Merge tag 'for-linus-4.8-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...
[sfrench/cifs-2.6.git] / arch / x86 / xen / enlighten.c
1 /*
2  * Core of Xen paravirt_ops implementation.
3  *
4  * This file contains the xen_paravirt_ops structure itself, and the
5  * implementations for:
6  * - privileged instructions
7  * - interrupt flags
8  * - segment operations
9  * - booting and setup
10  *
11  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
12  */
13
14 #include <linux/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 #include <linux/edd.h>
35 #include <linux/frame.h>
36
37 #ifdef CONFIG_KEXEC_CORE
38 #include <linux/kexec.h>
39 #endif
40
41 #include <xen/xen.h>
42 #include <xen/events.h>
43 #include <xen/interface/xen.h>
44 #include <xen/interface/version.h>
45 #include <xen/interface/physdev.h>
46 #include <xen/interface/vcpu.h>
47 #include <xen/interface/memory.h>
48 #include <xen/interface/nmi.h>
49 #include <xen/interface/xen-mca.h>
50 #include <xen/features.h>
51 #include <xen/page.h>
52 #include <xen/hvm.h>
53 #include <xen/hvc-console.h>
54 #include <xen/acpi.h>
55
56 #include <asm/paravirt.h>
57 #include <asm/apic.h>
58 #include <asm/page.h>
59 #include <asm/xen/pci.h>
60 #include <asm/xen/hypercall.h>
61 #include <asm/xen/hypervisor.h>
62 #include <asm/xen/cpuid.h>
63 #include <asm/fixmap.h>
64 #include <asm/processor.h>
65 #include <asm/proto.h>
66 #include <asm/msr-index.h>
67 #include <asm/traps.h>
68 #include <asm/setup.h>
69 #include <asm/desc.h>
70 #include <asm/pgalloc.h>
71 #include <asm/pgtable.h>
72 #include <asm/tlbflush.h>
73 #include <asm/reboot.h>
74 #include <asm/stackprotector.h>
75 #include <asm/hypervisor.h>
76 #include <asm/mach_traps.h>
77 #include <asm/mwait.h>
78 #include <asm/pci_x86.h>
79 #include <asm/cpu.h>
80
81 #ifdef CONFIG_ACPI
82 #include <linux/acpi.h>
83 #include <asm/acpi.h>
84 #include <acpi/pdc_intel.h>
85 #include <acpi/processor.h>
86 #include <xen/interface/platform.h>
87 #endif
88
89 #include "xen-ops.h"
90 #include "mmu.h"
91 #include "smp.h"
92 #include "multicalls.h"
93 #include "pmu.h"
94
95 EXPORT_SYMBOL_GPL(hypercall_page);
96
97 /*
98  * Pointer to the xen_vcpu_info structure or
99  * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
100  * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
101  * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point
102  * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to
103  * acknowledge pending events.
104  * Also more subtly it is used by the patched version of irq enable/disable
105  * e.g. xen_irq_enable_direct and xen_iret in PV mode.
106  *
107  * The desire to be able to do those mask/unmask operations as a single
108  * instruction by using the per-cpu offset held in %gs is the real reason
109  * vcpu info is in a per-cpu pointer and the original reason for this
110  * hypercall.
111  *
112  */
113 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
114
115 /*
116  * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info
117  * hypercall. This can be used both in PV and PVHVM mode. The structure
118  * overrides the default per_cpu(xen_vcpu, cpu) value.
119  */
120 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
121
122 /* Linux <-> Xen vCPU id mapping */
123 DEFINE_PER_CPU(int, xen_vcpu_id) = -1;
124 EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
125
126 enum xen_domain_type xen_domain_type = XEN_NATIVE;
127 EXPORT_SYMBOL_GPL(xen_domain_type);
128
129 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
130 EXPORT_SYMBOL(machine_to_phys_mapping);
131 unsigned long  machine_to_phys_nr;
132 EXPORT_SYMBOL(machine_to_phys_nr);
133
134 struct start_info *xen_start_info;
135 EXPORT_SYMBOL_GPL(xen_start_info);
136
137 struct shared_info xen_dummy_shared_info;
138
139 void *xen_initial_gdt;
140
141 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
142 __read_mostly int xen_have_vector_callback;
143 EXPORT_SYMBOL_GPL(xen_have_vector_callback);
144
145 /*
146  * Point at some empty memory to start with. We map the real shared_info
147  * page as soon as fixmap is up and running.
148  */
149 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info;
150
151 /*
152  * Flag to determine whether vcpu info placement is available on all
153  * VCPUs.  We assume it is to start with, and then set it to zero on
154  * the first failure.  This is because it can succeed on some VCPUs
155  * and not others, since it can involve hypervisor memory allocation,
156  * or because the guest failed to guarantee all the appropriate
157  * constraints on all VCPUs (ie buffer can't cross a page boundary).
158  *
159  * Note that any particular CPU may be using a placed vcpu structure,
160  * but we can only optimise if the all are.
161  *
162  * 0: not available, 1: available
163  */
164 static int have_vcpu_info_placement = 1;
165
166 struct tls_descs {
167         struct desc_struct desc[3];
168 };
169
170 /*
171  * Updating the 3 TLS descriptors in the GDT on every task switch is
172  * surprisingly expensive so we avoid updating them if they haven't
173  * changed.  Since Xen writes different descriptors than the one
174  * passed in the update_descriptor hypercall we keep shadow copies to
175  * compare against.
176  */
177 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
178
179 static void clamp_max_cpus(void)
180 {
181 #ifdef CONFIG_SMP
182         if (setup_max_cpus > MAX_VIRT_CPUS)
183                 setup_max_cpus = MAX_VIRT_CPUS;
184 #endif
185 }
186
187 void xen_vcpu_setup(int cpu)
188 {
189         struct vcpu_register_vcpu_info info;
190         int err;
191         struct vcpu_info *vcpup;
192
193         BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
194
195         /*
196          * This path is called twice on PVHVM - first during bootup via
197          * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being
198          * hotplugged: cpu_up -> xen_hvm_cpu_notify.
199          * As we can only do the VCPUOP_register_vcpu_info once lets
200          * not over-write its result.
201          *
202          * For PV it is called during restore (xen_vcpu_restore) and bootup
203          * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
204          * use this function.
205          */
206         if (xen_hvm_domain()) {
207                 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
208                         return;
209         }
210         if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)
211                 per_cpu(xen_vcpu, cpu) =
212                         &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
213
214         if (!have_vcpu_info_placement) {
215                 if (cpu >= MAX_VIRT_CPUS)
216                         clamp_max_cpus();
217                 return;
218         }
219
220         vcpup = &per_cpu(xen_vcpu_info, cpu);
221         info.mfn = arbitrary_virt_to_mfn(vcpup);
222         info.offset = offset_in_page(vcpup);
223
224         /* Check to see if the hypervisor will put the vcpu_info
225            structure where we want it, which allows direct access via
226            a percpu-variable.
227            N.B. This hypercall can _only_ be called once per CPU. Subsequent
228            calls will error out with -EINVAL. This is due to the fact that
229            hypervisor has no unregister variant and this hypercall does not
230            allow to over-write info.mfn and info.offset.
231          */
232         err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
233                                  &info);
234
235         if (err) {
236                 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
237                 have_vcpu_info_placement = 0;
238                 clamp_max_cpus();
239         } else {
240                 /* This cpu is using the registered vcpu info, even if
241                    later ones fail to. */
242                 per_cpu(xen_vcpu, cpu) = vcpup;
243         }
244 }
245
246 /*
247  * On restore, set the vcpu placement up again.
248  * If it fails, then we're in a bad state, since
249  * we can't back out from using it...
