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Xiaoyao Li authored
Current initialization flow of split lock detection has following issues: 1. It assumes the initial value of MSR_TEST_CTRL.SPLIT_LOCK_DETECT to be zero. However, it's possible that BIOS/firmware has set it. 2. X86_FEATURE_SPLIT_LOCK_DETECT flag is unconditionally set even if there is a virtualization flaw that FMS indicates the existence while it's actually not supported. Rework the initialization flow to solve above issues. In detail, explicitly clear and set split_lock_detect bit to verify MSR_TEST_CTRL can be accessed, and rdmsr after wrmsr to ensure bit is cleared/set successfully. X86_FEATURE_SPLIT_LOCK_DETECT flag is set only when the feature does exist and the feature is not disabled with kernel param "split_lock_detect=off" On each processor, explicitly updating the SPLIT_LOCK_DETECT bit based on sld_sate in split_lock_init() since BIOS/firmware may touch it. Originally-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200325030924.132881-2-xiaoyao.li@intel.com
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