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

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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: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-3-bp@alien8.de
This commit is contained in:
Tom Lendacky 2021-09-08 17:58:33 -05:00 committed by Borislav Petkov
parent 402fe0cb71
commit 46b49b12f3
2 changed files with 91 additions and 0 deletions
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3
arch/Kconfig
View File

@ -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

88
include/linux/cc_platform.h Normal file
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@ -0,0 +1,88 @@
/* 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 */