250  */
251 void xen_vcpu_restore(void)
252 {
253         int cpu;
254
255         for_each_possible_cpu(cpu) {
256                 bool other_cpu = (cpu != smp_processor_id());
257                 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu),
258                                                 NULL);
259
260                 if (other_cpu && is_up &&
261                     HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
262                         BUG();
263
264                 xen_setup_runstate_info(cpu);
265
266                 if (have_vcpu_info_placement)
267                         xen_vcpu_setup(cpu);
268
269                 if (other_cpu && is_up &&
270                     HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
271                         BUG();
272         }
273 }
274
275 static void __init xen_banner(void)
276 {
277         unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
278         struct xen_extraversion extra;
279         HYPERVISOR_xen_version(XENVER_extraversion, &extra);
280
281         pr_info("Booting paravirtualized kernel %son %s\n",
282                 xen_feature(XENFEAT_auto_translated_physmap) ?
283                         "with PVH extensions " : "", pv_info.name);
284         printk(KERN_INFO "Xen version: %d.%d%s%s\n",
285                version >> 16, version & 0xffff, extra.extraversion,
286                xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
287 }
288 /* Check if running on Xen version (major, minor) or later */
289 bool
290 xen_running_on_version_or_later(unsigned int major, unsigned int minor)
291 {
292         unsigned int version;
293
294         if (!xen_domain())
295                 return false;
296
297         version = HYPERVISOR_xen_version(XENVER_version, NULL);
298         if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
299                 ((version >> 16) > major))
300                 return true;
301         return false;
302 }
303
304 #define CPUID_THERM_POWER_LEAF 6
305 #define APERFMPERF_PRESENT 0
306
307 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
308 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
309
310 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask;
311 static __read_mostly unsigned int cpuid_leaf5_ecx_val;
312 static __read_mostly unsigned int cpuid_leaf5_edx_val;
313
314 static void xen_cpuid(unsigned int *ax, unsigned int *bx,
315                       unsigned int *cx, unsigned int *dx)
316 {
317         unsigned maskebx = ~0;
318         unsigned maskecx = ~0;
319         unsigned maskedx = ~0;
320         unsigned setecx = 0;
321         /*
322          * Mask out inconvenient features, to try and disable as many
323          * unsupported kernel subsystems as possible.
324          */
325         switch (*ax) {
326         case 1:
327                 maskecx = cpuid_leaf1_ecx_mask;
328                 setecx = cpuid_leaf1_ecx_set_mask;
329                 maskedx = cpuid_leaf1_edx_mask;
330                 break;
331
332         case CPUID_MWAIT_LEAF:
333                 /* Synthesize the values.. */
334                 *ax = 0;
335                 *bx = 0;
336                 *cx = cpuid_leaf5_ecx_val;
337                 *dx = cpuid_leaf5_edx_val;
338                 return;
339
340         case CPUID_THERM_POWER_LEAF:
341                 /* Disabling APERFMPERF for kernel usage */
342                 maskecx = ~(1 << APERFMPERF_PRESENT);
343                 break;
344
345         case 0xb:
346                 /* Suppress extended topology stuff */
347                 maskebx = 0;
348                 break;
349         }
350
351         asm(XEN_EMULATE_PREFIX "cpuid"
352                 : "=a" (*ax),
353                   "=b" (*bx),
354                   "=c" (*cx),
355                   "=d" (*dx)
356                 : "0" (*ax), "2" (*cx));
357
358         *bx &= maskebx;
359         *cx &= maskecx;
360         *cx |= setecx;
361         *dx &= maskedx;
362 }
363 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
364
365 static bool __init xen_check_mwait(void)
366 {
367 #ifdef CONFIG_ACPI
368         struct xen_platform_op op = {
369                 .cmd                    = XENPF_set_processor_pminfo,
370                 .u.set_pminfo.id        = -1,
371                 .u.set_pminfo.type      = XEN_PM_PDC,
372         };
373         uint32_t buf[3];
374         unsigned int ax, bx, cx, dx;
375         unsigned int mwait_mask;
376
377         /* We need to determine whether it is OK to expose the MWAIT
378          * capability to the kernel to harvest deeper than C3 states from ACPI
379          * _CST using the processor_harvest_xen.c module. For this to work, we
380          * need to gather the MWAIT_LEAF values (which the cstate.c code
381          * checks against). The hypervisor won't expose the MWAIT flag because
382          * it would break backwards compatibility; so we will find out directly
383          * from the hardware and hypercall.
384          */
385         if (!xen_initial_domain())
386                 return false;
387
388         /*
389          * When running under platform earlier than Xen4.2, do not expose
390          * mwait, to avoid the risk of loading native acpi pad driver
391          */
392         if (!xen_running_on_version_or_later(4, 2))
393                 return false;
394
395         ax = 1;
396         cx = 0;
397
398         native_cpuid(&ax, &bx, &cx, &dx);
399
400         mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
401                      (1 << (X86_FEATURE_MWAIT % 32));
402
403         if ((cx & mwait_mask) != mwait_mask)
404                 return false;
405
406         /* We need to emulate the MWAIT_LEAF and for that we need both
407          * ecx and edx. The hypercall provides only partial information.
408          */
409
410         ax = CPUID_MWAIT_LEAF;
411         bx = 0;
412         cx = 0;
413         dx = 0;
414
415         native_cpuid(&ax, &bx, &cx, &dx);
416
417         /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
418          * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
419          */
420         buf[0] = ACPI_PDC_REVISION_ID;
421         buf[1] = 1;
422         buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
423
424         set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
425
426         if ((HYPERVISOR_platform_op(&op) == 0) &&
427             (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
428                 cpuid_leaf5_ecx_val = cx;
429                 cpuid_leaf5_edx_val = dx;
430         }
431         return true;
432 #else
433         return false;
434 #endif
435 }
436 static void __init xen_init_cpuid_mask(void)
437 {
438         unsigned int ax, bx, cx, dx;
439         unsigned int xsave_mask;
440
441         cpuid_leaf1_edx_mask =
442                 ~((1 << X86_FEATURE_MTRR) |  /* disable MTRR */
443                   (1 << X86_FEATURE_ACC));   /* thermal monitoring */
444
445         if (!xen_initial_domain())
446                 cpuid_leaf1_edx_mask &=
447                         ~((1 << X86_FEATURE_ACPI));  /* disable ACPI */
448
449         cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32));
450
451         ax = 1;
452         cx = 0;
453         cpuid(1, &ax, &bx, &cx, &dx);
454
455         xsave_mask =
456                 (1 << (X86_FEATURE_XSAVE % 32)) |
457                 (1 << (X86_FEATURE_OSXSAVE % 32));
458
459         /* Xen will set CR4.OSXSAVE if supported and not disabled by force */
460         if ((cx & xsave_mask) != xsave_mask)
461                 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */
462         if (xen_check_mwait())
463                 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32));
464 }
465
466 static void xen_set_debugreg(int reg, unsigned long val)
467 {
468         HYPERVISOR_set_debugreg(reg, val);
469 }
470
471 static unsigned long xen_get_debugreg(int reg)
472 {
473         return HYPERVISOR_get_debugreg(reg);
474 }
475
476 static void xen_end_context_switch(struct task_struct *next)
477 {
478         xen_mc_flush();
479         paravirt_end_context_switch(next);
480 }
481
482 static unsigned long xen_store_tr(void)
483 {
484         return 0;
485 }
486
487 /*
488  * Set the page permissions for a particular virtual address.  If the
489  * address is a vmalloc mapping (or other non-linear mapping), then
490  * find the linear mapping of the page and also set its protections to
491  * match.
