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kvm_main.c

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

#include "kvm.h"
#include "x86_emulate.h"
#include "segment_descriptor.h"
#include "irq.h"

#include <linux/kvm.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/percpu.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/vmalloc.h>
#include <linux/reboot.h>
#include <linux/debugfs.h>
#include <linux/highmem.h>
#include <linux/file.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/smp.h>
#include <linux/anon_inodes.h>
#include <linux/profile.h>

#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/desc.h>

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

static DEFINE_SPINLOCK(kvm_lock);
static LIST_HEAD(vm_list);

static cpumask_t cpus_hardware_enabled;

struct kvm_x86_ops *kvm_x86_ops;
struct kmem_cache *kvm_vcpu_cache;
EXPORT_SYMBOL_GPL(kvm_vcpu_cache);

static __read_mostly struct preempt_ops kvm_preempt_ops;

#define STAT_OFFSET(x) offsetof(struct kvm_vcpu, stat.x)

static struct kvm_stats_debugfs_item {
      const char *name;
      int offset;
      struct dentry *dentry;
} debugfs_entries[] = {
      { "pf_fixed", STAT_OFFSET(pf_fixed) },
      { "pf_guest", STAT_OFFSET(pf_guest) },
      { "tlb_flush", STAT_OFFSET(tlb_flush) },
      { "invlpg", STAT_OFFSET(invlpg) },
      { "exits", STAT_OFFSET(exits) },
      { "io_exits", STAT_OFFSET(io_exits) },
      { "mmio_exits", STAT_OFFSET(mmio_exits) },
      { "signal_exits", STAT_OFFSET(signal_exits) },
      { "irq_window", STAT_OFFSET(irq_window_exits) },
      { "halt_exits", STAT_OFFSET(halt_exits) },
      { "halt_wakeup", STAT_OFFSET(halt_wakeup) },
      { "request_irq", STAT_OFFSET(request_irq_exits) },
      { "irq_exits", STAT_OFFSET(irq_exits) },
      { "light_exits", STAT_OFFSET(light_exits) },
      { "efer_reload", STAT_OFFSET(efer_reload) },
      { NULL }
};

static struct dentry *debugfs_dir;

#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 EFER_RESERVED_BITS 0xfffffffffffff2fe

#ifdef CONFIG_X86_64
// LDT or TSS descriptor in the GDT. 16 bytes.
struct segment_descriptor_64 {
      struct segment_descriptor s;
      u32 base_higher;
      u32 pad_zero;
};

#endif

static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                     unsigned long arg);

unsigned long segment_base(u16 selector)
{
      struct descriptor_table gdt;
      struct segment_descriptor *d;
      unsigned long table_base;
      typedef unsigned long ul;
      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 segment_descriptor *)(table_base + (selector & ~7));
      v = d->base_low | ((ul)d->base_mid << 16) | ((ul)d->base_high << 24);
#ifdef CONFIG_X86_64
      if (d->system == 0
          && (d->type == 2 || d->type == 9 || d->type == 11))
            v |= ((ul)((struct segment_descriptor_64 *)d)->base_higher) << 32;
#endif
      return v;
}
EXPORT_SYMBOL_GPL(segment_base);

static inline int valid_vcpu(int n)
{
      return likely(n >= 0 && n < KVM_MAX_VCPUS);
}

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

      vcpu->guest_fpu_loaded = 1;
      fx_save(&vcpu->host_fx_image);
      fx_restore(&vcpu->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;
      fx_save(&vcpu->guest_fx_image);
      fx_restore(&vcpu->host_fx_image);
}
EXPORT_SYMBOL_GPL(kvm_put_guest_fpu);

/*
 * Switches to specified vcpu, until a matching vcpu_put()
 */
static void vcpu_load(struct kvm_vcpu *vcpu)
{
      int cpu;

      mutex_lock(&vcpu->mutex);
      cpu = get_cpu();
      preempt_notifier_register(&vcpu->preempt_notifier);
      kvm_x86_ops->vcpu_load(vcpu, cpu);
      put_cpu();
}

static void vcpu_put(struct kvm_vcpu *vcpu)
{
      preempt_disable();
      kvm_x86_ops->vcpu_put(vcpu);
      preempt_notifier_unregister(&vcpu->preempt_notifier);
      preempt_enable();
      mutex_unlock(&vcpu->mutex);
}

static void ack_flush(void *_completed)
{
}

void kvm_flush_remote_tlbs(struct kvm *kvm)
{
      int i, cpu;
      cpumask_t cpus;
      struct kvm_vcpu *vcpu;

      cpus_clear(cpus);
      for (i = 0; i < KVM_MAX_VCPUS; ++i) {
            vcpu = kvm->vcpus[i];
            if (!vcpu)
                  continue;
            if (test_and_set_bit(KVM_TLB_FLUSH, &vcpu->requests))
                  continue;
            cpu = vcpu->cpu;
            if (cpu != -1 && cpu != raw_smp_processor_id())
                  cpu_set(cpu, cpus);
      }
      smp_call_function_mask(cpus, ack_flush, NULL, 1);
}

int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
{
      struct page *page;
      int r;

      mutex_init(&vcpu->mutex);
      vcpu->cpu = -1;
      vcpu->mmu.root_hpa = INVALID_PAGE;
      vcpu->kvm = kvm;
      vcpu->vcpu_id = id;
      if (!irqchip_in_kernel(kvm) || id == 0)
            vcpu->mp_state = VCPU_MP_STATE_RUNNABLE;
      else
            vcpu->mp_state = VCPU_MP_STATE_UNINITIALIZED;
      init_waitqueue_head(&vcpu->wq);

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

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

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

      return 0;

fail_free_pio_data:
      free_page((unsigned long)vcpu->pio_data);
fail_free_run:
      free_page((unsigned long)vcpu->run);
fail:
      return -ENOMEM;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_init);

void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
{
      kvm_mmu_destroy(vcpu);
      if (vcpu->apic)
            hrtimer_cancel(&vcpu->apic->timer.dev);
      kvm_free_apic(vcpu->apic);
      free_page((unsigned long)vcpu->pio_data);
      free_page((unsigned long)vcpu->run);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_uninit);

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

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

      kvm_io_bus_init(&kvm->pio_bus);
      mutex_init(&kvm->lock);
      INIT_LIST_HEAD(&kvm->active_mmu_pages);
      kvm_io_bus_init(&kvm->mmio_bus);
      spin_lock(&kvm_lock);
      list_add(&kvm->vm_list, &vm_list);
      spin_unlock(&kvm_lock);
      return kvm;
}

/*
 * Free any memory in @free but not in @dont.
 */
static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
                          struct kvm_memory_slot *dont)
{
      int i;

      if (!dont || free->phys_mem != dont->phys_mem)
            if (free->phys_mem) {
                  for (i = 0; i < free->npages; ++i)
                        if (free->phys_mem[i])
                              __free_page(free->phys_mem[i]);
                  vfree(free->phys_mem);
            }

      if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
            vfree(free->dirty_bitmap);

      free->phys_mem = NULL;
      free->npages = 0;
      free->dirty_bitmap = NULL;
}

static void kvm_free_physmem(struct kvm *kvm)
{
      int i;

      for (i = 0; i < kvm->nmemslots; ++i)
            kvm_free_physmem_slot(&kvm->memslots[i], NULL);
}

static void free_pio_guest_pages(struct kvm_vcpu *vcpu)
{
      int i;

      for (i = 0; i < ARRAY_SIZE(vcpu->pio.guest_pages); ++i)
            if (vcpu->pio.guest_pages[i]) {
                  __free_page(vcpu->pio.guest_pages[i]);
                  vcpu->pio.guest_pages[i] = NULL;
            }
}

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;

      /*
       * Unpin any mmu pages first.
       */
      for (i = 0; i < KVM_MAX_VCPUS; ++i)
            if (kvm->vcpus[i])
                  kvm_unload_vcpu_mmu(kvm->vcpus[i]);
      for (i = 0; i < KVM_MAX_VCPUS; ++i) {
            if (kvm->vcpus[i]) {
                  kvm_x86_ops->vcpu_free(kvm->vcpus[i]);
                  kvm->vcpus[i] = NULL;
            }
      }

}

static void kvm_destroy_vm(struct kvm *kvm)
{
      spin_lock(&kvm_lock);
      list_del(&kvm->vm_list);
      spin_unlock(&kvm_lock);
      kvm_io_bus_destroy(&kvm->pio_bus);
      kvm_io_bus_destroy(&kvm->mmio_bus);
      kfree(kvm->vpic);
      kfree(kvm->vioapic);
      kvm_free_vcpus(kvm);
      kvm_free_physmem(kvm);
      kfree(kvm);
}

static int kvm_vm_release(struct inode *inode, struct file *filp)
{
      struct kvm *kvm = filp->private_data;

      kvm_destroy_vm(kvm);
      return 0;
}

static void inject_gp(struct kvm_vcpu *vcpu)
{
      kvm_x86_ops->inject_gp(vcpu, 0);
}

