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    x86/speculation/mds: Add mitigation control for MDS · 29510670
    Thomas Gleixner 提交于
    commit bc1241700acd82ec69fde98c5763ce51086269f8 upstream
    
    Now that the mitigations are in place, add a command line parameter to
    control the mitigation, a mitigation selector function and a SMT update
    mechanism.
    
    This is the minimal straight forward initial implementation which just
    provides an always on/off mode. The command line parameter is:
    
      mds=[full|off]
    
    This is consistent with the existing mitigations for other speculative
    hardware vulnerabilities.
    
    The idle invocation is dynamically updated according to the SMT state of
    the system similar to the dynamic update of the STIBP mitigation. The idle
    mitigation is limited to CPUs which are only affected by MSBDS and not any
    other variant, because the other variants cannot be mitigated on SMT
    enabled systems.
    Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
    Reviewed-by: NBorislav Petkov <bp@suse.de>
    Reviewed-by: NJon Masters <jcm@redhat.com>
    Tested-by: NJon Masters <jcm@redhat.com>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    29510670
kernel-parameters.txt 178.0 KB