492  */
493 static void set_aliased_prot(void *v, pgprot_t prot)
494 {
495         int level;
496         pte_t *ptep;
497         pte_t pte;
498         unsigned long pfn;
499         struct page *page;
500         unsigned char dummy;
501
502         ptep = lookup_address((unsigned long)v, &level);
503         BUG_ON(ptep == NULL);
504
505         pfn = pte_pfn(*ptep);
506         page = pfn_to_page(pfn);
507
508         pte = pfn_pte(pfn, prot);
509
510         /*
511          * Careful: update_va_mapping() will fail if the virtual address
512          * we're poking isn't populated in the page tables.  We don't
513          * need to worry about the direct map (that's always in the page
514          * tables), but we need to be careful about vmap space.  In
515          * particular, the top level page table can lazily propagate
516          * entries between processes, so if we've switched mms since we
517          * vmapped the target in the first place, we might not have the
518          * top-level page table entry populated.
519          *
520          * We disable preemption because we want the same mm active when
521          * we probe the target and when we issue the hypercall.  We'll
522          * have the same nominal mm, but if we're a kernel thread, lazy
523          * mm dropping could change our pgd.
524          *
525          * Out of an abundance of caution, this uses __get_user() to fault
526          * in the target address just in case there's some obscure case
527          * in which the target address isn't readable.
528          */
529
530         preempt_disable();
531
532         probe_kernel_read(&dummy, v, 1);
533
534         if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
535                 BUG();
536
537         if (!PageHighMem(page)) {
538                 void *av = __va(PFN_PHYS(pfn));
539
540                 if (av != v)
541                         if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
542                                 BUG();
543         } else
544                 kmap_flush_unused();
545
546         preempt_enable();
547 }
548
549 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
550 {
551         const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
552         int i;
553
554         /*
555          * We need to mark the all aliases of the LDT pages RO.  We
556          * don't need to call vm_flush_aliases(), though, since that's
557          * only responsible for flushing aliases out the TLBs, not the
558          * page tables, and Xen will flush the TLB for us if needed.
559          *
560          * To avoid confusing future readers: none of this is necessary
561          * to load the LDT.  The hypervisor only checks this when the
562          * LDT is faulted in due to subsequent descriptor access.
563          */
564
565         for(i = 0; i < entries; i += entries_per_page)
566                 set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
567 }
568
569 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
570 {
571         const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
572         int i;
573
574         for(i = 0; i < entries; i += entries_per_page)
575                 set_aliased_prot(ldt + i, PAGE_KERNEL);
576 }
577
578 static void xen_set_ldt(const void *addr, unsigned entries)
579 {
580         struct mmuext_op *op;
581         struct multicall_space mcs = xen_mc_entry(sizeof(*op));
582
583         trace_xen_cpu_set_ldt(addr, entries);
584
585         op = mcs.args;
586         op->cmd = MMUEXT_SET_LDT;
587         op->arg1.linear_addr = (unsigned long)addr;
588         op->arg2.nr_ents = entries;
589
590         MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
591
592         xen_mc_issue(PARAVIRT_LAZY_CPU);
593 }
594
595 static void xen_load_gdt(const struct desc_ptr *dtr)
596 {
597         unsigned long va = dtr->address;
598         unsigned int size = dtr->size + 1;
599         unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
600         unsigned long frames[pages];
601         int f;
602
603         /*
604          * A GDT can be up to 64k in size, which corresponds to 8192
605          * 8-byte entries, or 16 4k pages..
606          */
607
608         BUG_ON(size > 65536);
609         BUG_ON(va & ~PAGE_MASK);
610
611         for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
612                 int level;
613                 pte_t *ptep;
614                 unsigned long pfn, mfn;
615                 void *virt;
616
617                 /*
618                  * The GDT is per-cpu and is in the percpu data area.
619                  * That can be virtually mapped, so we need to do a
620                  * page-walk to get the underlying MFN for the
621                  * hypercall.  The page can also be in the kernel's
622                  * linear range, so we need to RO that mapping too.
623                  */
624                 ptep = lookup_address(va, &level);
625                 BUG_ON(ptep == NULL);
626
627                 pfn = pte_pfn(*ptep);
628                 mfn = pfn_to_mfn(pfn);
629                 virt = __va(PFN_PHYS(pfn));
630
631                 frames[f] = mfn;
632
633                 make_lowmem_page_readonly((void *)va);
634                 make_lowmem_page_readonly(virt);
635         }
636
637         if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
638                 BUG();
639 }
640
641 /*
642  * load_gdt for early boot, when the gdt is only mapped once
643  */
644 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
645 {
646         unsigned long va = dtr->address;
647         unsigned int size = dtr->size + 1;
648         unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE);
649         unsigned long frames[pages];
650         int f;
651
652         /*
653          * A GDT can be up to 64k in size, which corresponds to 8192
654          * 8-byte entries, or 16 4k pages..
655          */
656
657         BUG_ON(size > 65536);
658         BUG_ON(va & ~PAGE_MASK);
659
660         for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
661                 pte_t pte;
662                 unsigned long pfn, mfn;
663
664                 pfn = virt_to_pfn(va);
665                 mfn = pfn_to_mfn(pfn);
666
667                 pte = pfn_pte(pfn, PAGE_KERNEL_RO);
668
669                 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
670                         BUG();
671
672                 frames[f] = mfn;
673         }
674
675         if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
676                 BUG();
677 }
678
679 static inline bool desc_equal(const struct desc_struct *d1,
680                               const struct desc_struct *d2)
681 {
682         return d1->a == d2->a && d1->b == d2->b;
683 }
684
685 static void load_TLS_descriptor(struct thread_struct *t,
686                                 unsigned int cpu, unsigned int i)
687 {
688         struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
689         struct desc_struct *gdt;
690         xmaddr_t maddr;
691         struct multicall_space mc;
692
693         if (desc_equal(shadow, &t->tls_array[i]))
694                 return;
695
696         *shadow = t->tls_array[i];
697
698         gdt = get_cpu_gdt_table(cpu);
699         maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
700         mc = __xen_mc_entry(0);
701
702         MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
703 }
704
705 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
706 {
707         /*
708          * XXX sleazy hack: If we're being called in a lazy-cpu zone
709          * and lazy gs handling is enabled, it means we're in a
710          * context switch, and %gs has just been saved.  This means we
711          * can zero it out to prevent faults on exit from the
712          * hypervisor if the next process has no %gs.  Either way, it
713          * has been saved, and the new value will get loaded properly.
714          * This will go away as soon as Xen has been modified to not
715          * save/restore %gs for normal hypercalls.
716          *
717          * On x86_64, this hack is not used for %gs, because gs points
718          * to KERNEL_GS_BASE (and uses it for PDA references), so we
719          * must not zero %gs on x86_64
720          *
721          * For x86_64, we need to zero %fs, otherwise we may get an
722          * exception between the new %fs descriptor being loaded and
723          * %fs being effectively cleared at __switch_to().
724          */
725         if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
726 #ifdef CONFIG_X86_32
727                 lazy_load_gs(0);
728 #else
729                 loadsegment(fs, 0);
730 #endif
731         }
732
733         xen_mc_batch();
734
735         load_TLS_descriptor(t, cpu, 0);
736         load_TLS_descriptor(t, cpu, 1);
737         load_TLS_descriptor(t, cpu, 2);
738
739         xen_mc_issue(PARAVIRT_LAZY_CPU);
740 }
741
742 #ifdef CONFIG_X86_64
743 static void xen_load_gs_index(unsigned int idx)
744 {
745         if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
746                 BUG();
747 }
748 #endif
749
750 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
751                                 const void *ptr)
752 {
753         xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
754         u64 entry = *(u64 *)ptr;
755
756         trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
757
758         preempt_disable();
759
760         xen_mc_flush();
761         if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
762                 BUG();
763
764         preempt_enable();
765 }
766
767 static int cvt_gate_to_trap(int vector, const gate_desc *val,
768                             struct trap_info *info)
769 {
770         unsigned long addr;
771
772         if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
773                 return 0;
774
775         info->vector = vector;
776
777         addr = gate_offset(*val);
778 #ifdef CONFIG_X86_64
779         /*
780          * Look for known traps using IST, and substitute them
781          * appropriately.  The debugger ones are the only ones we care
782          * about.  Xen will handle faults like double_fault,
783          * so we should never see them.  Warn if
784          * there's an unexpected IST-using fault handler.
