x86.c

/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * derived from drivers/kvm/kvm_main.c
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright (C) 2008 Qumranet, Inc.
 * Copyright IBM Corporation, 2008
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 *   Amit Shah    <amit.shah@qumranet.com>
 *   Ben-Ami Yassour <benami@il.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include <linux/kvm_host.h>
#include "irq.h"
#include "mmu.h"
#include "i8254.h"
#include "tss.h"
#include "kvm_cache_regs.h"
#include "x86.h"

#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/kvm.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/mman.h>
#include <linux/highmem.h>
#include <linux/iommu.h>
#include <linux/intel-iommu.h>
#include <linux/cpufreq.h>

#include <asm/uaccess.h>
#include <asm/msr.h>
#include <asm/desc.h>
#include <asm/mtrr.h>
#include <asm/mce.h>

#define MAX_IO_MSRS 256
#define CR0_RESERVED_BITS						\
	(~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
			  | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM \
			  | X86_CR0_NW | X86_CR0_CD | X86_CR0_PG))
#define CR4_RESERVED_BITS						\
	(~(unsigned long)(X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE\
			  | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE	\
			  | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR	\
			  | X86_CR4_OSXMMEXCPT | X86_CR4_VMXE))

#define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)

#define KVM_MAX_MCE_BANKS 32
#define KVM_MCE_CAP_SUPPORTED MCG_CTL_P

/* EFER defaults:
 * - enable syscall per default because its emulated by KVM
 * - enable LME and LMA per default on 64 bit KVM
 */
#ifdef CONFIG_X86_64
static u64 __read_mostly efer_reserved_bits = 0xfffffffffffffafeULL;
#else
static u64 __read_mostly efer_reserved_bits = 0xfffffffffffffffeULL;
#endif

#define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM
#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU

static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
				    struct kvm_cpuid_entry2 __user *entries);
struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
					      u32 function, u32 index);

struct kvm_x86_ops *kvm_x86_ops;
EXPORT_SYMBOL_GPL(kvm_x86_ops);

struct kvm_stats_debugfs_item debugfs_entries[] = {
	{ "pf_fixed", VCPU_STAT(pf_fixed) },
	{ "pf_guest", VCPU_STAT(pf_guest) },
	{ "tlb_flush", VCPU_STAT(tlb_flush) },
	{ "invlpg", VCPU_STAT(invlpg) },
	{ "exits", VCPU_STAT(exits) },
	{ "io_exits", VCPU_STAT(io_exits) },
	{ "mmio_exits", VCPU_STAT(mmio_exits) },
	{ "signal_exits", VCPU_STAT(signal_exits) },
	{ "irq_window", VCPU_STAT(irq_window_exits) },
	{ "nmi_window", VCPU_STAT(nmi_window_exits) },
	{ "halt_exits", VCPU_STAT(halt_exits) },
	{ "halt_wakeup", VCPU_STAT(halt_wakeup) },
	{ "hypercalls", VCPU_STAT(hypercalls) },
	{ "request_irq", VCPU_STAT(request_irq_exits) },
	{ "irq_exits", VCPU_STAT(irq_exits) },
	{ "host_state_reload", VCPU_STAT(host_state_reload) },
	{ "efer_reload", VCPU_STAT(efer_reload) },
	{ "fpu_reload", VCPU_STAT(fpu_reload) },
	{ "insn_emulation", VCPU_STAT(insn_emulation) },
	{ "insn_emulation_fail", VCPU_STAT(insn_emulation_fail) },
	{ "irq_injections", VCPU_STAT(irq_injections) },
	{ "nmi_injections", VCPU_STAT(nmi_injections) },
	{ "mmu_shadow_zapped", VM_STAT(mmu_shadow_zapped) },
	{ "mmu_pte_write", VM_STAT(mmu_pte_write) },
	{ "mmu_pte_updated", VM_STAT(mmu_pte_updated) },
	{ "mmu_pde_zapped", VM_STAT(mmu_pde_zapped) },
	{ "mmu_flooded", VM_STAT(mmu_flooded) },
	{ "mmu_recycled", VM_STAT(mmu_recycled) },
	{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
	{ "mmu_unsync", VM_STAT(mmu_unsync) },
	{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
	{ "largepages", VM_STAT(lpages) },
	{ NULL }
};

unsigned long segment_base(u16 selector)
{
	struct descriptor_table gdt;
	struct desc_struct *d;
	unsigned long table_base;
	unsigned long v;

	if (selector == 0)
		return 0;

	asm("sgdt %0" : "=m"(gdt));
	table_base = gdt.base;

	if (selector & 4) {           /* from ldt */
		u16 ldt_selector;

		asm("sldt %0" : "=g"(ldt_selector));
		table_base = segment_base(ldt_selector);
	}
	d = (struct desc_struct *)(table_base + (selector & ~7));
	v = d->base0 | ((unsigned long)d->base1 << 16) |
		((unsigned long)d->base2 << 24);
#ifdef CONFIG_X86_64
	if (d->s == 0 && (d->type == 2 || d->type == 9 || d->type == 11))
		v |= ((unsigned long)((struct ldttss_desc64 *)d)->base3) << 32;
#endif
	return v;
}
EXPORT_SYMBOL_GPL(segment_base);

u64 kvm_get_apic_base(struct kvm_vcpu *vcpu)
{
	if (irqchip_in_kernel(vcpu->kvm))
		return vcpu->arch.apic_base;
	else
		return vcpu->arch.apic_base;
}
EXPORT_SYMBOL_GPL(kvm_get_apic_base);

void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data)
{
	/* TODO: reserve bits check */
	if (irqchip_in_kernel(vcpu->kvm))
		kvm_lapic_set_base(vcpu, data);
	else
		vcpu->arch.apic_base = data;
}
EXPORT_SYMBOL_GPL(kvm_set_apic_base);

void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
{
	WARN_ON(vcpu->arch.exception.pending);
	vcpu->arch.exception.pending = true;
	vcpu->arch.exception.has_error_code = false;
	vcpu->arch.exception.nr = nr;
}
EXPORT_SYMBOL_GPL(kvm_queue_exception);

void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
			   u32 error_code)
{
	++vcpu->stat.pf_guest;

	if (vcpu->arch.exception.pending) {
		switch(vcpu->arch.exception.nr) {
		case DF_VECTOR:
			/* triple fault -> shutdown */
			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
			return;
		case PF_VECTOR:
			vcpu->arch.exception.nr = DF_VECTOR;
			vcpu->arch.exception.error_code = 0;
			return;
		default:
			/* replace previous exception with a new one in a hope
			   that instruction re-execution will regenerate lost
			   exception */
			vcpu->arch.exception.pending = false;
			break;
		}
	}
	vcpu->arch.cr2 = addr;
	kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
}

void kvm_inject_nmi(struct kvm_vcpu *vcpu)
{
	vcpu->arch.nmi_pending = 1;
}
EXPORT_SYMBOL_GPL(kvm_inject_nmi);

void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
{
	WARN_ON(vcpu->arch.exception.pending);
	vcpu->arch.exception.pending = true;
	vcpu->arch.exception.has_error_code = true;
	vcpu->arch.exception.nr = nr;
	vcpu->arch.exception.error_code = error_code;
}
EXPORT_SYMBOL_GPL(kvm_queue_exception_e);

static void __queue_exception(struct kvm_vcpu *vcpu)
{
	kvm_x86_ops->queue_exception(vcpu, vcpu->arch.exception.nr,
				     vcpu->arch.exception.has_error_code,
				     vcpu->arch.exception.error_code);
}

/*
 * Load the pae pdptrs.  Return true is they are all valid.
 */
int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
{
	gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT;
	unsigned offset = ((cr3 & (PAGE_SIZE-1)) >> 5) << 2;
	int i;
	int ret;
	u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];

	ret = kvm_read_guest_page(vcpu->kvm, pdpt_gfn, pdpte,
				  offset * sizeof(u64), sizeof(pdpte));
	if (ret < 0) {
		ret = 0;
		goto out;
	}
	for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
		if (is_present_gpte(pdpte[i]) &&
		    (pdpte[i] & vcpu->arch.mmu.rsvd_bits_mask[0][2])) {
			ret = 0;
			goto out;
		}
	}
	ret = 1;

	memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
	__set_bit(VCPU_EXREG_PDPTR,
		  (unsigned long *)&vcpu->arch.regs_avail);
	__set_bit(VCPU_EXREG_PDPTR,
		  (unsigned long *)&vcpu->arch.regs_dirty);
out:

	return ret;
}
EXPORT_SYMBOL_GPL(load_pdptrs);

static bool pdptrs_changed(struct kvm_vcpu *vcpu)
{
	u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
	bool changed = true;
	int r;

	if (is_long_mode(vcpu) || !is_pae(vcpu))
		return false;

	if (!test_bit(VCPU_EXREG_PDPTR,
		      (unsigned long *)&vcpu->arch.regs_avail))
		return true;

	r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
	if (r < 0)
		goto out;
	changed = memcmp(pdpte, vcpu->arch.pdptrs, sizeof(pdpte)) != 0;
out:

	return changed;
}

void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
	if (cr0 & CR0_RESERVED_BITS) {
		printk(KERN_DEBUG "set_cr0: 0x%lx #GP, reserved bits 0x%lx\n",
		       cr0, vcpu->arch.cr0);
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD)) {
		printk(KERN_DEBUG "set_cr0: #GP, CD == 0 && NW == 1\n");
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE)) {
		printk(KERN_DEBUG "set_cr0: #GP, set PG flag "
		       "and a clear PE flag\n");
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
#ifdef CONFIG_X86_64
		if ((vcpu->arch.shadow_efer & EFER_LME)) {
			int cs_db, cs_l;

			if (!is_pae(vcpu)) {
				printk(KERN_DEBUG "set_cr0: #GP, start paging "
				       "in long mode while PAE is disabled\n");
				kvm_inject_gp(vcpu, 0);
				return;
			}
			kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
			if (cs_l) {
				printk(KERN_DEBUG "set_cr0: #GP, start paging "
				       "in long mode while CS.L == 1\n");
				kvm_inject_gp(vcpu, 0);
				return;

			}
		} else
#endif
		if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->arch.cr3)) {
			printk(KERN_DEBUG "set_cr0: #GP, pdptrs "
			       "reserved bits\n");
			kvm_inject_gp(vcpu, 0);
			return;
		}

	}

	kvm_x86_ops->set_cr0(vcpu, cr0);
	vcpu->arch.cr0 = cr0;

	kvm_mmu_reset_context(vcpu);
	return;
}
EXPORT_SYMBOL_GPL(kvm_set_cr0);

void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
{
	kvm_set_cr0(vcpu, (vcpu->arch.cr0 & ~0x0ful) | (msw & 0x0f));
	KVMTRACE_1D(LMSW, vcpu,
		    (u32)((vcpu->arch.cr0 & ~0x0ful) | (msw & 0x0f)),
		    handler);
}
EXPORT_SYMBOL_GPL(kvm_lmsw);

void kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
	unsigned long old_cr4 = vcpu->arch.cr4;
	unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE;

	if (cr4 & CR4_RESERVED_BITS) {
		printk(KERN_DEBUG "set_cr4: #GP, reserved bits\n");
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if (is_long_mode(vcpu)) {
		if (!(cr4 & X86_CR4_PAE)) {
			printk(KERN_DEBUG "set_cr4: #GP, clearing PAE while "
			       "in long mode\n");
			kvm_inject_gp(vcpu, 0);
			return;
		}
	} else if (is_paging(vcpu) && (cr4 & X86_CR4_PAE)
		   && ((cr4 ^ old_cr4) & pdptr_bits)
		   && !load_pdptrs(vcpu, vcpu->arch.cr3)) {
		printk(KERN_DEBUG "set_cr4: #GP, pdptrs reserved bits\n");
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if (cr4 & X86_CR4_VMXE) {
		printk(KERN_DEBUG "set_cr4: #GP, setting VMXE\n");
		kvm_inject_gp(vcpu, 0);
		return;
	}
	kvm_x86_ops->set_cr4(vcpu, cr4);
	vcpu->arch.cr4 = cr4;
	vcpu->arch.mmu.base_role.cr4_pge = (cr4 & X86_CR4_PGE) && !tdp_enabled;
	kvm_mmu_reset_context(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_set_cr4);

void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
{
	if (cr3 == vcpu->arch.cr3 && !pdptrs_changed(vcpu)) {
		kvm_mmu_sync_roots(vcpu);
		kvm_mmu_flush_tlb(vcpu);
		return;
	}

	if (is_long_mode(vcpu)) {
		if (cr3 & CR3_L_MODE_RESERVED_BITS) {
			printk(KERN_DEBUG "set_cr3: #GP, reserved bits\n");
			kvm_inject_gp(vcpu, 0);
			return;
		}
	} else {
		if (is_pae(vcpu)) {
			if (cr3 & CR3_PAE_RESERVED_BITS) {
				printk(KERN_DEBUG
				       "set_cr3: #GP, reserved bits\n");
				kvm_inject_gp(vcpu, 0);
				return;
			}
			if (is_paging(vcpu) && !load_pdptrs(vcpu, cr3)) {
				printk(KERN_DEBUG "set_cr3: #GP, pdptrs "
				       "reserved bits\n");
				kvm_inject_gp(vcpu, 0);
				return;
			}
		}
		/*
		 * We don't check reserved bits in nonpae mode, because
		 * this isn't enforced, and VMware depends on this.
		 */
	}

	/*
	 * Does the new cr3 value map to physical memory? (Note, we
	 * catch an invalid cr3 even in real-mode, because it would
	 * cause trouble later on when we turn on paging anyway.)
	 *
	 * A real CPU would silently accept an invalid cr3 and would
	 * attempt to use it - with largely undefined (and often hard
	 * to debug) behavior on the guest side.
	 */
	if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT)))
		kvm_inject_gp(vcpu, 0);
	else {
		vcpu->arch.cr3 = cr3;
		vcpu->arch.mmu.new_cr3(vcpu);
	}
}
EXPORT_SYMBOL_GPL(kvm_set_cr3);

void kvm_set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8)
{
	if (cr8 & CR8_RESERVED_BITS) {
		printk(KERN_DEBUG "set_cr8: #GP, reserved bits 0x%lx\n", cr8);
		kvm_inject_gp(vcpu, 0);
		return;
	}
	if (irqchip_in_kernel(vcpu->kvm))
		kvm_lapic_set_tpr(vcpu, cr8);
	else
		vcpu->arch.cr8 = cr8;
}
EXPORT_SYMBOL_GPL(kvm_set_cr8);

unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
{
	if (irqchip_in_kernel(vcpu->kvm))
		return kvm_lapic_get_cr8(vcpu);
	else
		return vcpu->arch.cr8;
}
EXPORT_SYMBOL_GPL(kvm_get_cr8);

static inline u32 bit(int bitno)
{
	return 1 << (bitno & 31);
}

/*
 * List of msr numbers which we expose to userspace through KVM_GET_MSRS
 * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
 *
 * This list is modified at module load time to reflect the
 * capabilities of the host cpu.
 */
static u32 msrs_to_save[] = {
	MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
	MSR_K6_STAR,
#ifdef CONFIG_X86_64
	MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
#endif
	MSR_IA32_TSC, MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
	MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA
};

static unsigned num_msrs_to_save;

static u32 emulated_msrs[] = {
	MSR_IA32_MISC_ENABLE,
};

static void set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
	if (efer & efer_reserved_bits) {
		printk(KERN_DEBUG "set_efer: 0x%llx #GP, reserved bits\n",
		       efer);
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if (is_paging(vcpu)
	    && (vcpu->arch.shadow_efer & EFER_LME) != (efer & EFER_LME)) {
		printk(KERN_DEBUG "set_efer: #GP, change LME while paging\n");
		kvm_inject_gp(vcpu, 0);
		return;
	}

	if (efer & EFER_FFXSR) {
		struct kvm_cpuid_entry2 *feat;

		feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
		if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT))) {
			printk(KERN_DEBUG "set_efer: #GP, enable FFXSR w/o CPUID capability\n");
			kvm_inject_gp(vcpu, 0);
			return;
		}
	}

	if (efer & EFER_SVME) {
		struct kvm_cpuid_entry2 *feat;

		feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
		if (!feat || !(feat->ecx & bit(X86_FEATURE_SVM))) {
			printk(KERN_DEBUG "set_efer: #GP, enable SVM w/o SVM\n");
			kvm_inject_gp(vcpu, 0);
			return;
		}
	}

	kvm_x86_ops->set_efer(vcpu, efer);

	efer &= ~EFER_LMA;
	efer |= vcpu->arch.shadow_efer & EFER_LMA;

	vcpu->arch.shadow_efer = efer;

	vcpu->arch.mmu.base_role.nxe = (efer & EFER_NX) && !tdp_enabled;
	kvm_mmu_reset_context(vcpu);
}

void kvm_enable_efer_bits(u64 mask)
{
       efer_reserved_bits &= ~mask;
}
EXPORT_SYMBOL_GPL(kvm_enable_efer_bits);


/*
 * Writes msr value into into the appropriate "register".
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
int kvm_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
{
	return kvm_x86_ops->set_msr(vcpu, msr_index, data);
}

/*
 * Adapt set_msr() to msr_io()'s calling convention
 */
static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
{
	return kvm_set_msr(vcpu, index, *data);
}

static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
	static int version;
	struct pvclock_wall_clock wc;
	struct timespec now, sys, boot;

	if (!wall_clock)
		return;

	version++;

	kvm_write_guest(kvm, wall_clock, &version, sizeof(version));

	/*
	 * The guest calculates current wall clock time by adding
	 * system time (updated by kvm_write_guest_time below) to the
	 * wall clock specified here.  guest system time equals host
	 * system time for us, thus we must fill in host boot time here.
	 */
	now = current_kernel_time();
	ktime_get_ts(&sys);
	boot = ns_to_timespec(timespec_to_ns(&now) - timespec_to_ns(&sys));

	wc.sec = boot.tv_sec;
	wc.nsec = boot.tv_nsec;
	wc.version = version;

	kvm_write_guest(kvm, wall_clock, &wc, sizeof(wc));

	version++;
	kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
}

static uint32_t div_frac(uint32_t dividend, uint32_t divisor)
{
	uint32_t quotient, remainder;