/*
 * Load the pae pdptrs.  Return true is they are all valid.
 */
static 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;
      u64 *pdpt;
      int ret;
      struct page *page;
      u64 pdpte[ARRAY_SIZE(vcpu->pdptrs)];

      mutex_lock(&vcpu->kvm->lock);
      page = gfn_to_page(vcpu->kvm, pdpt_gfn);
      if (!page) {
            ret = 0;
            goto out;
      }

      pdpt = kmap_atomic(page, KM_USER0);
      memcpy(pdpte, pdpt+offset, sizeof(pdpte));
      kunmap_atomic(pdpt, KM_USER0);

      for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
            if ((pdpte[i] & 1) && (pdpte[i] & 0xfffffff0000001e6ull)) {
                  ret = 0;
                  goto out;
            }
      }
      ret = 1;

      memcpy(vcpu->pdptrs, pdpte, sizeof(vcpu->pdptrs));
out:
      mutex_unlock(&vcpu->kvm->lock);

      return ret;
}

void 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->cr0);
            inject_gp(vcpu);
            return;
      }

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

      if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
#ifdef CONFIG_X86_64
            if ((vcpu->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");
                        inject_gp(vcpu);
                        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");
                        inject_gp(vcpu);
                        return;

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

      }

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

      mutex_lock(&vcpu->kvm->lock);
      kvm_mmu_reset_context(vcpu);
      mutex_unlock(&vcpu->kvm->lock);
      return;
}
EXPORT_SYMBOL_GPL(set_cr0);

void lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
{
      set_cr0(vcpu, (vcpu->cr0 & ~0x0ful) | (msw & 0x0f));
}
EXPORT_SYMBOL_GPL(lmsw);

void set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
      if (cr4 & CR4_RESERVED_BITS) {
            printk(KERN_DEBUG "set_cr4: #GP, reserved bits\n");
            inject_gp(vcpu);
            return;
      }

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

      if (cr4 & X86_CR4_VMXE) {
            printk(KERN_DEBUG "set_cr4: #GP, setting VMXE\n");
            inject_gp(vcpu);
            return;
      }
      kvm_x86_ops->set_cr4(vcpu, cr4);
      vcpu->cr4 = cr4;
      mutex_lock(&vcpu->kvm->lock);
      kvm_mmu_reset_context(vcpu);
      mutex_unlock(&vcpu->kvm->lock);
}
EXPORT_SYMBOL_GPL(set_cr4);

void set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
{
      if (is_long_mode(vcpu)) {
            if (cr3 & CR3_L_MODE_RESERVED_BITS) {
                  printk(KERN_DEBUG "set_cr3: #GP, reserved bits\n");
                  inject_gp(vcpu);
                  return;
            }
      } else {
            if (is_pae(vcpu)) {
                  if (cr3 & CR3_PAE_RESERVED_BITS) {
                        printk(KERN_DEBUG
                               "set_cr3: #GP, reserved bits\n");
                        inject_gp(vcpu);
                        return;
                  }
                  if (is_paging(vcpu) && !load_pdptrs(vcpu, cr3)) {
                        printk(KERN_DEBUG "set_cr3: #GP, pdptrs "
                               "reserved bits\n");
                        inject_gp(vcpu);
                        return;
                  }
            } else {
                  if (cr3 & CR3_NONPAE_RESERVED_BITS) {
                        printk(KERN_DEBUG
                               "set_cr3: #GP, reserved bits\n");
                        inject_gp(vcpu);
                        return;
                  }
            }
      }

      mutex_lock(&vcpu->kvm->lock);
      /*
       * 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)))
            inject_gp(vcpu);
      else {
            vcpu->cr3 = cr3;
            vcpu->mmu.new_cr3(vcpu);
      }
      mutex_unlock(&vcpu->kvm->lock);
}
EXPORT_SYMBOL_GPL(set_cr3);

void 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);
            inject_gp(vcpu);
            return;
      }
      if (irqchip_in_kernel(vcpu->kvm))
            kvm_lapic_set_tpr(vcpu, cr8);
      else
            vcpu->cr8 = cr8;
}
EXPORT_SYMBOL_GPL(set_cr8);

unsigned long get_cr8(struct kvm_vcpu *vcpu)
{
      if (irqchip_in_kernel(vcpu->kvm))
            return kvm_lapic_get_cr8(vcpu);
      else
            return vcpu->cr8;
}
EXPORT_SYMBOL_GPL(get_cr8);

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

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

      /* Initialize guest FPU by resetting ours and saving into guest's */
      preempt_disable();
      fx_save(&vcpu->host_fx_image);
      fpu_init();
      fx_save(&vcpu->guest_fx_image);
      fx_restore(&vcpu->host_fx_image);
      preempt_enable();

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

/*
 * Allocate some memory and give it an address in the guest physical address
 * space.
 *
 * Discontiguous memory is allowed, mostly for framebuffers.
 */
static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
                                struct kvm_memory_region *mem)
{
      int r;
      gfn_t base_gfn;
      unsigned long npages;
      unsigned long i;
      struct kvm_memory_slot *memslot;
      struct kvm_memory_slot old, new;

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

      memslot = &kvm->memslots[mem->slot];
      base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
      npages = mem->memory_size >> PAGE_SHIFT;

      if (!npages)
            mem->flags &= ~KVM_MEM_LOG_DIRTY_PAGES;

      mutex_lock(&kvm->lock);

      new = old = *memslot;

      new.base_gfn = base_gfn;
      new.npages = npages;
      new.flags = mem->flags;

      /* Disallow changing a memory slot's size. */
      r = -EINVAL;
      if (npages && old.npages && npages != old.npages)
            goto out_unlock;

      /* Check for overlaps */
      r = -EEXIST;
      for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
            struct kvm_memory_slot *s = &kvm->memslots[i];

            if (s == memslot)
                  continue;
            if (!((base_gfn + npages <= s->base_gfn) ||
                  (base_gfn >= s->base_gfn + s->npages)))
                  goto out_unlock;
      }

      /* Deallocate if slot is being removed */
      if (!npages)
            new.phys_mem = NULL;

      /* Free page dirty bitmap if unneeded */
      if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
            new.dirty_bitmap = NULL;

      r = -ENOMEM;

      /* Allocate if a slot is being created */
      if (npages && !new.phys_mem) {
            new.phys_mem = vmalloc(npages * sizeof(struct page *));

            if (!new.phys_mem)
                  goto out_unlock;

            memset(new.phys_mem, 0, npages * sizeof(struct page *));
            for (i = 0; i < npages; ++i) {
                  new.phys_mem[i] = alloc_page(GFP_HIGHUSER
                                         | __GFP_ZERO);
                  if (!new.phys_mem[i])
                        goto out_unlock;
                  set_page_private(new.phys_mem[i],0);
            }
      }

      /* Allocate page dirty bitmap if needed */
      if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
            unsigned dirty_bytes = ALIGN(npages, BITS_PER_LONG) / 8;

            new.dirty_bitmap = vmalloc(dirty_bytes);
            if (!new.dirty_bitmap)
                  goto out_unlock;
            memset(new.dirty_bitmap, 0, dirty_bytes);
      }

      if (mem->slot >= kvm->nmemslots)
            kvm->nmemslots = mem->slot + 1;

      *memslot = new;

      kvm_mmu_slot_remove_write_access(kvm, mem->slot);
      kvm_flush_remote_tlbs(kvm);

      mutex_unlock(&kvm->lock);

      kvm_free_physmem_slot(&old, &new);
      return 0;

out_unlock:
      mutex_unlock(&kvm->lock);
      kvm_free_physmem_slot(&new, &old);
out:
      return r;
}

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

      mutex_lock(&kvm->lock);

      r = -EINVAL;
      if (log->slot >= KVM_MEMORY_SLOTS)
            goto out;

      memslot = &kvm->memslots[log->slot];
      r = -ENOENT;
      if (!memslot->dirty_bitmap)
            goto out;

      n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;

      for (i = 0; !any && i < n/sizeof(long); ++i)
            any = memslot->dirty_bitmap[i];

      r = -EFAULT;
      if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
            goto out;

      /* If nothing is dirty, don't bother messing with page tables. */
      if (any) {
            kvm_mmu_slot_remove_write_access(kvm, log->slot);
            kvm_flush_remote_tlbs(kvm);
            memset(memslot->dirty_bitmap, 0, n);
      }

      r = 0;

out:
      mutex_unlock(&kvm->lock);
      return r;
}

/*
 * 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;

      mutex_lock(&kvm->lock);

      p = &kvm->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->aliases[n - 1].npages)
                  break;
      kvm->naliases = n;

      kvm_mmu_zap_all(kvm);

      mutex_unlock(&kvm->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 gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
{
      int i;
      struct kvm_mem_alias *alias;

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

static struct kvm_memory_slot *__gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
      int i;

      for (i = 0; i < kvm->nmemslots; ++i) {
            struct kvm_memory_slot *memslot = &kvm->memslots[i];

            if (gfn >= memslot->base_gfn
                && gfn < memslot->base_gfn + memslot->npages)
                  return memslot;
      }
      return NULL;
}

struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
      gfn = unalias_gfn(kvm, gfn);
      return __gfn_to_memslot(kvm, gfn);
}

struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
{
      struct kvm_memory_slot *slot;

      gfn = unalias_gfn(kvm, gfn);
      slot = __gfn_to_memslot(kvm, gfn);
      if (!slot)
            return NULL;
      return slot->phys_mem[gfn - slot->base_gfn];
}
EXPORT_SYMBOL_GPL(gfn_to_page);

