aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/kvm/vmx.c
blob: 5561c5936c3de1451c6472ba88c6e6af3d287602 (plain) (tree)
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668























                                                                         
                     










                                                     
                    



































                                                                 
                    





                                                                   












                                                                               









                                                                           












































                                                                     
                    




























                                                                              
                    































































































































                                                                               
                     





























                                                                         
                    






                                                 
                                                                  












                                                       

                                                      


                                         
                 
                                                                  














                                                                      
                    

                                                                 















                                                       



                                           

                                                      


                                         
                 
                                                                 



























































































                                                                              
                           






























































































































































































                                                                                 
                                             







                                                                        
                    








































                                                                    
                    







































                                                                               
                    









































































                                                                        

                                                   


                                       











































































































































































































                                                                              
                    



































































                                                                            
                    

                                               
      






                                                             
                    


































































































































































































































































































































































































































































































































                                                                                                            
                    






















                                                                            
                    












                                                                 
                    



































                                                                           
                    


















































                                                                             
                    



















                                                                         
                     
















                                                                         
                    






































































































                                                                      




                                                           
                    






















                                                               
                                                         








                                 
/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * This module enables machines with Intel VT-x extensions to run virtual
 * machines without emulation or binary translation.
 *
 * Copyright (C) 2006 Qumranet, Inc.
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "kvm.h"
#include "vmx.h"
#include "kvm_vmx.h"
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <asm/io.h>
#include <asm/desc.h>

#include "segment_descriptor.h"

#define MSR_IA32_FEATURE_CONTROL 		0x03a

MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");

static DEFINE_PER_CPU(struct vmcs *, vmxarea);
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);

#ifdef CONFIG_X86_64
#define HOST_IS_64 1
#else
#define HOST_IS_64 0
#endif

static struct vmcs_descriptor {
	int size;
	int order;
	u32 revision_id;
} vmcs_descriptor;

#define VMX_SEGMENT_FIELD(seg)					\
	[VCPU_SREG_##seg] = {                                   \
		.selector = GUEST_##seg##_SELECTOR,		\
		.base = GUEST_##seg##_BASE,		   	\
		.limit = GUEST_##seg##_LIMIT,		   	\
		.ar_bytes = GUEST_##seg##_AR_BYTES,	   	\
	}

static struct kvm_vmx_segment_field {
	unsigned selector;
	unsigned base;
	unsigned limit;
	unsigned ar_bytes;
} kvm_vmx_segment_fields[] = {
	VMX_SEGMENT_FIELD(CS),
	VMX_SEGMENT_FIELD(DS),
	VMX_SEGMENT_FIELD(ES),
	VMX_SEGMENT_FIELD(FS),
	VMX_SEGMENT_FIELD(GS),
	VMX_SEGMENT_FIELD(SS),
	VMX_SEGMENT_FIELD(TR),
	VMX_SEGMENT_FIELD(LDTR),
};

static const u32 vmx_msr_index[] = {
#ifdef CONFIG_X86_64
	MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR, MSR_KERNEL_GS_BASE,
#endif
	MSR_EFER, MSR_K6_STAR,
};
#define NR_VMX_MSR (sizeof(vmx_msr_index) / sizeof(*vmx_msr_index))

static inline int is_page_fault(u32 intr_info)
{
	return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK |
			     INTR_INFO_VALID_MASK)) ==
		(INTR_TYPE_EXCEPTION | PF_VECTOR | INTR_INFO_VALID_MASK);
}

static inline int is_external_interrupt(u32 intr_info)
{
	return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
		== (INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
}

static struct vmx_msr_entry *find_msr_entry(struct kvm_vcpu *vcpu, u32 msr)
{
	int i;

	for (i = 0; i < vcpu->nmsrs; ++i)
		if (vcpu->guest_msrs[i].index == msr)
			return &vcpu->guest_msrs[i];
	return 0;
}

static void vmcs_clear(struct vmcs *vmcs)
{
	u64 phys_addr = __pa(vmcs);
	u8 error;

	asm volatile (ASM_VMX_VMCLEAR_RAX "; setna %0"
		      : "=g"(error) : "a"(&phys_addr), "m"(phys_addr)
		      : "cc", "memory");
	if (error)
		printk(KERN_ERR "kvm: vmclear fail: %p/%llx\n",
		       vmcs, phys_addr);
}

static void __vcpu_clear(void *arg)
{
	struct kvm_vcpu *vcpu = arg;
	int cpu = smp_processor_id();

	if (vcpu->cpu == cpu)
		vmcs_clear(vcpu->vmcs);
	if (per_cpu(current_vmcs, cpu) == vcpu->vmcs)
		per_cpu(current_vmcs, cpu) = NULL;
}

static unsigned long vmcs_readl(unsigned long field)
{
	unsigned long value;

	asm volatile (ASM_VMX_VMREAD_RDX_RAX
		      : "=a"(value) : "d"(field) : "cc");
	return value;
}

static u16 vmcs_read16(unsigned long field)
{
	return vmcs_readl(field);
}

static u32 vmcs_read32(unsigned long field)
{
	return vmcs_readl(field);
}

static u64 vmcs_read64(unsigned long field)
{
#ifdef CONFIG_X86_64
	return vmcs_readl(field);
#else
	return vmcs_readl(field) | ((u64)vmcs_readl(field+1) << 32);
#endif
}

static void vmcs_writel(unsigned long field, unsigned long value)
{
	u8 error;

	asm volatile (ASM_VMX_VMWRITE_RAX_RDX "; setna %0"
		       : "=q"(error) : "a"(value), "d"(field) : "cc" );
	if (error)
		printk(KERN_ERR "vmwrite error: reg %lx value %lx (err %d)\n",
		       field, value, vmcs_read32(VM_INSTRUCTION_ERROR));
}

static void vmcs_write16(unsigned long field, u16 value)
{
	vmcs_writel(field, value);
}

static void vmcs_write32(unsigned long field, u32 value)
{
	vmcs_writel(field, value);
}

static void vmcs_write64(unsigned long field, u64 value)
{
#ifdef CONFIG_X86_64
	vmcs_writel(field, value);
#else
	vmcs_writel(field, value);
	asm volatile ("");
	vmcs_writel(field+1, value >> 32);
#endif
}

/*
 * Switches to specified vcpu, until a matching vcpu_put(), but assumes
 * vcpu mutex is already taken.
 */
static struct kvm_vcpu *vmx_vcpu_load(struct kvm_vcpu *vcpu)
{
	u64 phys_addr = __pa(vcpu->vmcs);
	int cpu;

	cpu = get_cpu();

	if (vcpu->cpu != cpu) {
		smp_call_function(__vcpu_clear, vcpu, 0, 1);
		vcpu->launched = 0;
	}

	if (per_cpu(current_vmcs, cpu) != vcpu->vmcs) {
		u8 error;

		per_cpu(current_vmcs, cpu) = vcpu->vmcs;
		asm volatile (ASM_VMX_VMPTRLD_RAX "; setna %0"
			      : "=g"(error) : "a"(&phys_addr), "m"(phys_addr)
			      : "cc");
		if (error)
			printk(KERN_ERR "kvm: vmptrld %p/%llx fail\n",
			       vcpu->vmcs, phys_addr);
	}

	if (vcpu->cpu != cpu) {
		struct descriptor_table dt;
		unsigned long sysenter_esp;

		vcpu->cpu = cpu;
		/*
		 * Linux uses per-cpu TSS and GDT, so set these when switching
		 * processors.
		 */
		vmcs_writel(HOST_TR_BASE, read_tr_base()); /* 22.2.4 */
		get_gdt(&dt);
		vmcs_writel(HOST_GDTR_BASE, dt.base);   /* 22.2.4 */

		rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp);
		vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */
	}
	return vcpu;
}

static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
{
	put_cpu();
}

static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)
{
	return vmcs_readl(GUEST_RFLAGS);
}

static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
	vmcs_writel(GUEST_RFLAGS, rflags);
}

static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
{
	unsigned long rip;
	u32 interruptibility;

	rip = vmcs_readl(GUEST_RIP);
	rip += vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
	vmcs_writel(GUEST_RIP, rip);

	/*
	 * We emulated an instruction, so temporary interrupt blocking
	 * should be removed, if set.
	 */
	interruptibility = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
	if (interruptibility & 3)
		vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
			     interruptibility & ~3);
}

static void vmx_inject_gp(struct kvm_vcpu *vcpu, unsigned error_code)
{
	printk(KERN_DEBUG "inject_general_protection: rip 0x%lx\n",
	       vmcs_readl(GUEST_RIP));
	vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code);
	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
		     GP_VECTOR |
		     INTR_TYPE_EXCEPTION |
		     INTR_INFO_DELIEVER_CODE_MASK |
		     INTR_INFO_VALID_MASK);
}