	/* Don't try to replace with do_div(), this one calculates
	 * "(dividend << 32) / divisor" */
	__asm__ ( "divl %4"
		  : "=a" (quotient), "=d" (remainder)
		  : "0" (0), "1" (dividend), "r" (divisor) );
	return quotient;
}

static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info *hv_clock)
{
	uint64_t nsecs = 1000000000LL;
	int32_t  shift = 0;
	uint64_t tps64;
	uint32_t tps32;

	tps64 = tsc_khz * 1000LL;
	while (tps64 > nsecs*2) {
		tps64 >>= 1;
		shift--;
	}

	tps32 = (uint32_t)tps64;
	while (tps32 <= (uint32_t)nsecs) {
		tps32 <<= 1;
		shift++;
	}

	hv_clock->tsc_shift = shift;
	hv_clock->tsc_to_system_mul = div_frac(nsecs, tps32);

	pr_debug("%s: tsc_khz %u, tsc_shift %d, tsc_mul %u\n",
		 __func__, tsc_khz, hv_clock->tsc_shift,
		 hv_clock->tsc_to_system_mul);
}

static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);

static void kvm_write_guest_time(struct kvm_vcpu *v)
{
	struct timespec ts;
	unsigned long flags;
	struct kvm_vcpu_arch *vcpu = &v->arch;
	void *shared_kaddr;
	unsigned long this_tsc_khz;

	if ((!vcpu->time_page))
		return;

	this_tsc_khz = get_cpu_var(cpu_tsc_khz);
	if (unlikely(vcpu->hv_clock_tsc_khz != this_tsc_khz)) {
		kvm_set_time_scale(this_tsc_khz, &vcpu->hv_clock);
		vcpu->hv_clock_tsc_khz = this_tsc_khz;
	}
	put_cpu_var(cpu_tsc_khz);

	/* Keep irq disabled to prevent changes to the clock */
	local_irq_save(flags);
	kvm_get_msr(v, MSR_IA32_TSC, &vcpu->hv_clock.tsc_timestamp);
	ktime_get_ts(&ts);
	local_irq_restore(flags);

	/* With all the info we got, fill in the values */

	vcpu->hv_clock.system_time = ts.tv_nsec +
				     (NSEC_PER_SEC * (u64)ts.tv_sec);
	/*
	 * The interface expects us to write an even number signaling that the
	 * update is finished. Since the guest won't see the intermediate
	 * state, we just increase by 2 at the end.
	 */
	vcpu->hv_clock.version += 2;

	shared_kaddr = kmap_atomic(vcpu->time_page, KM_USER0);

	memcpy(shared_kaddr + vcpu->time_offset, &vcpu->hv_clock,
	       sizeof(vcpu->hv_clock));

	kunmap_atomic(shared_kaddr, KM_USER0);

	mark_page_dirty(v->kvm, vcpu->time >> PAGE_SHIFT);
}

static int kvm_request_guest_time_update(struct kvm_vcpu *v)
{
	struct kvm_vcpu_arch *vcpu = &v->arch;

	if (!vcpu->time_page)
		return 0;
	set_bit(KVM_REQ_KVMCLOCK_UPDATE, &v->requests);
	return 1;
}

static bool msr_mtrr_valid(unsigned msr)
{
	switch (msr) {
	case 0x200 ... 0x200 + 2 * KVM_NR_VAR_MTRR - 1:
	case MSR_MTRRfix64K_00000:
	case MSR_MTRRfix16K_80000:
	case MSR_MTRRfix16K_A0000:
	case MSR_MTRRfix4K_C0000:
	case MSR_MTRRfix4K_C8000:
	case MSR_MTRRfix4K_D0000:
	case MSR_MTRRfix4K_D8000:
	case MSR_MTRRfix4K_E0000:
	case MSR_MTRRfix4K_E8000:
	case MSR_MTRRfix4K_F0000:
	case MSR_MTRRfix4K_F8000:
	case MSR_MTRRdefType:
	case MSR_IA32_CR_PAT:
		return true;
	case 0x2f8:
		return true;
	}
	return false;
}

static bool valid_pat_type(unsigned t)
{
	return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
}

static bool valid_mtrr_type(unsigned t)
{
	return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
}

static bool mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
	int i;

	if (!msr_mtrr_valid(msr))
		return false;

	if (msr == MSR_IA32_CR_PAT) {
		for (i = 0; i < 8; i++)
			if (!valid_pat_type((data >> (i * 8)) & 0xff))
				return false;
		return true;
	} else if (msr == MSR_MTRRdefType) {
		if (data & ~0xcff)
			return false;
		return valid_mtrr_type(data & 0xff);
	} else if (msr >= MSR_MTRRfix64K_00000 && msr <= MSR_MTRRfix4K_F8000) {
		for (i = 0; i < 8 ; i++)
			if (!valid_mtrr_type((data >> (i * 8)) & 0xff))
				return false;
		return true;
	}

	/* variable MTRRs */
	return valid_mtrr_type(data & 0xff);
}

static int set_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
	u64 *p = (u64 *)&vcpu->arch.mtrr_state.fixed_ranges;

	if (!mtrr_valid(vcpu, msr, data))
		return 1;

	if (msr == MSR_MTRRdefType) {
		vcpu->arch.mtrr_state.def_type = data;
		vcpu->arch.mtrr_state.enabled = (data & 0xc00) >> 10;
	} else if (msr == MSR_MTRRfix64K_00000)
		p[0] = data;
	else if (msr == MSR_MTRRfix16K_80000 || msr == MSR_MTRRfix16K_A0000)
		p[1 + msr - MSR_MTRRfix16K_80000] = data;
	else if (msr >= MSR_MTRRfix4K_C0000 && msr <= MSR_MTRRfix4K_F8000)
		p[3 + msr - MSR_MTRRfix4K_C0000] = data;
	else if (msr == MSR_IA32_CR_PAT)
		vcpu->arch.pat = data;
	else {	/* Variable MTRRs */
		int idx, is_mtrr_mask;
		u64 *pt;

		idx = (msr - 0x200) / 2;
		is_mtrr_mask = msr - 0x200 - 2 * idx;
		if (!is_mtrr_mask)
			pt =
			  (u64 *)&vcpu->arch.mtrr_state.var_ranges[idx].base_lo;
		else
			pt =
			  (u64 *)&vcpu->arch.mtrr_state.var_ranges[idx].mask_lo;
		*pt = data;
	}

	kvm_mmu_reset_context(vcpu);
	return 0;
}

static int set_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
	u64 mcg_cap = vcpu->arch.mcg_cap;
	unsigned bank_num = mcg_cap & 0xff;

	switch (msr) {
	case MSR_IA32_MCG_STATUS:
		vcpu->arch.mcg_status = data;
		break;
	case MSR_IA32_MCG_CTL:
		if (!(mcg_cap & MCG_CTL_P))
			return 1;
		if (data != 0 && data != ~(u64)0)
			return -1;
		vcpu->arch.mcg_ctl = data;
		break;
	default:
		if (msr >= MSR_IA32_MC0_CTL &&
		    msr < MSR_IA32_MC0_CTL + 4 * bank_num) {
			u32 offset = msr - MSR_IA32_MC0_CTL;
			/* only 0 or all 1s can be written to IA32_MCi_CTL */
			if ((offset & 0x3) == 0 &&
			    data != 0 && data != ~(u64)0)
				return -1;
			vcpu->arch.mce_banks[offset] = data;
			break;
		}
		return 1;
	}
	return 0;
}

int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
	switch (msr) {
	case MSR_EFER:
		set_efer(vcpu, data);
		break;
	case MSR_IA32_DEBUGCTLMSR:
		if (!data) {
			/* We support the non-activated case already */
			break;
		} else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
			/* Values other than LBR and BTF are vendor-specific,
			   thus reserved and should throw a #GP */
			return 1;
		}
		pr_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
			__func__, data);
		break;
	case MSR_IA32_UCODE_REV:
	case MSR_IA32_UCODE_WRITE:
	case MSR_VM_HSAVE_PA:
		break;
	case 0x200 ... 0x2ff:
		return set_msr_mtrr(vcpu, msr, data);
	case MSR_IA32_APICBASE:
		kvm_set_apic_base(vcpu, data);
		break;
	case MSR_IA32_MISC_ENABLE:
		vcpu->arch.ia32_misc_enable_msr = data;
		break;
	case MSR_KVM_WALL_CLOCK:
		vcpu->kvm->arch.wall_clock = data;
		kvm_write_wall_clock(vcpu->kvm, data);
		break;
	case MSR_KVM_SYSTEM_TIME: {
		if (vcpu->arch.time_page) {
			kvm_release_page_dirty(vcpu->arch.time_page);
			vcpu->arch.time_page = NULL;
		}

		vcpu->arch.time = data;

		/* we verify if the enable bit is set... */
		if (!(data & 1))
			break;

		/* ...but clean it before doing the actual write */
		vcpu->arch.time_offset = data & ~(PAGE_MASK | 1);

		vcpu->arch.time_page =
				gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);

		if (is_error_page(vcpu->arch.time_page)) {
			kvm_release_page_clean(vcpu->arch.time_page);
			vcpu->arch.time_page = NULL;
		}

		kvm_request_guest_time_update(vcpu);
		break;
	}
	case MSR_IA32_MCG_CTL:
	case MSR_IA32_MCG_STATUS:
	case MSR_IA32_MC0_CTL ... MSR_IA32_MC0_CTL + 4 * KVM_MAX_MCE_BANKS - 1:
		return set_msr_mce(vcpu, msr, data);

	/* Performance counters are not protected by a CPUID bit,
	 * so we should check all of them in the generic path for the sake of
	 * cross vendor migration.
	 * Writing a zero into the event select MSRs disables them,
	 * which we perfectly emulate ;-). Any other value should be at least
	 * reported, some guests depend on them.
	 */
	case MSR_P6_EVNTSEL0:
	case MSR_P6_EVNTSEL1:
	case MSR_K7_EVNTSEL0:
	case MSR_K7_EVNTSEL1:
	case MSR_K7_EVNTSEL2:
	case MSR_K7_EVNTSEL3:
		if (data != 0)
			pr_unimpl(vcpu, "unimplemented perfctr wrmsr: "
				"0x%x data 0x%llx\n", msr, data);
		break;
	/* at least RHEL 4 unconditionally writes to the perfctr registers,
	 * so we ignore writes to make it happy.
	 */
	case MSR_P6_PERFCTR0:
	case MSR_P6_PERFCTR1:
	case MSR_K7_PERFCTR0:
	case MSR_K7_PERFCTR1:
	case MSR_K7_PERFCTR2:
	case MSR_K7_PERFCTR3:
		pr_unimpl(vcpu, "unimplemented perfctr wrmsr: "
			"0x%x data 0x%llx\n", msr, data);
		break;
	default:
		pr_unimpl(vcpu, "unhandled wrmsr: 0x%x data %llx\n", msr, data);
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_msr_common);


/*
 * Reads an msr value (of 'msr_index') into 'pdata'.
 * Returns 0 on success, non-0 otherwise.
 * Assumes vcpu_load() was already called.
 */
int kvm_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
{
	return kvm_x86_ops->get_msr(vcpu, msr_index, pdata);
}

static int get_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
	u64 *p = (u64 *)&vcpu->arch.mtrr_state.fixed_ranges;

	if (!msr_mtrr_valid(msr))
		return 1;

	if (msr == MSR_MTRRdefType)
		*pdata = vcpu->arch.mtrr_state.def_type +
			 (vcpu->arch.mtrr_state.enabled << 10);
	else if (msr == MSR_MTRRfix64K_00000)
		*pdata = p[0];
	else if (msr == MSR_MTRRfix16K_80000 || msr == MSR_MTRRfix16K_A0000)
		*pdata = p[1 + msr - MSR_MTRRfix16K_80000];
	else if (msr >= MSR_MTRRfix4K_C0000 && msr <= MSR_MTRRfix4K_F8000)
		*pdata = p[3 + msr - MSR_MTRRfix4K_C0000];
	else if (msr == MSR_IA32_CR_PAT)
		*pdata = vcpu->arch.pat;
	else {	/* Variable MTRRs */
		int idx, is_mtrr_mask;
		u64 *pt;

		idx = (msr - 0x200) / 2;
		is_mtrr_mask = msr - 0x200 - 2 * idx;
		if (!is_mtrr_mask)
			pt =
			  (u64 *)&vcpu->arch.mtrr_state.var_ranges[idx].base_lo;
		else
			pt =
			  (u64 *)&vcpu->arch.mtrr_state.var_ranges[idx].mask_lo;
		*pdata = *pt;
	}

	return 0;
}

static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
	u64 data;
	u64 mcg_cap = vcpu->arch.mcg_cap;
	unsigned bank_num = mcg_cap & 0xff;

	switch (msr) {
	case MSR_IA32_P5_MC_ADDR:
	case MSR_IA32_P5_MC_TYPE:
		data = 0;
		break;
	case MSR_IA32_MCG_CAP:
		data = vcpu->arch.mcg_cap;
		break;
	case MSR_IA32_MCG_CTL:
		if (!(mcg_cap & MCG_CTL_P))
			return 1;
		data = vcpu->arch.mcg_ctl;
		break;
	case MSR_IA32_MCG_STATUS:
		data = vcpu->arch.mcg_status;
		break;
	default:
		if (msr >= MSR_IA32_MC0_CTL &&
		    msr < MSR_IA32_MC0_CTL + 4 * bank_num) {
			u32 offset = msr - MSR_IA32_MC0_CTL;
			data = vcpu->arch.mce_banks[offset];
			break;
		}
		return 1;
	}
	*pdata = data;
	return 0;
}

int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
	u64 data;

	switch (msr) {
	case MSR_IA32_PLATFORM_ID:
	case MSR_IA32_UCODE_REV:
	case MSR_IA32_EBL_CR_POWERON:
	case MSR_IA32_DEBUGCTLMSR:
	case MSR_IA32_LASTBRANCHFROMIP:
	case MSR_IA32_LASTBRANCHTOIP:
	case MSR_IA32_LASTINTFROMIP:
	case MSR_IA32_LASTINTTOIP:
	case MSR_K8_SYSCFG:
	case MSR_K7_HWCR:
	case MSR_VM_HSAVE_PA:
	case MSR_P6_EVNTSEL0:
	case MSR_P6_EVNTSEL1:
	case MSR_K7_EVNTSEL0:
		data = 0;
		break;
	case MSR_MTRRcap:
		data = 0x500 | KVM_NR_VAR_MTRR;
		break;
	case 0x200 ... 0x2ff:
		return get_msr_mtrr(vcpu, msr, pdata);
	case 0xcd: /* fsb frequency */
		data = 3;
		break;
	case MSR_IA32_APICBASE:
		data = kvm_get_apic_base(vcpu);
		break;
	case MSR_IA32_MISC_ENABLE:
		data = vcpu->arch.ia32_misc_enable_msr;
		break;
	case MSR_IA32_PERF_STATUS:
		/* TSC increment by tick */
		data = 1000ULL;
		/* CPU multiplier */
		data |= (((uint64_t)4ULL) << 40);
		break;
	case MSR_EFER:
		data = vcpu->arch.shadow_efer;
		break;
	case MSR_KVM_WALL_CLOCK:
		data = vcpu->kvm->arch.wall_clock;
		break;
	case MSR_KVM_SYSTEM_TIME:
		data = vcpu->arch.time;
		break;
	case MSR_IA32_P5_MC_ADDR:
	case MSR_IA32_P5_MC_TYPE:
	case MSR_IA32_MCG_CAP:
	case MSR_IA32_MCG_CTL:
	case MSR_IA32_MCG_STATUS:
	case MSR_IA32_MC0_CTL ... MSR_IA32_MC0_CTL + 4 * KVM_MAX_MCE_BANKS - 1:
		return get_msr_mce(vcpu, msr, pdata);
	default:
		pr_unimpl(vcpu, "unhandled rdmsr: 0x%x\n", msr);
		return 1;
	}
	*pdata = data;
	return 0;
}
EXPORT_SYMBOL_GPL(kvm_get_msr_common);

/*
 * Read or write a bunch of msrs. All parameters are kernel addresses.
 *
 * @return number of msrs set successfully.
 */
static int __msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs *msrs,
		    struct kvm_msr_entry *entries,
		    int (*do_msr)(struct kvm_vcpu *vcpu,
				  unsigned index, u64 *data))
{
	int i;

	vcpu_load(vcpu);

	down_read(&vcpu->kvm->slots_lock);
	for (i = 0; i < msrs->nmsrs; ++i)
		if (do_msr(vcpu, entries[i].index, &entries[i].data))
			break;
	up_read(&vcpu->kvm->slots_lock);

	vcpu_put(vcpu);

	return i;
}

/*
 * Read or write a bunch of msrs. Parameters are user addresses.
 *
 * @return number of msrs set successfully.
 */
static int msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs __user *user_msrs,
		  int (*do_msr)(struct kvm_vcpu *vcpu,
				unsigned index, u64 *data),
		  int writeback)
{
	struct kvm_msrs msrs;
	struct kvm_msr_entry *entries;
	int r, n;
	unsigned size;

	r = -EFAULT;
	if (copy_from_user(&msrs, user_msrs, sizeof msrs))
		goto out;

	r = -E2BIG;
	if (msrs.nmsrs >= MAX_IO_MSRS)
		goto out;

	r = -ENOMEM;
	size = sizeof(struct kvm_msr_entry) * msrs.nmsrs;
	entries = vmalloc(size);
	if (!entries)
		goto out;

	r = -EFAULT;
	if (copy_from_user(entries, user_msrs->entries, size))
		goto out_free;

	r = n = __msr_io(vcpu, &msrs, entries, do_msr);
	if (r < 0)
		goto out_free;

	r = -EFAULT;
	if (writeback && copy_to_user(user_msrs->entries, entries, size))
		goto out_free;

	r = n;

out_free:
	vfree(entries);
out:
	return r;
}

int kvm_dev_ioctl_check_extension(long ext)
{
	int r;

	switch (ext) {
	case KVM_CAP_IRQCHIP:
	case KVM_CAP_HLT:
	case KVM_CAP_MMU_SHADOW_CACHE_CONTROL:
	case KVM_CAP_SET_TSS_ADDR:
	case KVM_CAP_EXT_CPUID:
	case KVM_CAP_CLOCKSOURCE:
	case KVM_CAP_PIT:
	case KVM_CAP_NOP_IO_DELAY:
	case KVM_CAP_MP_STATE:
	case KVM_CAP_SYNC_MMU:
	case KVM_CAP_REINJECT_CONTROL:
	case KVM_CAP_IRQ_INJECT_STATUS:
	case KVM_CAP_ASSIGN_DEV_IRQ:
	case KVM_CAP_IRQFD:
	case KVM_CAP_PIT2:
		r = 1;
		break;
	case KVM_CAP_COALESCED_MMIO:
		r = KVM_COALESCED_MMIO_PAGE_OFFSET;
		break;
	case KVM_CAP_VAPIC:
		r = !kvm_x86_ops->cpu_has_accelerated_tpr();
		break;
	case KVM_CAP_NR_VCPUS:
		r = KVM_MAX_VCPUS;
		break;
	case KVM_CAP_NR_MEMSLOTS:
		r = KVM_MEMORY_SLOTS;
		break;
	case KVM_CAP_PV_MMU:
		r = !tdp_enabled;
		break;
	case KVM_CAP_IOMMU:
		r = iommu_found();
		break;
	case KVM_CAP_MCE:
		r = KVM_MAX_MCE_BANKS;
		break;
	default:
		r = 0;
		break;
	}
	return r;

