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