cc_platform.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Confidential Computing Platform Capability checks
  4 *
  5 * Copyright (C) 2021 Advanced Micro Devices, Inc.
  6 *
  7 * Author: Tom Lendacky <thomas.lendacky@amd.com>
  8 */
  9
 10#ifndef _LINUX_CC_PLATFORM_H
 11#define _LINUX_CC_PLATFORM_H
 12
 13#include <linux/types.h>
 14#include <linux/stddef.h>
 15
 16/**
 17 * enum cc_attr - Confidential computing attributes
 18 *
 19 * These attributes represent confidential computing features that are
 20 * currently active.
 21 */
 22enum cc_attr {
 23	/**
 24	 * @CC_ATTR_MEM_ENCRYPT: Memory encryption is active
 25	 *
 26	 * The platform/OS is running with active memory encryption. This
 27	 * includes running either as a bare-metal system or a hypervisor
 28	 * and actively using memory encryption or as a guest/virtual machine
 29	 * and actively using memory encryption.
 30	 *
 31	 * Examples include SME, SEV and SEV-ES.
 32	 */
 33	CC_ATTR_MEM_ENCRYPT,
 34
 35	/**
 36	 * @CC_ATTR_HOST_MEM_ENCRYPT: Host memory encryption is active
 37	 *
 38	 * The platform/OS is running as a bare-metal system or a hypervisor
 39	 * and actively using memory encryption.
 40	 *
 41	 * Examples include SME.
 42	 */
 43	CC_ATTR_HOST_MEM_ENCRYPT,
 44
 45	/**
 46	 * @CC_ATTR_GUEST_MEM_ENCRYPT: Guest memory encryption is active
 47	 *
 48	 * The platform/OS is running as a guest/virtual machine and actively
 49	 * using memory encryption.
 50	 *
 51	 * Examples include SEV and SEV-ES.
 52	 */
 53	CC_ATTR_GUEST_MEM_ENCRYPT,
 54
 55	/**
 56	 * @CC_ATTR_GUEST_STATE_ENCRYPT: Guest state encryption is active
 57	 *
 58	 * The platform/OS is running as a guest/virtual machine and actively
 59	 * using memory encryption and register state encryption.
 60	 *
 61	 * Examples include SEV-ES.
 62	 */
 63	CC_ATTR_GUEST_STATE_ENCRYPT,
 64
 65	/**
 66	 * @CC_ATTR_GUEST_UNROLL_STRING_IO: String I/O is implemented with
 67	 *                                  IN/OUT instructions
 68	 *
 69	 * The platform/OS is running as a guest/virtual machine and uses
 70	 * IN/OUT instructions in place of string I/O.
 71	 *
 72	 * Examples include TDX guest & SEV.
 73	 */
 74	CC_ATTR_GUEST_UNROLL_STRING_IO,
 75
 76	/**
 77	 * @CC_ATTR_GUEST_SEV_SNP: Guest SNP is active.
 78	 *
 79	 * The platform/OS is running as a guest/virtual machine and actively
 80	 * using AMD SEV-SNP features.
 81	 */
 82	CC_ATTR_GUEST_SEV_SNP,
 83
 84	/**
 85	 * @CC_ATTR_GUEST_SNP_SECURE_TSC: SNP Secure TSC is active.
 86	 *
 87	 * The platform/OS is running as a guest/virtual machine and actively
 88	 * using AMD SEV-SNP Secure TSC feature.
 89	 */
 90	CC_ATTR_GUEST_SNP_SECURE_TSC,
 91
 92	/**
 93	 * @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host.
 94	 *
 95	 * The host kernel is running with the necessary features
 96	 * enabled to run SEV-SNP guests.
 97	 */
 98	CC_ATTR_HOST_SEV_SNP,
 99
100	/**
101	 * @CC_ATTR_SNP_SECURE_AVIC: Secure AVIC mode is active.
102	 *
103	 * The host kernel is running with the necessary features enabled
104	 * to run SEV-SNP guests with full Secure AVIC capabilities.
105	 */
106	CC_ATTR_SNP_SECURE_AVIC,
107};
108
109#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
110
111/**
112 * cc_platform_has() - Checks if the specified cc_attr attribute is active
113 * @attr: Confidential computing attribute to check
114 *
115 * The cc_platform_has() function will return an indicator as to whether the
116 * specified Confidential Computing attribute is currently active.
117 *
118 * Context: Any context
119 * Return:
120 * * TRUE  - Specified Confidential Computing attribute is active
121 * * FALSE - Specified Confidential Computing attribute is not active
122 */
123bool cc_platform_has(enum cc_attr attr);
124void cc_platform_set(enum cc_attr attr);
125void cc_platform_clear(enum cc_attr attr);
126
127#else	/* !CONFIG_ARCH_HAS_CC_PLATFORM */
128
129static inline bool cc_platform_has(enum cc_attr attr) { return false; }
130static inline void cc_platform_set(enum cc_attr attr) { }
131static inline void cc_platform_clear(enum cc_attr attr) { }
132
133#endif	/* CONFIG_ARCH_HAS_CC_PLATFORM */
134
135#endif	/* _LINUX_CC_PLATFORM_H */