 	if (!shared_info_page)
1777 		shared_info_page = (struct shared_info *)
1778 			extend_brk(PAGE_SIZE, PAGE_SIZE);
1779 	xatp.domid = DOMID_SELF;
1780 	xatp.idx = 0;
1781 	xatp.space = XENMAPSPACE_shared_info;
1782 	xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
1783 	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
1784 		BUG();
1785 
1786 	HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
1787 
1788 	/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
1789 	 * page, we use it in the event channel upcall and in some pvclock
1790 	 * related functions. We don't need the vcpu_info placement
1791 	 * optimizations because we don't use any pv_mmu or pv_irq op on
1792 	 * HVM.
1793 	 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
1794 	 * online but xen_hvm_init_shared_info is run at resume time too and
1795 	 * in that case multiple vcpus might be online. */
1796 	for_each_online_cpu(cpu) {
1797 		/* Leave it to be NULL. */
1798 		if (xen_vcpu_nr(cpu) >= MAX_VIRT_CPUS)
1799 			continue;
1800 		per_cpu(xen_vcpu, cpu) =
1801 			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
1802 	}
1803 }
1804 
1805 #ifdef CONFIG_XEN_PVHVM
1806 static void __init init_hvm_pv_info(void)
1807 {
1808 	int major, minor;
1809 	uint32_t eax, ebx, ecx, edx, base;
1810 
1811 	base = xen_cpuid_base();
1812 	eax = cpuid_eax(base + 1);
1813 
1814 	major = eax >> 16;
1815 	minor = eax & 0xffff;
1816 	printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
1817 
1818 	xen_domain_type = XEN_HVM_DOMAIN;
1819 
1820 	/* PVH set up hypercall page in xen_prepare_pvh(). */
1821 	if (xen_pvh_domain())
1822 		pv_info.name = "Xen PVH";
1823 	else {
1824 		u64 pfn;
1825 		uint32_t msr;
1826 
1827 		pv_info.name = "Xen HVM";
1828 		msr = cpuid_ebx(base + 2);
1829 		pfn = __pa(hypercall_page);
1830 		wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
1831 	}
1832 
1833 	xen_setup_features();
1834 
1835 	cpuid(base + 4, &eax, &ebx, &ecx, &edx);
1836 	if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
1837 		this_cpu_write(xen_vcpu_id, ebx);
1838 	else
1839 		this_cpu_write(xen_vcpu_id, smp_processor_id());
1840 }
1841 #endif
1842 
1843 static int xen_cpu_up_prepare(unsigned int cpu)
1844 {
1845 	int rc;
1846 
1847 	if (xen_hvm_domain()) {
1848 		/*
1849 		 * This can happen if CPU was offlined earlier and
1850 		 * offlining timed out in common_cpu_die().
1851 		 */
1852 		if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) {
1853 			xen_smp_intr_free(cpu);
1854 			xen_uninit_lock_cpu(cpu);
1855 		}
1856 
1857 		if (cpu_acpi_id(cpu) != U32_MAX)
1858 			per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
1859 		else
1860 			per_cpu(xen_vcpu_id, cpu) = cpu;
1861 		xen_vcpu_setup(cpu);
1862 	}
1863 
1864 	if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
1865 		xen_setup_timer(cpu);
1866 
1867 	rc = xen_smp_intr_init(cpu);
1868 	if (rc) {
1869 		WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
1870 		     cpu, rc);
1871 		return rc;
1872 	}
1873 	return 0;
1874 }
1875 
1876 static int xen_cpu_dead(unsigned int cpu)
1877 {
1878 	xen_smp_intr_free(cpu);
1879 
1880 	if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock))
1881 		xen_teardown_timer(cpu);
1882 
1883 	return 0;
1884 }
1885 
1886 static int xen_cpu_up_online(unsigned int cpu)
1887 {
1888 	xen_init_lock_cpu(cpu);
1889 	return 0;
1890 }
1891 
1892 #ifdef CONFIG_XEN_PVHVM
1893 #ifdef CONFIG_KEXEC_CORE
1894 static void xen_hvm_shutdown(void)
1895 {
1896 	native_machine_shutdown();
1897 	if (kexec_in_progress)
