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x86/sev: Add an x86 version of cc_platform_has()
Introduce an x86 version of the cc_platform_has() function. This will be used to replace vendor specific calls like sme_active(), sev_active(), etc. Signed-off-by: Tom Lendacky <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
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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 <[email protected]> | ||
*/ | ||
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#include <linux/export.h> | ||
#include <linux/cc_platform.h> | ||
#include <linux/mem_encrypt.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) | ||
{ | ||
#ifdef CONFIG_INTEL_TDX_GUEST | ||
return false; | ||
#else | ||
return false; | ||
#endif | ||
} | ||
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/* | ||
* SME and SEV are very similar but they are not the same, so there are | ||
* times that the kernel will need to distinguish between SME and SEV. The | ||
* cc_platform_has() function is used for this. When a distinction isn't | ||
* needed, the CC_ATTR_MEM_ENCRYPT attribute can be used. | ||
* | ||
* The trampoline code is a good example for this requirement. Before | ||
* paging is activated, SME will access all memory as decrypted, but SEV | ||
* will access all memory as encrypted. So, when APs are being brought | ||
* up under SME the trampoline area cannot be encrypted, whereas under SEV | ||
* the trampoline area must be encrypted. | ||
*/ | ||
static bool amd_cc_platform_has(enum cc_attr attr) | ||
{ | ||
#ifdef CONFIG_AMD_MEM_ENCRYPT | ||
switch (attr) { | ||
case CC_ATTR_MEM_ENCRYPT: | ||
return sme_me_mask; | ||
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case CC_ATTR_HOST_MEM_ENCRYPT: | ||
return sme_me_mask && !(sev_status & MSR_AMD64_SEV_ENABLED); | ||
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case CC_ATTR_GUEST_MEM_ENCRYPT: | ||
return sev_status & MSR_AMD64_SEV_ENABLED; | ||
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case CC_ATTR_GUEST_STATE_ENCRYPT: | ||
return sev_status & MSR_AMD64_SEV_ES_ENABLED; | ||
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default: | ||
return false; | ||
} | ||
#else | ||
return false; | ||
#endif | ||
} | ||
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bool cc_platform_has(enum cc_attr attr) | ||
{ | ||
if (sme_me_mask) | ||
return amd_cc_platform_has(attr); | ||
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return false; | ||
} | ||
EXPORT_SYMBOL_GPL(cc_platform_has); |
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