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    Subject[PATCH v5 02/12] x86/cpufeature: Enumerate Key Locker feature
    Date
    Key Locker is a CPU feature to minimize exposure of clear-text key
    material. An encoded form, called 'key handle', is referenced for data
    encryption or decryption instead of accessing the clear text key.

    A wrapping key loaded in the CPU's software-inaccessible state is used to
    transform a user key into a key handle.

    It supports Advanced Encryption Standard (AES) cipher algorithm with new
    SIMD instruction set like its predecessor (AES-NI). So a new AES
    implementation will follow in the kernel's crypto library.

    Here add it to enumerate the hardware capability, but it will not be
    shown in /proc/cpuinfo as userspace usage is not supported.

    Make the feature depend on XMM2 as it comes with AES SIMD instructions.

    Add X86_FEATURE_KEYLOCKER to the disabled features mask. It will be
    enabled under a new config option.

    Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
    Reviewed-by: Dan Williams <dan.j.williams@intel.com>
    Cc: x86@kernel.org
    Cc: linux-kernel@vger.kernel.org
    ---
    Changes from RFC v2:
    * Do not publish the feature flag to userspace.
    * Update the changelog.

    Changes from RFC v1:
    * Updated the changelog.
    ---
    arch/x86/include/asm/cpufeatures.h | 1 +
    arch/x86/include/asm/disabled-features.h | 8 +++++++-
    arch/x86/include/uapi/asm/processor-flags.h | 2 ++
    arch/x86/kernel/cpu/cpuid-deps.c | 1 +
    4 files changed, 11 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
    index d5b5f2ab87a0..e1964446bbe5 100644
    --- a/arch/x86/include/asm/cpufeatures.h
    +++ b/arch/x86/include/asm/cpufeatures.h
    @@ -361,6 +361,7 @@
    #define X86_FEATURE_AVX512_VPOPCNTDQ (16*32+14) /* POPCNT for vectors of DW/QW */
    #define X86_FEATURE_LA57 (16*32+16) /* 5-level page tables */
    #define X86_FEATURE_RDPID (16*32+22) /* RDPID instruction */
    +#define X86_FEATURE_KEYLOCKER (16*32+23) /* "" Key Locker */
    #define X86_FEATURE_BUS_LOCK_DETECT (16*32+24) /* Bus Lock detect */
    #define X86_FEATURE_CLDEMOTE (16*32+25) /* CLDEMOTE instruction */
    #define X86_FEATURE_MOVDIRI (16*32+27) /* MOVDIRI instruction */
    diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
    index 8f28fafa98b3..75e1e87640d4 100644
    --- a/arch/x86/include/asm/disabled-features.h
    +++ b/arch/x86/include/asm/disabled-features.h
    @@ -44,6 +44,12 @@
    # define DISABLE_OSPKE (1<<(X86_FEATURE_OSPKE & 31))
    #endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */

    +#ifdef CONFIG_X86_KEYLOCKER
    +# define DISABLE_KEYLOCKER 0
    +#else
    +# define DISABLE_KEYLOCKER (1<<(X86_FEATURE_KEYLOCKER & 31))
    +#endif /* CONFIG_X86_KEYLOCKER */
    +
    #ifdef CONFIG_X86_5LEVEL
    # define DISABLE_LA57 0
    #else
    @@ -85,7 +91,7 @@
    #define DISABLED_MASK14 0
    #define DISABLED_MASK15 0
    #define DISABLED_MASK16 (DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \
    - DISABLE_ENQCMD)
    + DISABLE_ENQCMD|DISABLE_KEYLOCKER)
    #define DISABLED_MASK17 0
    #define DISABLED_MASK18 0
    #define DISABLED_MASK19 0
    diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
    index bcba3c643e63..b958a95a0908 100644
    --- a/arch/x86/include/uapi/asm/processor-flags.h
    +++ b/arch/x86/include/uapi/asm/processor-flags.h
    @@ -124,6 +124,8 @@
    #define X86_CR4_PCIDE _BITUL(X86_CR4_PCIDE_BIT)
    #define X86_CR4_OSXSAVE_BIT 18 /* enable xsave and xrestore */
    #define X86_CR4_OSXSAVE _BITUL(X86_CR4_OSXSAVE_BIT)
    +#define X86_CR4_KEYLOCKER_BIT 19 /* enable Key Locker */
    +#define X86_CR4_KEYLOCKER _BITUL(X86_CR4_KEYLOCKER_BIT)
    #define X86_CR4_SMEP_BIT 20 /* enable SMEP support */
    #define X86_CR4_SMEP _BITUL(X86_CR4_SMEP_BIT)
    #define X86_CR4_SMAP_BIT 21 /* enable SMAP support */
    diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
    index c881bcafba7d..abe7e04b27d9 100644
    --- a/arch/x86/kernel/cpu/cpuid-deps.c
    +++ b/arch/x86/kernel/cpu/cpuid-deps.c
    @@ -78,6 +78,7 @@ static const struct cpuid_dep cpuid_deps[] = {
    { X86_FEATURE_XFD, X86_FEATURE_XSAVES },
    { X86_FEATURE_XFD, X86_FEATURE_XGETBV1 },
    { X86_FEATURE_AMX_TILE, X86_FEATURE_XFD },
    + { X86_FEATURE_KEYLOCKER, X86_FEATURE_XMM2 },
    {}
    };

    --
    2.17.1
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