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    Subject[PATCH v2 03/12] x86/sev: Add an x86 version of prot_guest_has()
    Date
    Introduce an x86 version of the prot_guest_has() function. This will be
    used in the more generic x86 code to replace vendor specific calls like
    sev_active(), etc.

    While the name suggests this is intended mainly for guests, it will
    also be used for host memory encryption checks in place of sme_active().

    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Reviewed-by: Joerg Roedel <jroedel@suse.de>
    Co-developed-by: Andi Kleen <ak@linux.intel.com>
    Signed-off-by: Andi Kleen <ak@linux.intel.com>
    Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
    Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
    Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
    ---
    arch/x86/Kconfig | 1 +
    arch/x86/include/asm/mem_encrypt.h | 2 ++
    arch/x86/include/asm/protected_guest.h | 29 ++++++++++++++++++++++++++
    arch/x86/mm/mem_encrypt.c | 25 ++++++++++++++++++++++
    include/linux/protected_guest.h | 5 +++++
    5 files changed, 62 insertions(+)
    create mode 100644 arch/x86/include/asm/protected_guest.h

    diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
    index 421fa9e38c60..82e5fb713261 100644
    --- a/arch/x86/Kconfig
    +++ b/arch/x86/Kconfig
    @@ -1514,6 +1514,7 @@ config AMD_MEM_ENCRYPT
    select ARCH_HAS_FORCE_DMA_UNENCRYPTED
    select INSTRUCTION_DECODER
    select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
    + select ARCH_HAS_PROTECTED_GUEST
    help
    Say yes to enable support for the encryption of system memory.
    This requires an AMD processor that supports Secure Memory
    diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
    index 9c80c68d75b5..a46d47662772 100644
    --- a/arch/x86/include/asm/mem_encrypt.h
    +++ b/arch/x86/include/asm/mem_encrypt.h
    @@ -53,6 +53,7 @@ void __init sev_es_init_vc_handling(void);
    bool sme_active(void);
    bool sev_active(void);
    bool sev_es_active(void);
    +bool amd_prot_guest_has(unsigned int attr);

    #define __bss_decrypted __section(".bss..decrypted")

    @@ -78,6 +79,7 @@ static inline void sev_es_init_vc_handling(void) { }
    static inline bool sme_active(void) { return false; }
    static inline bool sev_active(void) { return false; }
    static inline bool sev_es_active(void) { return false; }
    +static inline bool amd_prot_guest_has(unsigned int attr) { return false; }

    static inline int __init
    early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; }
    diff --git a/arch/x86/include/asm/protected_guest.h b/arch/x86/include/asm/protected_guest.h
    new file mode 100644
    index 000000000000..51e4eefd9542
    --- /dev/null
    +++ b/arch/x86/include/asm/protected_guest.h
    @@ -0,0 +1,29 @@
    +/* SPDX-License-Identifier: GPL-2.0-only */
    +/*
    + * Protected Guest (and Host) Capability checks
    + *
    + * Copyright (C) 2021 Advanced Micro Devices, Inc.
    + *
    + * Author: Tom Lendacky <thomas.lendacky@amd.com>
    + */
    +
    +#ifndef _X86_PROTECTED_GUEST_H
    +#define _X86_PROTECTED_GUEST_H
    +
    +#include <linux/mem_encrypt.h>
    +
    +#ifndef __ASSEMBLY__
    +
    +static inline bool prot_guest_has(unsigned int attr)
    +{
    +#ifdef CONFIG_AMD_MEM_ENCRYPT
    + if (sme_me_mask)
    + return amd_prot_guest_has(attr);
    +#endif
    +
    + return false;
    +}
    +
    +#endif /* __ASSEMBLY__ */
    +
    +#endif /* _X86_PROTECTED_GUEST_H */
    diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
    index ff08dc463634..edc67ddf065d 100644
    --- a/arch/x86/mm/mem_encrypt.c
    +++ b/arch/x86/mm/mem_encrypt.c
    @@ -20,6 +20,7 @@
    #include <linux/bitops.h>
    #include <linux/dma-mapping.h>
    #include <linux/virtio_config.h>
    +#include <linux/protected_guest.h>

    #include <asm/tlbflush.h>
    #include <asm/fixmap.h>
    @@ -389,6 +390,30 @@ bool noinstr sev_es_active(void)
    return sev_status & MSR_AMD64_SEV_ES_ENABLED;
    }

    +bool amd_prot_guest_has(unsigned int attr)
    +{
    + switch (attr) {
    + case PATTR_MEM_ENCRYPT:
    + return sme_me_mask != 0;
    +
    + case PATTR_SME:
    + case PATTR_HOST_MEM_ENCRYPT:
    + return sme_active();
    +
    + case PATTR_SEV:
    + case PATTR_GUEST_MEM_ENCRYPT:
    + return sev_active();
    +
    + case PATTR_SEV_ES:
    + case PATTR_GUEST_PROT_STATE:
    + return sev_es_active();
    +
    + default:
    + return false;
    + }
    +}
    +EXPORT_SYMBOL_GPL(amd_prot_guest_has);
    +
    /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
    bool force_dma_unencrypted(struct device *dev)
    {
    diff --git a/include/linux/protected_guest.h b/include/linux/protected_guest.h
    index 43d4dde94793..5ddef1b6a2ea 100644
    --- a/include/linux/protected_guest.h
    +++ b/include/linux/protected_guest.h
    @@ -20,6 +20,11 @@
    #define PATTR_GUEST_MEM_ENCRYPT 2 /* Guest encrypted memory */
    #define PATTR_GUEST_PROT_STATE 3 /* Guest encrypted state */

    +/* 0x800 - 0x8ff reserved for AMD */
    +#define PATTR_SME 0x800
    +#define PATTR_SEV 0x801
    +#define PATTR_SEV_ES 0x802
    +
    #ifdef CONFIG_ARCH_HAS_PROTECTED_GUEST

    #include <asm/protected_guest.h>
    --
    2.32.0
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