}

long kvm_arch_dev_ioctl(struct file *filp,
			unsigned int ioctl, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	long r;

	switch (ioctl) {
	case KVM_GET_MSR_INDEX_LIST: {
		struct kvm_msr_list __user *user_msr_list = argp;
		struct kvm_msr_list msr_list;
		unsigned n;

		r = -EFAULT;
		if (copy_from_user(&msr_list, user_msr_list, sizeof msr_list))
			goto out;
		n = msr_list.nmsrs;
		msr_list.nmsrs = num_msrs_to_save + ARRAY_SIZE(emulated_msrs);
		if (copy_to_user(user_msr_list, &msr_list, sizeof msr_list))
			goto out;
		r = -E2BIG;
		if (n < msr_list.nmsrs)
			goto out;
		r = -EFAULT;
		if (copy_to_user(user_msr_list->indices, &msrs_to_save,
				 num_msrs_to_save * sizeof(u32)))
			goto out;
		if (copy_to_user(user_msr_list->indices + num_msrs_to_save,
				 &emulated_msrs,
				 ARRAY_SIZE(emulated_msrs) * sizeof(u32)))
			goto out;
		r = 0;
		break;
	}
	case KVM_GET_SUPPORTED_CPUID: {
		struct kvm_cpuid2 __user *cpuid_arg = argp;
		struct kvm_cpuid2 cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_dev_ioctl_get_supported_cpuid(&cpuid,
						      cpuid_arg->entries);
		if (r)
			goto out;

		r = -EFAULT;
		if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
			goto out;
		r = 0;
		break;
	}
	case KVM_X86_GET_MCE_CAP_SUPPORTED: {
		u64 mce_cap;

		mce_cap = KVM_MCE_CAP_SUPPORTED;
		r = -EFAULT;
		if (copy_to_user(argp, &mce_cap, sizeof mce_cap))
			goto out;
		r = 0;
		break;
	}
	default:
		r = -EINVAL;
	}
out:
	return r;
}

void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
	kvm_x86_ops->vcpu_load(vcpu, cpu);
	kvm_request_guest_time_update(vcpu);
}

void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
	kvm_x86_ops->vcpu_put(vcpu);
	kvm_put_guest_fpu(vcpu);
}

static int is_efer_nx(void)
{
	unsigned long long efer = 0;

	rdmsrl_safe(MSR_EFER, &efer);
	return efer & EFER_NX;
}

static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
{
	int i;
	struct kvm_cpuid_entry2 *e, *entry;

	entry = NULL;
	for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
		e = &vcpu->arch.cpuid_entries[i];
		if (e->function == 0x80000001) {
			entry = e;
			break;
		}
	}
	if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) {
		entry->edx &= ~(1 << 20);
		printk(KERN_INFO "kvm: guest NX capability removed\n");
	}
}

/* when an old userspace process fills a new kernel module */
static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
				    struct kvm_cpuid *cpuid,
				    struct kvm_cpuid_entry __user *entries)
{
	int r, i;
	struct kvm_cpuid_entry *cpuid_entries;

	r = -E2BIG;
	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
		goto out;
	r = -ENOMEM;
	cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
	if (!cpuid_entries)
		goto out;
	r = -EFAULT;
	if (copy_from_user(cpuid_entries, entries,
			   cpuid->nent * sizeof(struct kvm_cpuid_entry)))
		goto out_free;
	for (i = 0; i < cpuid->nent; i++) {
		vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
		vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
		vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
		vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
		vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
		vcpu->arch.cpuid_entries[i].index = 0;
		vcpu->arch.cpuid_entries[i].flags = 0;
		vcpu->arch.cpuid_entries[i].padding[0] = 0;
		vcpu->arch.cpuid_entries[i].padding[1] = 0;
		vcpu->arch.cpuid_entries[i].padding[2] = 0;
	}
	vcpu->arch.cpuid_nent = cpuid->nent;
	cpuid_fix_nx_cap(vcpu);
	r = 0;

out_free:
	vfree(cpuid_entries);
out:
	return r;
}

static int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
				     struct kvm_cpuid2 *cpuid,
				     struct kvm_cpuid_entry2 __user *entries)
{
	int r;

	r = -E2BIG;
	if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
		goto out;
	r = -EFAULT;
	if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
			   cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
		goto out;
	vcpu->arch.cpuid_nent = cpuid->nent;
	return 0;

out:
	return r;
}

static int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
				     struct kvm_cpuid2 *cpuid,
				     struct kvm_cpuid_entry2 __user *entries)
{
	int r;

	r = -E2BIG;
	if (cpuid->nent < vcpu->arch.cpuid_nent)
		goto out;
	r = -EFAULT;
	if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
			 vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
		goto out;
	return 0;

out:
	cpuid->nent = vcpu->arch.cpuid_nent;
	return r;
}

static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
			   u32 index)
{
	entry->function = function;
	entry->index = index;
	cpuid_count(entry->function, entry->index,
		    &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
	entry->flags = 0;
}

#define F(x) bit(X86_FEATURE_##x)

static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
			 u32 index, int *nent, int maxnent)
{
	unsigned f_nx = is_efer_nx() ? F(NX) : 0;
#ifdef CONFIG_X86_64
	unsigned f_lm = F(LM);
#else
	unsigned f_lm = 0;
#endif

	/* cpuid 1.edx */
	const u32 kvm_supported_word0_x86_features =
		F(FPU) | F(VME) | F(DE) | F(PSE) |
		F(TSC) | F(MSR) | F(PAE) | F(MCE) |
		F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
		F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLSH) |
		0 /* Reserved, DS, ACPI */ | F(MMX) |
		F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
		0 /* HTT, TM, Reserved, PBE */;
	/* cpuid 0x80000001.edx */
	const u32 kvm_supported_word1_x86_features =
		F(FPU) | F(VME) | F(DE) | F(PSE) |
		F(TSC) | F(MSR) | F(PAE) | F(MCE) |
		F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
		F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
		F(PAT) | F(PSE36) | 0 /* Reserved */ |
		f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
		F(FXSR) | F(FXSR_OPT) | 0 /* GBPAGES */ | 0 /* RDTSCP */ |
		0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
	/* cpuid 1.ecx */
	const u32 kvm_supported_word4_x86_features =
		F(XMM3) | 0 /* Reserved, DTES64, MONITOR */ |
		0 /* DS-CPL, VMX, SMX, EST */ |
		0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
		0 /* Reserved */ | F(CX16) | 0 /* xTPR Update, PDCM */ |
		0 /* Reserved, DCA */ | F(XMM4_1) |
		F(XMM4_2) | 0 /* x2APIC */ | F(MOVBE) | F(POPCNT) |
		0 /* Reserved, XSAVE, OSXSAVE */;
	/* cpuid 0x80000001.ecx */
	const u32 kvm_supported_word6_x86_features =
		F(LAHF_LM) | F(CMP_LEGACY) | F(SVM) | 0 /* ExtApicSpace */ |
		F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
		F(3DNOWPREFETCH) | 0 /* OSVW */ | 0 /* IBS */ | F(SSE5) |
		0 /* SKINIT */ | 0 /* WDT */;

	/* all calls to cpuid_count() should be made on the same cpu */
	get_cpu();
	do_cpuid_1_ent(entry, function, index);
	++*nent;

	switch (function) {
	case 0:
		entry->eax = min(entry->eax, (u32)0xb);
		break;
	case 1:
		entry->edx &= kvm_supported_word0_x86_features;
		entry->ecx &= kvm_supported_word4_x86_features;
		break;
	/* function 2 entries are STATEFUL. That is, repeated cpuid commands
	 * may return different values. This forces us to get_cpu() before
	 * issuing the first command, and also to emulate this annoying behavior
	 * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
	case 2: {
		int t, times = entry->eax & 0xff;

		entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
		entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
		for (t = 1; t < times && *nent < maxnent; ++t) {
			do_cpuid_1_ent(&entry[t], function, 0);
			entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
			++*nent;
		}
		break;
	}
	/* function 4 and 0xb have additional index. */
	case 4: {
		int i, cache_type;

		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
		/* read more entries until cache_type is zero */
		for (i = 1; *nent < maxnent; ++i) {
			cache_type = entry[i - 1].eax & 0x1f;
			if (!cache_type)
				break;
			do_cpuid_1_ent(&entry[i], function, i);
			entry[i].flags |=
			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
			++*nent;
		}
		break;
	}
	case 0xb: {
		int i, level_type;

		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
		/* read more entries until level_type is zero */
		for (i = 1; *nent < maxnent; ++i) {
			level_type = entry[i - 1].ecx & 0xff00;
			if (!level_type)
				break;
			do_cpuid_1_ent(&entry[i], function, i);
			entry[i].flags |=
			       KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
			++*nent;
		}
		break;
	}
	case 0x80000000:
		entry->eax = min(entry->eax, 0x8000001a);
		break;
	case 0x80000001:
		entry->edx &= kvm_supported_word1_x86_features;
		entry->ecx &= kvm_supported_word6_x86_features;
		break;
	}
	put_cpu();
}

#undef F

static int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,
				     struct kvm_cpuid_entry2 __user *entries)
{
	struct kvm_cpuid_entry2 *cpuid_entries;
	int limit, nent = 0, r = -E2BIG;
	u32 func;

	if (cpuid->nent < 1)
		goto out;
	r = -ENOMEM;
	cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
	if (!cpuid_entries)
		goto out;

	do_cpuid_ent(&cpuid_entries[0], 0, 0, &nent, cpuid->nent);
	limit = cpuid_entries[0].eax;
	for (func = 1; func <= limit && nent < cpuid->nent; ++func)
		do_cpuid_ent(&cpuid_entries[nent], func, 0,
			     &nent, cpuid->nent);
	r = -E2BIG;
	if (nent >= cpuid->nent)
		goto out_free;

	do_cpuid_ent(&cpuid_entries[nent], 0x80000000, 0, &nent, cpuid->nent);
	limit = cpuid_entries[nent - 1].eax;
	for (func = 0x80000001; func <= limit && nent < cpuid->nent; ++func)
		do_cpuid_ent(&cpuid_entries[nent], func, 0,
			     &nent, cpuid->nent);
	r = -E2BIG;
	if (nent >= cpuid->nent)
		goto out_free;

	r = -EFAULT;
	if (copy_to_user(entries, cpuid_entries,
			 nent * sizeof(struct kvm_cpuid_entry2)))
		goto out_free;
	cpuid->nent = nent;
	r = 0;

out_free:
	vfree(cpuid_entries);
out:
	return r;
}

static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
				    struct kvm_lapic_state *s)
{
	vcpu_load(vcpu);
	memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);
	vcpu_put(vcpu);

	return 0;
}

static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
				    struct kvm_lapic_state *s)
{
	vcpu_load(vcpu);
	memcpy(vcpu->arch.apic->regs, s->regs, sizeof *s);
	kvm_apic_post_state_restore(vcpu);
	vcpu_put(vcpu);

	return 0;
}

static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
				    struct kvm_interrupt *irq)
{
	if (irq->irq < 0 || irq->irq >= 256)
		return -EINVAL;
	if (irqchip_in_kernel(vcpu->kvm))
		return -ENXIO;
	vcpu_load(vcpu);

	kvm_queue_interrupt(vcpu, irq->irq, false);

	vcpu_put(vcpu);

	return 0;
}

static int kvm_vcpu_ioctl_nmi(struct kvm_vcpu *vcpu)
{
	vcpu_load(vcpu);
	kvm_inject_nmi(vcpu);
	vcpu_put(vcpu);

	return 0;
}

static int vcpu_ioctl_tpr_access_reporting(struct kvm_vcpu *vcpu,
					   struct kvm_tpr_access_ctl *tac)
{
	if (tac->flags)
		return -EINVAL;
	vcpu->arch.tpr_access_reporting = !!tac->enabled;
	return 0;
}

static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
					u64 mcg_cap)
{
	int r;
	unsigned bank_num = mcg_cap & 0xff, bank;

	r = -EINVAL;
	if (!bank_num)
		goto out;
	if (mcg_cap & ~(KVM_MCE_CAP_SUPPORTED | 0xff | 0xff0000))
		goto out;
	r = 0;
	vcpu->arch.mcg_cap = mcg_cap;
	/* Init IA32_MCG_CTL to all 1s */
	if (mcg_cap & MCG_CTL_P)
		vcpu->arch.mcg_ctl = ~(u64)0;
	/* Init IA32_MCi_CTL to all 1s */
	for (bank = 0; bank < bank_num; bank++)
		vcpu->arch.mce_banks[bank*4] = ~(u64)0;
out:
	return r;
}

static int kvm_vcpu_ioctl_x86_set_mce(struct kvm_vcpu *vcpu,
				      struct kvm_x86_mce *mce)
{
	u64 mcg_cap = vcpu->arch.mcg_cap;
	unsigned bank_num = mcg_cap & 0xff;
	u64 *banks = vcpu->arch.mce_banks;

	if (mce->bank >= bank_num || !(mce->status & MCI_STATUS_VAL))
		return -EINVAL;
	/*
	 * if IA32_MCG_CTL is not all 1s, the uncorrected error
	 * reporting is disabled
	 */
	if ((mce->status & MCI_STATUS_UC) && (mcg_cap & MCG_CTL_P) &&
	    vcpu->arch.mcg_ctl != ~(u64)0)
		return 0;
	banks += 4 * mce->bank;
	/*
	 * if IA32_MCi_CTL is not all 1s, the uncorrected error
	 * reporting is disabled for the bank
	 */
	if ((mce->status & MCI_STATUS_UC) && banks[0] != ~(u64)0)
		return 0;
	if (mce->status & MCI_STATUS_UC) {
		if ((vcpu->arch.mcg_status & MCG_STATUS_MCIP) ||
		    !(vcpu->arch.cr4 & X86_CR4_MCE)) {
			printk(KERN_DEBUG "kvm: set_mce: "
			       "injects mce exception while "
			       "previous one is in progress!\n");
			set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
			return 0;
		}
		if (banks[1] & MCI_STATUS_VAL)
			mce->status |= MCI_STATUS_OVER;
		banks[2] = mce->addr;
		banks[3] = mce->misc;
		vcpu->arch.mcg_status = mce->mcg_status;
		banks[1] = mce->status;
		kvm_queue_exception(vcpu, MC_VECTOR);
	} else if (!(banks[1] & MCI_STATUS_VAL)
		   || !(banks[1] & MCI_STATUS_UC)) {
		if (banks[1] & MCI_STATUS_VAL)
			mce->status |= MCI_STATUS_OVER;
		banks[2] = mce->addr;
		banks[3] = mce->misc;
		banks[1] = mce->status;
	} else
		banks[1] |= MCI_STATUS_OVER;
	return 0;
}

long kvm_arch_vcpu_ioctl(struct file *filp,
			 unsigned int ioctl, unsigned long arg)
{
	struct kvm_vcpu *vcpu = filp->private_data;
	void __user *argp = (void __user *)arg;
	int r;
	struct kvm_lapic_state *lapic = NULL;

	switch (ioctl) {
	case KVM_GET_LAPIC: {
		lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);

		r = -ENOMEM;
		if (!lapic)
			goto out;
		r = kvm_vcpu_ioctl_get_lapic(vcpu, lapic);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(argp, lapic, sizeof(struct kvm_lapic_state)))
			goto out;
		r = 0;
		break;
	}
	case KVM_SET_LAPIC: {
		lapic = kmalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
		r = -ENOMEM;
		if (!lapic)
			goto out;
		r = -EFAULT;
		if (copy_from_user(lapic, argp, sizeof(struct kvm_lapic_state)))
			goto out;
		r = kvm_vcpu_ioctl_set_lapic(vcpu, lapic);
		if (r)
			goto out;
		r = 0;
		break;
	}
	case KVM_INTERRUPT: {
		struct kvm_interrupt irq;

		r = -EFAULT;
		if (copy_from_user(&irq, argp, sizeof irq))
			goto out;
		r = kvm_vcpu_ioctl_interrupt(vcpu, &irq);
		if (r)
			goto out;
		r = 0;
		break;
	}
	case KVM_NMI: {
		r = kvm_vcpu_ioctl_nmi(vcpu);
		if (r)
			goto out;
		r = 0;
		break;
	}
	case KVM_SET_CPUID: {
		struct kvm_cpuid __user *cpuid_arg = argp;
		struct kvm_cpuid cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_vcpu_ioctl_set_cpuid(vcpu, &cpuid, cpuid_arg->entries);
		if (r)
			goto out;
		break;
	}
	case KVM_SET_CPUID2: {
		struct kvm_cpuid2 __user *cpuid_arg = argp;
		struct kvm_cpuid2 cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_vcpu_ioctl_set_cpuid2(vcpu, &cpuid,
					      cpuid_arg->entries);
		if (r)
			goto out;
		break;
	}
	case KVM_GET_CPUID2: {
		struct kvm_cpuid2 __user *cpuid_arg = argp;
		struct kvm_cpuid2 cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_vcpu_ioctl_get_cpuid2(vcpu, &cpuid,
					      cpuid_arg->entries);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
			goto out;
		r = 0;
		break;
	}
	case KVM_GET_MSRS:
		r = msr_io(vcpu, argp, kvm_get_msr, 1);
		break;
	case KVM_SET_MSRS:
		r = msr_io(vcpu, argp, do_set_msr, 0);
		break;
	case KVM_TPR_ACCESS_REPORTING: {
		struct kvm_tpr_access_ctl tac;

		r = -EFAULT;
		if (copy_from_user(&tac, argp, sizeof tac))
			goto out;
		r = vcpu_ioctl_tpr_access_reporting(vcpu, &tac);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(argp, &tac, sizeof tac))
			goto out;
		r = 0;
		break;
	};
	case KVM_SET_VAPIC_ADDR: {
		struct kvm_vapic_addr va;

		r = -EINVAL;
		if (!irqchip_in_kernel(vcpu->kvm))
			goto out;
		r = -EFAULT;
		if (copy_from_user(&va, argp, sizeof va))
			goto out;
		r = 0;
		kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr);
		break;
	}
	case KVM_X86_SETUP_MCE: {
		u64 mcg_cap;

		r = -EFAULT;
		if (copy_from_user(&mcg_cap, argp, sizeof mcg_cap))
			goto out;
		r = kvm_vcpu_ioctl_x86_setup_mce(vcpu, mcg_cap);
		break;
	}
	case KVM_X86_SET_MCE: {
		struct kvm_x86_mce mce;

		r = -EFAULT;
		if (copy_from_user(&mce, argp, sizeof mce))
			goto out;
		r = kvm_vcpu_ioctl_x86_set_mce(vcpu, &mce);
		break;
	}
	default:
		r = -EINVAL;
	}
out:
	kfree(lapic);
	return r;
}

static int kvm_vm_ioctl_set_tss_addr(struct kvm *kvm, unsigned long addr)
{
	int ret;

	if (addr > (unsigned int)(-3 * PAGE_SIZE))
		return -1;
	ret = kvm_x86_ops->set_tss_addr(kvm, addr);
	return ret;
}

static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
					  u32 kvm_nr_mmu_pages)
{
	if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES)
		return -EINVAL;

	down_write(&kvm->slots_lock);
	spin_lock(&kvm->mmu_lock);

	kvm_mmu_change_mmu_pages(kvm, kvm_nr_mmu_pages);
	kvm->arch.n_requested_mmu_pages = kvm_nr_mmu_pages;

	spin_unlock(&kvm->mmu_lock);
	up_write(&kvm->slots_lock);
	return 0;
}

static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
{
	return kvm->arch.n_alloc_mmu_pages;
}

gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
	int i;
	struct kvm_mem_alias *alias;

	for (i = 0; i < kvm->arch.naliases; ++i) {
		alias = &kvm->arch.aliases[i];
		if (gfn >= alias->base_gfn
		    && gfn < alias->base_gfn + alias->npages)
			return alias->target_gfn + gfn - alias->base_gfn;
	}
	return gfn;
}

