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SubjectRe: [PATCH v5 2/9] x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR
"Luck, Tony" <> writes:

> On Sun, Mar 15, 2020 at 01:05:10PM +0800, Xiaoyao Li wrote:
>> In a context switch from a task that is detecting split locks
>> to one that is not (or vice versa) we need to update the TEST_CTRL
>> MSR. Currently this is done with the common sequence:
>> read the MSR
>> flip the bit
>> write the MSR
>> in order to avoid changing the value of any reserved bits in the MSR.
>> Cache the value of the TEST_CTRL MSR when we read it during initialization
>> so we can avoid an expensive RDMSR instruction during context switch.
>> Suggested-by: Sean Christopherson <>
>> Originally-by: Tony Luck <>
>> Signed-off-by: Xiaoyao Li <>
> Is it bad form to Ack/Review patches originally by oneself?

Only if they are broken ....

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