785          */
786         if (addr == (unsigned long)debug)
787                 addr = (unsigned long)xen_debug;
788         else if (addr == (unsigned long)int3)
789                 addr = (unsigned long)xen_int3;
790         else if (addr == (unsigned long)stack_segment)
791                 addr = (unsigned long)xen_stack_segment;
792         else if (addr == (unsigned long)double_fault) {
793                 /* Don't need to handle these */
794                 return 0;
795 #ifdef CONFIG_X86_MCE
796         } else if (addr == (unsigned long)machine_check) {
797                 /*
798                  * when xen hypervisor inject vMCE to guest,
799                  * use native mce handler to handle it
800                  */
801                 ;
802 #endif
803         } else if (addr == (unsigned long)nmi)
804                 /*
805                  * Use the native version as well.
806                  */
807                 ;
808         else {
809                 /* Some other trap using IST? */
810                 if (WARN_ON(val->ist != 0))
811                         return 0;
812         }
813 #endif  /* CONFIG_X86_64 */
814         info->address = addr;
815
816         info->cs = gate_segment(*val);
817         info->flags = val->dpl;
818         /* interrupt gates clear IF */
819         if (val->type == GATE_INTERRUPT)
820                 info->flags |= 1 << 2;
821
822         return 1;
823 }
824
825 /* Locations of each CPU's IDT */
826 static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
827
828 /* Set an IDT entry.  If the entry is part of the current IDT, then
829    also update Xen. */
830 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
831 {
832         unsigned long p = (unsigned long)&dt[entrynum];
833         unsigned long start, end;
834
835         trace_xen_cpu_write_idt_entry(dt, entrynum, g);
836
837         preempt_disable();
838
839         start = __this_cpu_read(idt_desc.address);
840         end = start + __this_cpu_read(idt_desc.size) + 1;
841
842         xen_mc_flush();
843
844         native_write_idt_entry(dt, entrynum, g);
845
846         if (p >= start && (p + 8) <= end) {
847                 struct trap_info info[2];
848
849                 info[1].address = 0;
850
851                 if (cvt_gate_to_trap(entrynum, g, &info[0]))
852                         if (HYPERVISOR_set_trap_table(info))
853                                 BUG();
854         }
855
856         preempt_enable();
857 }
858
859 static void xen_convert_trap_info(const struct desc_ptr *desc,
860                                   struct trap_info *traps)
861 {
862         unsigned in, out, count;
863
864         count = (desc->size+1) / sizeof(gate_desc);
865         BUG_ON(count > 256);
866
867         for (in = out = 0; in < count; in++) {
868                 gate_desc *entry = (gate_desc*)(desc->address) + in;
869
870                 if (cvt_gate_to_trap(in, entry, &traps[out]))
871                         out++;
872         }
873         traps[out].address = 0;
874 }
875
876 void xen_copy_trap_info(struct trap_info *traps)
877 {
878         const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
879
880         xen_convert_trap_info(desc, traps);
881 }
882
883 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
884    hold a spinlock to protect the static traps[] array (static because
885    it avoids allocation, and saves stack space). */
886 static void xen_load_idt(const struct desc_ptr *desc)
887 {
888         static DEFINE_SPINLOCK(lock);
889         static struct trap_info traps[257];
890
891         trace_xen_cpu_load_idt(desc);
892
893         spin_lock(&lock);
894
895         memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
896
897         xen_convert_trap_info(desc, traps);
898
899         xen_mc_flush();
900         if (HYPERVISOR_set_trap_table(traps))
901                 BUG();
902
903         spin_unlock(&lock);
904 }
905
906 /* Write a GDT descriptor entry.  Ignore LDT descriptors, since
907    they're handled differently. */
908 static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
909                                 const void *desc, int type)
910 {
911         trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
912
913         preempt_disable();
914
915         switch (type) {
916         case DESC_LDT:
917         case DESC_TSS:
918                 /* ignore */
919                 break;
920
921         default: {
922                 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
923
924                 xen_mc_flush();
925                 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
926                         BUG();
927         }
928
929         }
930
931         preempt_enable();
932 }
933
934 /*
935  * Version of write_gdt_entry for use at early boot-time needed to
936  * update an entry as simply as possible.
937  */
938 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
939                                             const void *desc, int type)
940 {
941         trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
942
943         switch (type) {
944         case DESC_LDT:
945         case DESC_TSS:
946                 /* ignore */
947                 break;
948
949         default: {
950                 xmaddr_t maddr = virt_to_machine(&dt[entry]);
951
952                 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
953                         dt[entry] = *(struct desc_struct *)desc;
954         }
955
956         }
957 }
958
959 static void xen_load_sp0(struct tss_struct *tss,
960                          struct thread_struct *thread)
961 {
962         struct multicall_space mcs;
963
964         mcs = xen_mc_entry(0);
965         MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
966         xen_mc_issue(PARAVIRT_LAZY_CPU);
967         tss->x86_tss.sp0 = thread->sp0;
968 }
969
970 void xen_set_iopl_mask(unsigned mask)
971 {
972         struct physdev_set_iopl set_iopl;
973
974         /* Force the change at ring 0. */
975         set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
976         HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
977 }
978
979 static void xen_io_delay(void)
980 {
981 }
982
983 static void xen_clts(void)
984 {
985         struct multicall_space mcs;
986
987         mcs = xen_mc_entry(0);
988
989         MULTI_fpu_taskswitch(mcs.mc, 0);
990
991         xen_mc_issue(PARAVIRT_LAZY_CPU);
992 }
993
994 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
995
996 static unsigned long xen_read_cr0(void)
997 {
998         unsigned long cr0 = this_cpu_read(xen_cr0_value);
999
1000         if (unlikely(cr0 == 0)) {
1001                 cr0 = native_read_cr0();
1002                 this_cpu_write(xen_cr0_value, cr0);
1003         }
1004
1005         return cr0;
1006 }
1007
1008 static void xen_write_cr0(unsigned long cr0)
1009 {
1010         struct multicall_space mcs;
1011
1012         this_cpu_write(xen_cr0_value, cr0);
1013
1014         /* Only pay attention to cr0.TS; everything else is
1015            ignored. */
1016         mcs = xen_mc_entry(0);
1017
1018         MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
1019
1020         xen_mc_issue(PARAVIRT_LAZY_CPU);
1021 }
1022
1023 static void xen_write_cr4(unsigned long cr4)
1024 {
1025         cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
1026
1027         native_write_cr4(cr4);
1028 }
1029 #ifdef CONFIG_X86_64
1030 static inline unsigned long xen_read_cr8(void)
1031 {
1032         return 0;
1033 }
1034 static inline void xen_write_cr8(unsigned long val)
1035 {
1036         BUG_ON(val);
1037 }
1038 #endif
1039
1040 static u64 xen_read_msr_safe(unsigned int msr, int *err)
1041 {
1042         u64 val;
1043
1044         if (pmu_msr_read(msr, &val, err))
1045                 return val;
1046
1047         val = native_read_msr_safe(msr, err);
1048         switch (msr) {
1049         case MSR_IA32_APICBASE:
1050 #ifdef CONFIG_X86_X2APIC
1051                 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31))))
1052 #endif
1053                         val &= ~X2APIC_ENABLE;
1054                 break;
1055         }
1056         return val;
1057 }
1058
1059 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
1060 {
1061         int ret;
1062
1063         ret = 0;
1064
1065         switch (msr) {
1066 #ifdef CONFIG_X86_64
1067                 unsigned which;
1068                 u64 base;
1069
1070         case MSR_FS_BASE:               which = SEGBASE_FS; goto set;
1071         case MSR_KERNEL_GS_BASE:        which = SEGBASE_GS_USER; goto set;
1072         case MSR_GS_BASE:               which = SEGBASE_GS_KERNEL; goto set;
1073
1074         set:
1075                 base = ((u64)high << 32) | low;
1076                 if (HYPERVISOR_set_segment_base(which, base) != 0)
1077                         ret = -EIO;
1078                 break;
1079 #endif
1080
1081         case MSR_STAR:
1082         case MSR_CSTAR:
1083         case MSR_LSTAR:
1084         case MSR_SYSCALL_MASK:
1085         case MSR_IA32_SYSENTER_CS:
1086         case MSR_IA32_SYSENTER_ESP:
1087         case MSR_IA32_SYSENTER_EIP:
1088                 /* Fast syscall setup is all done in hypercalls, so
1089                    these are all ignored.  Stub them out here to stop
1090                    Xen console noise. */
1091                 break;
1092
1093         default:
1094                 if (!pmu_msr_write(msr, low, high, &ret))
1095                         ret = native_write_msr_safe(msr, low, high);
1096         }
1097
1098         return ret;
1099 }
1100
1101 static u64 xen_read_msr(unsigned int msr)
1102 {
1103         /*
1104          * This will silently swallow a #GP from RDMSR.  It may be worth
1105          * changing that.