/*
 * Set a new alias region.  Aliases map a portion of physical memory into
 * another portion.  This is useful for memory windows, for example the PC
 * VGA region.
 */
static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
					 struct kvm_memory_alias *alias)
{
	int r, n;
	struct kvm_mem_alias *p;

	r = -EINVAL;
	/* General sanity checks */
	if (alias->memory_size & (PAGE_SIZE - 1))
		goto out;
	if (alias->guest_phys_addr & (PAGE_SIZE - 1))
		goto out;
	if (alias->slot >= KVM_ALIAS_SLOTS)
		goto out;
	if (alias->guest_phys_addr + alias->memory_size
	    < alias->guest_phys_addr)
		goto out;
	if (alias->target_phys_addr + alias->memory_size
	    < alias->target_phys_addr)
		goto out;

	down_write(&kvm->slots_lock);
	spin_lock(&kvm->mmu_lock);

	p = &kvm->arch.aliases[alias->slot];
	p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
	p->npages = alias->memory_size >> PAGE_SHIFT;
	p->target_gfn = alias->target_phys_addr >> PAGE_SHIFT;

	for (n = KVM_ALIAS_SLOTS; n > 0; --n)
		if (kvm->arch.aliases[n - 1].npages)
			break;
	kvm->arch.naliases = n;

	spin_unlock(&kvm->mmu_lock);
	kvm_mmu_zap_all(kvm);

	up_write(&kvm->slots_lock);

	return 0;

out:
	return r;
}

static int kvm_vm_ioctl_get_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
{
	int r;

	r = 0;
	switch (chip->chip_id) {
	case KVM_IRQCHIP_PIC_MASTER:
		memcpy(&chip->chip.pic,
			&pic_irqchip(kvm)->pics[0],
			sizeof(struct kvm_pic_state));
		break;
	case KVM_IRQCHIP_PIC_SLAVE:
		memcpy(&chip->chip.pic,
			&pic_irqchip(kvm)->pics[1],
			sizeof(struct kvm_pic_state));
		break;
	case KVM_IRQCHIP_IOAPIC:
		memcpy(&chip->chip.ioapic,
			ioapic_irqchip(kvm),
			sizeof(struct kvm_ioapic_state));
		break;
	default:
		r = -EINVAL;
		break;
	}
	return r;
}

static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
{
	int r;

	r = 0;
	switch (chip->chip_id) {
	case KVM_IRQCHIP_PIC_MASTER:
		memcpy(&pic_irqchip(kvm)->pics[0],
			&chip->chip.pic,
			sizeof(struct kvm_pic_state));
		break;
	case KVM_IRQCHIP_PIC_SLAVE:
		memcpy(&pic_irqchip(kvm)->pics[1],
			&chip->chip.pic,
			sizeof(struct kvm_pic_state));
		break;
	case KVM_IRQCHIP_IOAPIC:
		memcpy(ioapic_irqchip(kvm),
			&chip->chip.ioapic,
			sizeof(struct kvm_ioapic_state));
		break;
	default:
		r = -EINVAL;
		break;
	}
	kvm_pic_update_irq(pic_irqchip(kvm));
	return r;
}

static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
{
	int r = 0;

	memcpy(ps, &kvm->arch.vpit->pit_state, sizeof(struct kvm_pit_state));
	return r;
}

static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
{
	int r = 0;

	memcpy(&kvm->arch.vpit->pit_state, ps, sizeof(struct kvm_pit_state));
	kvm_pit_load_count(kvm, 0, ps->channels[0].count);
	return r;
}

static int kvm_vm_ioctl_reinject(struct kvm *kvm,
				 struct kvm_reinject_control *control)
{
	if (!kvm->arch.vpit)
		return -ENXIO;
	kvm->arch.vpit->pit_state.pit_timer.reinject = control->pit_reinject;
	return 0;
}

/*
 * Get (and clear) the dirty memory log for a memory slot.
 */
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
				      struct kvm_dirty_log *log)
{
	int r;
	int n;
	struct kvm_memory_slot *memslot;
	int is_dirty = 0;

	down_write(&kvm->slots_lock);

	r = kvm_get_dirty_log(kvm, log, &is_dirty);
	if (r)
		goto out;

	/* If nothing is dirty, don't bother messing with page tables. */
	if (is_dirty) {
		spin_lock(&kvm->mmu_lock);
		kvm_mmu_slot_remove_write_access(kvm, log->slot);
		spin_unlock(&kvm->mmu_lock);
		kvm_flush_remote_tlbs(kvm);
		memslot = &kvm->memslots[log->slot];
		n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
		memset(memslot->dirty_bitmap, 0, n);
	}
	r = 0;
out:
	up_write(&kvm->slots_lock);
	return r;
}

long kvm_arch_vm_ioctl(struct file *filp,
		       unsigned int ioctl, unsigned long arg)
{
	struct kvm *kvm = filp->private_data;
	void __user *argp = (void __user *)arg;
	int r = -EINVAL;
	/*
	 * This union makes it completely explicit to gcc-3.x
	 * that these two variables' stack usage should be
	 * combined, not added together.
	 */
	union {
		struct kvm_pit_state ps;
		struct kvm_memory_alias alias;
		struct kvm_pit_config pit_config;
	} u;

	switch (ioctl) {
	case KVM_SET_TSS_ADDR:
		r = kvm_vm_ioctl_set_tss_addr(kvm, arg);
		if (r < 0)
			goto out;
		break;
	case KVM_SET_MEMORY_REGION: {
		struct kvm_memory_region kvm_mem;
		struct kvm_userspace_memory_region kvm_userspace_mem;

		r = -EFAULT;
		if (copy_from_user(&kvm_mem, argp, sizeof kvm_mem))
			goto out;
		kvm_userspace_mem.slot = kvm_mem.slot;
		kvm_userspace_mem.flags = kvm_mem.flags;
		kvm_userspace_mem.guest_phys_addr = kvm_mem.guest_phys_addr;
		kvm_userspace_mem.memory_size = kvm_mem.memory_size;
		r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem, 0);
		if (r)
			goto out;
		break;
	}
	case KVM_SET_NR_MMU_PAGES:
		r = kvm_vm_ioctl_set_nr_mmu_pages(kvm, arg);
		if (r)
			goto out;
		break;
	case KVM_GET_NR_MMU_PAGES:
		r = kvm_vm_ioctl_get_nr_mmu_pages(kvm);
		break;
	case KVM_SET_MEMORY_ALIAS:
		r = -EFAULT;
		if (copy_from_user(&u.alias, argp, sizeof(struct kvm_memory_alias)))
			goto out;
		r = kvm_vm_ioctl_set_memory_alias(kvm, &u.alias);
		if (r)
			goto out;
		break;
	case KVM_CREATE_IRQCHIP:
		r = -ENOMEM;
		kvm->arch.vpic = kvm_create_pic(kvm);
		if (kvm->arch.vpic) {
			r = kvm_ioapic_init(kvm);
			if (r) {
				kfree(kvm->arch.vpic);
				kvm->arch.vpic = NULL;
				goto out;
			}
		} else
			goto out;
		r = kvm_setup_default_irq_routing(kvm);
		if (r) {
			kfree(kvm->arch.vpic);
			kfree(kvm->arch.vioapic);
			goto out;
		}
		break;
	case KVM_CREATE_PIT:
		u.pit_config.flags = KVM_PIT_SPEAKER_DUMMY;
		goto create_pit;
	case KVM_CREATE_PIT2:
		r = -EFAULT;
		if (copy_from_user(&u.pit_config, argp,
				   sizeof(struct kvm_pit_config)))
			goto out;
	create_pit:
		mutex_lock(&kvm->lock);
		r = -EEXIST;
		if (kvm->arch.vpit)
			goto create_pit_unlock;
		r = -ENOMEM;
		kvm->arch.vpit = kvm_create_pit(kvm, u.pit_config.flags);
		if (kvm->arch.vpit)
			r = 0;
	create_pit_unlock:
		mutex_unlock(&kvm->lock);
		break;
	case KVM_IRQ_LINE_STATUS:
	case KVM_IRQ_LINE: {
		struct kvm_irq_level irq_event;

		r = -EFAULT;
		if (copy_from_user(&irq_event, argp, sizeof irq_event))
			goto out;
		if (irqchip_in_kernel(kvm)) {
			__s32 status;
			mutex_lock(&kvm->irq_lock);
			status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
					irq_event.irq, irq_event.level);
			mutex_unlock(&kvm->irq_lock);
			if (ioctl == KVM_IRQ_LINE_STATUS) {
				irq_event.status = status;
				if (copy_to_user(argp, &irq_event,
							sizeof irq_event))
					goto out;
			}
			r = 0;
		}
		break;
	}
	case KVM_GET_IRQCHIP: {
		/* 0: PIC master, 1: PIC slave, 2: IOAPIC */
		struct kvm_irqchip *chip = kmalloc(sizeof(*chip), GFP_KERNEL);

		r = -ENOMEM;
		if (!chip)
			goto out;
		r = -EFAULT;
		if (copy_from_user(chip, argp, sizeof *chip))
			goto get_irqchip_out;
		r = -ENXIO;
		if (!irqchip_in_kernel(kvm))
			goto get_irqchip_out;
		r = kvm_vm_ioctl_get_irqchip(kvm, chip);
		if (r)
			goto get_irqchip_out;
		r = -EFAULT;
		if (copy_to_user(argp, chip, sizeof *chip))
			goto get_irqchip_out;
		r = 0;
	get_irqchip_out:
		kfree(chip);
		if (r)
			goto out;
		break;
	}
	case KVM_SET_IRQCHIP: {
		/* 0: PIC master, 1: PIC slave, 2: IOAPIC */
		struct kvm_irqchip *chip = kmalloc(sizeof(*chip), GFP_KERNEL);

		r = -ENOMEM;
		if (!chip)
			goto out;
		r = -EFAULT;
		if (copy_from_user(chip, argp, sizeof *chip))
			goto set_irqchip_out;
		r = -ENXIO;
		if (!irqchip_in_kernel(kvm))
			goto set_irqchip_out;
		r = kvm_vm_ioctl_set_irqchip(kvm, chip);
		if (r)
			goto set_irqchip_out;
		r = 0;
	set_irqchip_out:
		kfree(chip);
		if (r)
			goto out;
		break;
	}
	case KVM_GET_PIT: {
		r = -EFAULT;
		if (copy_from_user(&u.ps, argp, sizeof(struct kvm_pit_state)))
			goto out;
		r = -ENXIO;
		if (!kvm->arch.vpit)
			goto out;
		r = kvm_vm_ioctl_get_pit(kvm, &u.ps);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(argp, &u.ps, sizeof(struct kvm_pit_state)))
			goto out;
		r = 0;
		break;
	}
	case KVM_SET_PIT: {
		r = -EFAULT;
		if (copy_from_user(&u.ps, argp, sizeof u.ps))
			goto out;
		r = -ENXIO;
		if (!kvm->arch.vpit)
			goto out;
		r = kvm_vm_ioctl_set_pit(kvm, &u.ps);
		if (r)
			goto out;
		r = 0;
		break;
	}
	case KVM_REINJECT_CONTROL: {
		struct kvm_reinject_control control;
		r =  -EFAULT;
		if (copy_from_user(&control, argp, sizeof(control)))
			goto out;
		r = kvm_vm_ioctl_reinject(kvm, &control);
		if (r)
			goto out;
		r = 0;
		break;
	}
	default:
		;
	}
out:
	return r;
}

static void kvm_init_msr_list(void)
{
	u32 dummy[2];
	unsigned i, j;

	for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
		if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
			continue;
		if (j < i)
			msrs_to_save[j] = msrs_to_save[i];
		j++;
	}
	num_msrs_to_save = j;
}

/*
 * Only apic need an MMIO device hook, so shortcut now..
 */
static struct kvm_io_device *vcpu_find_pervcpu_dev(struct kvm_vcpu *vcpu,
						gpa_t addr, int len,
						int is_write)
{
	struct kvm_io_device *dev;

	if (vcpu->arch.apic) {
		dev = &vcpu->arch.apic->dev;
		if (kvm_iodevice_in_range(dev, addr, len, is_write))
			return dev;
	}
	return NULL;
}


static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
						gpa_t addr, int len,
						int is_write)
{
	struct kvm_io_device *dev;

	dev = vcpu_find_pervcpu_dev(vcpu, addr, len, is_write);
	if (dev == NULL)
		dev = kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr, len,
					  is_write);
	return dev;
}

static int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
			       struct kvm_vcpu *vcpu)
{
	void *data = val;
	int r = X86EMUL_CONTINUE;

	while (bytes) {
		gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
		unsigned offset = addr & (PAGE_SIZE-1);
		unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset);
		int ret;

		if (gpa == UNMAPPED_GVA) {
			r = X86EMUL_PROPAGATE_FAULT;
			goto out;
		}
		ret = kvm_read_guest(vcpu->kvm, gpa, data, toread);
		if (ret < 0) {
			r = X86EMUL_UNHANDLEABLE;
			goto out;
		}

		bytes -= toread;
		data += toread;
		addr += toread;
	}
out:
	return r;
}

static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
				struct kvm_vcpu *vcpu)
{
	void *data = val;
	int r = X86EMUL_CONTINUE;

	while (bytes) {
		gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
		unsigned offset = addr & (PAGE_SIZE-1);
		unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
		int ret;

		if (gpa == UNMAPPED_GVA) {
			r = X86EMUL_PROPAGATE_FAULT;
			goto out;
		}
		ret = kvm_write_guest(vcpu->kvm, gpa, data, towrite);
		if (ret < 0) {
			r = X86EMUL_UNHANDLEABLE;
			goto out;
		}

		bytes -= towrite;
		data += towrite;
		addr += towrite;
	}
out:
	return r;
}


static int emulator_read_emulated(unsigned long addr,
				  void *val,
				  unsigned int bytes,
				  struct kvm_vcpu *vcpu)
{
	struct kvm_io_device *mmio_dev;
	gpa_t                 gpa;

	if (vcpu->mmio_read_completed) {
		memcpy(val, vcpu->mmio_data, bytes);
		vcpu->mmio_read_completed = 0;
		return X86EMUL_CONTINUE;
	}

	gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);

	/* For APIC access vmexit */
	if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
		goto mmio;

	if (kvm_read_guest_virt(addr, val, bytes, vcpu)
				== X86EMUL_CONTINUE)
		return X86EMUL_CONTINUE;
	if (gpa == UNMAPPED_GVA)
		return X86EMUL_PROPAGATE_FAULT;

mmio:
	/*
	 * Is this MMIO handled locally?
	 */
	mutex_lock(&vcpu->kvm->lock);
	mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 0);
	mutex_unlock(&vcpu->kvm->lock);
	if (mmio_dev) {
		kvm_iodevice_read(mmio_dev, gpa, bytes, val);
		return X86EMUL_CONTINUE;
	}

	vcpu->mmio_needed = 1;
	vcpu->mmio_phys_addr = gpa;
	vcpu->mmio_size = bytes;
	vcpu->mmio_is_write = 0;

	return X86EMUL_UNHANDLEABLE;
}

int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
			  const void *val, int bytes)
{
	int ret;

	ret = kvm_write_guest(vcpu->kvm, gpa, val, bytes);
	if (ret < 0)
		return 0;
	kvm_mmu_pte_write(vcpu, gpa, val, bytes, 1);
	return 1;
}

static int emulator_write_emulated_onepage(unsigned long addr,
					   const void *val,
					   unsigned int bytes,
					   struct kvm_vcpu *vcpu)
{
	struct kvm_io_device *mmio_dev;
	gpa_t                 gpa;

	gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);

	if (gpa == UNMAPPED_GVA) {
		kvm_inject_page_fault(vcpu, addr, 2);
		return X86EMUL_PROPAGATE_FAULT;
	}

