aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/vmi_32.c
blob: 18673e0f193b9237910b33645f26c0bcb64dd99b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
/*
 * VMI specific paravirt-ops implementation
 *
 * Copyright (C) 2005, VMware, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send feedback to zach@vmware.com
 *
 */

#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/sched.h>
#include <asm/vmi.h>
#include <asm/io.h>
#include <asm/fixmap.h>
#include <asm/apicdef.h>
#include <asm/apic.h>
#include <asm/processor.h>
#include <asm/timer.h>
#include <asm/vmi_time.h>
#include <asm/kmap_types.h>

/* Convenient for calling VMI functions indirectly in the ROM */
typedef u32 __attribute__((regparm(1))) (VROMFUNC)(void);
typedef u64 __attribute__((regparm(2))) (VROMLONGFUNC)(int);

#define call_vrom_func(rom,func) \
   (((VROMFUNC *)(rom->func))())

#define call_vrom_long_func(rom,func,arg) \
   (((VROMLONGFUNC *)(rom->func)) (arg))

static struct vrom_header *vmi_rom;
static int disable_pge;
static int disable_pse;
static int disable_sep;
static int disable_tsc;
static int disable_mtrr;
static int disable_noidle;
static int disable_vmi_timer;

/* Cached VMI operations */
static struct {
	void (*cpuid)(void /* non-c */);
	void (*_set_ldt)(u32 selector);
	void (*set_tr)(u32 selector);
	void (*set_kernel_stack)(u32 selector, u32 esp0);
	void (*allocate_page)(u32, u32, u32, u32, u32);
	void (*release_page)(u32, u32);
	void (*set_pte)(pte_t, pte_t *, unsigned);
	void (*update_pte)(pte_t *, unsigned);
	void (*set_linear_mapping)(int, void *, u32, u32);
	void (*_flush_tlb)(int);
	void (*set_initial_ap_state)(int, int);
	void (*halt)(void);
  	void (*set_lazy_mode)(int mode);
} vmi_ops;

/* Cached VMI operations */
struct vmi_timer_ops vmi_timer_ops;

/*
 * VMI patching routines.
 */
#define MNEM_CALL 0xe8
#define MNEM_JMP  0xe9
#define MNEM_RET  0xc3

#define IRQ_PATCH_INT_MASK 0
#define IRQ_PATCH_DISABLE  5

static inline void patch_offset(void *insnbuf,
				unsigned long eip, unsigned long dest)
{
        *(unsigned long *)(insnbuf+1) = dest-eip-5;
}

static unsigned patch_internal(int call, unsigned len, void *insnbuf,
			       unsigned long eip)
{
	u64 reloc;
	struct vmi_relocation_info *const rel = (struct vmi_relocation_info *)&reloc;
	reloc = call_vrom_long_func(vmi_rom, get_reloc,	call);
	switch(rel->type) {
		case VMI_RELOCATION_CALL_REL:
			BUG_ON(len < 5);
			*(char *)insnbuf = MNEM_CALL;
			patch_offset(insnbuf, eip, (unsigned long)rel->eip);
			return 5;

		case VMI_RELOCATION_JUMP_REL:
			BUG_ON(len < 5);
			*(char *)insnbuf = MNEM_JMP;
			patch_offset(insnbuf, eip, (unsigned long)rel->eip);
			return 5;

		case VMI_RELOCATION_NOP:
			/* obliterate the whole thing */
			return 0;

		case VMI_RELOCATION_NONE:
			/* leave native code in place */
			break;

		default:
			BUG();
	}
	return len;
}

/*
 * Apply patch if appropriate, return length of new instruction
 * sequence.  The callee does nop padding for us.
 */
static unsigned vmi_patch(u8 type, u16 clobbers, void *insns,
			  unsigned long eip, unsigned len)
{
	switch (type) {
		case PARAVIRT_PATCH(irq_disable):
			return patch_internal(VMI_CALL_DisableInterrupts, len,
					      insns, eip);
		case PARAVIRT_PATCH(irq_enable):
			return patch_internal(VMI_CALL_EnableInterrupts, len,
					      insns, eip);
		case PARAVIRT_PATCH(restore_fl):
			return patch_internal(VMI_CALL_SetInterruptMask, len,
					      insns, eip);
		case PARAVIRT_PATCH(save_fl):
			return patch_internal(VMI_CALL_GetInterruptMask, len,
					      insns, eip);
		case PARAVIRT_PATCH(iret):
			return patch_internal(VMI_CALL_IRET, len, insns, eip);
		case PARAVIRT_PATCH(irq_enable_sysexit):
			return patch_internal(VMI_CALL_SYSEXIT, len, insns, eip);
		default:
			break;
	}
	return len;
}