1106          */
1107         int err;
1108
1109         return xen_read_msr_safe(msr, &err);
1110 }
1111
1112 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
1113 {
1114         /*
1115          * This will silently swallow a #GP from WRMSR.  It may be worth
1116          * changing that.
1117          */
1118         xen_write_msr_safe(msr, low, high);
1119 }
1120
1121 void xen_setup_shared_info(void)
1122 {
1123         if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1124                 set_fixmap(FIX_PARAVIRT_BOOTMAP,
1125                            xen_start_info->shared_info);
1126
1127                 HYPERVISOR_shared_info =
1128                         (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
1129         } else
1130                 HYPERVISOR_shared_info =
1131                         (struct shared_info *)__va(xen_start_info->shared_info);
1132
1133 #ifndef CONFIG_SMP
1134         /* In UP this is as good a place as any to set up shared info */
1135         xen_setup_vcpu_info_placement();
1136 #endif
1137
1138         xen_setup_mfn_list_list();
1139 }
1140
1141 /* This is called once we have the cpu_possible_mask */
1142 void xen_setup_vcpu_info_placement(void)
1143 {
1144         int cpu;
1145
1146         for_each_possible_cpu(cpu) {
1147                 /* Set up direct vCPU id mapping for PV guests. */
1148                 per_cpu(xen_vcpu_id, cpu) = cpu;
1149                 xen_vcpu_setup(cpu);
1150         }
1151
1152         /* xen_vcpu_setup managed to place the vcpu_info within the
1153          * percpu area for all cpus, so make use of it. Note that for
1154          * PVH we want to use native IRQ mechanism. */
1155         if (have_vcpu_info_placement && !xen_pvh_domain()) {
1156                 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
1157                 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
1158                 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
1159                 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
1160                 pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
1161         }
1162 }
1163
1164 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
1165                           unsigned long addr, unsigned len)
1166 {
1167         char *start, *end, *reloc;
1168         unsigned ret;
1169
1170         start = end = reloc = NULL;
1171
1172 #define SITE(op, x)                                                     \
1173         case PARAVIRT_PATCH(op.x):                                      \
1174         if (have_vcpu_info_placement) {                                 \
1175                 start = (char *)xen_##x##_direct;                       \
1176                 end = xen_##x##_direct_end;                             \
1177                 reloc = xen_##x##_direct_reloc;                         \
1178         }                                                               \
1179         goto patch_site
1180
1181         switch (type) {
1182                 SITE(pv_irq_ops, irq_enable);
1183                 SITE(pv_irq_ops, irq_disable);
1184                 SITE(pv_irq_ops, save_fl);
1185                 SITE(pv_irq_ops, restore_fl);
1186 #undef SITE
1187
1188         patch_site:
1189                 if (start == NULL || (end-start) > len)
1190                         goto default_patch;
1191
1192                 ret = paravirt_patch_insns(insnbuf, len, start, end);
1193
1194                 /* Note: because reloc is assigned from something that
1195                    appears to be an array, gcc assumes it's non-null,
1196                    but doesn't know its relationship with start and
1197                    end. */
1198                 if (reloc > start && reloc < end) {
1199                         int reloc_off = reloc - start;
1200                         long *relocp = (long *)(insnbuf + reloc_off);
1201                         long delta = start - (char *)addr;
1202
1203                         *relocp += delta;
1204                 }
1205                 break;
1206
1207         default_patch:
1208         default:
1209                 ret = paravirt_patch_default(type, clobbers, insnbuf,
1210                                              addr, len);
1211                 break;
1212         }
1213
1214         return ret;
1215 }
1216
1217 static const struct pv_info xen_info __initconst = {
1218         .shared_kernel_pmd = 0,
1219
1220 #ifdef CONFIG_X86_64
1221         .extra_user_64bit_cs = FLAT_USER_CS64,
1222 #endif
1223         .name = "Xen",
1224 };
1225
1226 static const struct pv_init_ops xen_init_ops __initconst = {
1227         .patch = xen_patch,
1228 };
1229
1230 static const struct pv_cpu_ops xen_cpu_ops __initconst = {
1231         .cpuid = xen_cpuid,
1232
1233         .set_debugreg = xen_set_debugreg,
1234         .get_debugreg = xen_get_debugreg,
1235
1236         .clts = xen_clts,
1237
1238         .read_cr0 = xen_read_cr0,
1239         .write_cr0 = xen_write_cr0,
1240
1241         .read_cr4 = native_read_cr4,
1242         .read_cr4_safe = native_read_cr4_safe,
1243         .write_cr4 = xen_write_cr4,
1244
1245 #ifdef CONFIG_X86_64
1246         .read_cr8 = xen_read_cr8,
1247         .write_cr8 = xen_write_cr8,
1248 #endif
1249
1250         .wbinvd = native_wbinvd,
1251
1252         .read_msr = xen_read_msr,
1253         .write_msr = xen_write_msr,
1254
1255         .read_msr_safe = xen_read_msr_safe,
1256         .write_msr_safe = xen_write_msr_safe,
1257
1258         .read_pmc = xen_read_pmc,
1259
1260         .iret = xen_iret,
1261 #ifdef CONFIG_X86_64
1262         .usergs_sysret64 = xen_sysret64,
1263 #endif
1264
1265         .load_tr_desc = paravirt_nop,
1266         .set_ldt = xen_set_ldt,
1267         .load_gdt = xen_load_gdt,
1268         .load_idt = xen_load_idt,
1269         .load_tls = xen_load_tls,
1270 #ifdef CONFIG_X86_64
1271         .load_gs_index = xen_load_gs_index,
1272 #endif
1273
1274         .alloc_ldt = xen_alloc_ldt,
1275         .free_ldt = xen_free_ldt,
1276
1277         .store_idt = native_store_idt,
1278         .store_tr = xen_store_tr,
1279
1280         .write_ldt_entry = xen_write_ldt_entry,
1281         .write_gdt_entry = xen_write_gdt_entry,
1282         .write_idt_entry = xen_write_idt_entry,
1283         .load_sp0 = xen_load_sp0,
1284
1285         .set_iopl_mask = xen_set_iopl_mask,
1286         .io_delay = xen_io_delay,
1287
1288         /* Xen takes care of %gs when switching to usermode for us */
1289         .swapgs = paravirt_nop,
1290
1291         .start_context_switch = paravirt_start_context_switch,
1292         .end_context_switch = xen_end_context_switch,
1293 };
1294
1295 static void xen_reboot(int reason)
1296 {
1297         struct sched_shutdown r = { .reason = reason };
1298         int cpu;
1299
1300         for_each_online_cpu(cpu)
1301                 xen_pmu_finish(cpu);
1302
1303         if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
1304                 BUG();
1305 }
1306
1307 static void xen_restart(char *msg)
1308 {
1309         xen_reboot(SHUTDOWN_reboot);
1310 }
1311
1312 static void xen_emergency_restart(void)
1313 {
1314         xen_reboot(SHUTDOWN_reboot);