	/* For APIC access vmexit */
	if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
		goto mmio;

	if (emulator_write_phys(vcpu, gpa, val, bytes))
		return X86EMUL_CONTINUE;

mmio:
	/*
	 * Is this MMIO handled locally?
	 */
	mutex_lock(&vcpu->kvm->lock);
	mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 1);
	mutex_unlock(&vcpu->kvm->lock);
	if (mmio_dev) {
		kvm_iodevice_write(mmio_dev, gpa, bytes, val);
		return X86EMUL_CONTINUE;
	}

	vcpu->mmio_needed = 1;
	vcpu->mmio_phys_addr = gpa;
	vcpu->mmio_size = bytes;
	vcpu->mmio_is_write = 1;
	memcpy(vcpu->mmio_data, val, bytes);

	return X86EMUL_CONTINUE;
}

int emulator_write_emulated(unsigned long addr,
				   const void *val,
				   unsigned int bytes,
				   struct kvm_vcpu *vcpu)
{
	/* Crossing a page boundary? */
	if (((addr + bytes - 1) ^ addr) & PAGE_MASK) {
		int rc, now;

		now = -addr & ~PAGE_MASK;
		rc = emulator_write_emulated_onepage(addr, val, now, vcpu);
		if (rc != X86EMUL_CONTINUE)
			return rc;
		addr += now;
		val += now;
		bytes -= now;
	}
	return emulator_write_emulated_onepage(addr, val, bytes, vcpu);
}
EXPORT_SYMBOL_GPL(emulator_write_emulated);

static int emulator_cmpxchg_emulated(unsigned long addr,
				     const void *old,
				     const void *new,
				     unsigned int bytes,
				     struct kvm_vcpu *vcpu)
{
	static int reported;

	if (!reported) {
		reported = 1;
		printk(KERN_WARNING "kvm: emulating exchange as write\n");
	}
#ifndef CONFIG_X86_64
	/* guests cmpxchg8b have to be emulated atomically */
	if (bytes == 8) {
		gpa_t gpa;
		struct page *page;
		char *kaddr;
		u64 val;

		gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);

		if (gpa == UNMAPPED_GVA ||
		   (gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
			goto emul_write;

		if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK))
			goto emul_write;

		val = *(u64 *)new;

		page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);

		kaddr = kmap_atomic(page, KM_USER0);
		set_64bit((u64 *)(kaddr + offset_in_page(gpa)), val);
		kunmap_atomic(kaddr, KM_USER0);
		kvm_release_page_dirty(page);
	}
emul_write:
#endif

	return emulator_write_emulated(addr, new, bytes, vcpu);
}

static unsigned long get_segment_base(struct kvm_vcpu *vcpu, int seg)
{
	return kvm_x86_ops->get_segment_base(vcpu, seg);
}

int emulate_invlpg(struct kvm_vcpu *vcpu, gva_t address)
{
	kvm_mmu_invlpg(vcpu, address);
	return X86EMUL_CONTINUE;
}

int emulate_clts(struct kvm_vcpu *vcpu)
{
	KVMTRACE_0D(CLTS, vcpu, handler);
	kvm_x86_ops->set_cr0(vcpu, vcpu->arch.cr0 & ~X86_CR0_TS);
	return X86EMUL_CONTINUE;
}

int emulator_get_dr(struct x86_emulate_ctxt *ctxt, int dr, unsigned long *dest)
{
	struct kvm_vcpu *vcpu = ctxt->vcpu;

	switch (dr) {
	case 0 ... 3:
		*dest = kvm_x86_ops->get_dr(vcpu, dr);
		return X86EMUL_CONTINUE;
	default:
		pr_unimpl(vcpu, "%s: unexpected dr %u\n", __func__, dr);
		return X86EMUL_UNHANDLEABLE;
	}
}

int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr, unsigned long value)
{
	unsigned long mask = (ctxt->mode == X86EMUL_MODE_PROT64) ? ~0ULL : ~0U;
	int exception;

	kvm_x86_ops->set_dr(ctxt->vcpu, dr, value & mask, &exception);
	if (exception) {
		/* FIXME: better handling */
		return X86EMUL_UNHANDLEABLE;
	}
	return X86EMUL_CONTINUE;
}

void kvm_report_emulation_failure(struct kvm_vcpu *vcpu, const char *context)
{
	u8 opcodes[4];
	unsigned long rip = kvm_rip_read(vcpu);
	unsigned long rip_linear;

	if (!printk_ratelimit())
		return;

	rip_linear = rip + get_segment_base(vcpu, VCPU_SREG_CS);

	kvm_read_guest_virt(rip_linear, (void *)opcodes, 4, vcpu);

	printk(KERN_ERR "emulation failed (%s) rip %lx %02x %02x %02x %02x\n",
	       context, rip, opcodes[0], opcodes[1], opcodes[2], opcodes[3]);
}
EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);

static struct x86_emulate_ops emulate_ops = {
	.read_std            = kvm_read_guest_virt,
	.read_emulated       = emulator_read_emulated,
	.write_emulated      = emulator_write_emulated,
	.cmpxchg_emulated    = emulator_cmpxchg_emulated,
};

static void cache_all_regs(struct kvm_vcpu *vcpu)
{
	kvm_register_read(vcpu, VCPU_REGS_RAX);
	kvm_register_read(vcpu, VCPU_REGS_RSP);
	kvm_register_read(vcpu, VCPU_REGS_RIP);
	vcpu->arch.regs_dirty = ~0;
}

int emulate_instruction(struct kvm_vcpu *vcpu,
			struct kvm_run *run,
			unsigned long cr2,
			u16 error_code,
			int emulation_type)
{
	int r, shadow_mask;
	struct decode_cache *c;

	kvm_clear_exception_queue(vcpu);
	vcpu->arch.mmio_fault_cr2 = cr2;
	/*
	 * TODO: fix x86_emulate.c to use guest_read/write_register
	 * instead of direct ->regs accesses, can save hundred cycles
	 * on Intel for instructions that don't read/change RSP, for
	 * for example.
	 */
	cache_all_regs(vcpu);

	vcpu->mmio_is_write = 0;
	vcpu->arch.pio.string = 0;

	if (!(emulation_type & EMULTYPE_NO_DECODE)) {
		int cs_db, cs_l;
		kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);

		vcpu->arch.emulate_ctxt.vcpu = vcpu;
		vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
		vcpu->arch.emulate_ctxt.mode =
			(vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)
			? X86EMUL_MODE_REAL : cs_l
			? X86EMUL_MODE_PROT64 :	cs_db
			? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;

		r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);

		/* Reject the instructions other than VMCALL/VMMCALL when
		 * try to emulate invalid opcode */
		c = &vcpu->arch.emulate_ctxt.decode;
		if ((emulation_type & EMULTYPE_TRAP_UD) &&
		    (!(c->twobyte && c->b == 0x01 &&
		      (c->modrm_reg == 0 || c->modrm_reg == 3) &&
		       c->modrm_mod == 3 && c->modrm_rm == 1)))
			return EMULATE_FAIL;

		++vcpu->stat.insn_emulation;
		if (r)  {
			++vcpu->stat.insn_emulation_fail;
			if (kvm_mmu_unprotect_page_virt(vcpu, cr2))
				return EMULATE_DONE;
			return EMULATE_FAIL;
		}
	}

	if (emulation_type & EMULTYPE_SKIP) {
		kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.decode.eip);
		return EMULATE_DONE;
	}

	r = x86_emulate_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
	shadow_mask = vcpu->arch.emulate_ctxt.interruptibility;

	if (r == 0)
		kvm_x86_ops->set_interrupt_shadow(vcpu, shadow_mask);

	if (vcpu->arch.pio.string)
		return EMULATE_DO_MMIO;

	if ((r || vcpu->mmio_is_write) && run) {
		run->exit_reason = KVM_EXIT_MMIO;
		run->mmio.phys_addr = vcpu->mmio_phys_addr;
		memcpy(run->mmio.data, vcpu->mmio_data, 8);
		run->mmio.len = vcpu->mmio_size;
		run->mmio.is_write = vcpu->mmio_is_write;
	}

	if (r) {
		if (kvm_mmu_unprotect_page_virt(vcpu, cr2))
			return EMULATE_DONE;
		if (!vcpu->mmio_needed) {
			kvm_report_emulation_failure(vcpu, "mmio");
			return EMULATE_FAIL;
		}
		return EMULATE_DO_MMIO;
	}

	kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);

	if (vcpu->mmio_is_write) {
		vcpu->mmio_needed = 0;
		return EMULATE_DO_MMIO;
	}

	return EMULATE_DONE;
}
EXPORT_SYMBOL_GPL(emulate_instruction);

static int pio_copy_data(struct kvm_vcpu *vcpu)
{
	void *p = vcpu->arch.pio_data;
	gva_t q = vcpu->arch.pio.guest_gva;
	unsigned bytes;
	int ret;

	bytes = vcpu->arch.pio.size * vcpu->arch.pio.cur_count;
	if (vcpu->arch.pio.in)
		ret = kvm_write_guest_virt(q, p, bytes, vcpu);
	else
		ret = kvm_read_guest_virt(q, p, bytes, vcpu);
	return ret;
}

int complete_pio(struct kvm_vcpu *vcpu)
{
	struct kvm_pio_request *io = &vcpu->arch.pio;
	long delta;
	int r;
	unsigned long val;

	if (!io->string) {
		if (io->in) {
			val = kvm_register_read(vcpu, VCPU_REGS_RAX);
			memcpy(&val, vcpu->arch.pio_data, io->size);
			kvm_register_write(vcpu, VCPU_REGS_RAX, val);
		}
	} else {
		if (io->in) {
			r = pio_copy_data(vcpu);
			if (r)
				return r;
		}

		delta = 1;
		if (io->rep) {
			delta *= io->cur_count;
			/*
			 * The size of the register should really depend on
			 * current address size.
			 */
			val = kvm_register_read(vcpu, VCPU_REGS_RCX);
			val -= delta;
			kvm_register_write(vcpu, VCPU_REGS_RCX, val);
		}
		if (io->down)
			delta = -delta;
		delta *= io->size;
		if (io->in) {
			val = kvm_register_read(vcpu, VCPU_REGS_RDI);
			val += delta;
			kvm_register_write(vcpu, VCPU_REGS_RDI, val);
		} else {
			val = kvm_register_read(vcpu, VCPU_REGS_RSI);
			val += delta;
			kvm_register_write(vcpu, VCPU_REGS_RSI, val);
		}
	}

	io->count -= io->cur_count;
	io->cur_count = 0;

	return 0;
}

static void kernel_pio(struct kvm_io_device *pio_dev,
		       struct kvm_vcpu *vcpu,
		       void *pd)
{
	/* TODO: String I/O for in kernel device */

	if (vcpu->arch.pio.in)
		kvm_iodevice_read(pio_dev, vcpu->arch.pio.port,
				  vcpu->arch.pio.size,
				  pd);
	else
		kvm_iodevice_write(pio_dev, vcpu->arch.pio.port,
				   vcpu->arch.pio.size,
				   pd);
}

static void pio_string_write(struct kvm_io_device *pio_dev,
			     struct kvm_vcpu *vcpu)
{
	struct kvm_pio_request *io = &vcpu->arch.pio;
	void *pd = vcpu->arch.pio_data;
	int i;

	for (i = 0; i < io->cur_count; i++) {
		kvm_iodevice_write(pio_dev, io->port,
				   io->size,
				   pd);
		pd += io->size;
	}
}

static struct kvm_io_device *vcpu_find_pio_dev(struct kvm_vcpu *vcpu,
					       gpa_t addr, int len,
					       int is_write)
{
	return kvm_io_bus_find_dev(&vcpu->kvm->pio_bus, addr, len, is_write);
}

int kvm_emulate_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
		  int size, unsigned port)
{
	struct kvm_io_device *pio_dev;
	unsigned long val;

	vcpu->run->exit_reason = KVM_EXIT_IO;
	vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
	vcpu->run->io.size = vcpu->arch.pio.size = size;
	vcpu->run->io.data_offset = KVM_PIO_PAGE_OFFSET * PAGE_SIZE;
	vcpu->run->io.count = vcpu->arch.pio.count = vcpu->arch.pio.cur_count = 1;
	vcpu->run->io.port = vcpu->arch.pio.port = port;
	vcpu->arch.pio.in = in;
	vcpu->arch.pio.string = 0;
	vcpu->arch.pio.down = 0;
	vcpu->arch.pio.rep = 0;

	if (vcpu->run->io.direction == KVM_EXIT_IO_IN)
		KVMTRACE_2D(IO_READ, vcpu, vcpu->run->io.port, (u32)size,
			    handler);
	else
		KVMTRACE_2D(IO_WRITE, vcpu, vcpu->run->io.port, (u32)size,
			    handler);

	val = kvm_register_read(vcpu, VCPU_REGS_RAX);
	memcpy(vcpu->arch.pio_data, &val, 4);

	mutex_lock(&vcpu->kvm->lock);
	pio_dev = vcpu_find_pio_dev(vcpu, port, size, !in);
	mutex_unlock(&vcpu->kvm->lock);
	if (pio_dev) {
		kernel_pio(pio_dev, vcpu, vcpu->arch.pio_data);
		complete_pio(vcpu);
		return 1;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(kvm_emulate_pio);

int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
		  int size, unsigned long count, int down,
		  gva_t address, int rep, unsigned port)
{
	unsigned now, in_page;
	int ret = 0;
	struct kvm_io_device *pio_dev;

	vcpu->run->exit_reason = KVM_EXIT_IO;
	vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
	vcpu->run->io.size = vcpu->arch.pio.size = size;
	vcpu->run->io.data_offset = KVM_PIO_PAGE_OFFSET * PAGE_SIZE;
	vcpu->run->io.count = vcpu->arch.pio.count = vcpu->arch.pio.cur_count = count;
	vcpu->run->io.port = vcpu->arch.pio.port = port;
	vcpu->arch.pio.in = in;
	vcpu->arch.pio.string = 1;
	vcpu->arch.pio.down = down;
	vcpu->arch.pio.rep = rep;

	if (vcpu->run->io.direction == KVM_EXIT_IO_IN)
		KVMTRACE_2D(IO_READ, vcpu, vcpu->run->io.port, (u32)size,
			    handler);
	else
		KVMTRACE_2D(IO_WRITE, vcpu, vcpu->run->io.port, (u32)size,
			    handler);

	if (!count) {
		kvm_x86_ops->skip_emulated_instruction(vcpu);
		return 1;
	}

	if (!down)
		in_page = PAGE_SIZE - offset_in_page(address);
	else
		in_page = offset_in_page(address) + size;
	now = min(count, (unsigned long)in_page / size);
	if (!now)
		now = 1;
	if (down) {
		/*
		 * String I/O in reverse.  Yuck.  Kill the guest, fix later.
		 */
		pr_unimpl(vcpu, "guest string pio down\n");
		kvm_inject_gp(vcpu, 0);
		return 1;
	}
	vcpu->run->io.count = now;
	vcpu->arch.pio.cur_count = now;

	if (vcpu->arch.pio.cur_count == vcpu->arch.pio.count)
		kvm_x86_ops->skip_emulated_instruction(vcpu);

	vcpu->arch.pio.guest_gva = address;

	mutex_lock(&vcpu->kvm->lock);
	pio_dev = vcpu_find_pio_dev(vcpu, port,
				    vcpu->arch.pio.cur_count,
				    !vcpu->arch.pio.in);
	mutex_unlock(&vcpu->kvm->lock);

	if (!vcpu->arch.pio.in) {
		/* string PIO write */
		ret = pio_copy_data(vcpu);
		if (ret == X86EMUL_PROPAGATE_FAULT) {
			kvm_inject_gp(vcpu, 0);
			return 1;
		}
		if (ret == 0 && pio_dev) {
			pio_string_write(pio_dev, vcpu);
			complete_pio(vcpu);
			if (vcpu->arch.pio.count == 0)
				ret = 1;
		}
	} else if (pio_dev)
		pr_unimpl(vcpu, "no string pio read support yet, "
		       "port %x size %d count %ld\n",
			port, size, count);

	return ret;
}
EXPORT_SYMBOL_GPL(kvm_emulate_pio_string);

static void bounce_off(void *info)
{
	/* nothing */
}

static unsigned int  ref_freq;
static unsigned long tsc_khz_ref;

static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
				     void *data)
{
	struct cpufreq_freqs *freq = data;
	struct kvm *kvm;
	struct kvm_vcpu *vcpu;
	int i, send_ipi = 0;

	if (!ref_freq)
		ref_freq = freq->old;

	if (val == CPUFREQ_PRECHANGE && freq->old > freq->new)
		return 0;
	if (val == CPUFREQ_POSTCHANGE && freq->old < freq->new)
		return 0;
	per_cpu(cpu_tsc_khz, freq->cpu) = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new);

	spin_lock(&kvm_lock);
	list_for_each_entry(kvm, &vm_list, vm_list) {
		kvm_for_each_vcpu(i, vcpu, kvm) {
			if (vcpu->cpu != freq->cpu)
				continue;
			if (!kvm_request_guest_time_update(vcpu))
				continue;
			if (vcpu->cpu != smp_processor_id())
				send_ipi++;
		}
	}
	spin_unlock(&kvm_lock);

	if (freq->old < freq->new && send_ipi) {
		/*
		 * We upscale the frequency.  Must make the guest
		 * doesn't see old kvmclock values while running with
		 * the new frequency, otherwise we risk the guest sees
		 * time go backwards.
		 *
		 * In case we update the frequency for another cpu
		 * (which might be in guest context) send an interrupt
		 * to kick the cpu out of guest context.  Next time
		 * guest context is entered kvmclock will be updated,
		 * so the guest will not see stale values.
		 */
		smp_call_function_single(freq->cpu, bounce_off, NULL, 1);
	}
	return 0;
}

static struct notifier_block kvmclock_cpufreq_notifier_block = {
        .notifier_call  = kvmclock_cpufreq_notifier
};

int kvm_arch_init(void *opaque)
{
	int r, cpu;
	struct kvm_x86_ops *ops = (struct kvm_x86_ops *)opaque;

	if (kvm_x86_ops) {
		printk(KERN_ERR "kvm: already loaded the other module\n");
		r = -EEXIST;
		goto out;
	}

	if (!ops->cpu_has_kvm_support()) {
		printk(KERN_ERR "kvm: no hardware support\n");
		r = -EOPNOTSUPP;
		goto out;
	}
	if (ops->disabled_by_bios()) {
		printk(KERN_ERR "kvm: disabled by bios\n");
		r = -EOPNOTSUPP;
		goto out;
	}

	r = kvm_mmu_module_init();
	if (r)
		goto out;

	kvm_init_msr_list();

	kvm_x86_ops = ops;
	kvm_mmu_set_nonpresent_ptes(0ull, 0ull);
	kvm_mmu_set_base_ptes(PT_PRESENT_MASK);
	kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
			PT_DIRTY_MASK, PT64_NX_MASK, 0);

	for_each_possible_cpu(cpu)
		per_cpu(cpu_tsc_khz, cpu) = tsc_khz;
	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
		tsc_khz_ref = tsc_khz;
		cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block,
					  CPUFREQ_TRANSITION_NOTIFIER);
	}

	return 0;

out:
	return r;
}

void kvm_arch_exit(void)
{
	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
		cpufreq_unregister_notifier(&kvmclock_cpufreq_notifier_block,
					    CPUFREQ_TRANSITION_NOTIFIER);
	kvm_x86_ops = NULL;
	kvm_mmu_module_exit();
}

int kvm_emulate_halt(struct kvm_vcpu *vcpu)
{
	++vcpu->stat.halt_exits;
	KVMTRACE_0D(HLT, vcpu, handler);
	if (irqchip_in_kernel(vcpu->kvm)) {
		vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
		return 1;
	} else {
		vcpu->run->exit_reason = KVM_EXIT_HLT;
		return 0;
	}
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);

static inline gpa_t hc_gpa(struct kvm_vcpu *vcpu, unsigned long a0,
			   unsigned long a1)
{
	if (is_long_mode(vcpu))
		return a0;
	else
		return a0 | ((gpa_t)a1 << 32);
}

int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
	unsigned long nr, a0, a1, a2, a3, ret;
	int r = 1;

	nr = kvm_register_read(vcpu, VCPU_REGS_RAX);
	a0 = kvm_register_read(vcpu, VCPU_REGS_RBX);
	a1 = kvm_register_read(vcpu, VCPU_REGS_RCX);
	a2 = kvm_register_read(vcpu, VCPU_REGS_RDX);
	a3 = kvm_register_read(vcpu, VCPU_REGS_RSI);

	KVMTRACE_1D(VMMCALL, vcpu, (u32)nr, handler);

	if (!is_long_mode(vcpu)) {
		nr &= 0xFFFFFFFF;
		a0 &= 0xFFFFFFFF;
		a1 &= 0xFFFFFFFF;
		a2 &= 0xFFFFFFFF;
		a3 &= 0xFFFFFFFF;
	}

	switch (nr) {
	case KVM_HC_VAPIC_POLL_IRQ:
		ret = 0;
		break;
	case KVM_HC_MMU_OP:
		r = kvm_pv_mmu_op(vcpu, a0, hc_gpa(vcpu, a1, a2), &ret);
		break;
	default:
		ret = -KVM_ENOSYS;
		break;
	}
	kvm_register_write(vcpu, VCPU_REGS_RAX, ret);
	++vcpu->stat.hypercalls;
	return r;
}
EXPORT_SYMBOL_GPL(kvm_emulate_hypercall);

int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
{
	char instruction[3];
	int ret = 0;
	unsigned long rip = kvm_rip_read(vcpu);


