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043405e1 CO |
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 | } |