1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * TDX guest user interface driver
4 *
5 * Copyright (C) 2022 Intel Corporation
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/miscdevice.h>
10 #include <linux/mm.h>
11 #include <linux/module.h>
12 #include <linux/mod_devicetable.h>
13 #include <linux/string.h>
14 #include <linux/uaccess.h>
15
16 #include <uapi/linux/tdx-guest.h>
17
18 #include <asm/cpu_device_id.h>
19 #include <asm/tdx.h>
20
tdx_get_report0(struct tdx_report_req __user * req)21 static long tdx_get_report0(struct tdx_report_req __user *req)
22 {
23 u8 *reportdata, *tdreport;
24 long ret;
25
26 reportdata = kmalloc(TDX_REPORTDATA_LEN, GFP_KERNEL);
27 if (!reportdata)
28 return -ENOMEM;
29
30 tdreport = kzalloc(TDX_REPORT_LEN, GFP_KERNEL);
31 if (!tdreport) {
32 ret = -ENOMEM;
33 goto out;
34 }
35
36 if (copy_from_user(reportdata, req->reportdata, TDX_REPORTDATA_LEN)) {
37 ret = -EFAULT;
38 goto out;
39 }
40
41 /* Generate TDREPORT0 using "TDG.MR.REPORT" TDCALL */
42 ret = tdx_mcall_get_report0(reportdata, tdreport);
43 if (ret)
44 goto out;
45
46 if (copy_to_user(req->tdreport, tdreport, TDX_REPORT_LEN))
47 ret = -EFAULT;
48
49 out:
50 kfree(reportdata);
51 kfree(tdreport);
52
53 return ret;
54 }
55
tdx_guest_ioctl(struct file * file,unsigned int cmd,unsigned long arg)56 static long tdx_guest_ioctl(struct file *file, unsigned int cmd,
57 unsigned long arg)
58 {
59 switch (cmd) {
60 case TDX_CMD_GET_REPORT0:
61 return tdx_get_report0((struct tdx_report_req __user *)arg);
62 default:
63 return -ENOTTY;
64 }
65 }
66
67 static const struct file_operations tdx_guest_fops = {
68 .owner = THIS_MODULE,
69 .unlocked_ioctl = tdx_guest_ioctl,
70 .llseek = no_llseek,
71 };
72
73 static struct miscdevice tdx_misc_dev = {
74 .name = KBUILD_MODNAME,
75 .minor = MISC_DYNAMIC_MINOR,
76 .fops = &tdx_guest_fops,
77 };
78
79 static const struct x86_cpu_id tdx_guest_ids[] = {
80 X86_MATCH_FEATURE(X86_FEATURE_TDX_GUEST, NULL),
81 {}
82 };
83 MODULE_DEVICE_TABLE(x86cpu, tdx_guest_ids);
84
tdx_guest_init(void)85 static int __init tdx_guest_init(void)
86 {
87 if (!x86_match_cpu(tdx_guest_ids))
88 return -ENODEV;
89
90 return misc_register(&tdx_misc_dev);
91 }
92 module_init(tdx_guest_init);
93
tdx_guest_exit(void)94 static void __exit tdx_guest_exit(void)
95 {
96 misc_deregister(&tdx_misc_dev);
97 }
98 module_exit(tdx_guest_exit);
99
100 MODULE_AUTHOR("Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>");
101 MODULE_DESCRIPTION("TDX Guest Driver");
102 MODULE_LICENSE("GPL");
103