drivers/virt/coco/tdx-guest/tdx-guest.c

   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 <[email protected]>");
 101 MODULE_DESCRIPTION("TDX Guest Driver");
 102 MODULE_LICENSE("GPL");