/* CPUID has non-C semantics, and paravirt-ops API doesn't match hardware ISA */
static void vmi_cpuid(unsigned int *eax, unsigned int *ebx,
                               unsigned int *ecx, unsigned int *edx)
{
	int override = 0;
	if (*eax == 1)
		override = 1;
        asm volatile ("call *%6"
                      : "=a" (*eax),
                        "=b" (*ebx),
                        "=c" (*ecx),
                        "=d" (*edx)
                      : "0" (*eax), "2" (*ecx), "r" (vmi_ops.cpuid));
	if (override) {
		if (disable_pse)
			*edx &= ~X86_FEATURE_PSE;
		if (disable_pge)
			*edx &= ~X86_FEATURE_PGE;
		if (disable_sep)
			*edx &= ~X86_FEATURE_SEP;
		if (disable_tsc)
			*edx &= ~X86_FEATURE_TSC;
		if (disable_mtrr)
			*edx &= ~X86_FEATURE_MTRR;
	}
}

static inline void vmi_maybe_load_tls(struct desc_struct *gdt, int nr, struct desc_struct *new)
{
	if (gdt[nr].a != new->a || gdt[nr].b != new->b)
		write_gdt_entry(gdt, nr, new->a, new->b);
}

static void vmi_load_tls(struct thread_struct *t, unsigned int cpu)
{
	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
	vmi_maybe_load_tls(gdt, GDT_ENTRY_TLS_MIN + 0, &t->tls_array[0]);
	vmi_maybe_load_tls(gdt, GDT_ENTRY_TLS_MIN + 1, &t->tls_array[1]);
	vmi_maybe_load_tls(gdt, GDT_ENTRY_TLS_MIN + 2, &t->tls_array[2]);
}

static void vmi_set_ldt(const void *addr, unsigned entries)
{
	unsigned cpu = smp_processor_id();
	u32 low, high;

	pack_descriptor(&low, &high, (unsigned long)addr,
			entries * sizeof(struct desc_struct) - 1,
			DESCTYPE_LDT, 0);
	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, low, high);
	vmi_ops._set_ldt(entries ? GDT_ENTRY_LDT*sizeof(struct desc_struct) : 0);
}

static void vmi_set_tr(void)
{
	vmi_ops.set_tr(GDT_ENTRY_TSS*sizeof(struct desc_struct));
}

static void vmi_load_esp0(struct tss_struct *tss,
				   struct thread_struct *thread)
{
	tss->x86_tss.esp0 = thread->esp0;

	/* This can only happen when SEP is enabled, no need to test "SEP"arately */
	if (unlikely(tss->x86_tss.ss1 != thread->sysenter_cs)) {
		tss->x86_tss.ss1 = thread->sysenter_cs;
		wrmsr(MSR_IA32_SYSENTER_CS, thread->sysenter_cs, 0);
	}
	vmi_ops.set_kernel_stack(__KERNEL_DS, tss->x86_tss.esp0);
}

static void vmi_flush_tlb_user(void)
{
	vmi_ops._flush_tlb(VMI_FLUSH_TLB);
}

static void vmi_flush_tlb_kernel(void)
{
	vmi_ops._flush_tlb(VMI_FLUSH_TLB | VMI_FLUSH_GLOBAL);
}

/* Stub to do nothing at all; used for delays and unimplemented calls */
static void vmi_nop(void)
{
}

#ifdef CONFIG_DEBUG_PAGE_TYPE

#ifdef CONFIG_X86_PAE
#define MAX_BOOT_PTS (2048+4+1)
#else
#define MAX_BOOT_PTS (1024+1)
#endif

/*
 * During boot, mem_map is not yet available in paging_init, so stash
 * all the boot page allocations here.
 */
static struct {
	u32 pfn;
	int type;
} boot_page_allocations[MAX_BOOT_PTS];
static int num_boot_page_allocations;
static int boot_allocations_applied;

void vmi_apply_boot_page_allocations(void)
{
	int i;
	BUG_ON(!mem_map);
	for (i = 0; i < num_boot_page_allocations; i++) {
		struct page *page = pfn_to_page(boot_page_allocations[i].pfn);
		page->type = boot_page_allocations[i].type;
		page->type = boot_page_allocations[i].type &
				~(VMI_PAGE_ZEROED | VMI_PAGE_CLONE);
	}
	boot_allocations_applied = 1;
}

static void record_page_type(u32 pfn, int type)
{
	BUG_ON(num_boot_page_allocations >= MAX_BOOT_PTS);
	boot_page_allocations[num_boot_page_allocations].pfn = pfn;
	boot_page_allocations[num_boot_page_allocations].type = type;
	num_boot_page_allocations++;
}

static void check_zeroed_page(u32 pfn, int type, struct page *page)
{
	u32 *ptr;
	int i;
	int limit = PAGE_SIZE / sizeof(int);

	if (page_address(page))
		ptr = (u32 *)page_address(page);
	else
		ptr = (u32 *)__va(pfn << PAGE_SHIFT);
	/*
	 * When cloning the root in non-PAE mode, only the userspace
	 * pdes need to be zeroed.
	 */
	if (type & VMI_PAGE_CLONE)
		limit = USER_PTRS_PER_PGD;
	for (i = 0; i < limit; i++)
		BUG_ON(ptr[i]);
}

