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85b60ca9ad
Add support for Secure TSC in SNP-enabled guests. Secure TSC allows guests
to securely use RDTSC/RDTSCP instructions, ensuring that the parameters used
cannot be altered by the hypervisor once the guest is launched.
Secure TSC-enabled guests need to query TSC information from the AMD Security
Processor. This communication channel is encrypted between the AMD Security
Processor and the guest, with the hypervisor acting merely as a conduit to
deliver the guest messages to the AMD Security Processor. Each message is
protected with AEAD (AES-256 GCM).
[ bp: Zap a stray newline over amd_cc_platform_has() while at it,
simplify CC_ATTR_GUEST_SNP_SECURE_TSC check ]
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250106124633.1418972-6-nikunj@amd.com
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Confidential Computing Platform Capability checks
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*
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* Copyright (C) 2021 Advanced Micro Devices, Inc.
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*
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* Author: Tom Lendacky <thomas.lendacky@amd.com>
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*/
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#ifndef _LINUX_CC_PLATFORM_H
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#define _LINUX_CC_PLATFORM_H
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#include <linux/types.h>
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#include <linux/stddef.h>
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/**
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* enum cc_attr - Confidential computing attributes
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*
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* These attributes represent confidential computing features that are
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* currently active.
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*/
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enum cc_attr {
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/**
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* @CC_ATTR_MEM_ENCRYPT: Memory encryption is active
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*
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* The platform/OS is running with active memory encryption. This
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* includes running either as a bare-metal system or a hypervisor
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* and actively using memory encryption or as a guest/virtual machine
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* and actively using memory encryption.
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*
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* Examples include SME, SEV and SEV-ES.
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*/
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CC_ATTR_MEM_ENCRYPT,
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/**
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* @CC_ATTR_HOST_MEM_ENCRYPT: Host memory encryption is active
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*
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* The platform/OS is running as a bare-metal system or a hypervisor
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* and actively using memory encryption.
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*
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* Examples include SME.
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*/
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CC_ATTR_HOST_MEM_ENCRYPT,
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/**
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* @CC_ATTR_GUEST_MEM_ENCRYPT: Guest memory encryption is active
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*
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* The platform/OS is running as a guest/virtual machine and actively
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* using memory encryption.
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*
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* Examples include SEV and SEV-ES.
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*/
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CC_ATTR_GUEST_MEM_ENCRYPT,
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/**
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* @CC_ATTR_GUEST_STATE_ENCRYPT: Guest state encryption is active
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*
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* The platform/OS is running as a guest/virtual machine and actively
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* using memory encryption and register state encryption.
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*
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* Examples include SEV-ES.
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*/
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CC_ATTR_GUEST_STATE_ENCRYPT,
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/**
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* @CC_ATTR_GUEST_UNROLL_STRING_IO: String I/O is implemented with
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* IN/OUT instructions
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*
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* The platform/OS is running as a guest/virtual machine and uses
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* IN/OUT instructions in place of string I/O.
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*
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* Examples include TDX guest & SEV.
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*/
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CC_ATTR_GUEST_UNROLL_STRING_IO,
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/**
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* @CC_ATTR_SEV_SNP: Guest SNP is active.
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*
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* The platform/OS is running as a guest/virtual machine and actively
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* using AMD SEV-SNP features.
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*/
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CC_ATTR_GUEST_SEV_SNP,
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/**
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* @CC_ATTR_GUEST_SNP_SECURE_TSC: SNP Secure TSC is active.
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*
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* The platform/OS is running as a guest/virtual machine and actively
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* using AMD SEV-SNP Secure TSC feature.
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*/
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CC_ATTR_GUEST_SNP_SECURE_TSC,
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/**
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* @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host.
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*
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* The host kernel is running with the necessary features
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* enabled to run SEV-SNP guests.
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*/
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CC_ATTR_HOST_SEV_SNP,
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};
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#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
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/**
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* cc_platform_has() - Checks if the specified cc_attr attribute is active
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* @attr: Confidential computing attribute to check
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*
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* The cc_platform_has() function will return an indicator as to whether the
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* specified Confidential Computing attribute is currently active.
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*
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* Context: Any context
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* Return:
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* * TRUE - Specified Confidential Computing attribute is active
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* * FALSE - Specified Confidential Computing attribute is not active
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*/
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bool cc_platform_has(enum cc_attr attr);
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void cc_platform_set(enum cc_attr attr);
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void cc_platform_clear(enum cc_attr attr);
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#else /* !CONFIG_ARCH_HAS_CC_PLATFORM */
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static inline bool cc_platform_has(enum cc_attr attr) { return false; }
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static inline void cc_platform_set(enum cc_attr attr) { }
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static inline void cc_platform_clear(enum cc_attr attr) { }
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#endif /* CONFIG_ARCH_HAS_CC_PLATFORM */
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#endif /* _LINUX_CC_PLATFORM_H */
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