/* WARNING: Does not work on aliased pages. */
void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
{
      struct kvm_memory_slot *memslot;

      memslot = __gfn_to_memslot(kvm, gfn);
      if (memslot && memslot->dirty_bitmap) {
            unsigned long rel_gfn = gfn - memslot->base_gfn;

            /* avoid RMW */
            if (!test_bit(rel_gfn, memslot->dirty_bitmap))
                  set_bit(rel_gfn, memslot->dirty_bitmap);
      }
}

int emulator_read_std(unsigned long addr,
                       void *val,
                       unsigned int bytes,
                       struct kvm_vcpu *vcpu)
{
      void *data = val;

      while (bytes) {
            gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
            unsigned offset = addr & (PAGE_SIZE-1);
            unsigned tocopy = min(bytes, (unsigned)PAGE_SIZE - offset);
            unsigned long pfn;
            struct page *page;
            void *page_virt;

            if (gpa == UNMAPPED_GVA)
                  return X86EMUL_PROPAGATE_FAULT;
            pfn = gpa >> PAGE_SHIFT;
            page = gfn_to_page(vcpu->kvm, pfn);
            if (!page)
                  return X86EMUL_UNHANDLEABLE;
            page_virt = kmap_atomic(page, KM_USER0);

            memcpy(data, page_virt + offset, tocopy);

            kunmap_atomic(page_virt, KM_USER0);

            bytes -= tocopy;
            data += tocopy;
            addr += tocopy;
      }

      return X86EMUL_CONTINUE;
}
EXPORT_SYMBOL_GPL(emulator_read_std);

static int emulator_write_std(unsigned long addr,
                        const void *val,
                        unsigned int bytes,
                        struct kvm_vcpu *vcpu)
{
      pr_unimpl(vcpu, "emulator_write_std: addr %lx n %d\n", addr, bytes);
      return X86EMUL_UNHANDLEABLE;
}

/*
 * 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)
{
      struct kvm_io_device *dev;

      if (vcpu->apic) {
            dev = &vcpu->apic->dev;
            if (dev->in_range(dev, addr))
                  return dev;
      }
      return NULL;
}

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

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

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

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;
      } else if (emulator_read_std(addr, val, bytes, vcpu)
               == X86EMUL_CONTINUE)
            return X86EMUL_CONTINUE;

      gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
      if (gpa == UNMAPPED_GVA)
            return X86EMUL_PROPAGATE_FAULT;

      /*
       * Is this MMIO handled locally?
       */
      mmio_dev = vcpu_find_mmio_dev(vcpu, gpa);
      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;
}

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

      if (((gpa + bytes - 1) >> PAGE_SHIFT) != (gpa >> PAGE_SHIFT))
            return 0;
      page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
      if (!page)
            return 0;
      mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
      virt = kmap_atomic(page, KM_USER0);
      kvm_mmu_pte_write(vcpu, gpa, val, bytes);
      memcpy(virt + offset_in_page(gpa), val, bytes);
      kunmap_atomic(virt, KM_USER0);
      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 = vcpu->mmu.gva_to_gpa(vcpu, addr);

      if (gpa == UNMAPPED_GVA) {
            kvm_x86_ops->inject_page_fault(vcpu, addr, 2);
            return X86EMUL_PROPAGATE_FAULT;
      }

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

      /*
       * Is this MMIO handled locally?
       */
      mmio_dev = vcpu_find_mmio_dev(vcpu, gpa);
      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");
      }
      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)
{
      return X86EMUL_CONTINUE;
}

int emulate_clts(struct kvm_vcpu *vcpu)
{
      kvm_x86_ops->set_cr0(vcpu, vcpu->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", __FUNCTION__, 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)
{
      static int reported;
      u8 opcodes[4];
      unsigned long rip = vcpu->rip;
      unsigned long rip_linear;

      rip_linear = rip + get_segment_base(vcpu, VCPU_SREG_CS);

      if (reported)
            return;

      emulator_read_std(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]);
      reported = 1;
}
EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);

struct x86_emulate_ops emulate_ops = {
      .read_std            = emulator_read_std,
      .write_std           = emulator_write_std,
      .read_emulated       = emulator_read_emulated,
      .write_emulated      = emulator_write_emulated,
      .cmpxchg_emulated    = emulator_cmpxchg_emulated,
};

int emulate_instruction(struct kvm_vcpu *vcpu,
                  struct kvm_run *run,
                  unsigned long cr2,
                  u16 error_code)
{
      struct x86_emulate_ctxt emulate_ctxt;
      int r;
      int cs_db, cs_l;

      vcpu->mmio_fault_cr2 = cr2;
      kvm_x86_ops->cache_regs(vcpu);

      kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);

      emulate_ctxt.vcpu = vcpu;
      emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
      emulate_ctxt.cr2 = cr2;
      emulate_ctxt.mode = (emulate_ctxt.eflags & X86_EFLAGS_VM)
            ? X86EMUL_MODE_REAL : cs_l
            ? X86EMUL_MODE_PROT64 : cs_db
            ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;

      if (emulate_ctxt.mode == X86EMUL_MODE_PROT64) {
            emulate_ctxt.cs_base = 0;
            emulate_ctxt.ds_base = 0;
            emulate_ctxt.es_base = 0;
            emulate_ctxt.ss_base = 0;
      } else {
            emulate_ctxt.cs_base = get_segment_base(vcpu, VCPU_SREG_CS);
            emulate_ctxt.ds_base = get_segment_base(vcpu, VCPU_SREG_DS);
            emulate_ctxt.es_base = get_segment_base(vcpu, VCPU_SREG_ES);
            emulate_ctxt.ss_base = get_segment_base(vcpu, VCPU_SREG_SS);
      }

      emulate_ctxt.gs_base = get_segment_base(vcpu, VCPU_SREG_GS);
      emulate_ctxt.fs_base = get_segment_base(vcpu, VCPU_SREG_FS);

      vcpu->mmio_is_write = 0;
      vcpu->pio.string = 0;
      r = x86_emulate_memop(&emulate_ctxt, &emulate_ops);
      if (vcpu->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->decache_regs(vcpu);
      kvm_x86_ops->set_rflags(vcpu, emulate_ctxt.eflags);

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

      return EMULATE_DONE;
}
EXPORT_SYMBOL_GPL(emulate_instruction);

/*
 * The vCPU has executed a HLT instruction with in-kernel mode enabled.
 */
static void kvm_vcpu_block(struct kvm_vcpu *vcpu)
{
      DECLARE_WAITQUEUE(wait, current);

      add_wait_queue(&vcpu->wq, &wait);

      /*
       * We will block until either an interrupt or a signal wakes us up
       */
      while (!kvm_cpu_has_interrupt(vcpu)
             && !signal_pending(current)
             && vcpu->mp_state != VCPU_MP_STATE_RUNNABLE
             && vcpu->mp_state != VCPU_MP_STATE_SIPI_RECEIVED) {
            set_current_state(TASK_INTERRUPTIBLE);
            vcpu_put(vcpu);
            schedule();
            vcpu_load(vcpu);
      }

      __set_current_state(TASK_RUNNING);
      remove_wait_queue(&vcpu->wq, &wait);
}

int kvm_emulate_halt(struct kvm_vcpu *vcpu)
{
      ++vcpu->stat.halt_exits;
      if (irqchip_in_kernel(vcpu->kvm)) {
            vcpu->mp_state = VCPU_MP_STATE_HALTED;
            kvm_vcpu_block(vcpu);
            if (vcpu->mp_state != VCPU_MP_STATE_RUNNABLE)
                  return -EINTR;
            return 1;
      } else {
            vcpu->run->exit_reason = KVM_EXIT_HLT;
            return 0;
      }
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);

int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
      unsigned long nr, a0, a1, a2, a3, a4, a5, ret;

      kvm_x86_ops->cache_regs(vcpu);
      ret = -KVM_EINVAL;
#ifdef CONFIG_X86_64
      if (is_long_mode(vcpu)) {
            nr = vcpu->regs[VCPU_REGS_RAX];
            a0 = vcpu->regs[VCPU_REGS_RDI];
            a1 = vcpu->regs[VCPU_REGS_RSI];
            a2 = vcpu->regs[VCPU_REGS_RDX];
            a3 = vcpu->regs[VCPU_REGS_RCX];
            a4 = vcpu->regs[VCPU_REGS_R8];
            a5 = vcpu->regs[VCPU_REGS_R9];
      } else
#endif
      {
            nr = vcpu->regs[VCPU_REGS_RBX] & -1u;
            a0 = vcpu->regs[VCPU_REGS_RAX] & -1u;
            a1 = vcpu->regs[VCPU_REGS_RCX] & -1u;
            a2 = vcpu->regs[VCPU_REGS_RDX] & -1u;
            a3 = vcpu->regs[VCPU_REGS_RSI] & -1u;
            a4 = vcpu->regs[VCPU_REGS_RDI] & -1u;
            a5 = vcpu->regs[VCPU_REGS_RBP] & -1u;
      }
      switch (nr) {
      default:
            run->hypercall.nr = nr;
            run->hypercall.args[0] = a0;
            run->hypercall.args[1] = a1;
            run->hypercall.args[2] = a2;
            run->hypercall.args[3] = a3;
            run->hypercall.args[4] = a4;
            run->hypercall.args[5] = a5;
            run->hypercall.ret = ret;
            run->hypercall.longmode = is_long_mode(vcpu);
            kvm_x86_ops->decache_regs(vcpu);
            return 0;
      }
      vcpu->regs[VCPU_REGS_RAX] = ret;
      kvm_x86_ops->decache_regs(vcpu);
      return 1;
}
EXPORT_SYMBOL_GPL(kvm_hypercall);