/*
 * We stash the page type into struct page so we can verify the page
 * types are used properly.
 */
static void vmi_set_page_type(u32 pfn, int type)
{
	/* PAE can have multiple roots per page - don't track */
	if (PTRS_PER_PMD > 1 && (type & VMI_PAGE_PDP))
		return;

	if (boot_allocations_applied) {
		struct page *page = pfn_to_page(pfn);
		if (type != VMI_PAGE_NORMAL)
			BUG_ON(page->type);
		else
			BUG_ON(page->type == VMI_PAGE_NORMAL);
		page->type = type & ~(VMI_PAGE_ZEROED | VMI_PAGE_CLONE);
		if (type & VMI_PAGE_ZEROED)
			check_zeroed_page(pfn, type, page);
	} else {
		record_page_type(pfn, type);
	}
}

static void vmi_check_page_type(u32 pfn, int type)
{
	/* PAE can have multiple roots per page - skip checks */
	if (PTRS_PER_PMD > 1 && (type & VMI_PAGE_PDP))
		return;

	type &= ~(VMI_PAGE_ZEROED | VMI_PAGE_CLONE);
	if (boot_allocations_applied) {
		struct page *page = pfn_to_page(pfn);
		BUG_ON((page->type ^ type) & VMI_PAGE_PAE);
		BUG_ON(type == VMI_PAGE_NORMAL && page->type);
		BUG_ON((type & page->type) == 0);
	}
}
#else
#define vmi_set_page_type(p,t) do { } while (0)
#define vmi_check_page_type(p,t) do { } while (0)
#endif

#ifdef CONFIG_HIGHPTE
static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
{
	void *va = kmap_atomic(page, type);

	/*
	 * Internally, the VMI ROM must map virtual addresses to physical
	 * addresses for processing MMU updates.  By the time MMU updates
	 * are issued, this information is typically already lost.
	 * Fortunately, the VMI provides a cache of mapping slots for active
	 * page tables.
	 *
	 * We use slot zero for the linear mapping of physical memory, and
	 * in HIGHPTE kernels, slot 1 and 2 for KM_PTE0 and KM_PTE1.
	 *
	 *  args:                 SLOT                 VA    COUNT PFN
	 */
	BUG_ON(type != KM_PTE0 && type != KM_PTE1);
	vmi_ops.set_linear_mapping((type - KM_PTE0)+1, va, 1, page_to_pfn(page));

	return va;
}
#endif

static void vmi_allocate_pt(struct mm_struct *mm, u32 pfn)
{
	vmi_set_page_type(pfn, VMI_PAGE_L1);
	vmi_ops.allocate_page(pfn, VMI_PAGE_L1, 0, 0, 0);
}

static void vmi_allocate_pd(u32 pfn)
{
 	/*
	 * This call comes in very early, before mem_map is setup.
	 * It is called only for swapper_pg_dir, which already has
	 * data on it.
	 */
 	vmi_set_page_type(pfn, VMI_PAGE_L2);
	vmi_ops.allocate_page(pfn, VMI_PAGE_L2, 0, 0, 0);
}

static void vmi_allocate_pd_clone(u32 pfn, u32 clonepfn, u32 start, u32 count)
{
 	vmi_set_page_type(pfn, VMI_PAGE_L2 | VMI_PAGE_CLONE);
	vmi_check_page_type(clonepfn, VMI_PAGE_L2);
	vmi_ops.allocate_page(pfn, VMI_PAGE_L2 | VMI_PAGE_CLONE, clonepfn, start, count);
}

static void vmi_release_pt(u32 pfn)
{
	vmi_ops.release_page(pfn, VMI_PAGE_L1);
	vmi_set_page_type(pfn, VMI_PAGE_NORMAL);
}

static void vmi_release_pd(u32 pfn)
{
	vmi_ops.release_page(pfn, VMI_PAGE_L2);
	vmi_set_page_type(pfn, VMI_PAGE_NORMAL);
}

