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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b3f0907c71
kvmclock defines few static variables which are shared with the hypervisor during the kvmclock initialization. When SEV is active, memory is encrypted with a guest-specific key, and if the guest OS wants to share the memory region with the hypervisor then it must clear the C-bit before sharing it. Currently, we use kernel_physical_mapping_init() to split large pages before clearing the C-bit on shared pages. But it fails when called from the kvmclock initialization (mainly because the memblock allocator is not ready that early during boot). Add a __bss_decrypted section attribute which can be used when defining such shared variable. The so-defined variables will be placed in the .bss..decrypted section. This section will be mapped with C=0 early during boot. The .bss..decrypted section has a big chunk of memory that may be unused when memory encryption is not active, free it when memory encryption is not active. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Radim Krčmář<rkrcmar@redhat.com> Cc: kvm@vger.kernel.org Link: https://lkml.kernel.org/r/1536932759-12905-2-git-send-email-brijesh.singh@amd.com
101 lines
3.0 KiB
C
101 lines
3.0 KiB
C
/*
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* AMD Memory Encryption Support
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*
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* Copyright (C) 2016 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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#ifndef __X86_MEM_ENCRYPT_H__
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#define __X86_MEM_ENCRYPT_H__
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#ifndef __ASSEMBLY__
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#include <linux/init.h>
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#include <asm/bootparam.h>
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#ifdef CONFIG_AMD_MEM_ENCRYPT
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extern u64 sme_me_mask;
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extern bool sev_enabled;
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void sme_encrypt_execute(unsigned long encrypted_kernel_vaddr,
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unsigned long decrypted_kernel_vaddr,
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unsigned long kernel_len,
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unsigned long encryption_wa,
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unsigned long encryption_pgd);
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void __init sme_early_encrypt(resource_size_t paddr,
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unsigned long size);
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void __init sme_early_decrypt(resource_size_t paddr,
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unsigned long size);
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void __init sme_map_bootdata(char *real_mode_data);
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void __init sme_unmap_bootdata(char *real_mode_data);
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void __init sme_early_init(void);
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void __init sme_encrypt_kernel(struct boot_params *bp);
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void __init sme_enable(struct boot_params *bp);
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int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size);
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int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size);
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/* Architecture __weak replacement functions */
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void __init mem_encrypt_init(void);
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void __init mem_encrypt_free_decrypted_mem(void);
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bool sme_active(void);
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bool sev_active(void);
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#define __bss_decrypted __attribute__((__section__(".bss..decrypted")))
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#else /* !CONFIG_AMD_MEM_ENCRYPT */
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#define sme_me_mask 0ULL
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static inline void __init sme_early_encrypt(resource_size_t paddr,
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unsigned long size) { }
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static inline void __init sme_early_decrypt(resource_size_t paddr,
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unsigned long size) { }
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static inline void __init sme_map_bootdata(char *real_mode_data) { }
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static inline void __init sme_unmap_bootdata(char *real_mode_data) { }
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static inline void __init sme_early_init(void) { }
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static inline void __init sme_encrypt_kernel(struct boot_params *bp) { }
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static inline void __init sme_enable(struct boot_params *bp) { }
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static inline bool sme_active(void) { return false; }
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static inline bool sev_active(void) { return false; }
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static inline int __init
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early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
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static inline int __init
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early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; }
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#define __bss_decrypted
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#endif /* CONFIG_AMD_MEM_ENCRYPT */
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/*
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* The __sme_pa() and __sme_pa_nodebug() macros are meant for use when
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* writing to or comparing values from the cr3 register. Having the
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* encryption mask set in cr3 enables the PGD entry to be encrypted and
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* avoid special case handling of PGD allocations.
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*/
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#define __sme_pa(x) (__pa(x) | sme_me_mask)
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#define __sme_pa_nodebug(x) (__pa_nodebug(x) | sme_me_mask)
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extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[];
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#endif /* __ASSEMBLY__ */
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#endif /* __X86_MEM_ENCRYPT_H__ */
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