1315 }
1316
1317 static void xen_machine_halt(void)
1318 {
1319         xen_reboot(SHUTDOWN_poweroff);
1320 }
1321
1322 static void xen_machine_power_off(void)
1323 {
1324         if (pm_power_off)
1325                 pm_power_off();
1326         xen_reboot(SHUTDOWN_poweroff);
1327 }
1328
1329 static void xen_crash_shutdown(struct pt_regs *regs)
1330 {
1331         xen_reboot(SHUTDOWN_crash);
1332 }
1333
1334 static int
1335 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
1336 {
1337         xen_reboot(SHUTDOWN_crash);
1338         return NOTIFY_DONE;
1339 }
1340
1341 static struct notifier_block xen_panic_block = {
1342         .notifier_call= xen_panic_event,
1343         .priority = INT_MIN
1344 };
1345
1346 int xen_panic_handler_init(void)
1347 {
1348         atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
1349         return 0;
1350 }
1351
1352 static const struct machine_ops xen_machine_ops __initconst = {
1353         .restart = xen_restart,
1354         .halt = xen_machine_halt,
1355         .power_off = xen_machine_power_off,
1356         .shutdown = xen_machine_halt,
1357         .crash_shutdown = xen_crash_shutdown,
1358         .emergency_restart = xen_emergency_restart,
1359 };
1360
1361 static unsigned char xen_get_nmi_reason(void)
1362 {
1363         unsigned char reason = 0;
1364
1365         /* Construct a value which looks like it came from port 0x61. */
1366         if (test_bit(_XEN_NMIREASON_io_error,
1367                      &HYPERVISOR_shared_info->arch.nmi_reason))
1368                 reason |= NMI_REASON_IOCHK;
1369         if (test_bit(_XEN_NMIREASON_pci_serr,
1370                      &HYPERVISOR_shared_info->arch.nmi_reason))
1371                 reason |= NMI_REASON_SERR;
1372
1373         return reason;
1374 }
1375
1376 static void __init xen_boot_params_init_edd(void)
1377 {
1378 #if IS_ENABLED(CONFIG_EDD)
1379         struct xen_platform_op op;
1380         struct edd_info *edd_info;
1381         u32 *mbr_signature;
1382         unsigned nr;
1383         int ret;
1384
1385         edd_info = boot_params.eddbuf;
1386         mbr_signature = boot_params.edd_mbr_sig_buffer;
1387
1388         op.cmd = XENPF_firmware_info;
1389
1390         op.u.firmware_info.type = XEN_FW_DISK_INFO;
1391         for (nr = 0; nr < EDDMAXNR; nr++) {
1392                 struct edd_info *info = edd_info + nr;
1393
1394                 op.u.firmware_info.index = nr;
1395                 info->params.length = sizeof(info->params);
1396                 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
1397                                      &info->params);
1398                 ret = HYPERVISOR_platform_op(&op);
1399                 if (ret)
1400                         break;
1401
1402 #define C(x) info->x = op.u.firmware_info.u.disk_info.x
1403                 C(device);
1404                 C(version);
1405                 C(interface_support);
1406                 C(legacy_max_cylinder);
1407                 C(legacy_max_head);
1408                 C(legacy_sectors_per_track);
1409 #undef C
1410         }
1411         boot_params.eddbuf_entries = nr;
1412
1413         op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
1414         for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
1415                 op.u.firmware_info.index = nr;
1416                 ret = HYPERVISOR_platform_op(&op);
1417                 if (ret)
1418                         break;
1419                 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
1420         }
1421         boot_params.edd_mbr_sig_buf_entries = nr;
1422 #endif
1423 }
1424
1425 /*
1426  * Set up the GDT and segment registers for -fstack-protector.  Until
1427  * we do this, we have to be careful not to call any stack-protected
1428  * function, which is most of the kernel.
1429  *
1430  * Note, that it is __ref because the only caller of this after init
1431  * is PVH which is not going to use xen_load_gdt_boot or other
1432  * __init functions.
1433  */
1434 static void __ref xen_setup_gdt(int cpu)
1435 {
1436         if (xen_feature(XENFEAT_auto_translated_physmap)) {
1437 #ifdef CONFIG_X86_64
1438                 unsigned long dummy;
1439
1440                 load_percpu_segment(cpu); /* We need to access per-cpu area */
1441                 switch_to_new_gdt(cpu); /* GDT and GS set */
1442
1443                 /* We are switching of the Xen provided GDT to our HVM mode
1444                  * GDT. The new GDT has  __KERNEL_CS with CS.L = 1
1445                  * and we are jumping to reload it.
1446                  */
1447                 asm volatile ("pushq %0\n"
1448                               "leaq 1f(%%rip),%0\n"
1449                               "pushq %0\n"
1450                               "lretq\n"
1451                               "1:\n"
1452                               : "=&r" (dummy) : "0" (__KERNEL_CS));
1453
1454                 /*
1455                  * While not needed, we also set the %es, %ds, and %fs
1456                  * to zero. We don't care about %ss as it is NULL.
1457                  * Strictly speaking this is not needed as Xen zeros those
1458                  * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE)
1459                  *
1460                  * Linux zeros them in cpu_init() and in secondary_startup_64
1461                  * (for BSP).
1462                  */
1463                 loadsegment(es, 0);
1464                 loadsegment(ds, 0);
1465                 loadsegment(fs, 0);
1466 #else
1467                 /* PVH: TODO Implement. */
1468                 BUG();
1469 #endif
1470                 return; /* PVH does not need any PV GDT ops. */
1471         }
1472         pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
1473         pv_cpu_ops.load_gdt = xen_load_gdt_boot;
1474
1475         setup_stack_canary_segment(0);
1476         switch_to_new_gdt(0);
1477
1478         pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
1479         pv_cpu_ops.load_gdt = xen_load_gdt;
1480 }
1481
1482 #ifdef CONFIG_XEN_PVH
1483 /*
1484  * A PV guest starts with default flags that are not set for PVH, set them
1485  * here asap.
1486  */
1487 static void xen_pvh_set_cr_flags(int cpu)
1488 {
1489
1490         /* Some of these are setup in 'secondary_startup_64'. The others:
1491          * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests
1492          * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */
1493         write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM);
1494
1495         if (!cpu)
1496                 return;
1497         /*
1498          * For BSP, PSE PGE are set in probe_page_size_mask(), for APs
1499          * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu().
1500         */
1501         if (boot_cpu_has(X86_FEATURE_PSE))
1502                 cr4_set_bits_and_update_boot(X86_CR4_PSE);
1503
1504         if (boot_cpu_has(X86_FEATURE_PGE))
1505                 cr4_set_bits_and_update_boot(X86_CR4_PGE);
1506 }
1507
1508 /*
1509  * Note, that it is ref - because the only caller of this after init
1510  * is PVH which is not going to use xen_load_gdt_boot or other
1511  * __init functions.