/*
 * Helper macros for MMU update flags.  We can defer updates until a flush
 * or page invalidation only if the update is to the current address space
 * (otherwise, there is no flush).  We must check against init_mm, since
 * this could be a kernel update, which usually passes init_mm, although
 * sometimes this check can be skipped if we know the particular function
 * is only called on user mode PTEs.  We could change the kernel to pass
 * current->active_mm here, but in particular, I was unsure if changing
 * mm/highmem.c to do this would still be correct on other architectures.
 */
#define is_current_as(mm, mustbeuser) ((mm) == current->active_mm ||    \
                                       (!mustbeuser && (mm) == &init_mm))
#define vmi_flags_addr(mm, addr, level, user)                           \
        ((level) | (is_current_as(mm, user) ?                           \
                (VMI_PAGE_CURRENT_AS | ((addr) & VMI_PAGE_VA_MASK)) : 0))
#define vmi_flags_addr_defer(mm, addr, level, user)                     \
        ((level) | (is_current_as(mm, user) ?                           \
                (VMI_PAGE_DEFER | VMI_PAGE_CURRENT_AS | ((addr) & VMI_PAGE_VA_MASK)) : 0))

static void vmi_update_pte(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
	vmi_ops.update_pte(ptep, vmi_flags_addr(mm, addr, VMI_PAGE_PT, 0));
}

static void vmi_update_pte_defer(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
	vmi_ops.update_pte(ptep, vmi_flags_addr_defer(mm, addr, VMI_PAGE_PT, 0));
}

static void vmi_set_pte(pte_t *ptep, pte_t pte)
{
	/* XXX because of set_pmd_pte, this can be called on PT or PD layers */
	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE | VMI_PAGE_PD);
	vmi_ops.set_pte(pte, ptep, VMI_PAGE_PT);
}

static void vmi_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
{
	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
	vmi_ops.set_pte(pte, ptep, vmi_flags_addr(mm, addr, VMI_PAGE_PT, 0));
}

static void vmi_set_pmd(pmd_t *pmdp, pmd_t pmdval)
{
#ifdef CONFIG_X86_PAE
	const pte_t pte = { pmdval.pmd, pmdval.pmd >> 32 };
	vmi_check_page_type(__pa(pmdp) >> PAGE_SHIFT, VMI_PAGE_PMD);
#else
	const pte_t pte = { pmdval.pud.pgd.pgd };
	vmi_check_page_type(__pa(pmdp) >> PAGE_SHIFT, VMI_PAGE_PGD);
#endif
	vmi_ops.set_pte(pte, (pte_t *)pmdp, VMI_PAGE_PD);
}

#ifdef CONFIG_X86_PAE

static void vmi_set_pte_atomic(pte_t *ptep, pte_t pteval)
{
	/*
	 * XXX This is called from set_pmd_pte, but at both PT
	 * and PD layers so the VMI_PAGE_PT flag is wrong.  But
	 * it is only called for large page mapping changes,
	 * the Xen backend, doesn't support large pages, and the
	 * ESX backend doesn't depend on the flag.
	 */
	set_64bit((unsigned long long *)ptep,pte_val(pteval));
	vmi_ops.update_pte(ptep, VMI_PAGE_PT);
}

static void vmi_set_pte_present(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
{
	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
	vmi_ops.set_pte(pte, ptep, vmi_flags_addr_defer(mm, addr, VMI_PAGE_PT, 1));
}

static void vmi_set_pud(pud_t *pudp, pud_t pudval)
{
	/* Um, eww */
	const pte_t pte = { pudval.pgd.pgd, pudval.pgd.pgd >> 32 };
	vmi_check_page_type(__pa(pudp) >> PAGE_SHIFT, VMI_PAGE_PGD);
	vmi_ops.set_pte(pte, (pte_t *)pudp, VMI_PAGE_PDP);
}

static void vmi_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
	const pte_t pte = { 0 };
	vmi_check_page_type(__pa(ptep) >> PAGE_SHIFT, VMI_PAGE_PTE);
	vmi_ops.set_pte(pte, ptep, vmi_flags_addr(mm, addr, VMI_PAGE_PT, 0));
}

static void vmi_pmd_clear(pmd_t *pmd)
{
	const pte_t pte = { 0 };
	vmi_check_page_type(__pa(pmd) >> PAGE_SHIFT, VMI_PAGE_PMD);
	vmi_ops.set_pte(pte, (pte_t *)pmd, VMI_PAGE_PD);
}
#endif

#ifdef CONFIG_SMP
static void __devinit
vmi_startup_ipi_hook(int phys_apicid, unsigned long start_eip,
		     unsigned long start_esp)
{
	struct vmi_ap_state ap;

