Messages in this thread | | | From | Benjamin Lamowski <> | Subject | [PATCH 0/1] x86/split_lock: check split lock feature on initialization | Date | Fri, 3 Apr 2020 19:44:02 +0200 |
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Hi,
During regression testing of our hypervisor[1] with the current git tip, we got writes to the TEST_CTRL MSR on hardware that does not support split lock detection. While the original split_lock implementation does not exhibit this behavior, the reworked initialization from dbaba47085b0c unconditionally calls split_lock_verify_msr() from split_lock_init().
After the elaborate checks in cpu_set_core_cap_bits() this seems like an oversight. The following simple patch fixes our regression by checking for X86_FEATURE_SPLIT_LOCK_DETECT before accessing the TEST_CTRL MSR.
Please CC me on replies - I am not subscribed to the LKML.
Kind regards,
Ben
[1] https://github.com/kernkonzept/uvmm
-- Benjamin Lamowski - +49.351.41883235 Operating Systems Engineer - https://www.kernkonzept.com
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