summaryrefslogtreecommitdiffstats
path: root/arch/x86/xen/setup.c
blob: 056d11faef21e96e5adf56a455a2827d2f97fbf1 (plain)
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
/*
 * Machine specific setup for xen
 *
 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/pm.h>
#include <linux/memblock.h>
#include <linux/cpuidle.h>
#include <linux/cpufreq.h>

#include <asm/elf.h>
#include <asm/vdso.h>
#include <asm/e820.h>
#include <asm/setup.h>
#include <asm/acpi.h>
#include <asm/numa.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>

#include <xen/xen.h>
#include <xen/page.h>
#include <xen/interface/callback.h>
#include <xen/interface/memory.h>
#include <xen/interface/physdev.h>
#include <xen/features.h>
#include "xen-ops.h"
#include "vdso.h"

/* These are code, but not functions.  Defined in entry.S */
extern const char xen_hypervisor_callback[];
extern const char xen_failsafe_callback[];
extern void xen_sysenter_target(void);
extern void xen_syscall_target(void);
extern void xen_syscall32_target(void);

/* Amount of extra memory space we add to the e820 ranges */
struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;

/* Number of pages released from the initial allocation. */
unsigned long xen_released_pages;

/* 
 * The maximum amount of extra memory compared to the base size.  The
 * main scaling factor is the size of struct page.  At extreme ratios
 * of base:extra, all the base memory can be filled with page
 * structures for the extra memory, leaving no space for anything
 * else.
 * 
 * 10x seems like a reasonable balance between scaling flexibility and
 * leaving a practically usable system.
 */
#define EXTRA_MEM_RATIO		(10)

static void __init xen_add_extra_mem(u64 start, u64 size)
{
	unsigned long pfn;
	int i;

	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
		/* Add new region. */
		if (xen_extra_mem[i].size == 0) {
			xen_extra_mem[i].start = start;
			xen_extra_mem[i].size  = size;
			break;
		}
		/* Append to existing region. */
		if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
			xen_extra_mem[i].size += size;
			break;
		}
	}
	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
		printk(KERN_WARNING "Warning: not enough extra memory regions\n");

	memblock_reserve(start, size);

	xen_max_p2m_pfn = PFN_DOWN(start + size);
	for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) {
		unsigned long mfn = pfn_to_mfn(pfn);

		if (WARN(mfn == pfn, "Trying to over-write 1-1 mapping (pfn: %lx)\n", pfn))
			continue;
		WARN(mfn != INVALID_P2M_ENTRY, "Trying to remove %lx which has %lx mfn!\n",
			pfn, mfn);

		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
	}
}

static unsigned long __init xen_do_chunk(unsigned long start,
					 unsigned long end, bool release)
{
	struct xen_memory_reservation reservation = {
		.address_bits = 0,
		.extent_order = 0,
		.domid        = DOMID_SELF
	};
	unsigned long len = 0;
	unsigned long pfn;
	int ret;

	for (pfn = start; pfn < end; pfn++) {
		unsigned long frame;
		unsigned long mfn = pfn_to_mfn(pfn);

		if (release) {
			/* Make sure pfn exists to start with */
			if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
				continue;
			frame = mfn;
		} else {
			if (mfn != INVALID_P2M_ENTRY)
				continue;
			frame = pfn;
		}
		set_xen_guest_handle(reservation.extent_start, &frame);
		reservation.nr_extents = 1;

		ret = HYPERVISOR_memory_op(release ? XENMEM_decrease_reservation : XENMEM_populate_physmap,
					   &reservation);
		WARN(ret != 1, "Failed to %s pfn %lx err=%d\n",
		     release ? "release" : "populate", pfn, ret);

		if (ret == 1) {
			if (!early_set_phys_to_machine(pfn, release ? INVALID_P2M_ENTRY : frame)) {
				if (release)
					break;
				set_xen_guest_handle(reservation.extent_start, &frame);
				reservation.nr_extents = 1;
				ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
							   &reservation);
				break;
			}
			len++;
		} else
			break;
	}
	if (len)
		printk(KERN_INFO "%s %lx-%lx pfn range: %lu pages %s\n",
		       release ? "Freeing" : "Populating",
		       start, end, len,
		       release ? "freed" : "added");