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)
{
      lmsw(vcpu, msw);
      *rflags = kvm_x86_ops->get_rflags(vcpu);
}

unsigned long realmode_get_cr(struct kvm_vcpu *vcpu, int cr)
{
      kvm_x86_ops->decache_cr4_guest_bits(vcpu);
      switch (cr) {
      case 0:
            return vcpu->cr0;
      case 2:
            return vcpu->cr2;
      case 3:
            return vcpu->cr3;
      case 4:
            return vcpu->cr4;
      default:
            vcpu_printf(vcpu, "%s: unexpected cr %u\n", __FUNCTION__, cr);
            return 0;
      }
}

void realmode_set_cr(struct kvm_vcpu *vcpu, int cr, unsigned long val,
                 unsigned long *rflags)
{
      switch (cr) {
      case 0:
            set_cr0(vcpu, mk_cr_64(vcpu->cr0, val));
            *rflags = kvm_x86_ops->get_rflags(vcpu);
            break;
      case 2:
            vcpu->cr2 = val;
            break;
      case 3:
            set_cr3(vcpu, val);
            break;
      case 4:
            set_cr4(vcpu, mk_cr_64(vcpu->cr4, val));
            break;
      default:
            vcpu_printf(vcpu, "%s: unexpected cr %u\n", __FUNCTION__, cr);
      }
}

/*
 * Register the para guest with the host:
 */
static int vcpu_register_para(struct kvm_vcpu *vcpu, gpa_t para_state_gpa)
{
      struct kvm_vcpu_para_state *para_state;
      hpa_t para_state_hpa, hypercall_hpa;
      struct page *para_state_page;
      unsigned char *hypercall;
      gpa_t hypercall_gpa;

      printk(KERN_DEBUG "kvm: guest trying to enter paravirtual mode\n");
      printk(KERN_DEBUG ".... para_state_gpa: %08Lx\n", para_state_gpa);

      /*
       * Needs to be page aligned:
       */
      if (para_state_gpa != PAGE_ALIGN(para_state_gpa))
            goto err_gp;

      para_state_hpa = gpa_to_hpa(vcpu, para_state_gpa);
      printk(KERN_DEBUG ".... para_state_hpa: %08Lx\n", para_state_hpa);
      if (is_error_hpa(para_state_hpa))
            goto err_gp;

      mark_page_dirty(vcpu->kvm, para_state_gpa >> PAGE_SHIFT);
      para_state_page = pfn_to_page(para_state_hpa >> PAGE_SHIFT);
      para_state = kmap(para_state_page);

      printk(KERN_DEBUG "....  guest version: %d\n", para_state->guest_version);
      printk(KERN_DEBUG "....           size: %d\n", para_state->size);

      para_state->host_version = KVM_PARA_API_VERSION;
      /*
       * We cannot support guests that try to register themselves
       * with a newer API version than the host supports:
       */
      if (para_state->guest_version > KVM_PARA_API_VERSION) {
            para_state->ret = -KVM_EINVAL;
            goto err_kunmap_skip;
      }

      hypercall_gpa = para_state->hypercall_gpa;
      hypercall_hpa = gpa_to_hpa(vcpu, hypercall_gpa);
      printk(KERN_DEBUG ".... hypercall_hpa: %08Lx\n", hypercall_hpa);
      if (is_error_hpa(hypercall_hpa)) {
            para_state->ret = -KVM_EINVAL;
            goto err_kunmap_skip;
      }

      printk(KERN_DEBUG "kvm: para guest successfully registered.\n");
      vcpu->para_state_page = para_state_page;
      vcpu->para_state_gpa = para_state_gpa;
      vcpu->hypercall_gpa = hypercall_gpa;

      mark_page_dirty(vcpu->kvm, hypercall_gpa >> PAGE_SHIFT);
      hypercall = kmap_atomic(pfn_to_page(hypercall_hpa >> PAGE_SHIFT),
                        KM_USER1) + (hypercall_hpa & ~PAGE_MASK);
      kvm_x86_ops->patch_hypercall(vcpu, hypercall);
      kunmap_atomic(hypercall, KM_USER1);

      para_state->ret = 0;
err_kunmap_skip:
      kunmap(para_state_page);
      return 0;
err_gp:
      return 1;
}

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

      switch (msr) {
      case 0xc0010010: /* SYSCFG */
      case 0xc0010015: /* HWCR */
      case MSR_IA32_PLATFORM_ID:
      case MSR_IA32_P5_MC_ADDR:
      case MSR_IA32_P5_MC_TYPE:
      case MSR_IA32_MC0_CTL:
      case MSR_IA32_MCG_STATUS:
      case MSR_IA32_MCG_CAP:
      case MSR_IA32_MC0_MISC:
      case MSR_IA32_MC0_MISC+4:
      case MSR_IA32_MC0_MISC+8:
      case MSR_IA32_MC0_MISC+12:
      case MSR_IA32_MC0_MISC+16:
      case MSR_IA32_UCODE_REV:
      case MSR_IA32_PERF_STATUS:
      case MSR_IA32_EBL_CR_POWERON:
            /* MTRR registers */
      case 0xfe:
      case 0x200 ... 0x2ff:
            data = 0;
            break;
      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->ia32_misc_enable_msr;
            break;
#ifdef CONFIG_X86_64
      case MSR_EFER:
            data = vcpu->shadow_efer;
            break;
#endif
      default:
            pr_unimpl(vcpu, "unhandled rdmsr: 0x%x\n", msr);
            return 1;
      }
      *pdata = data;
      return 0;
}
EXPORT_SYMBOL_GPL(kvm_get_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);
}

#ifdef CONFIG_X86_64

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);
            inject_gp(vcpu);
            return;
      }

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

      kvm_x86_ops->set_efer(vcpu, efer);

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

      vcpu->shadow_efer = efer;
}

#endif

int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
{
      switch (msr) {
#ifdef CONFIG_X86_64
      case MSR_EFER:
            set_efer(vcpu, data);
            break;
#endif
      case MSR_IA32_MC0_STATUS:
            pr_unimpl(vcpu, "%s: MSR_IA32_MC0_STATUS 0x%llx, nop\n",
                   __FUNCTION__, data);
            break;
      case MSR_IA32_MCG_STATUS:
            pr_unimpl(vcpu, "%s: MSR_IA32_MCG_STATUS 0x%llx, nop\n",
                  __FUNCTION__, data);
            break;
      case MSR_IA32_UCODE_REV:
      case MSR_IA32_UCODE_WRITE:
      case 0x200 ... 0x2ff: /* MTRRs */
            break;
      case MSR_IA32_APICBASE:
            kvm_set_apic_base(vcpu, data);
            break;
      case MSR_IA32_MISC_ENABLE:
            vcpu->ia32_misc_enable_msr = data;
            break;
      /*
       * This is the 'probe whether the host is KVM' logic:
       */
      case MSR_KVM_API_MAGIC:
            return vcpu_register_para(vcpu, data);

      default:
            pr_unimpl(vcpu, "unhandled wrmsr: 0x%x\n", msr);
            return 1;
      }
      return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_msr_common);

/*
 * 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);
}

void kvm_resched(struct kvm_vcpu *vcpu)
{
      if (!need_resched())
            return;
      cond_resched();
}
EXPORT_SYMBOL_GPL(kvm_resched);

void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
{
      int i;
      u32 function;
      struct kvm_cpuid_entry *e, *best;

      kvm_x86_ops->cache_regs(vcpu);
      function = vcpu->regs[VCPU_REGS_RAX];
      vcpu->regs[VCPU_REGS_RAX] = 0;
      vcpu->regs[VCPU_REGS_RBX] = 0;
      vcpu->regs[VCPU_REGS_RCX] = 0;
      vcpu->regs[VCPU_REGS_RDX] = 0;
      best = NULL;
      for (i = 0; i < vcpu->cpuid_nent; ++i) {
            e = &vcpu->cpuid_entries[i];
            if (e->function == function) {
                  best = e;
                  break;
            }
            /*
             * Both basic or both extended?
             */
            if (((e->function ^ function) & 0x80000000) == 0)
                  if (!best || e->function > best->function)
                        best = e;
      }
      if (best) {
            vcpu->regs[VCPU_REGS_RAX] = best->eax;
            vcpu->regs[VCPU_REGS_RBX] = best->ebx;
            vcpu->regs[VCPU_REGS_RCX] = best->ecx;
            vcpu->regs[VCPU_REGS_RDX] = best->edx;
      }
      kvm_x86_ops->decache_regs(vcpu);
      kvm_x86_ops->skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);

static int pio_copy_data(struct kvm_vcpu *vcpu)
{
      void *p = vcpu->pio_data;
      void *q;
      unsigned bytes;
      int nr_pages = vcpu->pio.guest_pages[1] ? 2 : 1;

      q = vmap(vcpu->pio.guest_pages, nr_pages, VM_READ|VM_WRITE,
             PAGE_KERNEL);
      if (!q) {
            free_pio_guest_pages(vcpu);
            return -ENOMEM;
      }
      q += vcpu->pio.guest_page_offset;
      bytes = vcpu->pio.size * vcpu->pio.cur_count;
      if (vcpu->pio.in)
            memcpy(q, p, bytes);
      else
            memcpy(p, q, bytes);
      q -= vcpu->pio.guest_page_offset;
      vunmap(q);
      free_pio_guest_pages(vcpu);
      return 0;
}

