Add a kernel config option to enable the feature (disabled by default) at compile-time. Also, add a new command-line parameter -- 'nokeylocker' to disable the feature at boot-time. Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx> Cc: x86@xxxxxxxxxx Cc: linux-doc@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx --- Documentation/admin-guide/kernel-parameters.txt | 2 ++ arch/x86/Kconfig | 14 ++++++++++++++ arch/x86/kernel/cpu/common.c | 16 ++++++++++++++++ 3 files changed, 32 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 44fde25bb221..c389ad8fb9de 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3220,6 +3220,8 @@ nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings. + nokeylocker [X86] Disables Key Locker hardware feature. + nosmt [KNL,S390] Disable symmetric multithreading (SMT). Equivalent to smt=1. diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index fbf26e0f7a6a..7623af32f919 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1886,6 +1886,20 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS If unsure, say y. +config X86_KEYLOCKER + prompt "Key Locker" + def_bool n + depends on CPU_SUP_INTEL + help + Key Locker is a new security feature to protect a data encryption + key for the Advanced Encryption Standard (AES) algorithm. + + When enabled, every CPU has a unique internal key to wrap the AES + key into an encoded format. The internal key is not accessible + to software once loaded. + + If unsure, say y. + choice prompt "TSX enable mode" depends on CPU_SUP_INTEL diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a446d5aff08f..ba5bd79fbac2 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -354,6 +354,22 @@ static __always_inline void setup_umip(struct cpuinfo_x86 *c) /* These bits should not change their value after CPU init is finished. */ static const unsigned long cr4_pinned_mask = X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP | X86_CR4_FSGSBASE; + +static __init int x86_nokeylocker_setup(char *arg) +{ + /* Expect an exact match without trailing characters */ + if (strlen(arg)) + return 0; + + if (!cpu_feature_enabled(X86_FEATURE_KEYLOCKER)) + return 1; + + setup_clear_cpu_cap(X86_FEATURE_KEYLOCKER); + pr_info("x86/keylocker: Disabled by kernel command line\n"); + return 1; +} +__setup("nokeylocker", x86_nokeylocker_setup); + static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning); static unsigned long cr4_pinned_bits __ro_after_init; -- 2.17.1