	return len;
}

static unsigned long __init xen_release_chunk(unsigned long start,
					      unsigned long end)
{
	return xen_do_chunk(start, end, true);
}

static unsigned long __init xen_populate_chunk(
	const struct e820entry *list, size_t map_size,
	unsigned long max_pfn, unsigned long *last_pfn,
	unsigned long credits_left)
{
	const struct e820entry *entry;
	unsigned int i;
	unsigned long done = 0;
	unsigned long dest_pfn;

	for (i = 0, entry = list; i < map_size; i++, entry++) {
		unsigned long s_pfn;
		unsigned long e_pfn;
		unsigned long pfns;
		long capacity;

		if (credits_left <= 0)
			break;

		if (entry->type != E820_RAM)
			continue;

		e_pfn = PFN_DOWN(entry->addr + entry->size);

		/* We only care about E820 after the xen_start_info->nr_pages */
		if (e_pfn <= max_pfn)
			continue;

		s_pfn = PFN_UP(entry->addr);
		/* If the E820 falls within the nr_pages, we want to start
		 * at the nr_pages PFN.
		 * If that would mean going past the E820 entry, skip it
		 */
		if (s_pfn <= max_pfn) {
			capacity = e_pfn - max_pfn;
			dest_pfn = max_pfn;
		} else {
			capacity = e_pfn - s_pfn;
			dest_pfn = s_pfn;
		}

		if (credits_left < capacity)
			capacity = credits_left;

		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
		done += pfns;
		*last_pfn = (dest_pfn + pfns);
		if (pfns < capacity)
			break;
		credits_left -= pfns;
	}
	return done;
}

static void __init xen_set_identity_and_release_chunk(
	unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
	unsigned long *released, unsigned long *identity)
{
	unsigned long pfn;

	/*
	 * If the PFNs are currently mapped, the VA mapping also needs
	 * to be updated to be 1:1.
	 */
	for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
		(void)HYPERVISOR_update_va_mapping(
			(unsigned long)__va(pfn << PAGE_SHIFT),
			mfn_pte(pfn, PAGE_KERNEL_IO), 0);

	if (start_pfn < nr_pages)
		*released += xen_release_chunk(
			start_pfn, min(end_pfn, nr_pages));

	*identity += set_phys_range_identity(start_pfn, end_pfn);
}

static unsigned long __init xen_set_identity_and_release(
	const struct e820entry *list, size_t map_size, unsigned long nr_pages)
{
	phys_addr_t start = 0;
	unsigned long released = 0;
	unsigned long identity = 0;
	const struct e820entry *entry;
	int i;

	/*
	 * Combine non-RAM regions and gaps until a RAM region (or the
	 * end of the map) is reached, then set the 1:1 map and
	 * release the pages (if available) in those non-RAM regions.
	 *
	 * The combined non-RAM regions are rounded to a whole number
	 * of pages so any partial pages are accessible via the 1:1
	 * mapping.  This is needed for some BIOSes that put (for
	 * example) the DMI tables in a reserved region that begins on
	 * a non-page boundary.
	 */
	for (i = 0, entry = list; i < map_size; i++, entry++) {
		phys_addr_t end = entry->addr + entry->size;
		if (entry->type == E820_RAM || i == map_size - 1) {
			unsigned long start_pfn = PFN_DOWN(start);
			unsigned long end_pfn = PFN_UP(end);

			if (entry->type == E820_RAM)
				end_pfn = PFN_UP(entry->addr);

			if (start_pfn < end_pfn)
				xen_set_identity_and_release_chunk(
					start_pfn, end_pfn, nr_pages,
					&released, &identity);

			start = end;
		}
	}

	if (released)
		printk(KERN_INFO "Released %lu pages of unused memory\n", released);
	if (identity)
		printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);

	return released;
}

static unsigned long __init xen_get_max_pages(void)
{
	unsigned long max_pages = MAX_DOMAIN_PAGES;
	domid_t domid = DOMID_SELF;
	int ret;

