Commit 46b49b12 authored by Tom Lendacky's avatar Tom Lendacky Committed by Borislav Petkov
Browse files

arch/cc: Introduce a function to check for confidential computing features 



In preparation for other confidential computing technologies, introduce
a generic helper function, cc_platform_has(), that can be used to
check for specific active confidential computing attributes, like
memory encryption. This is intended to eliminate having to add multiple
technology-specific checks to the code (e.g. if (sev_active() ||
tdx_active() || ... ).

 [ bp: s/_CC_PLATFORM_H/_LINUX_CC_PLATFORM_H/g ]

Co-developed-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Co-developed-by: default avatarKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: default avatarKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-3-bp@alien8.de
parent 402fe0cb

arch/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -1234,6 +1234,9 @@ config RELR 
config ARCH_HAS_MEM_ENCRYPT

	bool



config ARCH_HAS_CC_PLATFORM

	bool



config HAVE_SPARSE_SYSCALL_NR

       bool

       help

include/linux/cc_platform.h

0 → 100644
+88 −0
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/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Confidential Computing Platform Capability checks

 *

 * Copyright (C) 2021 Advanced Micro Devices, Inc.

 *

 * Author: Tom Lendacky <thomas.lendacky@amd.com>

 */



#ifndef _LINUX_CC_PLATFORM_H

#define _LINUX_CC_PLATFORM_H



#include <linux/types.h>

#include <linux/stddef.h>



/**

 * enum cc_attr - Confidential computing attributes

 *

 * These attributes represent confidential computing features that are

 * currently active.

 */

enum cc_attr {

	/**

	 * @CC_ATTR_MEM_ENCRYPT: Memory encryption is active

	 *

	 * The platform/OS is running with active memory encryption. This

	 * includes running either as a bare-metal system or a hypervisor

	 * and actively using memory encryption or as a guest/virtual machine

	 * and actively using memory encryption.

	 *

	 * Examples include SME, SEV and SEV-ES.

	 */

	CC_ATTR_MEM_ENCRYPT,



	/**

	 * @CC_ATTR_HOST_MEM_ENCRYPT: Host memory encryption is active

	 *

	 * The platform/OS is running as a bare-metal system or a hypervisor

	 * and actively using memory encryption.

	 *

	 * Examples include SME.

	 */

	CC_ATTR_HOST_MEM_ENCRYPT,



	/**

	 * @CC_ATTR_GUEST_MEM_ENCRYPT: Guest memory encryption is active

	 *

	 * The platform/OS is running as a guest/virtual machine and actively

	 * using memory encryption.

	 *

	 * Examples include SEV and SEV-ES.

	 */

	CC_ATTR_GUEST_MEM_ENCRYPT,



	/**

	 * @CC_ATTR_GUEST_STATE_ENCRYPT: Guest state encryption is active

	 *

	 * The platform/OS is running as a guest/virtual machine and actively

	 * using memory encryption and register state encryption.

	 *

	 * Examples include SEV-ES.

	 */

	CC_ATTR_GUEST_STATE_ENCRYPT,

};



#ifdef CONFIG_ARCH_HAS_CC_PLATFORM



/**

 * cc_platform_has() - Checks if the specified cc_attr attribute is active

 * @attr: Confidential computing attribute to check

 *

 * The cc_platform_has() function will return an indicator as to whether the

 * specified Confidential Computing attribute is currently active.

 *

 * Context: Any context

 * Return:

 * * TRUE  - Specified Confidential Computing attribute is active

 * * FALSE - Specified Confidential Computing attribute is not active

 */

bool cc_platform_has(enum cc_attr attr);



#else	/* !CONFIG_ARCH_HAS_CC_PLATFORM */



static inline bool cc_platform_has(enum cc_attr attr) { return false; }



#endif	/* CONFIG_ARCH_HAS_CC_PLATFORM */



#endif	/* _LINUX_CC_PLATFORM_H */