/*
 * reads and returns guest's timestamp counter "register"
 * guest_tsc = host_tsc + tsc_offset    -- 21.3
 */
static u64 guest_read_tsc(void)
{
	u64 host_tsc, tsc_offset;

	rdtscll(host_tsc);
	tsc_offset = vmcs_read64(TSC_OFFSET);
	return host_tsc + tsc_offset;
}

/*
 * writes 'guest_tsc' into guest's timestamp counter "register"
 * guest_tsc = host_tsc + tsc_offset ==> tsc_offset = guest_tsc - host_tsc
 */
static void guest_write_tsc(u64 guest_tsc)
{
	u64 host_tsc;

	rdtscll(host_tsc);
	vmcs_write64(TSC_OFFSET, guest_tsc - host_tsc);
}

static void reload_tss(void)
{
#ifndef CONFIG_X86_64

	/*
	 * VT restores TR but not its size.  Useless.
	 */
	struct descriptor_table gdt;
	struct segment_descriptor *descs;

	get_gdt(&gdt);
	descs = (void *)gdt.base;
	descs[GDT_ENTRY_TSS].type = 9; /* available TSS */
	load_TR_desc();
#endif
}

/*
 * Reads an msr value (of 'msr_index') into 'pdata'.
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
{
	u64 data;
	struct vmx_msr_entry *msr;

	if (!pdata) {
		printk(KERN_ERR "BUG: get_msr called with NULL pdata\n");
		return -EINVAL;
	}

	switch (msr_index) {
#ifdef CONFIG_X86_64
	case MSR_FS_BASE:
		data = vmcs_readl(GUEST_FS_BASE);
		break;
	case MSR_GS_BASE:
		data = vmcs_readl(GUEST_GS_BASE);
		break;
	case MSR_EFER:
		return kvm_get_msr_common(vcpu, msr_index, pdata);
#endif
	case MSR_IA32_TIME_STAMP_COUNTER:
		data = guest_read_tsc();
		break;
	case MSR_IA32_SYSENTER_CS:
		data = vmcs_read32(GUEST_SYSENTER_CS);
		break;
	case MSR_IA32_SYSENTER_EIP:
		data = vmcs_read32(GUEST_SYSENTER_EIP);
		break;
	case MSR_IA32_SYSENTER_ESP:
		data = vmcs_read32(GUEST_SYSENTER_ESP);
		break;
	default:
		msr = find_msr_entry(vcpu, msr_index);
		if (msr) {
			data = msr->data;
			break;
		}
		return kvm_get_msr_common(vcpu, msr_index, pdata);
	}

	*pdata = data;
	return 0;
}

/*
 * Writes msr value into into the appropriate "register".
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
{
	struct vmx_msr_entry *msr;
	switch (msr_index) {
#ifdef CONFIG_X86_64
	case MSR_EFER:
		return kvm_set_msr_common(vcpu, msr_index, data);
	case MSR_FS_BASE:
		vmcs_writel(GUEST_FS_BASE, data);
		break;
	case MSR_GS_BASE:
		vmcs_writel(GUEST_GS_BASE, data);
		break;
#endif
	case MSR_IA32_SYSENTER_CS:
		vmcs_write32(GUEST_SYSENTER_CS, data);
		break;
	case MSR_IA32_SYSENTER_EIP:
		vmcs_write32(GUEST_SYSENTER_EIP, data);
		break;
	case MSR_IA32_SYSENTER_ESP:
		vmcs_write32(GUEST_SYSENTER_ESP, data);
		break;
	case MSR_IA32_TIME_STAMP_COUNTER: {
		guest_write_tsc(data);
		break;
	}
	default:
		msr = find_msr_entry(vcpu, msr_index);
		if (msr) {
			msr->data = data;
			break;
		}
		return kvm_set_msr_common(vcpu, msr_index, data);
		msr->data = data;
		break;
	}

	return 0;
}

/*
 * Sync the rsp and rip registers into the vcpu structure.  This allows
 * registers to be accessed by indexing vcpu->regs.
 */
static void vcpu_load_rsp_rip(struct kvm_vcpu *vcpu)
{
	vcpu->regs[VCPU_REGS_RSP] = vmcs_readl(GUEST_RSP);
	vcpu->rip = vmcs_readl(GUEST_RIP);
}

/*
 * Syncs rsp and rip back into the vmcs.  Should be called after possible
 * modification.
 */
static void vcpu_put_rsp_rip(struct kvm_vcpu *vcpu)
{
	vmcs_writel(GUEST_RSP, vcpu->regs[VCPU_REGS_RSP]);
	vmcs_writel(GUEST_RIP, vcpu->rip);
}

static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
{
	unsigned long dr7 = 0x400;
	u32 exception_bitmap;
	int old_singlestep;

	exception_bitmap = vmcs_read32(EXCEPTION_BITMAP);
	old_singlestep = vcpu->guest_debug.singlestep;

	vcpu->guest_debug.enabled = dbg->enabled;
	if (vcpu->guest_debug.enabled) {
		int i;

		dr7 |= 0x200;  /* exact */
		for (i = 0; i < 4; ++i) {
			if (!dbg->breakpoints[i].enabled)
				continue;
			vcpu->guest_debug.bp[i] = dbg->breakpoints[i].address;
			dr7 |= 2 << (i*2);    /* global enable */
			dr7 |= 0 << (i*4+16); /* execution breakpoint */
		}

		exception_bitmap |= (1u << 1);  /* Trap debug exceptions */

		vcpu->guest_debug.singlestep = dbg->singlestep;
	} else {
		exception_bitmap &= ~(1u << 1); /* Ignore debug exceptions */
		vcpu->guest_debug.singlestep = 0;
	}

	if (old_singlestep && !vcpu->guest_debug.singlestep) {
		unsigned long flags;

		flags = vmcs_readl(GUEST_RFLAGS);
		flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
		vmcs_writel(GUEST_RFLAGS, flags);
	}

	vmcs_write32(EXCEPTION_BITMAP, exception_bitmap);
	vmcs_writel(GUEST_DR7, dr7);

	return 0;
}

static __init int cpu_has_kvm_support(void)
{
	unsigned long ecx = cpuid_ecx(1);
	return test_bit(5, &ecx); /* CPUID.1:ECX.VMX[bit 5] -> VT */
}

static __init int vmx_disabled_by_bios(void)
{
	u64 msr;

	rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
	return (msr & 5) == 1; /* locked but not enabled */
}

static __init void hardware_enable(void *garbage)
{
	int cpu = raw_smp_processor_id();
	u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
	u64 old;

	rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
	if ((old & 5) != 5)
		/* enable and lock */
		wrmsrl(MSR_IA32_FEATURE_CONTROL, old | 5);
	write_cr4(read_cr4() | CR4_VMXE); /* FIXME: not cpu hotplug safe */
	asm volatile (ASM_VMX_VMXON_RAX : : "a"(&phys_addr), "m"(phys_addr)
		      : "memory", "cc");
}

static void hardware_disable(void *garbage)
{
	asm volatile (ASM_VMX_VMXOFF : : : "cc");
}

static __init void setup_vmcs_descriptor(void)
{
	u32 vmx_msr_low, vmx_msr_high;

	rdmsr(MSR_IA32_VMX_BASIC_MSR, vmx_msr_low, vmx_msr_high);
	vmcs_descriptor.size = vmx_msr_high & 0x1fff;
	vmcs_descriptor.order = get_order(vmcs_descriptor.size);
	vmcs_descriptor.revision_id = vmx_msr_low;
};

static struct vmcs *alloc_vmcs_cpu(int cpu)
{
	int node = cpu_to_node(cpu);
	struct page *pages;
	struct vmcs *vmcs;

	pages = alloc_pages_node(node, GFP_KERNEL, vmcs_descriptor.order);
	if (!pages)
		return NULL;
	vmcs = page_address(pages);
	memset(vmcs, 0, vmcs_descriptor.size);
	vmcs->revision_id = vmcs_descriptor.revision_id; /* vmcs revision id */
	return vmcs;
}

static struct vmcs *alloc_vmcs(void)
{
	return alloc_vmcs_cpu(smp_processor_id());
}

static void free_vmcs(struct vmcs *vmcs)
{
	free_pages((unsigned long)vmcs, vmcs_descriptor.order);
}

static __exit void free_kvm_area(void)
{
	int cpu;

	for_each_online_cpu(cpu)
		free_vmcs(per_cpu(vmxarea, cpu));
}

extern struct vmcs *alloc_vmcs_cpu(int cpu);

static __init int alloc_kvm_area(void)
{
	int cpu;

	for_each_online_cpu(cpu) {
		struct vmcs *vmcs;

		vmcs = alloc_vmcs_cpu(cpu);
		if (!vmcs) {
			free_kvm_area();
			return -ENOMEM;
		}

		per_cpu(vmxarea, cpu) = vmcs;
	}
	return 0;
}

static __init int hardware_setup(void)
{
	setup_vmcs_descriptor();
	return alloc_kvm_area();
}

