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8260b9820f
INS/OUTS are not supported in TDX guests and cause #UD. Kernel has to avoid them when running in TDX guest. To support existing usage, string I/O operations are unrolled using IN/OUT instructions. AMD SEV platform implements this support by adding unroll logic in ins#bwl()/outs#bwl() macros with SEV-specific checks. Since TDX VM guests will also need similar support, use CC_ATTR_GUEST_UNROLL_STRING_IO and generic cc_platform_has() API to implement it. String I/O helpers were the last users of sev_key_active() interface and sev_enable_key static key. Remove them. [ bp: Move comment too and do not delete it. ] Suggested-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lkml.kernel.org/r/20211206135505.75045-2-kirill.shutemov@linux.intel.com
77 lines
1.9 KiB
C
77 lines
1.9 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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#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/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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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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return false;
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}
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EXPORT_SYMBOL_GPL(cc_platform_has);
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