1512  */
1513 void __ref xen_pvh_secondary_vcpu_init(int cpu)
1514 {
1515         xen_setup_gdt(cpu);
1516         xen_pvh_set_cr_flags(cpu);
1517 }
1518
1519 static void __init xen_pvh_early_guest_init(void)
1520 {
1521         if (!xen_feature(XENFEAT_auto_translated_physmap))
1522                 return;
1523
1524         if (!xen_feature(XENFEAT_hvm_callback_vector))
1525                 return;
1526
1527         xen_have_vector_callback = 1;
1528
1529         xen_pvh_early_cpu_init(0, false);
1530         xen_pvh_set_cr_flags(0);
1531
1532 #ifdef CONFIG_X86_32
1533         BUG(); /* PVH: Implement proper support. */
1534 #endif
1535 }
1536 #endif    /* CONFIG_XEN_PVH */
1537
1538 static void __init xen_dom0_set_legacy_features(void)
1539 {
1540         x86_platform.legacy.rtc = 1;
1541 }
1542
1543 /* First C function to be called on Xen boot */
1544 asmlinkage __visible void __init xen_start_kernel(void)
1545 {
1546         struct physdev_set_iopl set_iopl;
1547         unsigned long initrd_start = 0;
1548         int rc;
1549
1550         if (!xen_start_info)
1551                 return;
1552
1553         xen_domain_type = XEN_PV_DOMAIN;
1554
1555         xen_setup_features();
1556 #ifdef CONFIG_XEN_PVH
1557         xen_pvh_early_guest_init();
1558 #endif
1559         xen_setup_machphys_mapping();
1560
1561         /* Install Xen paravirt ops */
1562         pv_info = xen_info;
1563         pv_init_ops = xen_init_ops;
1564         if (!xen_pvh_domain()) {
1565                 pv_cpu_ops = xen_cpu_ops;
1566
1567                 x86_platform.get_nmi_reason = xen_get_nmi_reason;
1568         }
1569
1570         if (xen_feature(XENFEAT_auto_translated_physmap))
1571                 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup;
1572         else
1573                 x86_init.resources.memory_setup = xen_memory_setup;
1574         x86_init.oem.arch_setup = xen_arch_setup;
1575         x86_init.oem.banner = xen_banner;
1576
1577         xen_init_time_ops();
1578
1579         /*
1580          * Set up some pagetable state before starting to set any ptes.
1581          */
1582
1583         xen_init_mmu_ops();
1584
1585         /* Prevent unwanted bits from being set in PTEs. */
1586         __supported_pte_mask &= ~_PAGE_GLOBAL;
1587
1588         /*
1589          * Prevent page tables from being allocated in highmem, even
1590          * if CONFIG_HIGHPTE is enabled.
1591          */
1592         __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
1593
1594         /* Work out if we support NX */
1595         x86_configure_nx();
1596
1597         /* Get mfn list */
1598         xen_build_dynamic_phys_to_machine();
1599
1600         /*
1601          * Set up kernel GDT and segment registers, mainly so that
1602          * -fstack-protector code can be executed.
1603          */
1604         xen_setup_gdt(0);
1605
1606         xen_init_irq_ops();
1607         xen_init_cpuid_mask();
1608
1609 #ifdef CONFIG_X86_LOCAL_APIC
1610         /*
1611          * set up the basic apic ops.
1612          */
1613         xen_init_apic();
1614 #endif
1615
1616         if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
1617                 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
1618                 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
1619         }
1620
1621         machine_ops = xen_machine_ops;
1622
1623         /*
1624          * The only reliable way to retain the initial address of the
1625          * percpu gdt_page is to remember it here, so we can go and
1626          * mark it RW later, when the initial percpu area is freed.
1627          */
1628         xen_initial_gdt = &per_cpu(gdt_page, 0);
1629
1630         xen_smp_init();
1631
1632 #ifdef CONFIG_ACPI_NUMA
1633         /*
1634          * The pages we from Xen are not related to machine pages, so
1635          * any NUMA information the kernel tries to get from ACPI will
1636          * be meaningless.  Prevent it from trying.
1637          */
1638         acpi_numa = -1;
1639 #endif
1640         /* Don't do the full vcpu_info placement stuff until we have a
1641            possible map and a non-dummy shared_info. */
1642         per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
1643
1644         local_irq_disable();
1645         early_boot_irqs_disabled = true;
1646
1647         xen_raw_console_write("mapping kernel into physical memory\n");
1648         xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
1649                                    xen_start_info->nr_pages);
1650         xen_reserve_special_pages();
1651
1652         /* keep using Xen gdt for now; no urgent need to change it */
1653
1654 #ifdef CONFIG_X86_32
1655         pv_info.kernel_rpl = 1;
1656         if (xen_feature(XENFEAT_supervisor_mode_kernel))
1657                 pv_info.kernel_rpl = 0;
1658 #else
1659         pv_info.kernel_rpl = 0;
1660 #endif
1661         /* set the limit of our address space */
1662         xen_reserve_top();
1663
1664         /* PVH: runs at default kernel iopl of 0 */
1665         if (!xen_pvh_domain()) {
1666                 /*
1667                  * We used to do this in xen_arch_setup, but that is too late
1668                  * on AMD were early_cpu_init (run before ->arch_setup()) calls
1669                  * early_amd_init which pokes 0xcf8 port.
1670                  */
1671                 set_iopl.iopl = 1;
1672                 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
1673                 if (rc != 0)
1674                         xen_raw_printk("physdev_op failed %d\n", rc);
1675         }
1676
1677 #ifdef CONFIG_X86_32
1678         /* set up basic CPUID stuff */
1679         cpu_detect(&new_cpu_data);
1680         set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
1681         new_cpu_data.wp_works_ok = 1;
1682         new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
1683 #endif
1684
1685         if (xen_start_info->mod_start) {
1686             if (xen_start_info->flags & SIF_MOD_START_PFN)
1687                 initrd_start = PFN_PHYS(xen_start_info->mod_start);
1688             else
1689                 initrd_start = __pa(xen_start_info->mod_start);
1690         }
1691
1692         /* Poke various useful things into boot_params */
1693         boot_params.hdr.type_of_loader = (9 << 4) | 0;
1694         boot_params.hdr.ramdisk_image = initrd_start;
1695         boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
1696         boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
1697         boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
1698
1699         if (!xen_initial_domain()) {
1700                 add_preferred_console("xenboot", 0, NULL);
1701                 add_preferred_console("tty", 0, NULL);
1702                 add_preferred_console("hvc", 0, NULL);
1703                 if (pci_xen)
1704                         x86_init.pci.arch_init = pci_xen_init;
1705         } else {
1706                 const struct dom0_vga_console_info *info =
1707                         (void *)((char *)xen_start_info +
1708                                  xen_start_info->console.dom0.info_off);
1709                 struct xen_platform_op op = {
1710                         .cmd = XENPF_firmware_info,
1711                         .interface_version = XENPF_INTERFACE_VERSION,
1712                         .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
1713                 };
1714
1715                 x86_platform.set_legacy_features =
1716                                 xen_dom0_set_legacy_features;
1717                 xen_init_vga(info, xen_start_info->console.dom0.info_size);
1718                 xen_start_info->console.domU.mfn = 0;
1719                 xen_start_info->console.domU.evtchn = 0;
1720
1721                 if (HYPERVISOR_platform_op(&op) == 0)
1722                         boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
1723
1724                 /* Make sure ACS will be enabled */
1725                 pci_request_acs();
1726
1727                 xen_acpi_sleep_register();
1728
1729                 /* Avoid searching for BIOS MP tables */
1730                 x86_init.mpparse.find_smp_config = x86_init_noop;
1731                 x86_init.mpparse.get_smp_config = x86_init_uint_noop;
1732
1733                 xen_boot_params_init_edd();
1734         }
1735 #ifdef CONFIG_PCI
1736         /* PCI BIOS service won't work from a PV guest. */
1737         pci_probe &= ~PCI_PROBE_BIOS;
1738 #endif
1739         xen_raw_console_write("about to get started...\n");
1740
1741         /* Let's presume PV guests always boot on vCPU with id 0. */
1742         per_cpu(xen_vcpu_id, 0) = 0;
1743
1744         xen_setup_runstate_info(0);
1745
1746         xen_efi_init();
1747
1748         /* Start the world */
1749 #ifdef CONFIG_X86_32
1750         i386_start_kernel();
1751 #else
1752         cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
1753         x86_64_start_reservations((char *)__pa_symbol(&boot_params));
1754 #endif
1755 }
1756
1757 void __ref xen_hvm_init_shared_info(void)
1758 {
1759         int cpu;
1760         struct xen_add_to_physmap xatp;
1761         static struct shared_info *shared_info_page = 0;
1762
1763         if (!shared_info_page)
1764                 shared_info_page = (struct shared_info *)
1765                         extend_brk(PAGE_SIZE, PAGE_SIZE);
1766         xatp.domid = DOMID_SELF;
1767         xatp.idx = 0;
1768         xatp.space = XENMAPSPACE_shared_info;
1769         xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
1770         if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
1771                 BUG();
1772
1773         HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
1774
1775         /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
1776          * page, we use it in the event channel upcall and in some pvclock
1777          * related functions. We don't need the vcpu_info placement
1778          * optimizations because we don't use any pv_mmu or pv_irq op on
1779          * HVM.