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

      kvm_x86_ops->cache_regs(vcpu);

      if (!io->string) {
            if (io->in)
                  memcpy(&vcpu->regs[VCPU_REGS_RAX], vcpu->pio_data,
                         io->size);
      } else {
            if (io->in) {
                  r = pio_copy_data(vcpu);
                  if (r) {
                        kvm_x86_ops->cache_regs(vcpu);
                        return r;
                  }
            }

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

      kvm_x86_ops->decache_regs(vcpu);

      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 */

      mutex_lock(&vcpu->kvm->lock);
      if (vcpu->pio.in)
            kvm_iodevice_read(pio_dev, vcpu->pio.port,
                          vcpu->pio.size,
                          pd);
      else
            kvm_iodevice_write(pio_dev, vcpu->pio.port,
                           vcpu->pio.size,
                           pd);
      mutex_unlock(&vcpu->kvm->lock);
}

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

      mutex_lock(&vcpu->kvm->lock);
      for (i = 0; i < io->cur_count; i++) {
            kvm_iodevice_write(pio_dev, io->port,
                           io->size,
                           pd);
            pd += io->size;
      }
      mutex_unlock(&vcpu->kvm->lock);
}

int kvm_emulate_pio (struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
              int size, unsigned port)
{
      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->pio.size = size;
      vcpu->run->io.data_offset = KVM_PIO_PAGE_OFFSET * PAGE_SIZE;
      vcpu->run->io.count = vcpu->pio.count = vcpu->pio.cur_count = 1;
      vcpu->run->io.port = vcpu->pio.port = port;
      vcpu->pio.in = in;
      vcpu->pio.string = 0;
      vcpu->pio.down = 0;
      vcpu->pio.guest_page_offset = 0;
      vcpu->pio.rep = 0;

      kvm_x86_ops->cache_regs(vcpu);
      memcpy(vcpu->pio_data, &vcpu->regs[VCPU_REGS_RAX], 4);
      kvm_x86_ops->decache_regs(vcpu);

      kvm_x86_ops->skip_emulated_instruction(vcpu);

      pio_dev = vcpu_find_pio_dev(vcpu, port);
      if (pio_dev) {
            kernel_pio(pio_dev, vcpu, vcpu->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 i, ret = 0;
      int nr_pages = 1;
      struct page *page;
      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->pio.size = size;
      vcpu->run->io.data_offset = KVM_PIO_PAGE_OFFSET * PAGE_SIZE;
      vcpu->run->io.count = vcpu->pio.count = vcpu->pio.cur_count = count;
      vcpu->run->io.port = vcpu->pio.port = port;
      vcpu->pio.in = in;
      vcpu->pio.string = 1;
      vcpu->pio.down = down;
      vcpu->pio.guest_page_offset = offset_in_page(address);
      vcpu->pio.rep = rep;

      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) {
            /*
             * String I/O straddles page boundary.  Pin two guest pages
             * so that we satisfy atomicity constraints.  Do just one
             * transaction to avoid complexity.
             */
            nr_pages = 2;
            now = 1;
      }
      if (down) {
            /*
             * String I/O in reverse.  Yuck.  Kill the guest, fix later.
             */
            pr_unimpl(vcpu, "guest string pio down\n");
            inject_gp(vcpu);
            return 1;
      }
      vcpu->run->io.count = now;
      vcpu->pio.cur_count = now;

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

      for (i = 0; i < nr_pages; ++i) {
            mutex_lock(&vcpu->kvm->lock);
            page = gva_to_page(vcpu, address + i * PAGE_SIZE);
            if (page)
                  get_page(page);
            vcpu->pio.guest_pages[i] = page;
            mutex_unlock(&vcpu->kvm->lock);
            if (!page) {
                  inject_gp(vcpu);
                  free_pio_guest_pages(vcpu);
                  return 1;
            }
      }

      pio_dev = vcpu_find_pio_dev(vcpu, port);
      if (!vcpu->pio.in) {
            /* string PIO write */
            ret = pio_copy_data(vcpu);
            if (ret >= 0 && pio_dev) {
                  pio_string_write(pio_dev, vcpu);
                  complete_pio(vcpu);
                  if (vcpu->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);

/*
 * 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 (!vcpu->irq_summary &&
            kvm_run->request_interrupt_window &&
            vcpu->interrupt_window_open &&
            (kvm_x86_ops->get_rflags(vcpu) & X86_EFLAGS_IF));
}

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 = 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 =
                              (vcpu->interrupt_window_open &&
                               vcpu->irq_summary == 0);
}

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

      if (unlikely(vcpu->mp_state == VCPU_MP_STATE_SIPI_RECEIVED)) {
            printk("vcpu %d received sipi with vector # %x\n",
                   vcpu->vcpu_id, vcpu->sipi_vector);
            kvm_lapic_reset(vcpu);
            kvm_x86_ops->vcpu_reset(vcpu);
            vcpu->mp_state = VCPU_MP_STATE_RUNNABLE;
      }

preempted:
      if (vcpu->guest_debug.enabled)
            kvm_x86_ops->guest_debug_pre(vcpu);

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

      preempt_disable();

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

      local_irq_disable();

      if (signal_pending(current)) {
            local_irq_enable();
            preempt_enable();
            r = -EINTR;
            kvm_run->exit_reason = KVM_EXIT_INTR;
            ++vcpu->stat.signal_exits;
            goto out;
      }

      if (irqchip_in_kernel(vcpu->kvm))
            kvm_x86_ops->inject_pending_irq(vcpu);
      else if (!vcpu->mmio_read_completed)
            kvm_x86_ops->inject_pending_vectors(vcpu, kvm_run);

      vcpu->guest_mode = 1;
      kvm_guest_enter();

      if (vcpu->requests)
            if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
                  kvm_x86_ops->tlb_flush(vcpu);

      kvm_x86_ops->run(vcpu, kvm_run);

      vcpu->guest_mode = 0;
      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();

      /*
       * Profile KVM exit RIPs:
       */
      if (unlikely(prof_on == KVM_PROFILING)) {
            kvm_x86_ops->cache_regs(vcpu);
            profile_hit(KVM_PROFILING, (void *)vcpu->rip);
      }

      r = kvm_x86_ops->handle_exit(kvm_run, vcpu);

      if (r > 0) {
            if (dm_request_for_irq_injection(vcpu, kvm_run)) {
                  r = -EINTR;
                  kvm_run->exit_reason = KVM_EXIT_INTR;
                  ++vcpu->stat.request_irq_exits;
                  goto out;
            }
            if (!need_resched()) {
                  ++vcpu->stat.light_exits;
                  goto again;
            }
      }

out:
      if (r > 0) {
            kvm_resched(vcpu);
            goto preempted;
      }

      post_kvm_run_save(vcpu, kvm_run);

      return r;
}


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

      vcpu_load(vcpu);

      if (unlikely(vcpu->mp_state == VCPU_MP_STATE_UNINITIALIZED)) {
            kvm_vcpu_block(vcpu);
            vcpu_put(vcpu);
            return -EAGAIN;
      }

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

      /* re-sync apic's tpr */
      if (!irqchip_in_kernel(vcpu->kvm))
            set_cr8(vcpu, kvm_run->cr8);

      if (vcpu->pio.cur_count) {
            r = complete_pio(vcpu);
            if (r)
                  goto out;
      }

      if (vcpu->mmio_needed) {
            memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8);
            vcpu->mmio_read_completed = 1;
            vcpu->mmio_needed = 0;
            r = emulate_instruction(vcpu, kvm_run,
                              vcpu->mmio_fault_cr2, 0);
            if (r == EMULATE_DO_MMIO) {
                  /*
                   * Read-modify-write.  Back to userspace.
                   */
                  r = 0;
                  goto out;
            }
      }

      if (kvm_run->exit_reason == KVM_EXIT_HYPERCALL) {
            kvm_x86_ops->cache_regs(vcpu);
            vcpu->regs[VCPU_REGS_RAX] = kvm_run->hypercall.ret;
            kvm_x86_ops->decache_regs(vcpu);
      }

      r = __vcpu_run(vcpu, kvm_run);

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

      vcpu_put(vcpu);
      return r;
}

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

      kvm_x86_ops->cache_regs(vcpu);

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

      regs->rip = vcpu->rip;
      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.enabled && vcpu->guest_debug.singlestep)
            regs->rflags &= ~(X86_EFLAGS_TF | X86_EFLAGS_RF);

      vcpu_put(vcpu);

      return 0;
}

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

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

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

      kvm_x86_ops->decache_regs(vcpu);

      vcpu_put(vcpu);

      return 0;
}

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

static int kvm_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
                            struct kvm_sregs *sregs)
{
      struct descriptor_table dt;
      int pending_vec;

      vcpu_load(vcpu);