	/*
	 * For the initial domain we use the maximum reservation as
	 * the maximum page.
	 *
	 * For guest domains the current maximum reservation reflects
	 * the current maximum rather than the static maximum. In this
	 * case the e820 map provided to us will cover the static
	 * maximum region.
	 */
	if (xen_initial_domain()) {
		ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
		if (ret > 0)
			max_pages = ret;
	}

	return min(max_pages, MAX_DOMAIN_PAGES);
}

static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
{
	u64 end = start + size;

	/* Align RAM regions to page boundaries. */
	if (type == E820_RAM) {
		start = PAGE_ALIGN(start);
		end &= ~((u64)PAGE_SIZE - 1);
	}

	e820_add_region(start, end - start, type);
}

/**
 * machine_specific_memory_setup - Hook for machine specific memory setup.
 **/
char * __init xen_memory_setup(void)
{
	static struct e820entry map[E820MAX] __initdata;

	unsigned long max_pfn = xen_start_info->nr_pages;
	unsigned long long mem_end;
	int rc;
	struct xen_memory_map memmap;
	unsigned long max_pages;
	unsigned long last_pfn = 0;
	unsigned long extra_pages = 0;
	unsigned long populated;
	int i;
	int op;

	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
	mem_end = PFN_PHYS(max_pfn);

	memmap.nr_entries = E820MAX;
	set_xen_guest_handle(memmap.buffer, map);

	op = xen_initial_domain() ?
		XENMEM_machine_memory_map :
		XENMEM_memory_map;
	rc = HYPERVISOR_memory_op(op, &memmap);
	if (rc == -ENOSYS) {
		BUG_ON(xen_initial_domain());
		memmap.nr_entries = 1;
		map[0].addr = 0ULL;
		map[0].size = mem_end;
		/* 8MB slack (to balance backend allocations). */
		map[0].size += 8ULL << 20;
		map[0].type = E820_RAM;
		rc = 0;
	}
	BUG_ON(rc);

	/* Make sure the Xen-supplied memory map is well-ordered. */
	sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);

	max_pages = xen_get_max_pages();
	if (max_pages > max_pfn)
		extra_pages += max_pages - max_pfn;

	/*
	 * Set P2M for all non-RAM pages and E820 gaps to be identity
	 * type PFNs.  Any RAM pages that would be made inaccesible by
	 * this are first released.
	 */
	xen_released_pages = xen_set_identity_and_release(
		map, memmap.nr_entries, max_pfn);

	/*
	 * Populate back the non-RAM pages and E820 gaps that had been
	 * released. */
	populated = xen_populate_chunk(map, memmap.nr_entries,
			max_pfn, &last_pfn, xen_released_pages);

	xen_released_pages -= populated;
	extra_pages += xen_released_pages;

	if (last_pfn > max_pfn) {
		max_pfn = min(MAX_DOMAIN_PAGES, last_pfn);
		mem_end = PFN_PHYS(max_pfn);
	}
	/*
	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
	 * factor the base size.  On non-highmem systems, the base
	 * size is the full initial memory allocation; on highmem it
	 * is limited to the max size of lowmem, so that it doesn't
	 * get completely filled.
	 *
	 * In principle there could be a problem in lowmem systems if
	 * the initial memory is also very large with respect to
	 * lowmem, but we won't try to deal with that here.
	 */
	extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
			  extra_pages);
	i = 0;
	while (i < memmap.nr_entries) {
		u64 addr = map[i].addr;
		u64 size = map[i].size;
		u32 type = map[i].type;

		if (type == E820_RAM) {
			if (addr < mem_end) {
				size = min(size, mem_end - addr);
			} else if (extra_pages) {
				size = min(size, (u64)extra_pages * PAGE_SIZE);
				extra_pages -= size / PAGE_SIZE;
				xen_add_extra_mem(addr, size);
			} else
				type = E820_UNUSABLE;
		}

		xen_align_and_add_e820_region(addr, size, type);

		map[i].addr += size;
		map[i].size -= size;
		if (map[i].size == 0)
			i++;
	}

	/*
	 * In domU, the ISA region is normal, usable memory, but we
	 * reserve ISA memory anyway because too many things poke
	 * about in there.
	 */
	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
			E820_RESERVED);