static __exit void hardware_unsetup(void)
{
	free_kvm_area();
}

static void update_exception_bitmap(struct kvm_vcpu *vcpu)
{
	if (vcpu->rmode.active)
		vmcs_write32(EXCEPTION_BITMAP, ~0);
	else
		vmcs_write32(EXCEPTION_BITMAP, 1 << PF_VECTOR);
}

static void fix_pmode_dataseg(int seg, struct kvm_save_segment *save)
{
	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];

	if (vmcs_readl(sf->base) == save->base) {
		vmcs_write16(sf->selector, save->selector);
		vmcs_writel(sf->base, save->base);
		vmcs_write32(sf->limit, save->limit);
		vmcs_write32(sf->ar_bytes, save->ar);
	} else {
		u32 dpl = (vmcs_read16(sf->selector) & SELECTOR_RPL_MASK)
			<< AR_DPL_SHIFT;
		vmcs_write32(sf->ar_bytes, 0x93 | dpl);
	}
}

static void enter_pmode(struct kvm_vcpu *vcpu)
{
	unsigned long flags;

	vcpu->rmode.active = 0;

	vmcs_writel(GUEST_TR_BASE, vcpu->rmode.tr.base);
	vmcs_write32(GUEST_TR_LIMIT, vcpu->rmode.tr.limit);
	vmcs_write32(GUEST_TR_AR_BYTES, vcpu->rmode.tr.ar);

	flags = vmcs_readl(GUEST_RFLAGS);
	flags &= ~(IOPL_MASK | X86_EFLAGS_VM);
	flags |= (vcpu->rmode.save_iopl << IOPL_SHIFT);
	vmcs_writel(GUEST_RFLAGS, flags);

	vmcs_writel(GUEST_CR4, (vmcs_readl(GUEST_CR4) & ~CR4_VME_MASK) |
			(vmcs_readl(CR4_READ_SHADOW) & CR4_VME_MASK));

	update_exception_bitmap(vcpu);

	fix_pmode_dataseg(VCPU_SREG_ES, &vcpu->rmode.es);
	fix_pmode_dataseg(VCPU_SREG_DS, &vcpu->rmode.ds);
	fix_pmode_dataseg(VCPU_SREG_GS, &vcpu->rmode.gs);
	fix_pmode_dataseg(VCPU_SREG_FS, &vcpu->rmode.fs);

	vmcs_write16(GUEST_SS_SELECTOR, 0);
	vmcs_write32(GUEST_SS_AR_BYTES, 0x93);

	vmcs_write16(GUEST_CS_SELECTOR,
		     vmcs_read16(GUEST_CS_SELECTOR) & ~SELECTOR_RPL_MASK);
	vmcs_write32(GUEST_CS_AR_BYTES, 0x9b);
}

static int rmode_tss_base(struct kvm* kvm)
{
	gfn_t base_gfn = kvm->memslots[0].base_gfn + kvm->memslots[0].npages - 3;
	return base_gfn << PAGE_SHIFT;
}

static void fix_rmode_seg(int seg, struct kvm_save_segment *save)
{
	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];

	save->selector = vmcs_read16(sf->selector);
	save->base = vmcs_readl(sf->base);
	save->limit = vmcs_read32(sf->limit);
	save->ar = vmcs_read32(sf->ar_bytes);
	vmcs_write16(sf->selector, vmcs_readl(sf->base) >> 4);
	vmcs_write32(sf->limit, 0xffff);
	vmcs_write32(sf->ar_bytes, 0xf3);
}

static void enter_rmode(struct kvm_vcpu *vcpu)
{
	unsigned long flags;

	vcpu->rmode.active = 1;

	vcpu->rmode.tr.base = vmcs_readl(GUEST_TR_BASE);
	vmcs_writel(GUEST_TR_BASE, rmode_tss_base(vcpu->kvm));

	vcpu->rmode.tr.limit = vmcs_read32(GUEST_TR_LIMIT);
	vmcs_write32(GUEST_TR_LIMIT, RMODE_TSS_SIZE - 1);

	vcpu->rmode.tr.ar = vmcs_read32(GUEST_TR_AR_BYTES);
	vmcs_write32(GUEST_TR_AR_BYTES, 0x008b);

	flags = vmcs_readl(GUEST_RFLAGS);
	vcpu->rmode.save_iopl = (flags & IOPL_MASK) >> IOPL_SHIFT;

	flags |= IOPL_MASK | X86_EFLAGS_VM;

	vmcs_writel(GUEST_RFLAGS, flags);
	vmcs_writel(GUEST_CR4, vmcs_readl(GUEST_CR4) | CR4_VME_MASK);
	update_exception_bitmap(vcpu);

	vmcs_write16(GUEST_SS_SELECTOR, vmcs_readl(GUEST_SS_BASE) >> 4);
	vmcs_write32(GUEST_SS_LIMIT, 0xffff);
	vmcs_write32(GUEST_SS_AR_BYTES, 0xf3);

	vmcs_write32(GUEST_CS_AR_BYTES, 0xf3);
	vmcs_write32(GUEST_CS_LIMIT, 0xffff);
	vmcs_write16(GUEST_CS_SELECTOR, vmcs_readl(GUEST_CS_BASE) >> 4);

	fix_rmode_seg(VCPU_SREG_ES, &vcpu->rmode.es);
	fix_rmode_seg(VCPU_SREG_DS, &vcpu->rmode.ds);
	fix_rmode_seg(VCPU_SREG_GS, &vcpu->rmode.gs);
	fix_rmode_seg(VCPU_SREG_FS, &vcpu->rmode.fs);
}

#ifdef CONFIG_X86_64

static void enter_lmode(struct kvm_vcpu *vcpu)
{
	u32 guest_tr_ar;

	guest_tr_ar = vmcs_read32(GUEST_TR_AR_BYTES);
	if ((guest_tr_ar & AR_TYPE_MASK) != AR_TYPE_BUSY_64_TSS) {
		printk(KERN_DEBUG "%s: tss fixup for long mode. \n",
		       __FUNCTION__);
		vmcs_write32(GUEST_TR_AR_BYTES,
			     (guest_tr_ar & ~AR_TYPE_MASK)
			     | AR_TYPE_BUSY_64_TSS);
	}

	vcpu->shadow_efer |= EFER_LMA;

	find_msr_entry(vcpu, MSR_EFER)->data |= EFER_LMA | EFER_LME;
	vmcs_write32(VM_ENTRY_CONTROLS,
		     vmcs_read32(VM_ENTRY_CONTROLS)
		     | VM_ENTRY_CONTROLS_IA32E_MASK);
}

static void exit_lmode(struct kvm_vcpu *vcpu)
{
	vcpu->shadow_efer &= ~EFER_LMA;

	vmcs_write32(VM_ENTRY_CONTROLS,
		     vmcs_read32(VM_ENTRY_CONTROLS)
		     & ~VM_ENTRY_CONTROLS_IA32E_MASK);
}

#endif

static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
	if (vcpu->rmode.active && (cr0 & CR0_PE_MASK))
		enter_pmode(vcpu);

	if (!vcpu->rmode.active && !(cr0 & CR0_PE_MASK))
		enter_rmode(vcpu);

#ifdef CONFIG_X86_64
	if (vcpu->shadow_efer & EFER_LME) {
		if (!is_paging(vcpu) && (cr0 & CR0_PG_MASK))
			enter_lmode(vcpu);
		if (is_paging(vcpu) && !(cr0 & CR0_PG_MASK))
			exit_lmode(vcpu);
	}
#endif

	vmcs_writel(CR0_READ_SHADOW, cr0);
	vmcs_writel(GUEST_CR0,
		    (cr0 & ~KVM_GUEST_CR0_MASK) | KVM_VM_CR0_ALWAYS_ON);
	vcpu->cr0 = cr0;
}

/*
 * Used when restoring the VM to avoid corrupting segment registers
 */
static void vmx_set_cr0_no_modeswitch(struct kvm_vcpu *vcpu, unsigned long cr0)
{
	vcpu->rmode.active = ((cr0 & CR0_PE_MASK) == 0);
	update_exception_bitmap(vcpu);
	vmcs_writel(CR0_READ_SHADOW, cr0);
	vmcs_writel(GUEST_CR0,
		    (cr0 & ~KVM_GUEST_CR0_MASK) | KVM_VM_CR0_ALWAYS_ON);
	vcpu->cr0 = cr0;
}

static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
{
	vmcs_writel(GUEST_CR3, cr3);
}

static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
	vmcs_writel(CR4_READ_SHADOW, cr4);
	vmcs_writel(GUEST_CR4, cr4 | (vcpu->rmode.active ?
		    KVM_RMODE_VM_CR4_ALWAYS_ON : KVM_PMODE_VM_CR4_ALWAYS_ON));
	vcpu->cr4 = cr4;
}

#ifdef CONFIG_X86_64

static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
	struct vmx_msr_entry *msr = find_msr_entry(vcpu, MSR_EFER);

	vcpu->shadow_efer = efer;
	if (efer & EFER_LMA) {
		vmcs_write32(VM_ENTRY_CONTROLS,
				     vmcs_read32(VM_ENTRY_CONTROLS) |
				     VM_ENTRY_CONTROLS_IA32E_MASK);
		msr->data = efer;