	/*
	 * Blow out the MMU to ensure that no other VCPU has an active mapping
	 * to ensure that the updated hypercall appears atomically across all
	 * VCPUs.
	 */
	kvm_mmu_zap_all(vcpu->kvm);

	kvm_x86_ops->patch_hypercall(vcpu, instruction);
	if (emulator_write_emulated(rip, instruction, 3, vcpu)
	    != X86EMUL_CONTINUE)
		ret = -EFAULT;

	return ret;
}

static u64 mk_cr_64(u64 curr_cr, u32 new_val)
{
	return (curr_cr & ~((1ULL << 32) - 1)) | new_val;
}

void realmode_lgdt(struct kvm_vcpu *vcpu, u16 limit, unsigned long base)
{
	struct descriptor_table dt = { limit, base };

	kvm_x86_ops->set_gdt(vcpu, &dt);
}

void realmode_lidt(struct kvm_vcpu *vcpu, u16 limit, unsigned long base)
{
	struct descriptor_table dt = { limit, base };

	kvm_x86_ops->set_idt(vcpu, &dt);
}

void realmode_lmsw(struct kvm_vcpu *vcpu, unsigned long msw,
		   unsigned long *rflags)
{
	kvm_lmsw(vcpu, msw);
	*rflags = kvm_x86_ops->get_rflags(vcpu);
}

unsigned long realmode_get_cr(struct kvm_vcpu *vcpu, int cr)
{
	unsigned long value;

	kvm_x86_ops->decache_cr4_guest_bits(vcpu);
	switch (cr) {
	case 0:
		value = vcpu->arch.cr0;
		break;
	case 2:
		value = vcpu->arch.cr2;
		break;
	case 3:
		value = vcpu->arch.cr3;
		break;
	case 4:
		value = vcpu->arch.cr4;
		break;
	case 8:
		value = kvm_get_cr8(vcpu);
		break;
	default:
		vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
		return 0;
	}
	KVMTRACE_3D(CR_READ, vcpu, (u32)cr, (u32)value,
		    (u32)((u64)value >> 32), handler);

	return value;
}

void realmode_set_cr(struct kvm_vcpu *vcpu, int cr, unsigned long val,
		     unsigned long *rflags)
{
	KVMTRACE_3D(CR_WRITE, vcpu, (u32)cr, (u32)val,
		    (u32)((u64)val >> 32), handler);

	switch (cr) {
	case 0:
		kvm_set_cr0(vcpu, mk_cr_64(vcpu->arch.cr0, val));
		*rflags = kvm_x86_ops->get_rflags(vcpu);
		break;
	case 2:
		vcpu->arch.cr2 = val;
		break;
	case 3:
		kvm_set_cr3(vcpu, val);
		break;
	case 4:
		kvm_set_cr4(vcpu, mk_cr_64(vcpu->arch.cr4, val));
		break;
	case 8:
		kvm_set_cr8(vcpu, val & 0xfUL);
		break;
	default:
		vcpu_printf(vcpu, "%s: unexpected cr %u\n", __func__, cr);
	}
}

static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
{
	struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
	int j, nent = vcpu->arch.cpuid_nent;

	e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
	/* when no next entry is found, the current entry[i] is reselected */
	for (j = i + 1; ; j = (j + 1) % nent) {
		struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
		if (ej->function == e->function) {
			ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
			return j;
		}
	}
	return 0; /* silence gcc, even though control never reaches here */
}

/* find an entry with matching function, matching index (if needed), and that
 * should be read next (if it's stateful) */
static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
	u32 function, u32 index)
{
	if (e->function != function)
		return 0;
	if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
		return 0;
	if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
	    !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
		return 0;
	return 1;
}

struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
					      u32 function, u32 index)
{
	int i;
	struct kvm_cpuid_entry2 *best = NULL;

	for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
		struct kvm_cpuid_entry2 *e;

		e = &vcpu->arch.cpuid_entries[i];
		if (is_matching_cpuid_entry(e, function, index)) {
			if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
				move_to_next_stateful_cpuid_entry(vcpu, i);
			best = e;
			break;
		}
		/*
		 * Both basic or both extended?
		 */
		if (((e->function ^ function) & 0x80000000) == 0)
			if (!best || e->function > best->function)
				best = e;
	}
	return best;
}

int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
{
	struct kvm_cpuid_entry2 *best;

	best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
	if (best)
		return best->eax & 0xff;
	return 36;
}

void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
{
	u32 function, index;
	struct kvm_cpuid_entry2 *best;

	function = kvm_register_read(vcpu, VCPU_REGS_RAX);
	index = kvm_register_read(vcpu, VCPU_REGS_RCX);
	kvm_register_write(vcpu, VCPU_REGS_RAX, 0);
	kvm_register_write(vcpu, VCPU_REGS_RBX, 0);
	kvm_register_write(vcpu, VCPU_REGS_RCX, 0);
	kvm_register_write(vcpu, VCPU_REGS_RDX, 0);
	best = kvm_find_cpuid_entry(vcpu, function, index);
	if (best) {
		kvm_register_write(vcpu, VCPU_REGS_RAX, best->eax);
		kvm_register_write(vcpu, VCPU_REGS_RBX, best->ebx);
		kvm_register_write(vcpu, VCPU_REGS_RCX, best->ecx);
		kvm_register_write(vcpu, VCPU_REGS_RDX, best->edx);
	}
	kvm_x86_ops->skip_emulated_instruction(vcpu);
	KVMTRACE_5D(CPUID, vcpu, function,
		    (u32)kvm_register_read(vcpu, VCPU_REGS_RAX),
		    (u32)kvm_register_read(vcpu, VCPU_REGS_RBX),
		    (u32)kvm_register_read(vcpu, VCPU_REGS_RCX),
		    (u32)kvm_register_read(vcpu, VCPU_REGS_RDX), handler);
}
EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);

/*
 * Check if userspace requested an interrupt window, and that the
 * interrupt window is open.
 *
 * No need to exit to userspace if we already have an interrupt queued.
 */
static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu,
					  struct kvm_run *kvm_run)
{
	return (!irqchip_in_kernel(vcpu->kvm) && !kvm_cpu_has_interrupt(vcpu) &&
		kvm_run->request_interrupt_window &&
		kvm_arch_interrupt_allowed(vcpu));
}

static void post_kvm_run_save(struct kvm_vcpu *vcpu,
			      struct kvm_run *kvm_run)
{
	kvm_run->if_flag = (kvm_x86_ops->get_rflags(vcpu) & X86_EFLAGS_IF) != 0;
	kvm_run->cr8 = kvm_get_cr8(vcpu);
	kvm_run->apic_base = kvm_get_apic_base(vcpu);
	if (irqchip_in_kernel(vcpu->kvm))
		kvm_run->ready_for_interrupt_injection = 1;
	else
		kvm_run->ready_for_interrupt_injection =
			kvm_arch_interrupt_allowed(vcpu) &&
			!kvm_cpu_has_interrupt(vcpu) &&
			!kvm_event_needs_reinjection(vcpu);
}

static void vapic_enter(struct kvm_vcpu *vcpu)
{
	struct kvm_lapic *apic = vcpu->arch.apic;
	struct page *page;

	if (!apic || !apic->vapic_addr)
		return;

	page = gfn_to_page(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);

	vcpu->arch.apic->vapic_page = page;
}

static void vapic_exit(struct kvm_vcpu *vcpu)
{
	struct kvm_lapic *apic = vcpu->arch.apic;

	if (!apic || !apic->vapic_addr)
		return;

	down_read(&vcpu->kvm->slots_lock);
	kvm_release_page_dirty(apic->vapic_page);
	mark_page_dirty(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
	up_read(&vcpu->kvm->slots_lock);
}

static void update_cr8_intercept(struct kvm_vcpu *vcpu)
{
	int max_irr, tpr;

	if (!kvm_x86_ops->update_cr8_intercept)
		return;

	if (!vcpu->arch.apic->vapic_addr)
		max_irr = kvm_lapic_find_highest_irr(vcpu);
	else
		max_irr = -1;

	if (max_irr != -1)
		max_irr >>= 4;

	tpr = kvm_lapic_get_cr8(vcpu);

	kvm_x86_ops->update_cr8_intercept(vcpu, tpr, max_irr);
}

static void inject_pending_irq(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	/* try to reinject previous events if any */
	if (vcpu->arch.nmi_injected) {
		kvm_x86_ops->set_nmi(vcpu);
		return;
	}

	if (vcpu->arch.interrupt.pending) {
		kvm_x86_ops->set_irq(vcpu);
		return;
	}

	/* try to inject new event if pending */
	if (vcpu->arch.nmi_pending) {
		if (kvm_x86_ops->nmi_allowed(vcpu)) {
			vcpu->arch.nmi_pending = false;
			vcpu->arch.nmi_injected = true;
			kvm_x86_ops->set_nmi(vcpu);
		}
	} else if (kvm_cpu_has_interrupt(vcpu)) {
		if (kvm_x86_ops->interrupt_allowed(vcpu)) {
			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu),
					    false);
			kvm_x86_ops->set_irq(vcpu);
		}
	}
}

static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	int r;
	bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
		kvm_run->request_interrupt_window;

	if (vcpu->requests)
		if (test_and_clear_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests))
			kvm_mmu_unload(vcpu);

	r = kvm_mmu_reload(vcpu);
	if (unlikely(r))
		goto out;

	if (vcpu->requests) {
		if (test_and_clear_bit(KVM_REQ_MIGRATE_TIMER, &vcpu->requests))
			__kvm_migrate_timers(vcpu);
		if (test_and_clear_bit(KVM_REQ_KVMCLOCK_UPDATE, &vcpu->requests))
			kvm_write_guest_time(vcpu);
		if (test_and_clear_bit(KVM_REQ_MMU_SYNC, &vcpu->requests))
			kvm_mmu_sync_roots(vcpu);
		if (test_and_clear_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests))
			kvm_x86_ops->tlb_flush(vcpu);
		if (test_and_clear_bit(KVM_REQ_REPORT_TPR_ACCESS,
				       &vcpu->requests)) {
			kvm_run->exit_reason = KVM_EXIT_TPR_ACCESS;
			r = 0;
			goto out;
		}
		if (test_and_clear_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests)) {
			kvm_run->exit_reason = KVM_EXIT_SHUTDOWN;
			r = 0;
			goto out;
		}
	}

	preempt_disable();

	kvm_x86_ops->prepare_guest_switch(vcpu);
	kvm_load_guest_fpu(vcpu);

	local_irq_disable();

	clear_bit(KVM_REQ_KICK, &vcpu->requests);
	smp_mb__after_clear_bit();

	if (vcpu->requests || need_resched() || signal_pending(current)) {
		local_irq_enable();
		preempt_enable();
		r = 1;
		goto out;
	}

	if (vcpu->arch.exception.pending)
		__queue_exception(vcpu);
	else
		inject_pending_irq(vcpu, kvm_run);

	/* enable NMI/IRQ window open exits if needed */
	if (vcpu->arch.nmi_pending)
		kvm_x86_ops->enable_nmi_window(vcpu);
	else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
		kvm_x86_ops->enable_irq_window(vcpu);

	if (kvm_lapic_enabled(vcpu)) {
		update_cr8_intercept(vcpu);
		kvm_lapic_sync_to_vapic(vcpu);
	}

	up_read(&vcpu->kvm->slots_lock);

	kvm_guest_enter();

	get_debugreg(vcpu->arch.host_dr6, 6);
	get_debugreg(vcpu->arch.host_dr7, 7);
	if (unlikely(vcpu->arch.switch_db_regs)) {
		get_debugreg(vcpu->arch.host_db[0], 0);
		get_debugreg(vcpu->arch.host_db[1], 1);
		get_debugreg(vcpu->arch.host_db[2], 2);
		get_debugreg(vcpu->arch.host_db[3], 3);

		set_debugreg(0, 7);
		set_debugreg(vcpu->arch.eff_db[0], 0);
		set_debugreg(vcpu->arch.eff_db[1], 1);
		set_debugreg(vcpu->arch.eff_db[2], 2);
		set_debugreg(vcpu->arch.eff_db[3], 3);
	}

	KVMTRACE_0D(VMENTRY, vcpu, entryexit);
	kvm_x86_ops->run(vcpu, kvm_run);

	if (unlikely(vcpu->arch.switch_db_regs)) {
		set_debugreg(0, 7);
		set_debugreg(vcpu->arch.host_db[0], 0);
		set_debugreg(vcpu->arch.host_db[1], 1);
		set_debugreg(vcpu->arch.host_db[2], 2);
		set_debugreg(vcpu->arch.host_db[3], 3);
	}
	set_debugreg(vcpu->arch.host_dr6, 6);
	set_debugreg(vcpu->arch.host_dr7, 7);

	set_bit(KVM_REQ_KICK, &vcpu->requests);
	local_irq_enable();

	++vcpu->stat.exits;

	/*
	 * We must have an instruction between local_irq_enable() and
	 * kvm_guest_exit(), so the timer interrupt isn't delayed by
	 * the interrupt shadow.  The stat.exits increment will do nicely.
	 * But we need to prevent reordering, hence this barrier():
	 */
	barrier();

	kvm_guest_exit();

	preempt_enable();

	down_read(&vcpu->kvm->slots_lock);

	/*
	 * Profile KVM exit RIPs:
	 */
	if (unlikely(prof_on == KVM_PROFILING)) {
		unsigned long rip = kvm_rip_read(vcpu);
		profile_hit(KVM_PROFILING, (void *)rip);
	}


	kvm_lapic_sync_from_vapic(vcpu);

	r = kvm_x86_ops->handle_exit(kvm_run, vcpu);
out:
	return r;
}


static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	int r;

	if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED)) {
		pr_debug("vcpu %d received sipi with vector # %x\n",
			 vcpu->vcpu_id, vcpu->arch.sipi_vector);
		kvm_lapic_reset(vcpu);
		r = kvm_arch_vcpu_reset(vcpu);
		if (r)
			return r;
		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
	}

	down_read(&vcpu->kvm->slots_lock);
	vapic_enter(vcpu);

	r = 1;
	while (r > 0) {
		if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE)
			r = vcpu_enter_guest(vcpu, kvm_run);
		else {
			up_read(&vcpu->kvm->slots_lock);
			kvm_vcpu_block(vcpu);
			down_read(&vcpu->kvm->slots_lock);
			if (test_and_clear_bit(KVM_REQ_UNHALT, &vcpu->requests))
			{
				switch(vcpu->arch.mp_state) {
				case KVM_MP_STATE_HALTED:
					vcpu->arch.mp_state =
						KVM_MP_STATE_RUNNABLE;
				case KVM_MP_STATE_RUNNABLE:
					break;
				case KVM_MP_STATE_SIPI_RECEIVED:
				default:
					r = -EINTR;
					break;
				}
			}
		}

		if (r <= 0)
			break;

		clear_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
		if (kvm_cpu_has_pending_timer(vcpu))
			kvm_inject_pending_timer_irqs(vcpu);

		if (dm_request_for_irq_injection(vcpu, kvm_run)) {
			r = -EINTR;
			kvm_run->exit_reason = KVM_EXIT_INTR;
			++vcpu->stat.request_irq_exits;
		}
		if (signal_pending(current)) {
			r = -EINTR;
			kvm_run->exit_reason = KVM_EXIT_INTR;
			++vcpu->stat.signal_exits;
		}
		if (need_resched()) {
			up_read(&vcpu->kvm->slots_lock);
			kvm_resched(vcpu);
			down_read(&vcpu->kvm->slots_lock);
		}
	}

	up_read(&vcpu->kvm->slots_lock);
	post_kvm_run_save(vcpu, kvm_run);

	vapic_exit(vcpu);

	return r;
}

int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
	int r;
	sigset_t sigsaved;

	vcpu_load(vcpu);

	if (vcpu->sigset_active)
		sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);

	if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {
		kvm_vcpu_block(vcpu);
		clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
		r = -EAGAIN;
		goto out;
	}

	/* re-sync apic's tpr */
	if (!irqchip_in_kernel(vcpu->kvm))
		kvm_set_cr8(vcpu, kvm_run->cr8);

	if (vcpu->arch.pio.cur_count) {
		r = complete_pio(vcpu);
		if (r)
			goto out;
	}
#if CONFIG_HAS_IOMEM
	if (vcpu->mmio_needed) {
		memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8);
		vcpu->mmio_read_completed = 1;
		vcpu->mmio_needed = 0;

		down_read(&vcpu->kvm->slots_lock);
		r = emulate_instruction(vcpu, kvm_run,
					vcpu->arch.mmio_fault_cr2, 0,
					EMULTYPE_NO_DECODE);
		up_read(&vcpu->kvm->slots_lock);
		if (r == EMULATE_DO_MMIO) {
			/*
			 * Read-modify-write.  Back to userspace.
			 */
			r = 0;
			goto out;
		}
	}
#endif
	if (kvm_run->exit_reason == KVM_EXIT_HYPERCALL)
		kvm_register_write(vcpu, VCPU_REGS_RAX,
				     kvm_run->hypercall.ret);

	r = __vcpu_run(vcpu, kvm_run);

out:
	if (vcpu->sigset_active)
		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	vcpu_put(vcpu);
	return r;
}

int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
	vcpu_load(vcpu);

	regs->rax = kvm_register_read(vcpu, VCPU_REGS_RAX);
	regs->rbx = kvm_register_read(vcpu, VCPU_REGS_RBX);
	regs->rcx = kvm_register_read(vcpu, VCPU_REGS_RCX);
	regs->rdx = kvm_register_read(vcpu, VCPU_REGS_RDX);
	regs->rsi = kvm_register_read(vcpu, VCPU_REGS_RSI);
	regs->rdi = kvm_register_read(vcpu, VCPU_REGS_RDI);
	regs->rsp = kvm_register_read(vcpu, VCPU_REGS_RSP);
	regs->rbp = kvm_register_read(vcpu, VCPU_REGS_RBP);
#ifdef CONFIG_X86_64
	regs->r8 = kvm_register_read(vcpu, VCPU_REGS_R8);
	regs->r9 = kvm_register_read(vcpu, VCPU_REGS_R9);
	regs->r10 = kvm_register_read(vcpu, VCPU_REGS_R10);
	regs->r11 = kvm_register_read(vcpu, VCPU_REGS_R11);
	regs->r12 = kvm_register_read(vcpu, VCPU_REGS_R12);
	regs->r13 = kvm_register_read(vcpu, VCPU_REGS_R13);
	regs->r14 = kvm_register_read(vcpu, VCPU_REGS_R14);
	regs->r15 = kvm_register_read(vcpu, VCPU_REGS_R15);
#endif

	regs->rip = kvm_rip_read(vcpu);
	regs->rflags = kvm_x86_ops->get_rflags(vcpu);