	/* Default everything to zero.  This is fine for most GPRs. */
	memset(&ap, 0, sizeof(struct vmi_ap_state));

	ap.gdtr_limit = GDT_SIZE - 1;
	ap.gdtr_base = (unsigned long) get_cpu_gdt_table(phys_apicid);

	ap.idtr_limit = IDT_ENTRIES * 8 - 1;
	ap.idtr_base = (unsigned long) idt_table;

	ap.ldtr = 0;

	ap.cs = __KERNEL_CS;
	ap.eip = (unsigned long) start_eip;
	ap.ss = __KERNEL_DS;
	ap.esp = (unsigned long) start_esp;

	ap.ds = __USER_DS;
	ap.es = __USER_DS;
	ap.fs = __KERNEL_PERCPU;
	ap.gs = 0;

	ap.eflags = 0;

#ifdef CONFIG_X86_PAE
	/* efer should match BSP efer. */
	if (cpu_has_nx) {
		unsigned l, h;
		rdmsr(MSR_EFER, l, h);
		ap.efer = (unsigned long long) h << 32 | l;
	}
#endif

	ap.cr3 = __pa(swapper_pg_dir);
	/* Protected mode, paging, AM, WP, NE, MP. */
	ap.cr0 = 0x80050023;
	ap.cr4 = mmu_cr4_features;
	vmi_ops.set_initial_ap_state((u32)&ap, phys_apicid);
}
#endif

static void vmi_set_lazy_mode(enum paravirt_lazy_mode mode)
{
	static DEFINE_PER_CPU(enum paravirt_lazy_mode, lazy_mode);

	if (!vmi_ops.set_lazy_mode)
		return;

	/* Modes should never nest or overlap */
	BUG_ON(__get_cpu_var(lazy_mode) && !(mode == PARAVIRT_LAZY_NONE ||
					     mode == PARAVIRT_LAZY_FLUSH));

	if (mode == PARAVIRT_LAZY_FLUSH) {
		vmi_ops.set_lazy_mode(0);
		vmi_ops.set_lazy_mode(__get_cpu_var(lazy_mode));
	} else {
		vmi_ops.set_lazy_mode(mode);
		__get_cpu_var(lazy_mode) = mode;
	}
}

static inline int __init check_vmi_rom(struct vrom_header *rom)
{
	struct pci_header *pci;
	struct pnp_header *pnp;
	const char *manufacturer = "UNKNOWN";
	const char *product = "UNKNOWN";
	const char *license = "unspecified";

	if (rom->rom_signature != 0xaa55)
		return 0;
	if (rom->vrom_signature != VMI_SIGNATURE)
		return 0;
	if (rom->api_version_maj != VMI_API_REV_MAJOR ||
	    rom->api_version_min+1 < VMI_API_REV_MINOR+1) {
		printk(KERN_WARNING "VMI: Found mismatched rom version %d.%d\n",
				rom->api_version_maj,
				rom->api_version_min);
		return 0;
	}

	/*
	 * Relying on the VMI_SIGNATURE field is not 100% safe, so check
	 * the PCI header and device type to make sure this is really a
	 * VMI device.
	 */
	if (!rom->pci_header_offs) {
		printk(KERN_WARNING "VMI: ROM does not contain PCI header.\n");
		return 0;
	}

	pci = (struct pci_header *)((char *)rom+rom->pci_header_offs);
	if (pci->vendorID != PCI_VENDOR_ID_VMWARE ||
	    pci->deviceID != PCI_DEVICE_ID_VMWARE_VMI) {
		/* Allow it to run... anyways, but warn */
		printk(KERN_WARNING "VMI: ROM from unknown manufacturer\n");
	}

	if (rom->pnp_header_offs) {
		pnp = (struct pnp_header *)((char *)rom+rom->pnp_header_offs);
		if (pnp->manufacturer_offset)
			manufacturer = (const char *)rom+pnp->manufacturer_offset;
		if (pnp->product_offset)
			product = (const char *)rom+pnp->product_offset;
	}

	if (rom->license_offs)
		license = (char *)rom+rom->license_offs;

	printk(KERN_INFO "VMI: Found %s %s, API version %d.%d, ROM version %d.%d\n",
		manufacturer, product,
		rom->api_version_maj, rom->api_version_min,
		pci->rom_version_maj, pci->rom_version_min);

	/* Don't allow BSD/MIT here for now because we don't want to end up
	   with any binary only shim layers */
	if (strcmp(license, "GPL") && strcmp(license, "GPL v2")) {
		printk(KERN_WARNING "VMI: Non GPL license `%s' found for ROM. Not used.\n",
			license);
		return 0;
	}

	return 1;
}

/*
 * Probe for the VMI option ROM
 */
static inline int __init probe_vmi_rom(void)
{
	unsigned long base;