	} else {
		vmcs_write32(VM_ENTRY_CONTROLS,
				     vmcs_read32(VM_ENTRY_CONTROLS) &
				     ~VM_ENTRY_CONTROLS_IA32E_MASK);

		msr->data = efer & ~EFER_LME;
	}
}

#endif

static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
{
	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];

	return vmcs_readl(sf->base);
}

static void vmx_get_segment(struct kvm_vcpu *vcpu,
			    struct kvm_segment *var, int seg)
{
	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
	u32 ar;

	var->base = vmcs_readl(sf->base);
	var->limit = vmcs_read32(sf->limit);
	var->selector = vmcs_read16(sf->selector);
	ar = vmcs_read32(sf->ar_bytes);
	if (ar & AR_UNUSABLE_MASK)
		ar = 0;
	var->type = ar & 15;
	var->s = (ar >> 4) & 1;
	var->dpl = (ar >> 5) & 3;
	var->present = (ar >> 7) & 1;
	var->avl = (ar >> 12) & 1;
	var->l = (ar >> 13) & 1;
	var->db = (ar >> 14) & 1;
	var->g = (ar >> 15) & 1;
	var->unusable = (ar >> 16) & 1;
}

static void vmx_set_segment(struct kvm_vcpu *vcpu,
			    struct kvm_segment *var, int seg)
{
	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
	u32 ar;

	vmcs_writel(sf->base, var->base);
	vmcs_write32(sf->limit, var->limit);
	vmcs_write16(sf->selector, var->selector);
	if (var->unusable)
		ar = 1 << 16;
	else {
		ar = var->type & 15;
		ar |= (var->s & 1) << 4;
		ar |= (var->dpl & 3) << 5;
		ar |= (var->present & 1) << 7;
		ar |= (var->avl & 1) << 12;
		ar |= (var->l & 1) << 13;
		ar |= (var->db & 1) << 14;
		ar |= (var->g & 1) << 15;
	}
	if (ar == 0) /* a 0 value means unusable */
		ar = AR_UNUSABLE_MASK;
	vmcs_write32(sf->ar_bytes, ar);
}

static void vmx_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
{
	u32 ar = vmcs_read32(GUEST_CS_AR_BYTES);

	*db = (ar >> 14) & 1;
	*l = (ar >> 13) & 1;
}

static void vmx_get_idt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
	dt->limit = vmcs_read32(GUEST_IDTR_LIMIT);
	dt->base = vmcs_readl(GUEST_IDTR_BASE);
}

static void vmx_set_idt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
	vmcs_write32(GUEST_IDTR_LIMIT, dt->limit);
	vmcs_writel(GUEST_IDTR_BASE, dt->base);
}

static void vmx_get_gdt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
	dt->limit = vmcs_read32(GUEST_GDTR_LIMIT);
	dt->base = vmcs_readl(GUEST_GDTR_BASE);
}

static void vmx_set_gdt(struct kvm_vcpu *vcpu, struct descriptor_table *dt)
{
	vmcs_write32(GUEST_GDTR_LIMIT, dt->limit);
	vmcs_writel(GUEST_GDTR_BASE, dt->base);
}

static int init_rmode_tss(struct kvm* kvm)
{
	struct page *p1, *p2, *p3;
	gfn_t fn = rmode_tss_base(kvm) >> PAGE_SHIFT;
	char *page;

	p1 = _gfn_to_page(kvm, fn++);
	p2 = _gfn_to_page(kvm, fn++);
	p3 = _gfn_to_page(kvm, fn);

	if (!p1 || !p2 || !p3) {
		kvm_printf(kvm,"%s: gfn_to_page failed\n", __FUNCTION__);
		return 0;
	}

	page = kmap_atomic(p1, KM_USER0);
	memset(page, 0, PAGE_SIZE);
	*(u16*)(page + 0x66) = TSS_BASE_SIZE + TSS_REDIRECTION_SIZE;
	kunmap_atomic(page, KM_USER0);

	page = kmap_atomic(p2, KM_USER0);
	memset(page, 0, PAGE_SIZE);
	kunmap_atomic(page, KM_USER0);

	page = kmap_atomic(p3, KM_USER0);
	memset(page, 0, PAGE_SIZE);
	*(page + RMODE_TSS_SIZE - 2 * PAGE_SIZE - 1) = ~0;
	kunmap_atomic(page, KM_USER0);

	return 1;
}

static void vmcs_write32_fixedbits(u32 msr, u32 vmcs_field, u32 val)
{
	u32 msr_high, msr_low;

	rdmsr(msr, msr_low, msr_high);

	val &= msr_high;
	val |= msr_low;
	vmcs_write32(vmcs_field, val);
}

static void seg_setup(int seg)
{
	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];

	vmcs_write16(sf->selector, 0);
	vmcs_writel(sf->base, 0);
	vmcs_write32(sf->limit, 0xffff);
	vmcs_write32(sf->ar_bytes, 0x93);
}

/*
 * Sets up the vmcs for emulated real mode.
 */
static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
{
	u32 host_sysenter_cs;
	u32 junk;
	unsigned long a;
	struct descriptor_table dt;
	int i;
	int ret = 0;
	int nr_good_msrs;
	extern asmlinkage void kvm_vmx_return(void);

	if (!init_rmode_tss(vcpu->kvm)) {
		ret = -ENOMEM;
		goto out;
	}

	memset(vcpu->regs, 0, sizeof(vcpu->regs));
	vcpu->regs[VCPU_REGS_RDX] = get_rdx_init_val();
	vcpu->cr8 = 0;
	vcpu->apic_base = 0xfee00000 |
			/*for vcpu 0*/ MSR_IA32_APICBASE_BSP |
			MSR_IA32_APICBASE_ENABLE;

	fx_init(vcpu);

	/*
	 * GUEST_CS_BASE should really be 0xffff0000, but VT vm86 mode
	 * insists on having GUEST_CS_BASE == GUEST_CS_SELECTOR << 4.  Sigh.
	 */
	vmcs_write16(GUEST_CS_SELECTOR, 0xf000);
	vmcs_writel(GUEST_CS_BASE, 0x000f0000);
	vmcs_write32(GUEST_CS_LIMIT, 0xffff);
	vmcs_write32(GUEST_CS_AR_BYTES, 0x9b);

	seg_setup(VCPU_SREG_DS);
	seg_setup(VCPU_SREG_ES);
	seg_setup(VCPU_SREG_FS);
	seg_setup(VCPU_SREG_GS);
	seg_setup(VCPU_SREG_SS);

	vmcs_write16(GUEST_TR_SELECTOR, 0);
	vmcs_writel(GUEST_TR_BASE, 0);
	vmcs_write32(GUEST_TR_LIMIT, 0xffff);
	vmcs_write32(GUEST_TR_AR_BYTES, 0x008b);

	vmcs_write16(GUEST_LDTR_SELECTOR, 0);
	vmcs_writel(GUEST_LDTR_BASE, 0);
	vmcs_write32(GUEST_LDTR_LIMIT, 0xffff);
	vmcs_write32(GUEST_LDTR_AR_BYTES, 0x00082);

	vmcs_write32(GUEST_SYSENTER_CS, 0);
	vmcs_writel(GUEST_SYSENTER_ESP, 0);
	vmcs_writel(GUEST_SYSENTER_EIP, 0);

	vmcs_writel(GUEST_RFLAGS, 0x02);
	vmcs_writel(GUEST_RIP, 0xfff0);
	vmcs_writel(GUEST_RSP, 0);

	vmcs_writel(GUEST_CR3, 0);

	//todo: dr0 = dr1 = dr2 = dr3 = 0; dr6 = 0xffff0ff0
	vmcs_writel(GUEST_DR7, 0x400);

	vmcs_writel(GUEST_GDTR_BASE, 0);
	vmcs_write32(GUEST_GDTR_LIMIT, 0xffff);

	vmcs_writel(GUEST_IDTR_BASE, 0);
	vmcs_write32(GUEST_IDTR_LIMIT, 0xffff);

	vmcs_write32(GUEST_ACTIVITY_STATE, 0);
	vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, 0);
	vmcs_write32(GUEST_PENDING_DBG_EXCEPTIONS, 0);

	/* I/O */
	vmcs_write64(IO_BITMAP_A, 0);
	vmcs_write64(IO_BITMAP_B, 0);

	guest_write_tsc(0);

	vmcs_write64(VMCS_LINK_POINTER, -1ull); /* 22.3.1.5 */

	/* Special registers */
	vmcs_write64(GUEST_IA32_DEBUGCTL, 0);

