Messages in this thread | | | Date | Mon, 19 Oct 2020 11:48:49 -0700 | From | Ira Weiny <> | Subject | Re: [PATCH RFC V3 4/9] x86/pks: Preserve the PKRS MSR on context switch |
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On Mon, Oct 19, 2020 at 11:37:14AM +0200, Peter Zijlstra wrote: > On Fri, Oct 16, 2020 at 10:14:10PM -0700, Ira Weiny wrote: > > > so it either needs to > > > explicitly do so, or have an assertion that preemption is indeed > > > disabled. > > > > However, I don't think I understand clearly. Doesn't [get|put]_cpu_ptr() > > handle the preempt_disable() for us? > > It does. > > > Is it not sufficient to rely on that? > > It is. > > > Dave's comment seems to be the opposite where we need to eliminate preempt > > disable before calling write_pkrs(). > > > > FWIW I think I'm mistaken in my response to Dave regarding the > > preempt_disable() in pks_update_protection(). > > Dave's concern is that we're calling with with preemption already > disabled so disabling it again is superfluous.
Ok, thanks, and after getting my head straight I think I agree with him, and you.
Thanks I've reworked the code to removed the superfluous calls. Sorry about being so dense... :-D
Ira
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