	/*
	 * Reserve Xen bits:
	 *  - mfn_list
	 *  - xen_start_info
	 * See comment above "struct start_info" in <xen/interface/xen.h>
	 * We tried to make the the memblock_reserve more selective so
	 * that it would be clear what region is reserved. Sadly we ran
	 * in the problem wherein on a 64-bit hypervisor with a 32-bit
	 * initial domain, the pt_base has the cr3 value which is not
	 * neccessarily where the pagetable starts! As Jan put it: "
	 * Actually, the adjustment turns out to be correct: The page
	 * tables for a 32-on-64 dom0 get allocated in the order "first L1",
	 * "first L2", "first L3", so the offset to the page table base is
	 * indeed 2. When reading xen/include/public/xen.h's comment
	 * very strictly, this is not a violation (since there nothing is said
	 * that the first thing in the page table space is pointed to by
	 * pt_base; I admit that this seems to be implied though, namely
	 * do I think that it is implied that the page table space is the
	 * range [pt_base, pt_base + nt_pt_frames), whereas that
	 * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames),
	 * which - without a priori knowledge - the kernel would have
	 * difficulty to figure out)." - so lets just fall back to the
	 * easy way and reserve the whole region.
	 */
	memblock_reserve(__pa(xen_start_info->mfn_list),
			 xen_start_info->pt_base - xen_start_info->mfn_list);

	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

	return "Xen";
}

/*
 * Set the bit indicating "nosegneg" library variants should be used.
 * We only need to bother in pure 32-bit mode; compat 32-bit processes
 * can have un-truncated segments, so wrapping around is allowed.
 */
static void __init fiddle_vdso(void)
{
#ifdef CONFIG_X86_32
	u32 *mask;
	mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
	mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
#endif
}

static int register_callback(unsigned type, const void *func)
{
	struct callback_register callback = {
		.type = type,
		.address = XEN_CALLBACK(__KERNEL_CS, func),
		.flags = CALLBACKF_mask_events,
	};

	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
}

void xen_enable_sysenter(void)
{
	int ret;
	unsigned sysenter_feature;

#ifdef CONFIG_X86_32
	sysenter_feature = X86_FEATURE_SEP;
#else
	sysenter_feature = X86_FEATURE_SYSENTER32;
#endif

	if (!boot_cpu_has(sysenter_feature))
		return;

	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
	if(ret != 0)
		setup_clear_cpu_cap(sysenter_feature);
}

void xen_enable_syscall(void)
{
#ifdef CONFIG_X86_64
	int ret;

	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
	if (ret != 0) {
		printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
		/* Pretty fatal; 64-bit userspace has no other
		   mechanism for syscalls. */
	}

	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
		ret = register_callback(CALLBACKTYPE_syscall32,
					xen_syscall32_target);
		if (ret != 0)
			setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
	}
#endif /* CONFIG_X86_64 */
}

void __init xen_arch_setup(void)
{
	xen_panic_handler_init();

	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);

	if (!xen_feature(XENFEAT_auto_translated_physmap))
		HYPERVISOR_vm_assist(VMASST_CMD_enable,
				     VMASST_TYPE_pae_extended_cr3);

	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
	    register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
		BUG();

	xen_enable_sysenter();
	xen_enable_syscall();

#ifdef CONFIG_ACPI
	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
		disable_acpi();
	}
#endif

	memcpy(boot_command_line, xen_start_info->cmd_line,
	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);

	/* Set up idle, making sure it calls safe_halt() pvop */
	disable_cpuidle();
	disable_cpufreq();
	WARN_ON(xen_set_default_idle());
	fiddle_vdso();
#ifdef CONFIG_NUMA
	numa_off = 1;
#endif
}
OpenPOWER on IntegriCloud