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

      get_segment(vcpu, &sregs->tr, VCPU_SREG_TR);
      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->cr0;
      sregs->cr2 = vcpu->cr2;
      sregs->cr3 = vcpu->cr3;
      sregs->cr4 = vcpu->cr4;
      sregs->cr8 = get_cr8(vcpu);
      sregs->efer = vcpu->shadow_efer;
      sregs->apic_base = kvm_get_apic_base(vcpu);

      if (irqchip_in_kernel(vcpu->kvm)) {
            memset(sregs->interrupt_bitmap, 0,
                   sizeof sregs->interrupt_bitmap);
            pending_vec = kvm_x86_ops->get_irq(vcpu);
            if (pending_vec >= 0)
                  set_bit(pending_vec, (unsigned long *)sregs->interrupt_bitmap);
      } else
            memcpy(sregs->interrupt_bitmap, vcpu->irq_pending,
                   sizeof sregs->interrupt_bitmap);

      vcpu_put(vcpu);

      return 0;
}

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

static int kvm_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
                            struct kvm_sregs *sregs)
{
      int mmu_reset_needed = 0;
      int i, 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->cr2 = sregs->cr2;
      mmu_reset_needed |= vcpu->cr3 != sregs->cr3;
      vcpu->cr3 = sregs->cr3;

      set_cr8(vcpu, sregs->cr8);

      mmu_reset_needed |= vcpu->shadow_efer != sregs->efer;
#ifdef CONFIG_X86_64
      kvm_x86_ops->set_efer(vcpu, sregs->efer);
#endif
      kvm_set_apic_base(vcpu, sregs->apic_base);

      kvm_x86_ops->decache_cr4_guest_bits(vcpu);

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

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

      if (mmu_reset_needed)
            kvm_mmu_reset_context(vcpu);

      if (!irqchip_in_kernel(vcpu->kvm)) {
            memcpy(vcpu->irq_pending, sregs->interrupt_bitmap,
                   sizeof vcpu->irq_pending);
            vcpu->irq_summary = 0;
            for (i = 0; i < ARRAY_SIZE(vcpu->irq_pending); ++i)
                  if (vcpu->irq_pending[i])
                        __set_bit(i, &vcpu->irq_summary);
      } else {
            max_bits = (sizeof sregs->interrupt_bitmap) << 3;
            pending_vec = find_first_bit(
                  (const unsigned long *)sregs->interrupt_bitmap,
                  max_bits);
            /* Only pending external irq is handled here */
            if (pending_vec < max_bits) {
                  kvm_x86_ops->set_irq(vcpu, pending_vec);
                  printk("Set back pending irq %d\n", pending_vec);
            }
      }

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

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

      vcpu_put(vcpu);

      return 0;
}

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

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

/*
 * 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_TIME_STAMP_COUNTER,
};

static unsigned num_msrs_to_save;

static u32 emulated_msrs[] = {
      MSR_IA32_MISC_ENABLE,
};

static __init 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;
}

/*
 * 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);
}

/*
 * 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);

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

      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;
}

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

      vcpu_load(vcpu);
      mutex_lock(&vcpu->kvm->lock);
      gpa = vcpu->mmu.gva_to_gpa(vcpu, vaddr);
      tr->physical_address = gpa;
      tr->valid = gpa != UNMAPPED_GVA;
      tr->writeable = 1;
      tr->usermode = 0;
      mutex_unlock(&vcpu->kvm->lock);
      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);

      set_bit(irq->irq, vcpu->irq_pending);
      set_bit(irq->irq / BITS_PER_LONG, &vcpu->irq_summary);

      vcpu_put(vcpu);

      return 0;
}

static int kvm_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
                              struct kvm_debug_guest *dbg)
{
      int r;

      vcpu_load(vcpu);

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

      vcpu_put(vcpu);

      return r;
}

static struct page *kvm_vcpu_nopage(struct vm_area_struct *vma,
                            unsigned long address,
                            int *type)
{
      struct kvm_vcpu *vcpu = vma->vm_file->private_data;
      unsigned long pgoff;
      struct page *page;

      pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
      if (pgoff == 0)
            page = virt_to_page(vcpu->run);
      else if (pgoff == KVM_PIO_PAGE_OFFSET)
            page = virt_to_page(vcpu->pio_data);
      else
            return NOPAGE_SIGBUS;
      get_page(page);
      if (type != NULL)
            *type = VM_FAULT_MINOR;

      return page;
}

static struct vm_operations_struct kvm_vcpu_vm_ops = {
      .nopage = kvm_vcpu_nopage,
};

static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
{
      vma->vm_ops = &kvm_vcpu_vm_ops;
      return 0;
}

static int kvm_vcpu_release(struct inode *inode, struct file *filp)
{
      struct kvm_vcpu *vcpu = filp->private_data;

      fput(vcpu->kvm->filp);
      return 0;
}

static struct file_operations kvm_vcpu_fops = {
      .release        = kvm_vcpu_release,
      .unlocked_ioctl = kvm_vcpu_ioctl,
      .compat_ioctl   = kvm_vcpu_ioctl,
      .mmap           = kvm_vcpu_mmap,
};

/*
 * Allocates an inode for the vcpu.
 */
static int create_vcpu_fd(struct kvm_vcpu *vcpu)
{
      int fd, r;
      struct inode *inode;
      struct file *file;

      r = anon_inode_getfd(&fd, &inode, &file,
                       "kvm-vcpu", &kvm_vcpu_fops, vcpu);
      if (r)
            return r;
      atomic_inc(&vcpu->kvm->filp->f_count);
      return fd;
}

/*
 * Creates some virtual cpus.  Good luck creating more than one.
 */
static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
{
      int r;
      struct kvm_vcpu *vcpu;

      if (!valid_vcpu(n))
            return -EINVAL;

      vcpu = kvm_x86_ops->vcpu_create(kvm, n);
      if (IS_ERR(vcpu))
            return PTR_ERR(vcpu);

      preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);

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

      vcpu_load(vcpu);
      r = kvm_mmu_setup(vcpu);
      vcpu_put(vcpu);
      if (r < 0)
            goto free_vcpu;

      mutex_lock(&kvm->lock);
      if (kvm->vcpus[n]) {
            r = -EEXIST;
            mutex_unlock(&kvm->lock);
            goto mmu_unload;
      }
      kvm->vcpus[n] = vcpu;
      mutex_unlock(&kvm->lock);

      /* Now it's all set up, let userspace reach it */
      r = create_vcpu_fd(vcpu);
      if (r < 0)
            goto unlink;
      return r;

unlink:
      mutex_lock(&kvm->lock);
      kvm->vcpus[n] = NULL;
      mutex_unlock(&kvm->lock);

mmu_unload:
      vcpu_load(vcpu);
      kvm_mmu_unload(vcpu);
      vcpu_put(vcpu);

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

static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
{
      u64 efer;
      int i;
      struct kvm_cpuid_entry *e, *entry;

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

static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
                            struct kvm_cpuid *cpuid,
                            struct kvm_cpuid_entry __user *entries)
{
      int r;

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

out:
      return r;
}

static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
{
      if (sigset) {
            sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));
            vcpu->sigset_active = 1;
            vcpu->sigset = *sigset;
      } else
            vcpu->sigset_active = 0;
      return 0;
}

/*
 * 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
};

static int kvm_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
      struct fxsave *fxsave = (struct fxsave *)&vcpu->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;
}

static int kvm_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
      struct fxsave *fxsave = (struct fxsave *)&vcpu->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;
}

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

      return 0;
}

static long kvm_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 = -EINVAL;

      switch (ioctl) {
      case KVM_RUN:
            r = -EINVAL;
            if (arg)
                  goto out;
            r = kvm_vcpu_ioctl_run(vcpu, vcpu->run);
            break;
      case KVM_GET_REGS: {
            struct kvm_regs kvm_regs;

            memset(&kvm_regs, 0, sizeof kvm_regs);
            r = kvm_vcpu_ioctl_get_regs(vcpu, &kvm_regs);
            if (r)
                  goto out;
            r = -EFAULT;
            if (copy_to_user(argp, &kvm_regs, sizeof kvm_regs))
                  goto out;
            r = 0;
            break;
      }
      case KVM_SET_REGS: {
            struct kvm_regs kvm_regs;

            r = -EFAULT;
            if (copy_from_user(&kvm_regs, argp, sizeof kvm_regs))
                  goto out;
            r = kvm_vcpu_ioctl_set_regs(vcpu, &kvm_regs);
            if (r)
                  goto out;
            r = 0;
            break;
      }
      case KVM_GET_SREGS: {
            struct kvm_sregs kvm_sregs;

            memset(&kvm_sregs, 0, sizeof kvm_sregs);
            r = kvm_vcpu_ioctl_get_sregs(vcpu, &kvm_sregs);
            if (r)
                  goto out;
            r = -EFAULT;
            if (copy_to_user(argp, &kvm_sregs, sizeof kvm_sregs))
                  goto out;
            r = 0;
            break;
      }
      case KVM_SET_SREGS: {
            struct kvm_sregs kvm_sregs;

            r = -EFAULT;
            if (copy_from_user(&kvm_sregs, argp, sizeof kvm_sregs))
                  goto out;
            r = kvm_vcpu_ioctl_set_sregs(vcpu, &kvm_sregs);
            if (r)
                  goto out;
            r = 0;
            break;
      }
      case KVM_TRANSLATE: {
            struct kvm_translation tr;