	/* VMI ROM is in option ROM area, check signature */
	for (base = 0xC0000; base < 0xE0000; base += 2048) {
		struct vrom_header *romstart;
		romstart = (struct vrom_header *)isa_bus_to_virt(base);
		if (check_vmi_rom(romstart)) {
			vmi_rom = romstart;
			return 1;
		}
	}
	return 0;
}

/*
 * VMI setup common to all processors
 */
void vmi_bringup(void)
{
 	/* We must establish the lowmem mapping for MMU ops to work */
	if (vmi_ops.set_linear_mapping)
		vmi_ops.set_linear_mapping(0, (void *)__PAGE_OFFSET, max_low_pfn, 0);
}

/*
 * Return a pointer to a VMI function or NULL if unimplemented
 */
static void *vmi_get_function(int vmicall)
{
	u64 reloc;
	const struct vmi_relocation_info *rel = (struct vmi_relocation_info *)&reloc;
	reloc = call_vrom_long_func(vmi_rom, get_reloc,	vmicall);
	BUG_ON(rel->type == VMI_RELOCATION_JUMP_REL);
	if (rel->type == VMI_RELOCATION_CALL_REL)
		return (void *)rel->eip;
	else
		return NULL;
}

/*
 * Helper macro for making the VMI paravirt-ops fill code readable.
 * For unimplemented operations, fall back to default, unless nop
 * is returned by the ROM.
 */
#define para_fill(opname, vmicall)				\
do {								\
	reloc = call_vrom_long_func(vmi_rom, get_reloc,		\
				    VMI_CALL_##vmicall);	\
	if (rel->type == VMI_RELOCATION_CALL_REL) 		\
		paravirt_ops.opname = (void *)rel->eip;		\
	else if (rel->type == VMI_RELOCATION_NOP) 		\
		paravirt_ops.opname = (void *)vmi_nop;		\
	else if (rel->type != VMI_RELOCATION_NONE)		\
		printk(KERN_WARNING "VMI: Unknown relocation "	\
				    "type %d for " #vmicall"\n",\
					rel->type);		\
} while (0)

/*
 * Helper macro for making the VMI paravirt-ops fill code readable.
 * For cached operations which do not match the VMI ROM ABI and must
 * go through a tranlation stub.  Ignore NOPs, since it is not clear
 * a NOP * VMI function corresponds to a NOP paravirt-op when the
 * functions are not in 1-1 correspondence.
 */
#define para_wrap(opname, wrapper, cache, vmicall)		\
do {								\
	reloc = call_vrom_long_func(vmi_rom, get_reloc,		\
				    VMI_CALL_##vmicall);	\
	BUG_ON(rel->type == VMI_RELOCATION_JUMP_REL);		\
	if (rel->type == VMI_RELOCATION_CALL_REL) {		\
		paravirt_ops.opname = wrapper;			\
		vmi_ops.cache = (void *)rel->eip;		\
	}							\
} while (0)

/*
 * Activate the VMI interface and switch into paravirtualized mode
 */
static inline int __init activate_vmi(void)
{
	short kernel_cs;
	u64 reloc;
	const struct vmi_relocation_info *rel = (struct vmi_relocation_info *)&reloc;

	if (call_vrom_func(vmi_rom, vmi_init) != 0) {
		printk(KERN_ERR "VMI ROM failed to initialize!");
		return 0;
	}
	savesegment(cs, kernel_cs);

	paravirt_ops.paravirt_enabled = 1;
	paravirt_ops.kernel_rpl = kernel_cs & SEGMENT_RPL_MASK;

	paravirt_ops.patch = vmi_patch;
	paravirt_ops.name = "vmi";

	/*
	 * Many of these operations are ABI compatible with VMI.
	 * This means we can fill in the paravirt-ops with direct
	 * pointers into the VMI ROM.  If the calling convention for
	 * these operations changes, this code needs to be updated.
	 *
	 * Exceptions
	 *  CPUID paravirt-op uses pointers, not the native ISA
	 *  halt has no VMI equivalent; all VMI halts are "safe"
	 *  no MSR support yet - just trap and emulate.  VMI uses the
	 *    same ABI as the native ISA, but Linux wants exceptions
	 *    from bogus MSR read / write handled
	 *  rdpmc is not yet used in Linux
	 */

