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 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 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 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 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