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    SubjectRe: [patch V3 41/66] x86/cpu: Sanitize X86_FEATURE_OSPKE
    On Fri, Jun 18, 2021 at 04:19:04PM +0200, Thomas Gleixner wrote:
    > X86_FEATURE_OSPKE is enabled first on the boot CPU and the feature flag is
    > set. Secondary CPUs have to enable CR4.PKE as well and set their per CPU
    > feature flag. That's ineffective because all call sites have checks for
    > boot_cpu_data.
    >
    > Make it smarter and force the feature flag when PKU is enabled on the boot
    > cpu which allows then to use cpu_feature_enabled(X86_FEATURE_OSPKE) all
    > over the place. That either compiles the code out when PKEY support is
    > disabled in Kconfig or uses a static_cpu_has() for the feature check which
    > makes a significant difference in hotpathes, e.g. context switch.

    "hotpaths"

    >
    > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    > ---
    > arch/x86/include/asm/pkeys.h | 8 ++++----
    > arch/x86/include/asm/pkru.h | 4 ++--
    > arch/x86/kernel/cpu/common.c | 24 +++++++++++-------------
    > arch/x86/kernel/fpu/core.c | 2 +-
    > arch/x86/kernel/fpu/xstate.c | 2 +-
    > arch/x86/kernel/process_64.c | 2 +-
    > arch/x86/mm/fault.c | 2 +-
    > 7 files changed, 21 insertions(+), 23 deletions(-)

    Other than that:

    Reviewed-by: Borislav Petkov <bp@suse.de>

    --
    Regards/Gruss,
    Boris.

    SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg

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