Messages in this thread | | | Subject | Re: [PATCH 09/15] x86/split_lock: Explicitly enable or disable #AC for split locked accesses | From | Dave Hansen <> | Date | Tue, 15 May 2018 09:15:16 -0700 |
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On 05/14/2018 11:52 AM, Fenghua Yu wrote: > By default, we don't set or clear the bit 29 in TEST_CTL MSR 0x33 and > the bit is inherited from BIOS/hardware setting. > > The kernel parameter "split_lock_ac=on/off" explicitly sets or clears > the bit during boot time.
The more I think about this... Why do we need this at boot anyway? Surely boot-time kernel code can't cause performance issues in the same way that untrusted repeated userspace can. Why don't we just let userspace turn this on?
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