            r = -EFAULT;
            if (copy_from_user(&tr, argp, sizeof tr))
                  goto out;
            r = kvm_vcpu_ioctl_translate(vcpu, &tr);
            if (r)
                  goto out;
            r = -EFAULT;
            if (copy_to_user(argp, &tr, sizeof tr))
                  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_DEBUG_GUEST: {
            struct kvm_debug_guest dbg;

            r = -EFAULT;
            if (copy_from_user(&dbg, argp, sizeof dbg))
                  goto out;
            r = kvm_vcpu_ioctl_debug_guest(vcpu, &dbg);
            if (r)
                  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_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_SIGNAL_MASK: {
            struct kvm_signal_mask __user *sigmask_arg = argp;
            struct kvm_signal_mask kvm_sigmask;
            sigset_t sigset, *p;

            p = NULL;
            if (argp) {
                  r = -EFAULT;
                  if (copy_from_user(&kvm_sigmask, argp,
                                 sizeof kvm_sigmask))
                        goto out;
                  r = -EINVAL;
                  if (kvm_sigmask.len != sizeof sigset)
                        goto out;
                  r = -EFAULT;
                  if (copy_from_user(&sigset, sigmask_arg->sigset,
                                 sizeof sigset))
                        goto out;
                  p = &sigset;
            }
            r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
            break;
      }
      case KVM_GET_FPU: {
            struct kvm_fpu fpu;

            memset(&fpu, 0, sizeof fpu);
            r = kvm_vcpu_ioctl_get_fpu(vcpu, &fpu);
            if (r)
                  goto out;
            r = -EFAULT;
            if (copy_to_user(argp, &fpu, sizeof fpu))
                  goto out;
            r = 0;
            break;
      }
      case KVM_SET_FPU: {
            struct kvm_fpu fpu;

            r = -EFAULT;
            if (copy_from_user(&fpu, argp, sizeof fpu))
                  goto out;
            r = kvm_vcpu_ioctl_set_fpu(vcpu, &fpu);
            if (r)
                  goto out;
            r = 0;
            break;
      }
      case KVM_GET_LAPIC: {
            struct kvm_lapic_state lapic;

            memset(&lapic, 0, sizeof lapic);
            r = kvm_vcpu_ioctl_get_lapic(vcpu, &lapic);
            if (r)
                  goto out;
            r = -EFAULT;
            if (copy_to_user(argp, &lapic, sizeof lapic))
                  goto out;
            r = 0;
            break;
      }
      case KVM_SET_LAPIC: {
            struct kvm_lapic_state lapic;

            r = -EFAULT;
            if (copy_from_user(&lapic, argp, sizeof lapic))
                  goto out;
            r = kvm_vcpu_ioctl_set_lapic(vcpu, &lapic);;
            if (r)
                  goto out;
            r = 0;
            break;
      }
      default:
            ;
      }
out:
      return r;
}

static long kvm_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;

      switch (ioctl) {
      case KVM_CREATE_VCPU:
            r = kvm_vm_ioctl_create_vcpu(kvm, arg);
            if (r < 0)
                  goto out;
            break;
      case KVM_SET_MEMORY_REGION: {
            struct kvm_memory_region kvm_mem;

            r = -EFAULT;
            if (copy_from_user(&kvm_mem, argp, sizeof kvm_mem))
                  goto out;
            r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_mem);
            if (r)
                  goto out;
            break;
      }
      case KVM_GET_DIRTY_LOG: {
            struct kvm_dirty_log log;

            r = -EFAULT;
            if (copy_from_user(&log, argp, sizeof log))
                  goto out;
            r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
            if (r)
                  goto out;
            break;
      }
      case KVM_SET_MEMORY_ALIAS: {
            struct kvm_memory_alias alias;

            r = -EFAULT;
            if (copy_from_user(&alias, argp, sizeof alias))
                  goto out;
            r = kvm_vm_ioctl_set_memory_alias(kvm, &alias);
            if (r)
                  goto out;
            break;
      }
      case KVM_CREATE_IRQCHIP:
            r = -ENOMEM;
            kvm->vpic = kvm_create_pic(kvm);
            if (kvm->vpic) {
                  r = kvm_ioapic_init(kvm);
                  if (r) {
                        kfree(kvm->vpic);
                        kvm->vpic = NULL;
                        goto out;
                  }
            }
            else
                  goto out;
            break;
      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)) {
                  mutex_lock(&kvm->lock);
                  if (irq_event.irq < 16)
                        kvm_pic_set_irq(pic_irqchip(kvm),
                              irq_event.irq,
                              irq_event.level);
                  kvm_ioapic_set_irq(kvm->vioapic,
                              irq_event.irq,
                              irq_event.level);
                  mutex_unlock(&kvm->lock);
                  r = 0;
            }
            break;
      }
      case KVM_GET_IRQCHIP: {
            /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
            struct kvm_irqchip chip;

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

            r = -EFAULT;
            if (copy_from_user(&chip, argp, sizeof chip))
                  goto out;
            r = -ENXIO;
            if (!irqchip_in_kernel(kvm))
                  goto out;
            r = kvm_vm_ioctl_set_irqchip(kvm, &chip);
            if (r)
                  goto out;
            r = 0;
            break;
      }
      default:
            ;
      }
out:
      return r;
}

static struct page *kvm_vm_nopage(struct vm_area_struct *vma,
                          unsigned long address,
                          int *type)
{
      struct kvm *kvm = vma->vm_file->private_data;
      unsigned long pgoff;
      struct page *page;

      pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
      page = gfn_to_page(kvm, pgoff);
      if (!page)
            return NOPAGE_SIGBUS;
      get_page(page);
      if (type != NULL)
            *type = VM_FAULT_MINOR;

      return page;
}

static struct vm_operations_struct kvm_vm_vm_ops = {
      .nopage = kvm_vm_nopage,
};

static int kvm_vm_mmap(struct file *file, struct vm_area_struct *vma)
{
      vma->vm_ops = &kvm_vm_vm_ops;
      return 0;
}

static struct file_operations kvm_vm_fops = {
      .release        = kvm_vm_release,
      .unlocked_ioctl = kvm_vm_ioctl,
      .compat_ioctl   = kvm_vm_ioctl,
      .mmap           = kvm_vm_mmap,
};

static int kvm_dev_ioctl_create_vm(void)
{
      int fd, r;
      struct inode *inode;
      struct file *file;
      struct kvm *kvm;

      kvm = kvm_create_vm();
      if (IS_ERR(kvm))
            return PTR_ERR(kvm);
      r = anon_inode_getfd(&fd, &inode, &file, "kvm-vm", &kvm_vm_fops, kvm);
      if (r) {
            kvm_destroy_vm(kvm);
            return r;
      }

      kvm->filp = file;

      return fd;
}

static long kvm_dev_ioctl(struct file *filp,
                    unsigned int ioctl, unsigned long arg)
{
      void __user *argp = (void __user *)arg;
      long r = -EINVAL;

      switch (ioctl) {
      case KVM_GET_API_VERSION:
            r = -EINVAL;
            if (arg)
                  goto out;
            r = KVM_API_VERSION;
            break;
      case KVM_CREATE_VM:
            r = -EINVAL;
            if (arg)
                  goto out;
            r = kvm_dev_ioctl_create_vm();
            break;
      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 < num_msrs_to_save)
                  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 * sizeof(u32),
                         &emulated_msrs,
                         ARRAY_SIZE(emulated_msrs) * sizeof(u32)))
                  goto out;
            r = 0;
            break;
      }
      case KVM_CHECK_EXTENSION: {
            int ext = (long)argp;

            switch (ext) {
            case KVM_CAP_IRQCHIP:
            case KVM_CAP_HLT:
                  r = 1;
                  break;
            default:
                  r = 0;
                  break;
            }
            break;
      }
      case KVM_GET_VCPU_MMAP_SIZE:
            r = -EINVAL;
            if (arg)
                  goto out;
            r = 2 * PAGE_SIZE;
            break;
      default:
            ;
      }
out:
      return r;
}

static struct file_operations kvm_chardev_ops = {
      .unlocked_ioctl = kvm_dev_ioctl,
      .compat_ioctl   = kvm_dev_ioctl,
};

static struct miscdevice kvm_dev = {
      KVM_MINOR,
      "kvm",
      &kvm_chardev_ops,
};