	/* Control */
	vmcs_write32_fixedbits(MSR_IA32_VMX_PINBASED_CTLS_MSR,
			       PIN_BASED_VM_EXEC_CONTROL,
			       PIN_BASED_EXT_INTR_MASK   /* 20.6.1 */
			       | PIN_BASED_NMI_EXITING   /* 20.6.1 */
			);
	vmcs_write32_fixedbits(MSR_IA32_VMX_PROCBASED_CTLS_MSR,
			       CPU_BASED_VM_EXEC_CONTROL,
			       CPU_BASED_HLT_EXITING         /* 20.6.2 */
			       | CPU_BASED_CR8_LOAD_EXITING    /* 20.6.2 */
			       | CPU_BASED_CR8_STORE_EXITING   /* 20.6.2 */
			       | CPU_BASED_UNCOND_IO_EXITING   /* 20.6.2 */
			       | CPU_BASED_INVDPG_EXITING
			       | CPU_BASED_MOV_DR_EXITING
			       | CPU_BASED_USE_TSC_OFFSETING   /* 21.3 */
			);

	vmcs_write32(EXCEPTION_BITMAP, 1 << PF_VECTOR);
	vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, 0);
	vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, 0);
	vmcs_write32(CR3_TARGET_COUNT, 0);           /* 22.2.1 */

	vmcs_writel(HOST_CR0, read_cr0());  /* 22.2.3 */
	vmcs_writel(HOST_CR4, read_cr4());  /* 22.2.3, 22.2.5 */
	vmcs_writel(HOST_CR3, read_cr3());  /* 22.2.3  FIXME: shadow tables */

	vmcs_write16(HOST_CS_SELECTOR, __KERNEL_CS);  /* 22.2.4 */
	vmcs_write16(HOST_DS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
	vmcs_write16(HOST_ES_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
	vmcs_write16(HOST_FS_SELECTOR, read_fs());    /* 22.2.4 */
	vmcs_write16(HOST_GS_SELECTOR, read_gs());    /* 22.2.4 */
	vmcs_write16(HOST_SS_SELECTOR, __KERNEL_DS);  /* 22.2.4 */
#ifdef CONFIG_X86_64
	rdmsrl(MSR_FS_BASE, a);
	vmcs_writel(HOST_FS_BASE, a); /* 22.2.4 */
	rdmsrl(MSR_GS_BASE, a);
	vmcs_writel(HOST_GS_BASE, a); /* 22.2.4 */
#else
	vmcs_writel(HOST_FS_BASE, 0); /* 22.2.4 */
	vmcs_writel(HOST_GS_BASE, 0); /* 22.2.4 */
#endif

	vmcs_write16(HOST_TR_SELECTOR, GDT_ENTRY_TSS*8);  /* 22.2.4 */

	get_idt(&dt);
	vmcs_writel(HOST_IDTR_BASE, dt.base);   /* 22.2.4 */


	vmcs_writel(HOST_RIP, (unsigned long)kvm_vmx_return); /* 22.2.5 */

	rdmsr(MSR_IA32_SYSENTER_CS, host_sysenter_cs, junk);
	vmcs_write32(HOST_IA32_SYSENTER_CS, host_sysenter_cs);
	rdmsrl(MSR_IA32_SYSENTER_ESP, a);
	vmcs_writel(HOST_IA32_SYSENTER_ESP, a);   /* 22.2.3 */
	rdmsrl(MSR_IA32_SYSENTER_EIP, a);
	vmcs_writel(HOST_IA32_SYSENTER_EIP, a);   /* 22.2.3 */

	ret = -ENOMEM;
	vcpu->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!vcpu->guest_msrs)
		goto out;
	vcpu->host_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!vcpu->host_msrs)
		goto out_free_guest_msrs;

	for (i = 0; i < NR_VMX_MSR; ++i) {
		u32 index = vmx_msr_index[i];
		u32 data_low, data_high;
		u64 data;
		int j = vcpu->nmsrs;

		if (rdmsr_safe(index, &data_low, &data_high) < 0)
			continue;
		data = data_low | ((u64)data_high << 32);
		vcpu->host_msrs[j].index = index;
		vcpu->host_msrs[j].reserved = 0;
		vcpu->host_msrs[j].data = data;
		vcpu->guest_msrs[j] = vcpu->host_msrs[j];
		++vcpu->nmsrs;
	}
	printk(KERN_DEBUG "kvm: msrs: %d\n", vcpu->nmsrs);

	nr_good_msrs = vcpu->nmsrs - NR_BAD_MSRS;
	vmcs_writel(VM_ENTRY_MSR_LOAD_ADDR,
		    virt_to_phys(vcpu->guest_msrs + NR_BAD_MSRS));
	vmcs_writel(VM_EXIT_MSR_STORE_ADDR,
		    virt_to_phys(vcpu->guest_msrs + NR_BAD_MSRS));
	vmcs_writel(VM_EXIT_MSR_LOAD_ADDR,
		    virt_to_phys(vcpu->host_msrs + NR_BAD_MSRS));
	vmcs_write32_fixedbits(MSR_IA32_VMX_EXIT_CTLS_MSR, VM_EXIT_CONTROLS,
		     	       (HOST_IS_64 << 9));  /* 22.2,1, 20.7.1 */
	vmcs_write32(VM_EXIT_MSR_STORE_COUNT, nr_good_msrs); /* 22.2.2 */
	vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, nr_good_msrs);  /* 22.2.2 */
	vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, nr_good_msrs); /* 22.2.2 */


	/* 22.2.1, 20.8.1 */
	vmcs_write32_fixedbits(MSR_IA32_VMX_ENTRY_CTLS_MSR,
                               VM_ENTRY_CONTROLS, 0);
	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0);  /* 22.2.1 */

#ifdef CONFIG_X86_64
	vmcs_writel(VIRTUAL_APIC_PAGE_ADDR, 0);
	vmcs_writel(TPR_THRESHOLD, 0);
#endif

	vmcs_writel(CR0_GUEST_HOST_MASK, KVM_GUEST_CR0_MASK);
	vmcs_writel(CR4_GUEST_HOST_MASK, KVM_GUEST_CR4_MASK);

	vcpu->cr0 = 0x60000010;
	vmx_set_cr0(vcpu, vcpu->cr0); // enter rmode
	vmx_set_cr4(vcpu, 0);
#ifdef CONFIG_X86_64
	vmx_set_efer(vcpu, 0);
#endif

	return 0;

out_free_guest_msrs:
	kfree(vcpu->guest_msrs);
out:
	return ret;
}

static void inject_rmode_irq(struct kvm_vcpu *vcpu, int irq)
{
	u16 ent[2];
	u16 cs;
	u16 ip;
	unsigned long flags;
	unsigned long ss_base = vmcs_readl(GUEST_SS_BASE);
	u16 sp =  vmcs_readl(GUEST_RSP);
	u32 ss_limit = vmcs_read32(GUEST_SS_LIMIT);

	if (sp > ss_limit || sp - 6 > sp) {
		vcpu_printf(vcpu, "%s: #SS, rsp 0x%lx ss 0x%lx limit 0x%x\n",
			    __FUNCTION__,
			    vmcs_readl(GUEST_RSP),
			    vmcs_readl(GUEST_SS_BASE),
			    vmcs_read32(GUEST_SS_LIMIT));
		return;
	}

	if (kvm_read_guest(vcpu, irq * sizeof(ent), sizeof(ent), &ent) !=
								sizeof(ent)) {
		vcpu_printf(vcpu, "%s: read guest err\n", __FUNCTION__);
		return;
	}

	flags =  vmcs_readl(GUEST_RFLAGS);
	cs =  vmcs_readl(GUEST_CS_BASE) >> 4;
	ip =  vmcs_readl(GUEST_RIP);


	if (kvm_write_guest(vcpu, ss_base + sp - 2, 2, &flags) != 2 ||
	    kvm_write_guest(vcpu, ss_base + sp - 4, 2, &cs) != 2 ||
	    kvm_write_guest(vcpu, ss_base + sp - 6, 2, &ip) != 2) {
		vcpu_printf(vcpu, "%s: write guest err\n", __FUNCTION__);
		return;
	}

	vmcs_writel(GUEST_RFLAGS, flags &
		    ~( X86_EFLAGS_IF | X86_EFLAGS_AC | X86_EFLAGS_TF));
	vmcs_write16(GUEST_CS_SELECTOR, ent[1]) ;
	vmcs_writel(GUEST_CS_BASE, ent[1] << 4);
	vmcs_writel(GUEST_RIP, ent[0]);
	vmcs_writel(GUEST_RSP, (vmcs_readl(GUEST_RSP) & ~0xffff) | (sp - 6));
}

static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
{
	int word_index = __ffs(vcpu->irq_summary);
	int bit_index = __ffs(vcpu->irq_pending[word_index]);
	int irq = word_index * BITS_PER_LONG + bit_index;

	clear_bit(bit_index, &vcpu->irq_pending[word_index]);
	if (!vcpu->irq_pending[word_index])
		clear_bit(word_index, &vcpu->irq_summary);

	if (vcpu->rmode.active) {
		inject_rmode_irq(vcpu, irq);
		return;
	}
	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
			irq | INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
}