	/* CPUID is special, so very special it gets wrapped like a present */
	para_wrap(cpuid, vmi_cpuid, cpuid, CPUID);

	para_fill(clts, CLTS);
	para_fill(get_debugreg, GetDR);
	para_fill(set_debugreg, SetDR);
	para_fill(read_cr0, GetCR0);
	para_fill(read_cr2, GetCR2);
	para_fill(read_cr3, GetCR3);
	para_fill(read_cr4, GetCR4);
	para_fill(write_cr0, SetCR0);
	para_fill(write_cr2, SetCR2);
	para_fill(write_cr3, SetCR3);
	para_fill(write_cr4, SetCR4);
	para_fill(save_fl, GetInterruptMask);
	para_fill(restore_fl, SetInterruptMask);
	para_fill(irq_disable, DisableInterrupts);
	para_fill(irq_enable, EnableInterrupts);

	para_fill(wbinvd, WBINVD);
	para_fill(read_tsc, RDTSC);

	/* The following we emulate with trap and emulate for now */
	/* paravirt_ops.read_msr = vmi_rdmsr */
	/* paravirt_ops.write_msr = vmi_wrmsr */
	/* paravirt_ops.rdpmc = vmi_rdpmc */

	/* TR interface doesn't pass TR value, wrap */
	para_wrap(load_tr_desc, vmi_set_tr, set_tr, SetTR);

	/* LDT is special, too */
	para_wrap(set_ldt, vmi_set_ldt, _set_ldt, SetLDT);

	para_fill(load_gdt, SetGDT);
	para_fill(load_idt, SetIDT);
	para_fill(store_gdt, GetGDT);
	para_fill(store_idt, GetIDT);
	para_fill(store_tr, GetTR);
	paravirt_ops.load_tls = vmi_load_tls;
	para_fill(write_ldt_entry, WriteLDTEntry);
	para_fill(write_gdt_entry, WriteGDTEntry);
	para_fill(write_idt_entry, WriteIDTEntry);
	para_wrap(load_esp0, vmi_load_esp0, set_kernel_stack, UpdateKernelStack);
	para_fill(set_iopl_mask, SetIOPLMask);
	para_fill(io_delay, IODelay);
	para_wrap(set_lazy_mode, vmi_set_lazy_mode, set_lazy_mode, SetLazyMode);

	/* user and kernel flush are just handled with different flags to FlushTLB */
	para_wrap(flush_tlb_user, vmi_flush_tlb_user, _flush_tlb, FlushTLB);
	para_wrap(flush_tlb_kernel, vmi_flush_tlb_kernel, _flush_tlb, FlushTLB);
	para_fill(flush_tlb_single, InvalPage);

	/*
	 * Until a standard flag format can be agreed on, we need to
	 * implement these as wrappers in Linux.  Get the VMI ROM
	 * function pointers for the two backend calls.
	 */
#ifdef CONFIG_X86_PAE
	vmi_ops.set_pte = vmi_get_function(VMI_CALL_SetPxELong);
	vmi_ops.update_pte = vmi_get_function(VMI_CALL_UpdatePxELong);
#else
	vmi_ops.set_pte = vmi_get_function(VMI_CALL_SetPxE);
	vmi_ops.update_pte = vmi_get_function(VMI_CALL_UpdatePxE);
#endif

	if (vmi_ops.set_pte) {
		paravirt_ops.set_pte = vmi_set_pte;
		paravirt_ops.set_pte_at = vmi_set_pte_at;
		paravirt_ops.set_pmd = vmi_set_pmd;
#ifdef CONFIG_X86_PAE
		paravirt_ops.set_pte_atomic = vmi_set_pte_atomic;
		paravirt_ops.set_pte_present = vmi_set_pte_present;
		paravirt_ops.set_pud = vmi_set_pud;
		paravirt_ops.pte_clear = vmi_pte_clear;
		paravirt_ops.pmd_clear = vmi_pmd_clear;
#endif
	}

	if (vmi_ops.update_pte) {
		paravirt_ops.pte_update = vmi_update_pte;
		paravirt_ops.pte_update_defer = vmi_update_pte_defer;
	}

	vmi_ops.allocate_page = vmi_get_function(VMI_CALL_AllocatePage);
	if (vmi_ops.allocate_page) {
		paravirt_ops.alloc_pt = vmi_allocate_pt;
		paravirt_ops.alloc_pd = vmi_allocate_pd;
		paravirt_ops.alloc_pd_clone = vmi_allocate_pd_clone;
	}

	vmi_ops.release_page = vmi_get_function(VMI_CALL_ReleasePage);
	if (vmi_ops.release_page) {
		paravirt_ops.release_pt = vmi_release_pt;
		paravirt_ops.release_pd = vmi_release_pd;
	}

	/* Set linear is needed in all cases */
	vmi_ops.set_linear_mapping = vmi_get_function(VMI_CALL_SetLinearMapping);
#ifdef CONFIG_HIGHPTE
	if (vmi_ops.set_linear_mapping)
		paravirt_ops.kmap_atomic_pte = vmi_kmap_atomic_pte;
#endif