/*
 * Make sure that a cpu that is being hot-unplugged does not have any vcpus
 * cached on it.
 */
static void decache_vcpus_on_cpu(int cpu)
{
      struct kvm *vm;
      struct kvm_vcpu *vcpu;
      int i;

      spin_lock(&kvm_lock);
      list_for_each_entry(vm, &vm_list, vm_list)
            for (i = 0; i < KVM_MAX_VCPUS; ++i) {
                  vcpu = vm->vcpus[i];
                  if (!vcpu)
                        continue;
                  /*
                   * If the vcpu is locked, then it is running on some
                   * other cpu and therefore it is not cached on the
                   * cpu in question.
                   *
                   * If it's not locked, check the last cpu it executed
                   * on.
                   */
                  if (mutex_trylock(&vcpu->mutex)) {
                        if (vcpu->cpu == cpu) {
                              kvm_x86_ops->vcpu_decache(vcpu);
                              vcpu->cpu = -1;
                        }
                        mutex_unlock(&vcpu->mutex);
                  }
            }
      spin_unlock(&kvm_lock);
}

static void hardware_enable(void *junk)
{
      int cpu = raw_smp_processor_id();

      if (cpu_isset(cpu, cpus_hardware_enabled))
            return;
      cpu_set(cpu, cpus_hardware_enabled);
      kvm_x86_ops->hardware_enable(NULL);
}

static void hardware_disable(void *junk)
{
      int cpu = raw_smp_processor_id();

      if (!cpu_isset(cpu, cpus_hardware_enabled))
            return;
      cpu_clear(cpu, cpus_hardware_enabled);
      decache_vcpus_on_cpu(cpu);
      kvm_x86_ops->hardware_disable(NULL);
}

static int kvm_cpu_hotplug(struct notifier_block *notifier, unsigned long val,
                     void *v)
{
      int cpu = (long)v;

      switch (val) {
      case CPU_DYING:
      case CPU_DYING_FROZEN:
            printk(KERN_INFO "kvm: disabling virtualization on CPU%d\n",
                   cpu);
            hardware_disable(NULL);
            break;
      case CPU_UP_CANCELED:
      case CPU_UP_CANCELED_FROZEN:
            printk(KERN_INFO "kvm: disabling virtualization on CPU%d\n",
                   cpu);
            smp_call_function_single(cpu, hardware_disable, NULL, 0, 1);
            break;
      case CPU_ONLINE:
      case CPU_ONLINE_FROZEN:
            printk(KERN_INFO "kvm: enabling virtualization on CPU%d\n",
                   cpu);
            smp_call_function_single(cpu, hardware_enable, NULL, 0, 1);
            break;
      }
      return NOTIFY_OK;
}

static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
                       void *v)
{
      if (val == SYS_RESTART) {
            /*
             * Some (well, at least mine) BIOSes hang on reboot if
             * in vmx root mode.
             */
            printk(KERN_INFO "kvm: exiting hardware virtualization\n");
            on_each_cpu(hardware_disable, NULL, 0, 1);
      }
      return NOTIFY_OK;
}

static struct notifier_block kvm_reboot_notifier = {
      .notifier_call = kvm_reboot,
      .priority = 0,
};

void kvm_io_bus_init(struct kvm_io_bus *bus)
{
      memset(bus, 0, sizeof(*bus));
}

void kvm_io_bus_destroy(struct kvm_io_bus *bus)
{
      int i;

      for (i = 0; i < bus->dev_count; i++) {
            struct kvm_io_device *pos = bus->devs[i];

            kvm_iodevice_destructor(pos);
      }
}

struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus, gpa_t addr)
{
      int i;

      for (i = 0; i < bus->dev_count; i++) {
            struct kvm_io_device *pos = bus->devs[i];

            if (pos->in_range(pos, addr))
                  return pos;
      }

      return NULL;
}

void kvm_io_bus_register_dev(struct kvm_io_bus *bus, struct kvm_io_device *dev)
{
      BUG_ON(bus->dev_count > (NR_IOBUS_DEVS-1));

      bus->devs[bus->dev_count++] = dev;
}

static struct notifier_block kvm_cpu_notifier = {
      .notifier_call = kvm_cpu_hotplug,
      .priority = 20, /* must be > scheduler priority */
};

static u64 stat_get(void *_offset)
{
      unsigned offset = (long)_offset;
      u64 total = 0;
      struct kvm *kvm;
      struct kvm_vcpu *vcpu;
      int i;

      spin_lock(&kvm_lock);
      list_for_each_entry(kvm, &vm_list, vm_list)
            for (i = 0; i < KVM_MAX_VCPUS; ++i) {
                  vcpu = kvm->vcpus[i];
                  if (vcpu)
                        total += *(u32 *)((void *)vcpu + offset);
            }
      spin_unlock(&kvm_lock);
      return total;
}

DEFINE_SIMPLE_ATTRIBUTE(stat_fops, stat_get, NULL, "%llu\n");

static __init void kvm_init_debug(void)
{
      struct kvm_stats_debugfs_item *p;

      debugfs_dir = debugfs_create_dir("kvm", NULL);
      for (p = debugfs_entries; p->name; ++p)
            p->dentry = debugfs_create_file(p->name, 0444, debugfs_dir,
                                    (void *)(long)p->offset,
                                    &stat_fops);
}

static void kvm_exit_debug(void)
{
      struct kvm_stats_debugfs_item *p;

      for (p = debugfs_entries; p->name; ++p)
            debugfs_remove(p->dentry);
      debugfs_remove(debugfs_dir);
}

static int kvm_suspend(struct sys_device *dev, pm_message_t state)
{
      hardware_disable(NULL);
      return 0;
}

static int kvm_resume(struct sys_device *dev)
{
      hardware_enable(NULL);
      return 0;
}

static struct sysdev_class kvm_sysdev_class = {
      set_kset_name("kvm"),
      .suspend = kvm_suspend,
      .resume = kvm_resume,
};

static struct sys_device kvm_sysdev = {
      .id = 0,
      .cls = &kvm_sysdev_class,
};

hpa_t bad_page_address;

static inline
struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
{
      return container_of(pn, struct kvm_vcpu, preempt_notifier);
}

static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
{
      struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);

      kvm_x86_ops->vcpu_load(vcpu, cpu);
}

static void kvm_sched_out(struct preempt_notifier *pn,
                    struct task_struct *next)
{
      struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);

      kvm_x86_ops->vcpu_put(vcpu);
}

int kvm_init_x86(struct kvm_x86_ops *ops, unsigned int vcpu_size,
              struct module *module)
{
      int r;
      int cpu;

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

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

      kvm_x86_ops = ops;

      r = kvm_x86_ops->hardware_setup();
      if (r < 0)
            goto out;

      for_each_online_cpu(cpu) {
            smp_call_function_single(cpu,
                        kvm_x86_ops->check_processor_compatibility,
                        &r, 0, 1);
            if (r < 0)
                  goto out_free_0;
      }

      on_each_cpu(hardware_enable, NULL, 0, 1);
      r = register_cpu_notifier(&kvm_cpu_notifier);
      if (r)
            goto out_free_1;
      register_reboot_notifier(&kvm_reboot_notifier);

      r = sysdev_class_register(&kvm_sysdev_class);
      if (r)
            goto out_free_2;

      r = sysdev_register(&kvm_sysdev);
      if (r)
            goto out_free_3;

      /* A kmem cache lets us meet the alignment requirements of fx_save. */
      kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size,
                                 __alignof__(struct kvm_vcpu), 0, 0);
      if (!kvm_vcpu_cache) {
            r = -ENOMEM;
            goto out_free_4;
      }

      kvm_chardev_ops.owner = module;

      r = misc_register(&kvm_dev);
      if (r) {
            printk (KERN_ERR "kvm: misc device register failed\n");
            goto out_free;
      }

      kvm_preempt_ops.sched_in = kvm_sched_in;
      kvm_preempt_ops.sched_out = kvm_sched_out;

      return r;

out_free:
      kmem_cache_destroy(kvm_vcpu_cache);
out_free_4:
      sysdev_unregister(&kvm_sysdev);
out_free_3:
      sysdev_class_unregister(&kvm_sysdev_class);
out_free_2:
      unregister_reboot_notifier(&kvm_reboot_notifier);
      unregister_cpu_notifier(&kvm_cpu_notifier);
out_free_1:
      on_each_cpu(hardware_disable, NULL, 0, 1);
out_free_0:
      kvm_x86_ops->hardware_unsetup();
out:
      kvm_x86_ops = NULL;
      return r;
}

void kvm_exit_x86(void)
{
      misc_deregister(&kvm_dev);
      kmem_cache_destroy(kvm_vcpu_cache);
      sysdev_unregister(&kvm_sysdev);
      sysdev_class_unregister(&kvm_sysdev_class);
      unregister_reboot_notifier(&kvm_reboot_notifier);
      unregister_cpu_notifier(&kvm_cpu_notifier);
      on_each_cpu(hardware_disable, NULL, 0, 1);
      kvm_x86_ops->hardware_unsetup();
      kvm_x86_ops = NULL;
}

static __init int kvm_init(void)
{
      static struct page *bad_page;
      int r;

      r = kvm_mmu_module_init();
      if (r)
            goto out4;

      kvm_init_debug();

      kvm_init_msr_list();

      if ((bad_page = alloc_page(GFP_KERNEL)) == NULL) {
            r = -ENOMEM;
            goto out;
      }

      bad_page_address = page_to_pfn(bad_page) << PAGE_SHIFT;
      memset(__va(bad_page_address), 0, PAGE_SIZE);

      return 0;

out:
      kvm_exit_debug();
      kvm_mmu_module_exit();
out4:
      return r;
}

static __exit void kvm_exit(void)
{
      kvm_exit_debug();
      __free_page(pfn_to_page(bad_page_address >> PAGE_SHIFT));
      kvm_mmu_module_exit();
}

module_init(kvm_init)
module_exit(kvm_exit)

EXPORT_SYMBOL_GPL(kvm_init_x86);
EXPORT_SYMBOL_GPL(kvm_exit_x86);

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