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07344b15a9
In arch/x86/boot/compressed/kaslr_64.c, CONFIG_AMD_MEM_ENCRYPT support was initially #undef'd to support SME with minimal effort. When support for SEV was added, the #undef remained and some minimal support for setting the encryption bit was added for building identity mapped pagetable entries. Commitb83ce5ee91("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52") changed __PHYSICAL_MASK_SHIFT from 46 to 52 in support of 5-level paging. This change resulted in SEV guests failing to boot because the encryption bit was no longer being automatically masked out. The compressed boot path now requires sme_me_mask to be defined in order for the pagetable functions, such as pud_present(), to properly mask out the encryption bit (currently bit 47) when evaluating pagetable entries. Add an sme_me_mask variable in arch/x86/boot/compressed/mem_encrypt.S, which is set when SEV is active, delete the #undef CONFIG_AMD_MEM_ENCRYPT from arch/x86/boot/compressed/kaslr_64.c and use sme_me_mask when building the identify mapped pagetable entries. Fixes:b83ce5ee91("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52") Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/20180327220711.8702.55842.stgit@tlendack-t1.amdoffice.net
124 lines
2.4 KiB
ArmAsm
124 lines
2.4 KiB
ArmAsm
/*
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* AMD Memory Encryption Support
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*
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* Copyright (C) 2017 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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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#include <asm/processor-flags.h>
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#include <asm/msr.h>
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#include <asm/asm-offsets.h>
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.text
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.code32
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ENTRY(get_sev_encryption_bit)
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xor %eax, %eax
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#ifdef CONFIG_AMD_MEM_ENCRYPT
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push %ebx
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push %ecx
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push %edx
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push %edi
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/*
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* RIP-relative addressing is needed to access the encryption bit
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* variable. Since we are running in 32-bit mode we need this call/pop
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* sequence to get the proper relative addressing.
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*/
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call 1f
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1: popl %edi
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subl $1b, %edi
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movl enc_bit(%edi), %eax
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cmpl $0, %eax
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jge .Lsev_exit
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/* Check if running under a hypervisor */
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movl $1, %eax
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cpuid
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bt $31, %ecx /* Check the hypervisor bit */
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jnc .Lno_sev
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movl $0x80000000, %eax /* CPUID to check the highest leaf */
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cpuid
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cmpl $0x8000001f, %eax /* See if 0x8000001f is available */
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jb .Lno_sev
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/*
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* Check for the SEV feature:
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* CPUID Fn8000_001F[EAX] - Bit 1
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* CPUID Fn8000_001F[EBX] - Bits 5:0
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* Pagetable bit position used to indicate encryption
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*/
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movl $0x8000001f, %eax
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cpuid
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bt $1, %eax /* Check if SEV is available */
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jnc .Lno_sev
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movl $MSR_AMD64_SEV, %ecx /* Read the SEV MSR */
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rdmsr
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bt $MSR_AMD64_SEV_ENABLED_BIT, %eax /* Check if SEV is active */
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jnc .Lno_sev
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movl %ebx, %eax
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andl $0x3f, %eax /* Return the encryption bit location */
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movl %eax, enc_bit(%edi)
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jmp .Lsev_exit
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.Lno_sev:
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xor %eax, %eax
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movl %eax, enc_bit(%edi)
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.Lsev_exit:
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pop %edi
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pop %edx
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pop %ecx
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pop %ebx
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#endif /* CONFIG_AMD_MEM_ENCRYPT */
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ret
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ENDPROC(get_sev_encryption_bit)
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.code64
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ENTRY(set_sev_encryption_mask)
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#ifdef CONFIG_AMD_MEM_ENCRYPT
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push %rbp
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push %rdx
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movq %rsp, %rbp /* Save current stack pointer */
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call get_sev_encryption_bit /* Get the encryption bit position */
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testl %eax, %eax
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jz .Lno_sev_mask
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bts %rax, sme_me_mask(%rip) /* Create the encryption mask */
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.Lno_sev_mask:
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movq %rbp, %rsp /* Restore original stack pointer */
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pop %rdx
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pop %rbp
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#endif
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xor %rax, %rax
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ret
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ENDPROC(set_sev_encryption_mask)
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.data
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enc_bit:
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.int 0xffffffff
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#ifdef CONFIG_AMD_MEM_ENCRYPT
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.balign 8
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GLOBAL(sme_me_mask)
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.quad 0
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#endif
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