1898 		xen_reboot(SHUTDOWN_soft_reset);
1899 }
1900 
1901 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
1902 {
1903 	native_machine_crash_shutdown(regs);
1904 	xen_reboot(SHUTDOWN_soft_reset);
1905 }
1906 #endif
1907 
1908 static void __init xen_hvm_guest_init(void)
1909 {
1910 	if (xen_pv_domain())
1911 		return;
1912 
1913 	init_hvm_pv_info();
1914 
1915 	xen_hvm_init_shared_info();
1916 
1917 	xen_panic_handler_init();
1918 
1919 	BUG_ON(!xen_feature(XENFEAT_hvm_callback_vector));
1920 
1921 	xen_hvm_smp_init();
1922 	WARN_ON(xen_cpuhp_setup());
1923 	xen_unplug_emulated_devices();
1924 	x86_init.irqs.intr_init = xen_init_IRQ;
1925 	xen_hvm_init_time_ops();
1926 	xen_hvm_init_mmu_ops();
1927 
1928 	if (xen_pvh_domain())
1929 		machine_ops.emergency_restart = xen_emergency_restart;
1930 #ifdef CONFIG_KEXEC_CORE
1931 	machine_ops.shutdown = xen_hvm_shutdown;
1932 	machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
1933 #endif
1934 }
1935 #endif
1936 
1937 static bool xen_nopv = false;
1938 static __init int xen_parse_nopv(char *arg)
1939 {
1940        xen_nopv = true;
1941        return 0;
1942 }
1943 early_param("xen_nopv", xen_parse_nopv);
1944 
1945 static uint32_t __init xen_platform(void)
1946 {
1947 	if (xen_nopv)
1948 		return 0;
1949 
1950 	return xen_cpuid_base();
1951 }
1952 
1953 bool xen_hvm_need_lapic(void)
1954 {
1955 	if (xen_nopv)
1956 		return false;
1957 	if (xen_pv_domain())
1958 		return false;
1959 	if (!xen_hvm_domain())
1960 		return false;
1961 	if (xen_feature(XENFEAT_hvm_pirqs))
1962 		return false;
1963 	return true;
1964 }
1965 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
1966 
1967 static void xen_set_cpu_features(struct cpuinfo_x86 *c)
1968 {
1969 	if (xen_pv_domain()) {
1970 		clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
1971 		set_cpu_cap(c, X86_FEATURE_XENPV);
1972 	}
1973 }
1974 
1975 static void xen_pin_vcpu(int cpu)
1976 {
1977 	static bool disable_pinning;
1978 	struct sched_pin_override pin_override;
1979 	int ret;
1980 
1981 	if (disable_pinning)
1982 		return;
1983 
1984 	pin_override.pcpu = cpu;
1985 	ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);
1986 
1987 	/* Ignore errors when removing override. */
1988 	if (cpu < 0)
1989 		return;
1990 
1991 	switch (ret) {
1992 	case -ENOSYS:
1993 		pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
1994 			cpu);
1995 		disable_pinning = true;
1996 		break;
1997 	case -EPERM:
1998 		WARN(1, "Trying to pin vcpu without having privilege to do so\n");
1999 		disable_pinning = true;
2000 		break;
2001 	case -EINVAL:
2002 	case -EBUSY:
2003 		pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
2004 			cpu);
2005 		break;
2006 	case 0:
2007 		break;
2008 	default:
2009 		WARN(1, "rc %d while trying to pin vcpu\n", ret);
2010 		disable_pinning = true;
2011 	}
2012 }
2013 
2014 const struct hypervisor_x86 x86_hyper_xen = {
2015 	.name			= "Xen",
2016 	.detect			= xen_platform,
2017 #ifdef CONFIG_XEN_PVHVM
2018 	.init_platform		= xen_hvm_guest_init,
2019 #endif
2020 	.x2apic_available	= xen_x2apic_para_available,
2021 	.set_cpu_features       = xen_set_cpu_features,
2022 	.pin_vcpu               = xen_pin_vcpu,
2023 };
2024 EXPORT_SYMBOL(x86_hyper_xen);
2025 
2026 #ifdef CONFIG_HOTPLUG_CPU
2027 void xen_arch_register_cpu(int num)
2028 {
2029 	arch_register_cpu(num);
2030 }
2031 EXPORT_SYMBOL(xen_arch_register_cpu);
2032 
2033 void xen_arch_unregister_cpu(int num)
2034 {
2035 	arch_unregister_cpu(num);
2036 }
2037 EXPORT_SYMBOL(xen_arch_unregister_cpu);
2038 #endif
2039