static void kvm_try_inject_irq(struct kvm_vcpu *vcpu)
{
	if ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF)
	    && (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0)
		/*
		 * Interrupts enabled, and not blocked by sti or mov ss. Good.
		 */
		kvm_do_inject_irq(vcpu);
	else
		/*
		 * Interrupts blocked.  Wait for unblock.
		 */
		vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
			     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)
			     | CPU_BASED_VIRTUAL_INTR_PENDING);
}

static void kvm_guest_debug_pre(struct kvm_vcpu *vcpu)
{
	struct kvm_guest_debug *dbg = &vcpu->guest_debug;

	set_debugreg(dbg->bp[0], 0);
	set_debugreg(dbg->bp[1], 1);
	set_debugreg(dbg->bp[2], 2);
	set_debugreg(dbg->bp[3], 3);

	if (dbg->singlestep) {
		unsigned long flags;

		flags = vmcs_readl(GUEST_RFLAGS);
		flags |= X86_EFLAGS_TF | X86_EFLAGS_RF;
		vmcs_writel(GUEST_RFLAGS, flags);
	}
}

static int handle_rmode_exception(struct kvm_vcpu *vcpu,
				  int vec, u32 err_code)
{
	if (!vcpu->rmode.active)
		return 0;

	if (vec == GP_VECTOR && err_code == 0)
		if (emulate_instruction(vcpu, NULL, 0, 0) == EMULATE_DONE)
			return 1;
	return 0;
}

static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u32 intr_info, error_code;
	unsigned long cr2, rip;
	u32 vect_info;
	enum emulation_result er;

	vect_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
	intr_info = vmcs_read32(VM_EXIT_INTR_INFO);

	if ((vect_info & VECTORING_INFO_VALID_MASK) &&
						!is_page_fault(intr_info)) {
		printk(KERN_ERR "%s: unexpected, vectoring info 0x%x "
		       "intr info 0x%x\n", __FUNCTION__, vect_info, intr_info);
	}

	if (is_external_interrupt(vect_info)) {
		int irq = vect_info & VECTORING_INFO_VECTOR_MASK;
		set_bit(irq, vcpu->irq_pending);
		set_bit(irq / BITS_PER_LONG, &vcpu->irq_summary);
	}

	if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200) { /* nmi */
		asm ("int $2");
		return 1;
	}
	error_code = 0;
	rip = vmcs_readl(GUEST_RIP);
	if (intr_info & INTR_INFO_DELIEVER_CODE_MASK)
		error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
	if (is_page_fault(intr_info)) {
		cr2 = vmcs_readl(EXIT_QUALIFICATION);

		spin_lock(&vcpu->kvm->lock);
		if (!vcpu->mmu.page_fault(vcpu, cr2, error_code)) {
			spin_unlock(&vcpu->kvm->lock);
			return 1;
		}

		er = emulate_instruction(vcpu, kvm_run, cr2, error_code);
		spin_unlock(&vcpu->kvm->lock);

		switch (er) {
		case EMULATE_DONE:
			return 1;
		case EMULATE_DO_MMIO:
			++kvm_stat.mmio_exits;
			kvm_run->exit_reason = KVM_EXIT_MMIO;
			return 0;
		 case EMULATE_FAIL:
			vcpu_printf(vcpu, "%s: emulate fail\n", __FUNCTION__);
			break;
		default:
			BUG();
		}
	}

	if (vcpu->rmode.active &&
	    handle_rmode_exception(vcpu, intr_info & INTR_INFO_VECTOR_MASK,
								error_code))
		return 1;

	if ((intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VECTOR_MASK)) == (INTR_TYPE_EXCEPTION | 1)) {
		kvm_run->exit_reason = KVM_EXIT_DEBUG;
		return 0;
	}
	kvm_run->exit_reason = KVM_EXIT_EXCEPTION;
	kvm_run->ex.exception = intr_info & INTR_INFO_VECTOR_MASK;
	kvm_run->ex.error_code = error_code;
	return 0;
}

static int handle_external_interrupt(struct kvm_vcpu *vcpu,
				     struct kvm_run *kvm_run)
{
	++kvm_stat.irq_exits;
	return 1;
}


static int get_io_count(struct kvm_vcpu *vcpu, u64 *count)
{
	u64 inst;
	gva_t rip;
	int countr_size;
	int i, n;

	if ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_VM)) {
		countr_size = 2;
	} else {
		u32 cs_ar = vmcs_read32(GUEST_CS_AR_BYTES);

		countr_size = (cs_ar & AR_L_MASK) ? 8:
			      (cs_ar & AR_DB_MASK) ? 4: 2;
	}

	rip =  vmcs_readl(GUEST_RIP);
	if (countr_size != 8)
		rip += vmcs_readl(GUEST_CS_BASE);

	n = kvm_read_guest(vcpu, rip, sizeof(inst), &inst);

	for (i = 0; i < n; i++) {
		switch (((u8*)&inst)[i]) {
		case 0xf0:
		case 0xf2:
		case 0xf3:
		case 0x2e:
		case 0x36:
		case 0x3e:
		case 0x26:
		case 0x64:
		case 0x65:
		case 0x66:
			break;
		case 0x67:
			countr_size = (countr_size == 2) ? 4: (countr_size >> 1);
		default:
			goto done;
		}
	}
	return 0;
done:
	countr_size *= 8;
	*count = vcpu->regs[VCPU_REGS_RCX] & (~0ULL >> (64 - countr_size));
	return 1;
}

static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u64 exit_qualification;

	++kvm_stat.io_exits;
	exit_qualification = vmcs_read64(EXIT_QUALIFICATION);
	kvm_run->exit_reason = KVM_EXIT_IO;
	if (exit_qualification & 8)
		kvm_run->io.direction = KVM_EXIT_IO_IN;
	else
		kvm_run->io.direction = KVM_EXIT_IO_OUT;
	kvm_run->io.size = (exit_qualification & 7) + 1;
	kvm_run->io.string = (exit_qualification & 16) != 0;
	kvm_run->io.string_down
		= (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_DF) != 0;
	kvm_run->io.rep = (exit_qualification & 32) != 0;
	kvm_run->io.port = exit_qualification >> 16;
	if (kvm_run->io.string) {
		if (!get_io_count(vcpu, &kvm_run->io.count))
			return 1;
		kvm_run->io.address = vmcs_readl(GUEST_LINEAR_ADDRESS);
	} else
		kvm_run->io.value = vcpu->regs[VCPU_REGS_RAX]; /* rax */
	return 0;
}

static int handle_invlpg(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u64 address = vmcs_read64(EXIT_QUALIFICATION);
	int instruction_length = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
	spin_lock(&vcpu->kvm->lock);
	vcpu->mmu.inval_page(vcpu, address);
	spin_unlock(&vcpu->kvm->lock);
	vmcs_writel(GUEST_RIP, vmcs_readl(GUEST_RIP) + instruction_length);
	return 1;
}

static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u64 exit_qualification;
	int cr;
	int reg;

	exit_qualification = vmcs_read64(EXIT_QUALIFICATION);
	cr = exit_qualification & 15;
	reg = (exit_qualification >> 8) & 15;
	switch ((exit_qualification >> 4) & 3) {
	case 0: /* mov to cr */
		switch (cr) {
		case 0:
			vcpu_load_rsp_rip(vcpu);
			set_cr0(vcpu, vcpu->regs[reg]);
			skip_emulated_instruction(vcpu);
			return 1;
		case 3:
			vcpu_load_rsp_rip(vcpu);
			set_cr3(vcpu, vcpu->regs[reg]);
			skip_emulated_instruction(vcpu);
			return 1;
		case 4:
			vcpu_load_rsp_rip(vcpu);
			set_cr4(vcpu, vcpu->regs[reg]);
			skip_emulated_instruction(vcpu);
			return 1;
		case 8:
			vcpu_load_rsp_rip(vcpu);
			set_cr8(vcpu, vcpu->regs[reg]);
			skip_emulated_instruction(vcpu);
			return 1;
		};
		break;
	case 1: /*mov from cr*/
		switch (cr) {
		case 3:
			vcpu_load_rsp_rip(vcpu);
			vcpu->regs[reg] = vcpu->cr3;
			vcpu_put_rsp_rip(vcpu);
			skip_emulated_instruction(vcpu);
			return 1;
		case 8:
			printk(KERN_DEBUG "handle_cr: read CR8 "
			       "cpu erratum AA15\n");
			vcpu_load_rsp_rip(vcpu);
			vcpu->regs[reg] = vcpu->cr8;
			vcpu_put_rsp_rip(vcpu);
			skip_emulated_instruction(vcpu);
			return 1;
		}
		break;
	case 3: /* lmsw */
		lmsw(vcpu, (exit_qualification >> LMSW_SOURCE_DATA_SHIFT) & 0x0f);

		skip_emulated_instruction(vcpu);
		return 1;
	default:
		break;
	}
	kvm_run->exit_reason = 0;
	printk(KERN_ERR "kvm: unhandled control register: op %d cr %d\n",
	       (int)(exit_qualification >> 4) & 3, cr);
	return 0;
}

static int handle_dr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u64 exit_qualification;
	unsigned long val;
	int dr, reg;