	/*
	 * These MUST always be patched.  Don't support indirect jumps
	 * through these operations, as the VMI interface may use either
	 * a jump or a call to get to these operations, depending on
	 * the backend.  They are performance critical anyway, so requiring
	 * a patch is not a big problem.
	 */
	paravirt_ops.irq_enable_sysexit = (void *)0xfeedbab0;
	paravirt_ops.iret = (void *)0xbadbab0;

#ifdef CONFIG_SMP
	para_wrap(startup_ipi_hook, vmi_startup_ipi_hook, set_initial_ap_state, SetInitialAPState);
#endif

#ifdef CONFIG_X86_LOCAL_APIC
	para_fill(apic_read, APICRead);
	para_fill(apic_write, APICWrite);
	para_fill(apic_write_atomic, APICWrite);
#endif

	/*
	 * Check for VMI timer functionality by probing for a cycle frequency method
	 */
	reloc = call_vrom_long_func(vmi_rom, get_reloc, VMI_CALL_GetCycleFrequency);
	if (!disable_vmi_timer && rel->type != VMI_RELOCATION_NONE) {
		vmi_timer_ops.get_cycle_frequency = (void *)rel->eip;
		vmi_timer_ops.get_cycle_counter =
			vmi_get_function(VMI_CALL_GetCycleCounter);
		vmi_timer_ops.get_wallclock =
			vmi_get_function(VMI_CALL_GetWallclockTime);
		vmi_timer_ops.wallclock_updated =
			vmi_get_function(VMI_CALL_WallclockUpdated);
		vmi_timer_ops.set_alarm = vmi_get_function(VMI_CALL_SetAlarm);
		vmi_timer_ops.cancel_alarm =
			 vmi_get_function(VMI_CALL_CancelAlarm);
		paravirt_ops.time_init = vmi_time_init;
		paravirt_ops.get_wallclock = vmi_get_wallclock;
		paravirt_ops.set_wallclock = vmi_set_wallclock;
#ifdef CONFIG_X86_LOCAL_APIC
		paravirt_ops.setup_boot_clock = vmi_time_bsp_init;
		paravirt_ops.setup_secondary_clock = vmi_time_ap_init;
#endif
		paravirt_ops.sched_clock = vmi_sched_clock;
 		paravirt_ops.get_cpu_khz = vmi_cpu_khz;

		/* We have true wallclock functions; disable CMOS clock sync */
		no_sync_cmos_clock = 1;
	} else {
		disable_noidle = 1;
		disable_vmi_timer = 1;
	}

	para_fill(safe_halt, Halt);

	/*
	 * Alternative instruction rewriting doesn't happen soon enough
	 * to convert VMI_IRET to a call instead of a jump; so we have
	 * to do this before IRQs get reenabled.  Fortunately, it is
	 * idempotent.
	 */
	apply_paravirt(__parainstructions, __parainstructions_end);

	vmi_bringup();

	return 1;
}

#undef para_fill

void __init vmi_init(void)
{
	unsigned long flags;

	if (!vmi_rom)
		probe_vmi_rom();
	else
		check_vmi_rom(vmi_rom);

	/* In case probing for or validating the ROM failed, basil */
	if (!vmi_rom)
		return;

	reserve_top_address(-vmi_rom->virtual_top);

	local_irq_save(flags);
	activate_vmi();

#ifdef CONFIG_X86_IO_APIC
	/* This is virtual hardware; timer routing is wired correctly */
	no_timer_check = 1;
#endif
	local_irq_restore(flags & X86_EFLAGS_IF);
}

static int __init parse_vmi(char *arg)
{
	if (!arg)
		return -EINVAL;

	if (!strcmp(arg, "disable_pge")) {
		clear_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
		disable_pge = 1;
	} else if (!strcmp(arg, "disable_pse")) {
		clear_bit(X86_FEATURE_PSE, boot_cpu_data.x86_capability);
		disable_pse = 1;
	} else if (!strcmp(arg, "disable_sep")) {
		clear_bit(X86_FEATURE_SEP, boot_cpu_data.x86_capability);
		disable_sep = 1;
	} else if (!strcmp(arg, "disable_tsc")) {
		clear_bit(X86_FEATURE_TSC, boot_cpu_data.x86_capability);
		disable_tsc = 1;
	} else if (!strcmp(arg, "disable_mtrr")) {
		clear_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability);
		disable_mtrr = 1;
	} else if (!strcmp(arg, "disable_timer")) {
		disable_vmi_timer = 1;
		disable_noidle = 1;
	} else if (!strcmp(arg, "disable_noidle"))
		disable_noidle = 1;
	return 0;
}

early_param("vmi", parse_vmi);