UMIP and clearcpuid=

[Ronan Pigott]

Hi,

In [1] the clearcpuid= flag was hidden, but afaik this remains the only way to
disable UMIP. At the time UMIP was enabled, clearcpuid was apparently
determined to be the appropriate method of disablement in [2], and it remains
recommended by the documentation in [3].

If clearcpuid is no good, can we have a sanctioned method to disable UMIP
protections instead then?

[1] https://patch.msgid.link/20260520202508.160112-1-bp@xxxxxxxxxx

[2] https://lore.kernel.org/lkml/1478760361.2551.21.camel@ranerica-desktop/

[3] https://docs.kernel.org/arch/x86/cpuinfo.html#the-feature-is-disabled-at-boot-time

Cheers,

Ronan