	/*
	 * FIXME: this code assumes the host is debugging the guest.
	 *        need to deal with guest debugging itself too.
	 */
	exit_qualification = vmcs_read64(EXIT_QUALIFICATION);
	dr = exit_qualification & 7;
	reg = (exit_qualification >> 8) & 15;
	vcpu_load_rsp_rip(vcpu);
	if (exit_qualification & 16) {
		/* mov from dr */
		switch (dr) {
		case 6:
			val = 0xffff0ff0;
			break;
		case 7:
			val = 0x400;
			break;
		default:
			val = 0;
		}
		vcpu->regs[reg] = val;
	} else {
		/* mov to dr */
	}
	vcpu_put_rsp_rip(vcpu);
	skip_emulated_instruction(vcpu);
	return 1;
}

static int handle_cpuid(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	kvm_run->exit_reason = KVM_EXIT_CPUID;
	return 0;
}

static int handle_rdmsr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u32 ecx = vcpu->regs[VCPU_REGS_RCX];
	u64 data;

	if (vmx_get_msr(vcpu, ecx, &data)) {
		vmx_inject_gp(vcpu, 0);
		return 1;
	}

	/* FIXME: handling of bits 32:63 of rax, rdx */
	vcpu->regs[VCPU_REGS_RAX] = data & -1u;
	vcpu->regs[VCPU_REGS_RDX] = (data >> 32) & -1u;
	skip_emulated_instruction(vcpu);
	return 1;
}

static int handle_wrmsr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u32 ecx = vcpu->regs[VCPU_REGS_RCX];
	u64 data = (vcpu->regs[VCPU_REGS_RAX] & -1u)
		| ((u64)(vcpu->regs[VCPU_REGS_RDX] & -1u) << 32);

	if (vmx_set_msr(vcpu, ecx, data) != 0) {
		vmx_inject_gp(vcpu, 0);
		return 1;
	}

	skip_emulated_instruction(vcpu);
	return 1;
}

static int handle_interrupt_window(struct kvm_vcpu *vcpu,
				   struct kvm_run *kvm_run)
{
	/* Turn off interrupt window reporting. */
	vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
		     vmcs_read32(CPU_BASED_VM_EXEC_CONTROL)
		     & ~CPU_BASED_VIRTUAL_INTR_PENDING);
	return 1;
}

static int handle_halt(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	skip_emulated_instruction(vcpu);
	if (vcpu->irq_summary && (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF))
		return 1;

	kvm_run->exit_reason = KVM_EXIT_HLT;
	return 0;
}

/*
 * The exit handlers return 1 if the exit was handled fully and guest execution
 * may resume.  Otherwise they set the kvm_run parameter to indicate what needs
 * to be done to userspace and return 0.
 */
static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu,
				      struct kvm_run *kvm_run) = {
	[EXIT_REASON_EXCEPTION_NMI]           = handle_exception,
	[EXIT_REASON_EXTERNAL_INTERRUPT]      = handle_external_interrupt,
	[EXIT_REASON_IO_INSTRUCTION]          = handle_io,
	[EXIT_REASON_INVLPG]                  = handle_invlpg,
	[EXIT_REASON_CR_ACCESS]               = handle_cr,
	[EXIT_REASON_DR_ACCESS]               = handle_dr,
	[EXIT_REASON_CPUID]                   = handle_cpuid,
	[EXIT_REASON_MSR_READ]                = handle_rdmsr,
	[EXIT_REASON_MSR_WRITE]               = handle_wrmsr,
	[EXIT_REASON_PENDING_INTERRUPT]       = handle_interrupt_window,
	[EXIT_REASON_HLT]                     = handle_halt,
};

static const int kvm_vmx_max_exit_handlers =
	sizeof(kvm_vmx_exit_handlers) / sizeof(*kvm_vmx_exit_handlers);

/*
 * The guest has exited.  See if we can fix it or if we need userspace
 * assistance.
 */
static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
{
	u32 vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
	u32 exit_reason = vmcs_read32(VM_EXIT_REASON);

	if ( (vectoring_info & VECTORING_INFO_VALID_MASK) &&
				exit_reason != EXIT_REASON_EXCEPTION_NMI )
		printk(KERN_WARNING "%s: unexpected, valid vectoring info and "
		       "exit reason is 0x%x\n", __FUNCTION__, exit_reason);
	kvm_run->instruction_length = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
	if (exit_reason < kvm_vmx_max_exit_handlers
	    && kvm_vmx_exit_handlers[exit_reason])
		return kvm_vmx_exit_handlers[exit_reason](vcpu, kvm_run);
	else {
		kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
		kvm_run->hw.hardware_exit_reason = exit_reason;
	}
	return 0;
}

static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	u8 fail;
	u16 fs_sel, gs_sel, ldt_sel;
	int fs_gs_ldt_reload_needed;

again:
	/*
	 * Set host fs and gs selectors.  Unfortunately, 22.2.3 does not
	 * allow segment selectors with cpl > 0 or ti == 1.
	 */
	fs_sel = read_fs();
	gs_sel = read_gs();
	ldt_sel = read_ldt();
	fs_gs_ldt_reload_needed = (fs_sel & 7) | (gs_sel & 7) | ldt_sel;
	if (!fs_gs_ldt_reload_needed) {
		vmcs_write16(HOST_FS_SELECTOR, fs_sel);
		vmcs_write16(HOST_GS_SELECTOR, gs_sel);
	} else {
		vmcs_write16(HOST_FS_SELECTOR, 0);
		vmcs_write16(HOST_GS_SELECTOR, 0);
	}

#ifdef CONFIG_X86_64
	vmcs_writel(HOST_FS_BASE, read_msr(MSR_FS_BASE));
	vmcs_writel(HOST_GS_BASE, read_msr(MSR_GS_BASE));
#else
	vmcs_writel(HOST_FS_BASE, segment_base(fs_sel));
	vmcs_writel(HOST_GS_BASE, segment_base(gs_sel));
#endif

	if (vcpu->irq_summary &&
	    !(vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) & INTR_INFO_VALID_MASK))
		kvm_try_inject_irq(vcpu);

	if (vcpu->guest_debug.enabled)
		kvm_guest_debug_pre(vcpu);

	fx_save(vcpu->host_fx_image);
	fx_restore(vcpu->guest_fx_image);

	save_msrs(vcpu->host_msrs, vcpu->nmsrs);
	load_msrs(vcpu->guest_msrs, NR_BAD_MSRS);

	asm (
		/* Store host registers */
		"pushf \n\t"
#ifdef CONFIG_X86_64
		"push %%rax; push %%rbx; push %%rdx;"
		"push %%rsi; push %%rdi; push %%rbp;"
		"push %%r8;  push %%r9;  push %%r10; push %%r11;"
		"push %%r12; push %%r13; push %%r14; push %%r15;"
		"push %%rcx \n\t"
		ASM_VMX_VMWRITE_RSP_RDX "\n\t"
#else
		"pusha; push %%ecx \n\t"
		ASM_VMX_VMWRITE_RSP_RDX "\n\t"
#endif
		/* Check if vmlaunch of vmresume is needed */
		"cmp $0, %1 \n\t"
		/* Load guest registers.  Don't clobber flags. */
#ifdef CONFIG_X86_64
		"mov %c[cr2](%3), %%rax \n\t"
		"mov %%rax, %%cr2 \n\t"
		"mov %c[rax](%3), %%rax \n\t"
		"mov %c[rbx](%3), %%rbx \n\t"
		"mov %c[rdx](%3), %%rdx \n\t"
		"mov %c[rsi](%3), %%rsi \n\t"
		"mov %c[rdi](%3), %%rdi \n\t"
		"mov %c[rbp](%3), %%rbp \n\t"
		"mov %c[r8](%3),  %%r8  \n\t"
		"mov %c[r9](%3),  %%r9  \n\t"
		"mov %c[r10](%3), %%r10 \n\t"
		"mov %c[r11](%3), %%r11 \n\t"
		"mov %c[r12](%3), %%r12 \n\t"
		"mov %c[r13](%3), %%r13 \n\t"
		"mov %c[r14](%3), %%r14 \n\t"
		"mov %c[r15](%3), %%r15 \n\t"
		"mov %c[rcx](%3), %%rcx \n\t" /* kills %3 (rcx) */
#else
		"mov %c[cr2](%3), %%eax \n\t"
		"mov %%eax,   %%cr2 \n\t"
		"mov %c[rax](%3), %%eax \n\t"
		"mov %c[rbx](%3), %%ebx \n\t"
		"mov %c[rdx](%3), %%edx \n\t"
		"mov %c[rsi](%3), %%esi \n\t"
		"mov %c[rdi](%3), %%edi \n\t"
		"mov %c[rbp](%3), %%ebp \n\t"
		"mov %c[rcx](%3), %%ecx \n\t" /* kills %3 (ecx) */
#endif
		/* Enter guest mode */
		"jne launched \n\t"
		ASM_VMX_VMLAUNCH "\n\t"
		"jmp kvm_vmx_return \n\t"
		"launched: " ASM_VMX_VMRESUME "\n\t"
		".globl kvm_vmx_return \n\t"
		"kvm_vmx_return: "
		/* Save guest registers, load host registers, keep flags */
#ifdef CONFIG_X86_64
		"xchg %3,     0(%%rsp) \n\t"
		"mov %%rax, %c[rax](%3) \n\t"
		"mov %%rbx, %c[rbx](%3) \n\t"
		"pushq 0(%%rsp); popq %c[rcx](%3) \n\t"
		"mov %%rdx, %c[rdx](%3) \n\t"
		"mov %%rsi, %c[rsi](%3) \n\t"
		"mov %%rdi, %c[rdi](%3) \n\t"
		"mov %%rbp, %c[rbp](%3) \n\t"
		"mov %%r8,  %c[r8](%3) \n\t"
		"mov %%r9,  %c[r9](%3) \n\t"
		"mov %%r10, %c[r10](%3) \n\t"
		"mov %%r11, %c[r11](%3) \n\t"
		"mov %%r12, %c[r12](%3) \n\t"
		"mov %%r13, %c[r13](%3) \n\t"
		"mov %%r14, %c[r14](%3) \n\t"
		"mov %%r15, %c[r15](%3) \n\t"
		"mov %%cr2, %%rax   \n\t"
		"mov %%rax, %c[cr2](%3) \n\t"
		"mov 0(%%rsp), %3 \n\t"