	/*
	 * Don't leak debug flags in case they were set for guest debugging
	 */
	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
		regs->rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);

	vcpu_put(vcpu);

	return 0;
}

int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
	vcpu_load(vcpu);

	kvm_register_write(vcpu, VCPU_REGS_RAX, regs->rax);
	kvm_register_write(vcpu, VCPU_REGS_RBX, regs->rbx);
	kvm_register_write(vcpu, VCPU_REGS_RCX, regs->rcx);
	kvm_register_write(vcpu, VCPU_REGS_RDX, regs->rdx);
	kvm_register_write(vcpu, VCPU_REGS_RSI, regs->rsi);
	kvm_register_write(vcpu, VCPU_REGS_RDI, regs->rdi);
	kvm_register_write(vcpu, VCPU_REGS_RSP, regs->rsp);
	kvm_register_write(vcpu, VCPU_REGS_RBP, regs->rbp);
#ifdef CONFIG_X86_64
	kvm_register_write(vcpu, VCPU_REGS_R8, regs->r8);
	kvm_register_write(vcpu, VCPU_REGS_R9, regs->r9);
	kvm_register_write(vcpu, VCPU_REGS_R10, regs->r10);
	kvm_register_write(vcpu, VCPU_REGS_R11, regs->r11);
	kvm_register_write(vcpu, VCPU_REGS_R12, regs->r12);
	kvm_register_write(vcpu, VCPU_REGS_R13, regs->r13);
	kvm_register_write(vcpu, VCPU_REGS_R14, regs->r14);
	kvm_register_write(vcpu, VCPU_REGS_R15, regs->r15);

#endif

	kvm_rip_write(vcpu, regs->rip);
	kvm_x86_ops->set_rflags(vcpu, regs->rflags);


	vcpu->arch.exception.pending = false;

	vcpu_put(vcpu);

	return 0;
}

void kvm_get_segment(struct kvm_vcpu *vcpu,
		     struct kvm_segment *var, int seg)
{
	kvm_x86_ops->get_segment(vcpu, var, seg);
}

void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
{
	struct kvm_segment cs;

	kvm_get_segment(vcpu, &cs, VCPU_SREG_CS);
	*db = cs.db;
	*l = cs.l;
}
EXPORT_SYMBOL_GPL(kvm_get_cs_db_l_bits);

int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
				  struct kvm_sregs *sregs)
{
	struct descriptor_table dt;

	vcpu_load(vcpu);

	kvm_get_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
	kvm_get_segment(vcpu, &sregs->ds, VCPU_SREG_DS);
	kvm_get_segment(vcpu, &sregs->es, VCPU_SREG_ES);
	kvm_get_segment(vcpu, &sregs->fs, VCPU_SREG_FS);
	kvm_get_segment(vcpu, &sregs->gs, VCPU_SREG_GS);
	kvm_get_segment(vcpu, &sregs->ss, VCPU_SREG_SS);

	kvm_get_segment(vcpu, &sregs->tr, VCPU_SREG_TR);
	kvm_get_segment(vcpu, &sregs->ldt, VCPU_SREG_LDTR);

	kvm_x86_ops->get_idt(vcpu, &dt);
	sregs->idt.limit = dt.limit;
	sregs->idt.base = dt.base;
	kvm_x86_ops->get_gdt(vcpu, &dt);
	sregs->gdt.limit = dt.limit;
	sregs->gdt.base = dt.base;

	kvm_x86_ops->decache_cr4_guest_bits(vcpu);
	sregs->cr0 = vcpu->arch.cr0;
	sregs->cr2 = vcpu->arch.cr2;
	sregs->cr3 = vcpu->arch.cr3;
	sregs->cr4 = vcpu->arch.cr4;
	sregs->cr8 = kvm_get_cr8(vcpu);
	sregs->efer = vcpu->arch.shadow_efer;
	sregs->apic_base = kvm_get_apic_base(vcpu);

	memset(sregs->interrupt_bitmap, 0, sizeof sregs->interrupt_bitmap);

	if (vcpu->arch.interrupt.pending && !vcpu->arch.interrupt.soft)
		set_bit(vcpu->arch.interrupt.nr,
			(unsigned long *)sregs->interrupt_bitmap);

	vcpu_put(vcpu);

	return 0;
}

int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
				    struct kvm_mp_state *mp_state)
{
	vcpu_load(vcpu);
	mp_state->mp_state = vcpu->arch.mp_state;
	vcpu_put(vcpu);
	return 0;
}

int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
				    struct kvm_mp_state *mp_state)
{
	vcpu_load(vcpu);
	vcpu->arch.mp_state = mp_state->mp_state;
	vcpu_put(vcpu);
	return 0;
}

static void kvm_set_segment(struct kvm_vcpu *vcpu,
			struct kvm_segment *var, int seg)
{
	kvm_x86_ops->set_segment(vcpu, var, seg);
}

static void seg_desct_to_kvm_desct(struct desc_struct *seg_desc, u16 selector,
				   struct kvm_segment *kvm_desct)
{
	kvm_desct->base = seg_desc->base0;
	kvm_desct->base |= seg_desc->base1 << 16;
	kvm_desct->base |= seg_desc->base2 << 24;
	kvm_desct->limit = seg_desc->limit0;
	kvm_desct->limit |= seg_desc->limit << 16;
	if (seg_desc->g) {
		kvm_desct->limit <<= 12;
		kvm_desct->limit |= 0xfff;
	}
	kvm_desct->selector = selector;
	kvm_desct->type = seg_desc->type;
	kvm_desct->present = seg_desc->p;
	kvm_desct->dpl = seg_desc->dpl;
	kvm_desct->db = seg_desc->d;
	kvm_desct->s = seg_desc->s;
	kvm_desct->l = seg_desc->l;
	kvm_desct->g = seg_desc->g;
	kvm_desct->avl = seg_desc->avl;
	if (!selector)
		kvm_desct->unusable = 1;
	else
		kvm_desct->unusable = 0;
	kvm_desct->padding = 0;
}

static void get_segment_descriptor_dtable(struct kvm_vcpu *vcpu,
					  u16 selector,
					  struct descriptor_table *dtable)
{
	if (selector & 1 << 2) {
		struct kvm_segment kvm_seg;

		kvm_get_segment(vcpu, &kvm_seg, VCPU_SREG_LDTR);

		if (kvm_seg.unusable)
			dtable->limit = 0;
		else
			dtable->limit = kvm_seg.limit;
		dtable->base = kvm_seg.base;
	}
	else
		kvm_x86_ops->get_gdt(vcpu, dtable);
}

/* allowed just for 8 bytes segments */
static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
					 struct desc_struct *seg_desc)
{
	gpa_t gpa;
	struct descriptor_table dtable;
	u16 index = selector >> 3;

	get_segment_descriptor_dtable(vcpu, selector, &dtable);

	if (dtable.limit < index * 8 + 7) {
		kvm_queue_exception_e(vcpu, GP_VECTOR, selector & 0xfffc);
		return 1;
	}
	gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, dtable.base);
	gpa += index * 8;
	return kvm_read_guest(vcpu->kvm, gpa, seg_desc, 8);
}

/* allowed just for 8 bytes segments */
static int save_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
					 struct desc_struct *seg_desc)
{
	gpa_t gpa;
	struct descriptor_table dtable;
	u16 index = selector >> 3;

	get_segment_descriptor_dtable(vcpu, selector, &dtable);

	if (dtable.limit < index * 8 + 7)
		return 1;
	gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, dtable.base);
	gpa += index * 8;
	return kvm_write_guest(vcpu->kvm, gpa, seg_desc, 8);
}

static u32 get_tss_base_addr(struct kvm_vcpu *vcpu,
			     struct desc_struct *seg_desc)
{
	u32 base_addr;

	base_addr = seg_desc->base0;
	base_addr |= (seg_desc->base1 << 16);
	base_addr |= (seg_desc->base2 << 24);

	return vcpu->arch.mmu.gva_to_gpa(vcpu, base_addr);
}

static u16 get_segment_selector(struct kvm_vcpu *vcpu, int seg)
{
	struct kvm_segment kvm_seg;

	kvm_get_segment(vcpu, &kvm_seg, seg);
	return kvm_seg.selector;
}

static int load_segment_descriptor_to_kvm_desct(struct kvm_vcpu *vcpu,
						u16 selector,
						struct kvm_segment *kvm_seg)
{
	struct desc_struct seg_desc;

	if (load_guest_segment_descriptor(vcpu, selector, &seg_desc))
		return 1;
	seg_desct_to_kvm_desct(&seg_desc, selector, kvm_seg);
	return 0;
}

static int kvm_load_realmode_segment(struct kvm_vcpu *vcpu, u16 selector, int seg)
{
	struct kvm_segment segvar = {
		.base = selector << 4,
		.limit = 0xffff,
		.selector = selector,
		.type = 3,
		.present = 1,
		.dpl = 3,
		.db = 0,
		.s = 1,
		.l = 0,
		.g = 0,
		.avl = 0,
		.unusable = 0,
	};
	kvm_x86_ops->set_segment(vcpu, &segvar, seg);
	return 0;
}

int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
				int type_bits, int seg)
{
	struct kvm_segment kvm_seg;

	if (!(vcpu->arch.cr0 & X86_CR0_PE))
		return kvm_load_realmode_segment(vcpu, selector, seg);
	if (load_segment_descriptor_to_kvm_desct(vcpu, selector, &kvm_seg))
		return 1;
	kvm_seg.type |= type_bits;

	if (seg != VCPU_SREG_SS && seg != VCPU_SREG_CS &&
	    seg != VCPU_SREG_LDTR)
		if (!kvm_seg.s)
			kvm_seg.unusable = 1;

	kvm_set_segment(vcpu, &kvm_seg, seg);
	return 0;
}

static void save_state_to_tss32(struct kvm_vcpu *vcpu,
				struct tss_segment_32 *tss)
{
	tss->cr3 = vcpu->arch.cr3;
	tss->eip = kvm_rip_read(vcpu);
	tss->eflags = kvm_x86_ops->get_rflags(vcpu);
	tss->eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
	tss->ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
	tss->edx = kvm_register_read(vcpu, VCPU_REGS_RDX);
	tss->ebx = kvm_register_read(vcpu, VCPU_REGS_RBX);
	tss->esp = kvm_register_read(vcpu, VCPU_REGS_RSP);
	tss->ebp = kvm_register_read(vcpu, VCPU_REGS_RBP);
	tss->esi = kvm_register_read(vcpu, VCPU_REGS_RSI);
	tss->edi = kvm_register_read(vcpu, VCPU_REGS_RDI);
	tss->es = get_segment_selector(vcpu, VCPU_SREG_ES);
	tss->cs = get_segment_selector(vcpu, VCPU_SREG_CS);
	tss->ss = get_segment_selector(vcpu, VCPU_SREG_SS);
	tss->ds = get_segment_selector(vcpu, VCPU_SREG_DS);
	tss->fs = get_segment_selector(vcpu, VCPU_SREG_FS);
	tss->gs = get_segment_selector(vcpu, VCPU_SREG_GS);
	tss->ldt_selector = get_segment_selector(vcpu, VCPU_SREG_LDTR);
}

static int load_state_from_tss32(struct kvm_vcpu *vcpu,
				  struct tss_segment_32 *tss)
{
	kvm_set_cr3(vcpu, tss->cr3);

	kvm_rip_write(vcpu, tss->eip);
	kvm_x86_ops->set_rflags(vcpu, tss->eflags | 2);

	kvm_register_write(vcpu, VCPU_REGS_RAX, tss->eax);
	kvm_register_write(vcpu, VCPU_REGS_RCX, tss->ecx);
	kvm_register_write(vcpu, VCPU_REGS_RDX, tss->edx);
	kvm_register_write(vcpu, VCPU_REGS_RBX, tss->ebx);
	kvm_register_write(vcpu, VCPU_REGS_RSP, tss->esp);
	kvm_register_write(vcpu, VCPU_REGS_RBP, tss->ebp);
	kvm_register_write(vcpu, VCPU_REGS_RSI, tss->esi);
	kvm_register_write(vcpu, VCPU_REGS_RDI, tss->edi);

	if (kvm_load_segment_descriptor(vcpu, tss->ldt_selector, 0, VCPU_SREG_LDTR))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->es, 1, VCPU_SREG_ES))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->cs, 9, VCPU_SREG_CS))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->ss, 1, VCPU_SREG_SS))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->ds, 1, VCPU_SREG_DS))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->fs, 1, VCPU_SREG_FS))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->gs, 1, VCPU_SREG_GS))
		return 1;
	return 0;
}

static void save_state_to_tss16(struct kvm_vcpu *vcpu,
				struct tss_segment_16 *tss)
{
	tss->ip = kvm_rip_read(vcpu);
	tss->flag = kvm_x86_ops->get_rflags(vcpu);
	tss->ax = kvm_register_read(vcpu, VCPU_REGS_RAX);
	tss->cx = kvm_register_read(vcpu, VCPU_REGS_RCX);
	tss->dx = kvm_register_read(vcpu, VCPU_REGS_RDX);
	tss->bx = kvm_register_read(vcpu, VCPU_REGS_RBX);
	tss->sp = kvm_register_read(vcpu, VCPU_REGS_RSP);
	tss->bp = kvm_register_read(vcpu, VCPU_REGS_RBP);
	tss->si = kvm_register_read(vcpu, VCPU_REGS_RSI);
	tss->di = kvm_register_read(vcpu, VCPU_REGS_RDI);

	tss->es = get_segment_selector(vcpu, VCPU_SREG_ES);
	tss->cs = get_segment_selector(vcpu, VCPU_SREG_CS);
	tss->ss = get_segment_selector(vcpu, VCPU_SREG_SS);
	tss->ds = get_segment_selector(vcpu, VCPU_SREG_DS);
	tss->ldt = get_segment_selector(vcpu, VCPU_SREG_LDTR);
	tss->prev_task_link = get_segment_selector(vcpu, VCPU_SREG_TR);
}

static int load_state_from_tss16(struct kvm_vcpu *vcpu,
				 struct tss_segment_16 *tss)
{
	kvm_rip_write(vcpu, tss->ip);
	kvm_x86_ops->set_rflags(vcpu, tss->flag | 2);
	kvm_register_write(vcpu, VCPU_REGS_RAX, tss->ax);
	kvm_register_write(vcpu, VCPU_REGS_RCX, tss->cx);
	kvm_register_write(vcpu, VCPU_REGS_RDX, tss->dx);
	kvm_register_write(vcpu, VCPU_REGS_RBX, tss->bx);
	kvm_register_write(vcpu, VCPU_REGS_RSP, tss->sp);
	kvm_register_write(vcpu, VCPU_REGS_RBP, tss->bp);
	kvm_register_write(vcpu, VCPU_REGS_RSI, tss->si);
	kvm_register_write(vcpu, VCPU_REGS_RDI, tss->di);

	if (kvm_load_segment_descriptor(vcpu, tss->ldt, 0, VCPU_SREG_LDTR))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->es, 1, VCPU_SREG_ES))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->cs, 9, VCPU_SREG_CS))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->ss, 1, VCPU_SREG_SS))
		return 1;

	if (kvm_load_segment_descriptor(vcpu, tss->ds, 1, VCPU_SREG_DS))
		return 1;
	return 0;
}

static int kvm_task_switch_16(struct kvm_vcpu *vcpu, u16 tss_selector,
			      u16 old_tss_sel, u32 old_tss_base,
			      struct desc_struct *nseg_desc)
{
	struct tss_segment_16 tss_segment_16;
	int ret = 0;

	if (kvm_read_guest(vcpu->kvm, old_tss_base, &tss_segment_16,
			   sizeof tss_segment_16))
		goto out;

	save_state_to_tss16(vcpu, &tss_segment_16);

	if (kvm_write_guest(vcpu->kvm, old_tss_base, &tss_segment_16,
			    sizeof tss_segment_16))
		goto out;

	if (kvm_read_guest(vcpu->kvm, get_tss_base_addr(vcpu, nseg_desc),
			   &tss_segment_16, sizeof tss_segment_16))
		goto out;

	if (old_tss_sel != 0xffff) {
		tss_segment_16.prev_task_link = old_tss_sel;

		if (kvm_write_guest(vcpu->kvm,
				    get_tss_base_addr(vcpu, nseg_desc),
				    &tss_segment_16.prev_task_link,
				    sizeof tss_segment_16.prev_task_link))
			goto out;
	}

	if (load_state_from_tss16(vcpu, &tss_segment_16))
		goto out;

	ret = 1;
out:
	return ret;
}

static int kvm_task_switch_32(struct kvm_vcpu *vcpu, u16 tss_selector,
		       u16 old_tss_sel, u32 old_tss_base,
		       struct desc_struct *nseg_desc)
{
	struct tss_segment_32 tss_segment_32;
	int ret = 0;

	if (kvm_read_guest(vcpu->kvm, old_tss_base, &tss_segment_32,
			   sizeof tss_segment_32))
		goto out;

	save_state_to_tss32(vcpu, &tss_segment_32);

	if (kvm_write_guest(vcpu->kvm, old_tss_base, &tss_segment_32,
			    sizeof tss_segment_32))
		goto out;

	if (kvm_read_guest(vcpu->kvm, get_tss_base_addr(vcpu, nseg_desc),
			   &tss_segment_32, sizeof tss_segment_32))
		goto out;

	if (old_tss_sel != 0xffff) {
		tss_segment_32.prev_task_link = old_tss_sel;

		if (kvm_write_guest(vcpu->kvm,
				    get_tss_base_addr(vcpu, nseg_desc),
				    &tss_segment_32.prev_task_link,
				    sizeof tss_segment_32.prev_task_link))
			goto out;
	}

	if (load_state_from_tss32(vcpu, &tss_segment_32))
		goto out;

	ret = 1;
out:
	return ret;
}

int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
{
	struct kvm_segment tr_seg;
	struct desc_struct cseg_desc;
	struct desc_struct nseg_desc;
	int ret = 0;
	u32 old_tss_base = get_segment_base(vcpu, VCPU_SREG_TR);
	u16 old_tss_sel = get_segment_selector(vcpu, VCPU_SREG_TR);

	old_tss_base = vcpu->arch.mmu.gva_to_gpa(vcpu, old_tss_base);

	/* FIXME: Handle errors. Failure to read either TSS or their
	 * descriptors should generate a pagefault.
	 */
	if (load_guest_segment_descriptor(vcpu, tss_selector, &nseg_desc))
		goto out;

	if (load_guest_segment_descriptor(vcpu, old_tss_sel, &cseg_desc))
		goto out;

	if (reason != TASK_SWITCH_IRET) {
		int cpl;

		cpl = kvm_x86_ops->get_cpl(vcpu);
		if ((tss_selector & 3) > nseg_desc.dpl || cpl > nseg_desc.dpl) {
			kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
			return 1;
		}
	}

	if (!nseg_desc.p || (nseg_desc.limit0 | nseg_desc.limit << 16) < 0x67) {
		kvm_queue_exception_e(vcpu, TS_VECTOR, tss_selector & 0xfffc);
		return 1;
	}

	if (reason == TASK_SWITCH_IRET || reason == TASK_SWITCH_JMP) {
		cseg_desc.type &= ~(1 << 1); //clear the B flag
		save_guest_segment_descriptor(vcpu, old_tss_sel, &cseg_desc);
	}

	if (reason == TASK_SWITCH_IRET) {
		u32 eflags = kvm_x86_ops->get_rflags(vcpu);
		kvm_x86_ops->set_rflags(vcpu, eflags & ~X86_EFLAGS_NT);
	}

