Messages in this thread | | | Date | Thu, 21 Feb 2019 14:37:45 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86/fpu: Parse comma separated list passed in clearcpuid |
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On Thu, Feb 21, 2019 at 08:12:25AM -0500, Prarit Bhargava wrote: > Users cannot disable multiple CPU features with the kernel parameter > clearcpuid=. For example, "clearcpuid=154 clearcpuid=227" only disables > CPUID bit 154. > > Previous to commit 0c2a3913d6f5 ("x86/fpu: Parse clearcpuid= as early XSAVE > argument") it was possible to pass multiple clearcpuid options as kernel > parameters using individual entries. With the new code it isn't easy to > replicate exactly that behaviour but a comma separated list can be easily > implemented, eg) "clearcpuid=154,227" > > Make the clearcpuid parse a comma-separated list of values instead of only > a single value.
So I think the feature is broken as is; because it doesn't clear the CPUID bits for userspace.
something along the lines of:
https://lkml.kernel.org/r/20190212164833.GK32494@hirez.programming.kicks-ass.net
would be required to make it so.
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