err.no Git - linux-2.6/blob - drivers/kvm/x86.c

   1 /*
   2  * Kernel-based Virtual Machine driver for Linux
   3  *
   4  * derived from drivers/kvm/kvm_main.c
   5  *
   6  * Copyright (C) 2006 Qumranet, Inc.
   7  *
   8  * Authors:
   9  *   Avi Kivity   <avi@qumranet.com>
  10  *   Yaniv Kamay  <yaniv@qumranet.com>
  11  *
  12  * This work is licensed under the terms of the GNU GPL, version 2.  See
  13  * the COPYING file in the top-level directory.
  14  *
  15  */
  16
  17 #include "x86.h"
  18
  19 #include <asm/uaccess.h>
  20
  21 /*
  22  * List of msr numbers which we expose to userspace through KVM_GET_MSRS
  23  * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
  24  *
  25  * This list is modified at module load time to reflect the
  26  * capabilities of the host cpu.
  27  */
  28 static u32 msrs_to_save[] = {
  29         MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
  30         MSR_K6_STAR,
  31 #ifdef CONFIG_X86_64
  32         MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
  33 #endif
  34         MSR_IA32_TIME_STAMP_COUNTER,
  35 };
  36
  37 static unsigned num_msrs_to_save;
  38
  39 static u32 emulated_msrs[] = {
  40         MSR_IA32_MISC_ENABLE,
  41 };
  42
  43 long kvm_arch_dev_ioctl(struct file *filp,
  44                         unsigned int ioctl, unsigned long arg)
  45 {
  46         void __user *argp = (void __user *)arg;
  47         long r;
  48
  49         switch (ioctl) {
  50         case KVM_GET_MSR_INDEX_LIST: {
  51                 struct kvm_msr_list __user *user_msr_list = argp;
  52                 struct kvm_msr_list msr_list;
  53                 unsigned n;
  54
  55                 r = -EFAULT;
  56                 if (copy_from_user(&msr_list, user_msr_list, sizeof msr_list))
  57                         goto out;
  58                 n = msr_list.nmsrs;
  59                 msr_list.nmsrs = num_msrs_to_save + ARRAY_SIZE(emulated_msrs);
  60                 if (copy_to_user(user_msr_list, &msr_list, sizeof msr_list))
  61                         goto out;
  62                 r = -E2BIG;
  63                 if (n < num_msrs_to_save)
  64                         goto out;
  65                 r = -EFAULT;
  66                 if (copy_to_user(user_msr_list->indices, &msrs_to_save,
  67                                  num_msrs_to_save * sizeof(u32)))
  68                         goto out;
  69                 if (copy_to_user(user_msr_list->indices
  70                                  + num_msrs_to_save * sizeof(u32),
  71                                  &emulated_msrs,
  72                                  ARRAY_SIZE(emulated_msrs) * sizeof(u32)))
  73                         goto out;
  74                 r = 0;
  75                 break;
  76         }
  77         default:
  78                 r = -EINVAL;
  79         }
  80 out:
  81         return r;
  82 }
  83
  84 static __init void kvm_init_msr_list(void)
  85 {
  86         u32 dummy[2];
  87         unsigned i, j;
  88
  89         for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
  90                 if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
  91                         continue;
  92                 if (j < i)
  93                         msrs_to_save[j] = msrs_to_save[i];
  94                 j++;
  95         }
  96         num_msrs_to_save = j;
  97 }
  98
  99 __init void kvm_arch_init(void)
 100 {
 101         kvm_init_msr_list();
 102 }