		"pop  %%rcx; pop  %%r15; pop  %%r14; pop  %%r13; pop  %%r12;"
		"pop  %%r11; pop  %%r10; pop  %%r9;  pop  %%r8;"
		"pop  %%rbp; pop  %%rdi; pop  %%rsi;"
		"pop  %%rdx; pop  %%rbx; pop  %%rax \n\t"
#else
		"xchg %3, 0(%%esp) \n\t"
		"mov %%eax, %c[rax](%3) \n\t"
		"mov %%ebx, %c[rbx](%3) \n\t"
		"pushl 0(%%esp); popl %c[rcx](%3) \n\t"
		"mov %%edx, %c[rdx](%3) \n\t"
		"mov %%esi, %c[rsi](%3) \n\t"
		"mov %%edi, %c[rdi](%3) \n\t"
		"mov %%ebp, %c[rbp](%3) \n\t"
		"mov %%cr2, %%eax  \n\t"
		"mov %%eax, %c[cr2](%3) \n\t"
		"mov 0(%%esp), %3 \n\t"

		"pop %%ecx; popa \n\t"
#endif
		"setbe %0 \n\t"
		"popf \n\t"
	      : "=g" (fail)
	      : "r"(vcpu->launched), "d"((unsigned long)HOST_RSP),
		"c"(vcpu),
		[rax]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])),
		[rbx]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RBX])),
		[rcx]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RCX])),
		[rdx]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RDX])),
		[rsi]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RSI])),
		[rdi]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RDI])),
		[rbp]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RBP])),
#ifdef CONFIG_X86_64
		[r8 ]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R8 ])),
		[r9 ]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R9 ])),
		[r10]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R10])),
		[r11]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R11])),
		[r12]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R12])),
		[r13]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R13])),
		[r14]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R14])),
		[r15]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_R15])),
#endif
		[cr2]"i"(offsetof(struct kvm_vcpu, cr2))
	      : "cc", "memory" );

	++kvm_stat.exits;

	save_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
	load_msrs(vcpu->host_msrs, NR_BAD_MSRS);

	fx_save(vcpu->guest_fx_image);
	fx_restore(vcpu->host_fx_image);

#ifndef CONFIG_X86_64
	asm ("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
#endif

	kvm_run->exit_type = 0;
	if (fail) {
		kvm_run->exit_type = KVM_EXIT_TYPE_FAIL_ENTRY;
		kvm_run->exit_reason = vmcs_read32(VM_INSTRUCTION_ERROR);
	} else {
		if (fs_gs_ldt_reload_needed) {
			load_ldt(ldt_sel);
			load_fs(fs_sel);
			/*
			 * If we have to reload gs, we must take care to
			 * preserve our gs base.
			 */
			local_irq_disable();
			load_gs(gs_sel);
#ifdef CONFIG_X86_64
			wrmsrl(MSR_GS_BASE, vmcs_readl(HOST_GS_BASE));
#endif
			local_irq_enable();

			reload_tss();
		}
		vcpu->launched = 1;
		kvm_run->exit_type = KVM_EXIT_TYPE_VM_EXIT;
		if (kvm_handle_exit(kvm_run, vcpu)) {
			/* Give scheduler a change to reschedule. */
			if (signal_pending(current)) {
				++kvm_stat.signal_exits;
				return -EINTR;
			}
			kvm_resched(vcpu);
			goto again;
		}
	}
	return 0;
}

static void vmx_flush_tlb(struct kvm_vcpu *vcpu)
{
	vmcs_writel(GUEST_CR3, vmcs_readl(GUEST_CR3));
}

static void vmx_inject_page_fault(struct kvm_vcpu *vcpu,
				  unsigned long addr,
				  u32 err_code)
{
	u32 vect_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);

	++kvm_stat.pf_guest;

	if (is_page_fault(vect_info)) {
		printk(KERN_DEBUG "inject_page_fault: "
		       "double fault 0x%lx @ 0x%lx\n",
		       addr, vmcs_readl(GUEST_RIP));
		vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, 0);
		vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
			     DF_VECTOR |
			     INTR_TYPE_EXCEPTION |
			     INTR_INFO_DELIEVER_CODE_MASK |
			     INTR_INFO_VALID_MASK);
		return;
	}
	vcpu->cr2 = addr;
	vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, err_code);
	vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
		     PF_VECTOR |
		     INTR_TYPE_EXCEPTION |
		     INTR_INFO_DELIEVER_CODE_MASK |
		     INTR_INFO_VALID_MASK);

}

static void vmx_free_vmcs(struct kvm_vcpu *vcpu)
{
	if (vcpu->vmcs) {
		on_each_cpu(__vcpu_clear, vcpu, 0, 1);
		free_vmcs(vcpu->vmcs);
		vcpu->vmcs = NULL;
	}
}

static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
{
	vmx_free_vmcs(vcpu);
}

static int vmx_create_vcpu(struct kvm_vcpu *vcpu)
{
	struct vmcs *vmcs;

	vmcs = alloc_vmcs();
	if (!vmcs)
		return -ENOMEM;
	vmcs_clear(vmcs);
	vcpu->vmcs = vmcs;
	vcpu->launched = 0;
	return 0;
}

static struct kvm_arch_ops vmx_arch_ops = {
	.cpu_has_kvm_support = cpu_has_kvm_support,
	.disabled_by_bios = vmx_disabled_by_bios,
	.hardware_setup = hardware_setup,
	.hardware_unsetup = hardware_unsetup,
	.hardware_enable = hardware_enable,
	.hardware_disable = hardware_disable,

	.vcpu_create = vmx_create_vcpu,
	.vcpu_free = vmx_free_vcpu,

	.vcpu_load = vmx_vcpu_load,
	.vcpu_put = vmx_vcpu_put,

	.set_guest_debug = set_guest_debug,
	.get_msr = vmx_get_msr,
	.set_msr = vmx_set_msr,
	.get_segment_base = vmx_get_segment_base,
	.get_segment = vmx_get_segment,
	.set_segment = vmx_set_segment,
	.get_cs_db_l_bits = vmx_get_cs_db_l_bits,
	.set_cr0 = vmx_set_cr0,
	.set_cr0_no_modeswitch = vmx_set_cr0_no_modeswitch,
	.set_cr3 = vmx_set_cr3,
	.set_cr4 = vmx_set_cr4,
#ifdef CONFIG_X86_64
	.set_efer = vmx_set_efer,
#endif
	.get_idt = vmx_get_idt,
	.set_idt = vmx_set_idt,
	.get_gdt = vmx_get_gdt,
	.set_gdt = vmx_set_gdt,
	.cache_regs = vcpu_load_rsp_rip,
	.decache_regs = vcpu_put_rsp_rip,
	.get_rflags = vmx_get_rflags,
	.set_rflags = vmx_set_rflags,

	.tlb_flush = vmx_flush_tlb,
	.inject_page_fault = vmx_inject_page_fault,

	.inject_gp = vmx_inject_gp,

	.run = vmx_vcpu_run,
	.skip_emulated_instruction = skip_emulated_instruction,
	.vcpu_setup = vmx_vcpu_setup,
};

static int __init vmx_init(void)
{
	return kvm_init_arch(&vmx_arch_ops, THIS_MODULE);
}

static void __exit vmx_exit(void)
{
	kvm_exit_arch();
}

module_init(vmx_init)
module_exit(vmx_exit)