	/* set back link to prev task only if NT bit is set in eflags
	   note that old_tss_sel is not used afetr this point */
	if (reason != TASK_SWITCH_CALL && reason != TASK_SWITCH_GATE)
		old_tss_sel = 0xffff;

	/* set back link to prev task only if NT bit is set in eflags
	   note that old_tss_sel is not used afetr this point */
	if (reason != TASK_SWITCH_CALL && reason != TASK_SWITCH_GATE)
		old_tss_sel = 0xffff;

	if (nseg_desc.type & 8)
		ret = kvm_task_switch_32(vcpu, tss_selector, old_tss_sel,
					 old_tss_base, &nseg_desc);
	else
		ret = kvm_task_switch_16(vcpu, tss_selector, old_tss_sel,
					 old_tss_base, &nseg_desc);

	if (reason == TASK_SWITCH_CALL || reason == TASK_SWITCH_GATE) {
		u32 eflags = kvm_x86_ops->get_rflags(vcpu);
		kvm_x86_ops->set_rflags(vcpu, eflags | X86_EFLAGS_NT);
	}

	if (reason != TASK_SWITCH_IRET) {
		nseg_desc.type |= (1 << 1);
		save_guest_segment_descriptor(vcpu, tss_selector,
					      &nseg_desc);
	}

	kvm_x86_ops->set_cr0(vcpu, vcpu->arch.cr0 | X86_CR0_TS);
	seg_desct_to_kvm_desct(&nseg_desc, tss_selector, &tr_seg);
	tr_seg.type = 11;
	kvm_set_segment(vcpu, &tr_seg, VCPU_SREG_TR);
out:
	return ret;
}
EXPORT_SYMBOL_GPL(kvm_task_switch);

int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
				  struct kvm_sregs *sregs)
{
	int mmu_reset_needed = 0;
	int pending_vec, max_bits;
	struct descriptor_table dt;

	vcpu_load(vcpu);

	dt.limit = sregs->idt.limit;
	dt.base = sregs->idt.base;
	kvm_x86_ops->set_idt(vcpu, &dt);
	dt.limit = sregs->gdt.limit;
	dt.base = sregs->gdt.base;
	kvm_x86_ops->set_gdt(vcpu, &dt);

	vcpu->arch.cr2 = sregs->cr2;
	mmu_reset_needed |= vcpu->arch.cr3 != sregs->cr3;

	down_read(&vcpu->kvm->slots_lock);
	if (gfn_to_memslot(vcpu->kvm, sregs->cr3 >> PAGE_SHIFT))
		vcpu->arch.cr3 = sregs->cr3;
	else
		set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
	up_read(&vcpu->kvm->slots_lock);

	kvm_set_cr8(vcpu, sregs->cr8);

	mmu_reset_needed |= vcpu->arch.shadow_efer != sregs->efer;
	kvm_x86_ops->set_efer(vcpu, sregs->efer);
	kvm_set_apic_base(vcpu, sregs->apic_base);

	kvm_x86_ops->decache_cr4_guest_bits(vcpu);

	mmu_reset_needed |= vcpu->arch.cr0 != sregs->cr0;
	kvm_x86_ops->set_cr0(vcpu, sregs->cr0);
	vcpu->arch.cr0 = sregs->cr0;

	mmu_reset_needed |= vcpu->arch.cr4 != sregs->cr4;
	kvm_x86_ops->set_cr4(vcpu, sregs->cr4);
	if (!is_long_mode(vcpu) && is_pae(vcpu))
		load_pdptrs(vcpu, vcpu->arch.cr3);

	if (mmu_reset_needed)
		kvm_mmu_reset_context(vcpu);

	max_bits = (sizeof sregs->interrupt_bitmap) << 3;
	pending_vec = find_first_bit(
		(const unsigned long *)sregs->interrupt_bitmap, max_bits);
	if (pending_vec < max_bits) {
		kvm_queue_interrupt(vcpu, pending_vec, false);
		pr_debug("Set back pending irq %d\n", pending_vec);
		if (irqchip_in_kernel(vcpu->kvm))
			kvm_pic_clear_isr_ack(vcpu->kvm);
	}

	kvm_set_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
	kvm_set_segment(vcpu, &sregs->ds, VCPU_SREG_DS);
	kvm_set_segment(vcpu, &sregs->es, VCPU_SREG_ES);
	kvm_set_segment(vcpu, &sregs->fs, VCPU_SREG_FS);
	kvm_set_segment(vcpu, &sregs->gs, VCPU_SREG_GS);
	kvm_set_segment(vcpu, &sregs->ss, VCPU_SREG_SS);

	kvm_set_segment(vcpu, &sregs->tr, VCPU_SREG_TR);
	kvm_set_segment(vcpu, &sregs->ldt, VCPU_SREG_LDTR);

	/* Older userspace won't unhalt the vcpu on reset. */
	if (kvm_vcpu_is_bsp(vcpu) && kvm_rip_read(vcpu) == 0xfff0 &&
	    sregs->cs.selector == 0xf000 && sregs->cs.base == 0xffff0000 &&
	    !(vcpu->arch.cr0 & X86_CR0_PE))
		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;

	vcpu_put(vcpu);

	return 0;
}

int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
					struct kvm_guest_debug *dbg)
{
	int i, r;

	vcpu_load(vcpu);

	if ((dbg->control & (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) ==
	    (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP)) {
		for (i = 0; i < KVM_NR_DB_REGS; ++i)
			vcpu->arch.eff_db[i] = dbg->arch.debugreg[i];
		vcpu->arch.switch_db_regs =
			(dbg->arch.debugreg[7] & DR7_BP_EN_MASK);
	} else {
		for (i = 0; i < KVM_NR_DB_REGS; i++)
			vcpu->arch.eff_db[i] = vcpu->arch.db[i];
		vcpu->arch.switch_db_regs = (vcpu->arch.dr7 & DR7_BP_EN_MASK);
	}

	r = kvm_x86_ops->set_guest_debug(vcpu, dbg);

	if (dbg->control & KVM_GUESTDBG_INJECT_DB)
		kvm_queue_exception(vcpu, DB_VECTOR);
	else if (dbg->control & KVM_GUESTDBG_INJECT_BP)
		kvm_queue_exception(vcpu, BP_VECTOR);

	vcpu_put(vcpu);

	return r;
}

/*
 * fxsave fpu state.  Taken from x86_64/processor.h.  To be killed when
 * we have asm/x86/processor.h
 */
struct fxsave {
	u16	cwd;
	u16	swd;
	u16	twd;
	u16	fop;
	u64	rip;
	u64	rdp;
	u32	mxcsr;
	u32	mxcsr_mask;
	u32	st_space[32];	/* 8*16 bytes for each FP-reg = 128 bytes */
#ifdef CONFIG_X86_64
	u32	xmm_space[64];	/* 16*16 bytes for each XMM-reg = 256 bytes */
#else
	u32	xmm_space[32];	/* 8*16 bytes for each XMM-reg = 128 bytes */
#endif
};

/*
 * Translate a guest virtual address to a guest physical address.
 */
int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
				    struct kvm_translation *tr)
{
	unsigned long vaddr = tr->linear_address;
	gpa_t gpa;

	vcpu_load(vcpu);
	down_read(&vcpu->kvm->slots_lock);
	gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, vaddr);
	up_read(&vcpu->kvm->slots_lock);
	tr->physical_address = gpa;
	tr->valid = gpa != UNMAPPED_GVA;
	tr->writeable = 1;
	tr->usermode = 0;
	vcpu_put(vcpu);

	return 0;
}

int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
	struct fxsave *fxsave = (struct fxsave *)&vcpu->arch.guest_fx_image;

	vcpu_load(vcpu);

	memcpy(fpu->fpr, fxsave->st_space, 128);
	fpu->fcw = fxsave->cwd;
	fpu->fsw = fxsave->swd;
	fpu->ftwx = fxsave->twd;
	fpu->last_opcode = fxsave->fop;
	fpu->last_ip = fxsave->rip;
	fpu->last_dp = fxsave->rdp;
	memcpy(fpu->xmm, fxsave->xmm_space, sizeof fxsave->xmm_space);

	vcpu_put(vcpu);

	return 0;
}

int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
	struct fxsave *fxsave = (struct fxsave *)&vcpu->arch.guest_fx_image;

	vcpu_load(vcpu);

	memcpy(fxsave->st_space, fpu->fpr, 128);
	fxsave->cwd = fpu->fcw;
	fxsave->swd = fpu->fsw;
	fxsave->twd = fpu->ftwx;
	fxsave->fop = fpu->last_opcode;
	fxsave->rip = fpu->last_ip;
	fxsave->rdp = fpu->last_dp;
	memcpy(fxsave->xmm_space, fpu->xmm, sizeof fxsave->xmm_space);

	vcpu_put(vcpu);

	return 0;
}

void fx_init(struct kvm_vcpu *vcpu)
{
	unsigned after_mxcsr_mask;

	/*
	 * Touch the fpu the first time in non atomic context as if
	 * this is the first fpu instruction the exception handler
	 * will fire before the instruction returns and it'll have to
	 * allocate ram with GFP_KERNEL.
	 */
	if (!used_math())
		kvm_fx_save(&vcpu->arch.host_fx_image);

	/* Initialize guest FPU by resetting ours and saving into guest's */
	preempt_disable();
	kvm_fx_save(&vcpu->arch.host_fx_image);
	kvm_fx_finit();
	kvm_fx_save(&vcpu->arch.guest_fx_image);
	kvm_fx_restore(&vcpu->arch.host_fx_image);
	preempt_enable();

	vcpu->arch.cr0 |= X86_CR0_ET;
	after_mxcsr_mask = offsetof(struct i387_fxsave_struct, st_space);
	vcpu->arch.guest_fx_image.mxcsr = 0x1f80;
	memset((void *)&vcpu->arch.guest_fx_image + after_mxcsr_mask,
	       0, sizeof(struct i387_fxsave_struct) - after_mxcsr_mask);
}
EXPORT_SYMBOL_GPL(fx_init);

void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
{
	if (!vcpu->fpu_active || vcpu->guest_fpu_loaded)
		return;

	vcpu->guest_fpu_loaded = 1;
	kvm_fx_save(&vcpu->arch.host_fx_image);
	kvm_fx_restore(&vcpu->arch.guest_fx_image);
}
EXPORT_SYMBOL_GPL(kvm_load_guest_fpu);

void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
{
	if (!vcpu->guest_fpu_loaded)
		return;

	vcpu->guest_fpu_loaded = 0;
	kvm_fx_save(&vcpu->arch.guest_fx_image);
	kvm_fx_restore(&vcpu->arch.host_fx_image);
	++vcpu->stat.fpu_reload;
}
EXPORT_SYMBOL_GPL(kvm_put_guest_fpu);

void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
	if (vcpu->arch.time_page) {
		kvm_release_page_dirty(vcpu->arch.time_page);
		vcpu->arch.time_page = NULL;
	}

	kvm_x86_ops->vcpu_free(vcpu);
}

struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
						unsigned int id)
{
	return kvm_x86_ops->vcpu_create(kvm, id);
}

int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
	int r;

	/* We do fxsave: this must be aligned. */
	BUG_ON((unsigned long)&vcpu->arch.host_fx_image & 0xF);

	vcpu->arch.mtrr_state.have_fixed = 1;
	vcpu_load(vcpu);
	r = kvm_arch_vcpu_reset(vcpu);
	if (r == 0)
		r = kvm_mmu_setup(vcpu);
	vcpu_put(vcpu);
	if (r < 0)
		goto free_vcpu;

	return 0;
free_vcpu:
	kvm_x86_ops->vcpu_free(vcpu);
	return r;
}

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
	vcpu_load(vcpu);
	kvm_mmu_unload(vcpu);
	vcpu_put(vcpu);

	kvm_x86_ops->vcpu_free(vcpu);
}

int kvm_arch_vcpu_reset(struct kvm_vcpu *vcpu)
{
	vcpu->arch.nmi_pending = false;
	vcpu->arch.nmi_injected = false;

	vcpu->arch.switch_db_regs = 0;
	memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
	vcpu->arch.dr6 = DR6_FIXED_1;
	vcpu->arch.dr7 = DR7_FIXED_1;

	return kvm_x86_ops->vcpu_reset(vcpu);
}

void kvm_arch_hardware_enable(void *garbage)
{
	kvm_x86_ops->hardware_enable(garbage);
}

void kvm_arch_hardware_disable(void *garbage)
{
	kvm_x86_ops->hardware_disable(garbage);
}

int kvm_arch_hardware_setup(void)
{
	return kvm_x86_ops->hardware_setup();
}

void kvm_arch_hardware_unsetup(void)
{
	kvm_x86_ops->hardware_unsetup();
}

void kvm_arch_check_processor_compat(void *rtn)
{
	kvm_x86_ops->check_processor_compatibility(rtn);
}

int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
	struct page *page;
	struct kvm *kvm;
	int r;

	BUG_ON(vcpu->kvm == NULL);
	kvm = vcpu->kvm;

	vcpu->arch.mmu.root_hpa = INVALID_PAGE;
	if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))
		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
	else
		vcpu->arch.mp_state = KVM_MP_STATE_UNINITIALIZED;

	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
	if (!page) {
		r = -ENOMEM;
		goto fail;
	}
	vcpu->arch.pio_data = page_address(page);

	r = kvm_mmu_create(vcpu);
	if (r < 0)
		goto fail_free_pio_data;

	if (irqchip_in_kernel(kvm)) {
		r = kvm_create_lapic(vcpu);
		if (r < 0)
			goto fail_mmu_destroy;
	}

	vcpu->arch.mce_banks = kzalloc(KVM_MAX_MCE_BANKS * sizeof(u64) * 4,
				       GFP_KERNEL);
	if (!vcpu->arch.mce_banks) {
		r = -ENOMEM;
		goto fail_mmu_destroy;
	}
	vcpu->arch.mcg_cap = KVM_MAX_MCE_BANKS;

	return 0;

fail_mmu_destroy:
	kvm_mmu_destroy(vcpu);
fail_free_pio_data:
	free_page((unsigned long)vcpu->arch.pio_data);
fail:
	return r;
}

void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
	kvm_free_lapic(vcpu);
	down_read(&vcpu->kvm->slots_lock);
	kvm_mmu_destroy(vcpu);
	up_read(&vcpu->kvm->slots_lock);
	free_page((unsigned long)vcpu->arch.pio_data);
}

struct  kvm *kvm_arch_create_vm(void)
{
	struct kvm *kvm = kzalloc(sizeof(struct kvm), GFP_KERNEL);

	if (!kvm)
		return ERR_PTR(-ENOMEM);

	INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
	INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);

	/* Reserve bit 0 of irq_sources_bitmap for userspace irq source */
	set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap);

	rdtscll(kvm->arch.vm_init_tsc);

	return kvm;
}

static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
{
	vcpu_load(vcpu);
	kvm_mmu_unload(vcpu);
	vcpu_put(vcpu);
}

static void kvm_free_vcpus(struct kvm *kvm)
{
	unsigned int i;
	struct kvm_vcpu *vcpu;

	/*
	 * Unpin any mmu pages first.
	 */
	kvm_for_each_vcpu(i, vcpu, kvm)
		kvm_unload_vcpu_mmu(vcpu);
	kvm_for_each_vcpu(i, vcpu, kvm)
		kvm_arch_vcpu_free(vcpu);

	mutex_lock(&kvm->lock);
	for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
		kvm->vcpus[i] = NULL;

	atomic_set(&kvm->online_vcpus, 0);
	mutex_unlock(&kvm->lock);
}

void kvm_arch_sync_events(struct kvm *kvm)
{
	kvm_free_all_assigned_devices(kvm);
}

void kvm_arch_destroy_vm(struct kvm *kvm)
{
	kvm_iommu_unmap_guest(kvm);
	kvm_free_pit(kvm);
	kfree(kvm->arch.vpic);
	kfree(kvm->arch.vioapic);
	kvm_free_vcpus(kvm);
	kvm_free_physmem(kvm);
	if (kvm->arch.apic_access_page)
		put_page(kvm->arch.apic_access_page);
	if (kvm->arch.ept_identity_pagetable)
		put_page(kvm->arch.ept_identity_pagetable);
	kfree(kvm);
}

int kvm_arch_set_memory_region(struct kvm *kvm,
				struct kvm_userspace_memory_region *mem,
				struct kvm_memory_slot old,
				int user_alloc)
{
	int npages = mem->memory_size >> PAGE_SHIFT;
	struct kvm_memory_slot *memslot = &kvm->memslots[mem->slot];

	/*To keep backward compatibility with older userspace,
	 *x86 needs to hanlde !user_alloc case.
	 */
	if (!user_alloc) {
		if (npages && !old.rmap) {
			unsigned long userspace_addr;

			down_write(&current->mm->mmap_sem);
			userspace_addr = do_mmap(NULL, 0,
						 npages * PAGE_SIZE,
						 PROT_READ | PROT_WRITE,
						 MAP_PRIVATE | MAP_ANONYMOUS,
						 0);
			up_write(&current->mm->mmap_sem);

			if (IS_ERR((void *)userspace_addr))
				return PTR_ERR((void *)userspace_addr);

			/* set userspace_addr atomically for kvm_hva_to_rmapp */
			spin_lock(&kvm->mmu_lock);
			memslot->userspace_addr = userspace_addr;
			spin_unlock(&kvm->mmu_lock);
		} else {
			if (!old.user_alloc && old.rmap) {
				int ret;

				down_write(&current->mm->mmap_sem);
				ret = do_munmap(current->mm, old.userspace_addr,
						old.npages * PAGE_SIZE);
				up_write(&current->mm->mmap_sem);
				if (ret < 0)
					printk(KERN_WARNING
				       "kvm_vm_ioctl_set_memory_region: "
				       "failed to munmap memory\n");
			}
		}
	}

	spin_lock(&kvm->mmu_lock);
	if (!kvm->arch.n_requested_mmu_pages) {
		unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
		kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
	}

	kvm_mmu_slot_remove_write_access(kvm, mem->slot);
	spin_unlock(&kvm->mmu_lock);
	kvm_flush_remote_tlbs(kvm);

	return 0;
}

void kvm_arch_flush_shadow(struct kvm *kvm)
{
	kvm_mmu_zap_all(kvm);
	kvm_reload_remote_mmus(kvm);
}

int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
	return vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE
	       || vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED
	       || vcpu->arch.nmi_pending;
}

void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
{
	int me;
	int cpu = vcpu->cpu;

	if (waitqueue_active(&vcpu->wq)) {
		wake_up_interruptible(&vcpu->wq);
		++vcpu->stat.halt_wakeup;
	}

	me = get_cpu();
	if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
		if (!test_and_set_bit(KVM_REQ_KICK, &vcpu->requests))
			smp_send_reschedule(cpu);
	put_cpu();
}

int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu)
{
	return kvm_x86_ops->interrupt_allowed(vcpu);
}