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85 lines
2.1 KiB
85 lines
2.1 KiB
// 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 <[email protected]> |
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*/ |
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#include <linux/export.h> |
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#include <linux/cc_platform.h> |
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#include <linux/mem_encrypt.h> |
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#include <asm/mshyperv.h> |
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#include <asm/processor.h> |
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static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr) |
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{ |
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#ifdef CONFIG_INTEL_TDX_GUEST |
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return false; |
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#else |
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return false; |
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#endif |
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} |
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/* |
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* SME and SEV are very similar but they are not the same, so there are |
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* times that the kernel will need to distinguish between SME and SEV. The |
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* cc_platform_has() function is used for this. When a distinction isn't |
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* needed, the CC_ATTR_MEM_ENCRYPT attribute can be used. |
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* |
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* The trampoline code is a good example for this requirement. Before |
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* paging is activated, SME will access all memory as decrypted, but SEV |
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* will access all memory as encrypted. So, when APs are being brought |
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* up under SME the trampoline area cannot be encrypted, whereas under SEV |
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* the trampoline area must be encrypted. |
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*/ |
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static bool amd_cc_platform_has(enum cc_attr attr) |
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{ |
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#ifdef CONFIG_AMD_MEM_ENCRYPT |
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switch (attr) { |
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case CC_ATTR_MEM_ENCRYPT: |
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return sme_me_mask; |
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case CC_ATTR_HOST_MEM_ENCRYPT: |
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return sme_me_mask && !(sev_status & MSR_AMD64_SEV_ENABLED); |
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case CC_ATTR_GUEST_MEM_ENCRYPT: |
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return sev_status & MSR_AMD64_SEV_ENABLED; |
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case CC_ATTR_GUEST_STATE_ENCRYPT: |
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return sev_status & MSR_AMD64_SEV_ES_ENABLED; |
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/* |
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* With SEV, the rep string I/O instructions need to be unrolled |
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* but SEV-ES supports them through the #VC handler. |
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*/ |
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case CC_ATTR_GUEST_UNROLL_STRING_IO: |
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return (sev_status & MSR_AMD64_SEV_ENABLED) && |
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!(sev_status & MSR_AMD64_SEV_ES_ENABLED); |
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default: |
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return false; |
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} |
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#else |
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return false; |
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#endif |
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} |
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static bool hyperv_cc_platform_has(enum cc_attr attr) |
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{ |
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return attr == CC_ATTR_GUEST_MEM_ENCRYPT; |
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} |
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bool cc_platform_has(enum cc_attr attr) |
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{ |
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if (sme_me_mask) |
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return amd_cc_platform_has(attr); |
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if (hv_is_isolation_supported()) |
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return hyperv_cc_platform_has(attr); |
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return false; |
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} |
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EXPORT_SYMBOL_GPL(cc_platform_has);
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