1780          * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
1781          * online but xen_hvm_init_shared_info is run at resume time too and
1782          * in that case multiple vcpus might be online. */
1783         for_each_online_cpu(cpu) {
1784                 /* Leave it to be NULL. */
1785                 if (xen_vcpu_nr(cpu) >= MAX_VIRT_CPUS)
1786                         continue;
1787                 per_cpu(xen_vcpu, cpu) =
1788                         &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
1789         }
1790 }
1791
1792 #ifdef CONFIG_XEN_PVHVM
1793 static void __init init_hvm_pv_info(void)
1794 {
1795         int major, minor;
1796         uint32_t eax, ebx, ecx, edx, pages, msr, base;
1797         u64 pfn;
1798
1799         base = xen_cpuid_base();
1800         cpuid(base + 1, &eax, &ebx, &ecx, &edx);
1801
1802         major = eax >> 16;
1803         minor = eax & 0xffff;
1804         printk(KERN_INFO "Xen version %d.%d.\n", major, minor);
1805
1806         cpuid(base + 2, &pages, &msr, &ecx, &edx);
1807
1808         pfn = __pa(hypercall_page);
1809         wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
1810
1811         xen_setup_features();
1812
1813         cpuid(base + 4, &eax, &ebx, &ecx, &edx);
1814         if (eax & XEN_HVM_CPUID_VCPU_ID_PRESENT)
1815                 this_cpu_write(xen_vcpu_id, ebx);
1816         else
1817                 this_cpu_write(xen_vcpu_id, smp_processor_id());
1818
1819         pv_info.name = "Xen HVM";
1820
1821         xen_domain_type = XEN_HVM_DOMAIN;
1822 }
1823
1824 static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action,
1825                               void *hcpu)
1826 {
1827         int cpu = (long)hcpu;
1828         switch (action) {
1829         case CPU_UP_PREPARE:
1830                 if (cpu_acpi_id(cpu) != U32_MAX)
1831                         per_cpu(xen_vcpu_id, cpu) = cpu_acpi_id(cpu);
1832                 else
1833                         per_cpu(xen_vcpu_id, cpu) = cpu;
1834                 xen_vcpu_setup(cpu);
1835                 if (xen_have_vector_callback) {
1836                         if (xen_feature(XENFEAT_hvm_safe_pvclock))
1837                                 xen_setup_timer(cpu);
1838                 }
1839                 break;
1840         default:
1841                 break;
1842         }
1843         return NOTIFY_OK;
1844 }
1845
1846 static struct notifier_block xen_hvm_cpu_notifier = {
1847         .notifier_call  = xen_hvm_cpu_notify,
1848 };
1849
1850 #ifdef CONFIG_KEXEC_CORE
1851 static void xen_hvm_shutdown(void)
1852 {
1853         native_machine_shutdown();
1854         if (kexec_in_progress)
1855                 xen_reboot(SHUTDOWN_soft_reset);
1856 }
1857
1858 static void xen_hvm_crash_shutdown(struct pt_regs *regs)
1859 {
1860         native_machine_crash_shutdown(regs);
1861         xen_reboot(SHUTDOWN_soft_reset);
1862 }
1863 #endif
1864
1865 static void __init xen_hvm_guest_init(void)
1866 {
1867         if (xen_pv_domain())
1868                 return;
1869
1870         init_hvm_pv_info();
1871
1872         xen_hvm_init_shared_info();
1873
1874         xen_panic_handler_init();
1875
1876         if (xen_feature(XENFEAT_hvm_callback_vector))
1877                 xen_have_vector_callback = 1;
1878         xen_hvm_smp_init();
1879         register_cpu_notifier(&xen_hvm_cpu_notifier);
1880         xen_unplug_emulated_devices();
1881         x86_init.irqs.intr_init = xen_init_IRQ;
1882         xen_hvm_init_time_ops();
1883         xen_hvm_init_mmu_ops();
1884 #ifdef CONFIG_KEXEC_CORE
1885         machine_ops.shutdown = xen_hvm_shutdown;
1886         machine_ops.crash_shutdown = xen_hvm_crash_shutdown;
1887 #endif
1888 }
1889 #endif
1890
1891 static bool xen_nopv = false;
1892 static __init int xen_parse_nopv(char *arg)
1893 {
1894        xen_nopv = true;
1895        return 0;
1896 }
1897 early_param("xen_nopv", xen_parse_nopv);
1898
1899 static uint32_t __init xen_platform(void)
1900 {
1901         if (xen_nopv)
1902                 return 0;
1903
1904         return xen_cpuid_base();
1905 }
1906
1907 bool xen_hvm_need_lapic(void)
1908 {
1909         if (xen_nopv)
1910                 return false;
1911         if (xen_pv_domain())
1912                 return false;
1913         if (!xen_hvm_domain())
1914                 return false;
1915         if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
1916                 return false;
1917         return true;
1918 }
1919 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
1920
1921 static void xen_set_cpu_features(struct cpuinfo_x86 *c)
1922 {
1923         if (xen_pv_domain()) {
1924                 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS);
1925                 set_cpu_cap(c, X86_FEATURE_XENPV);
1926         }
1927 }
1928
1929 const struct hypervisor_x86 x86_hyper_xen = {
1930         .name                   = "Xen",
1931         .detect                 = xen_platform,
1932 #ifdef CONFIG_XEN_PVHVM
1933         .init_platform          = xen_hvm_guest_init,
1934 #endif
1935         .x2apic_available       = xen_x2apic_para_available,
1936         .set_cpu_features       = xen_set_cpu_features,
1937 };
1938 EXPORT_SYMBOL(x86_hyper_xen);
1939
1940 #ifdef CONFIG_HOTPLUG_CPU
1941 void xen_arch_register_cpu(int num)
1942 {
1943         arch_register_cpu(num);
1944 }
1945 EXPORT_SYMBOL(xen_arch_register_cpu);
1946
1947 void xen_arch_unregister_cpu(int num)
1948 {
1949         arch_unregister_cpu(num);
1950 }
1951 EXPORT_SYMBOL(xen_arch_unregister_cpu);
1952 #endif