Messages in this thread | | | Date | Mon, 12 Jun 2023 06:46:16 -0700 | From | Breno Leitao <> | Subject | Re: [PATCH] cpu/bugs: Disable CPU mitigations at compilation time |
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On Mon, Jun 12, 2023 at 03:32:30PM +0200, Borislav Petkov wrote: > On Mon, Jun 12, 2023 at 05:54:56AM -0700, Breno Leitao wrote: > > 1) We keep consistency with other CONFIG options. Linux already has a > > CONFIG option to enable/disable mitigations for speculations > > (CONFIG_SPECULATION_MITIGATIONS), so, this will be a similar one. > > So you can get what you want by disabling all those options there, > right?
This patch proposes creating CONFIG_CPU_MITIGATIONS_DEFAULT_OFF that will turn all the mitigations off in a binary, which is the same as passing mitigations=off in the command line when the kernel boots.
Setting CONFIG_SPECULATION_MITIGATIONS=n does *not* disable all the mitigations, as, there are some mitigations that are *not* disabled when you pass CONFIG_SPECULATION_MITIGATIONS=n. As an example (from my memory - need to double check in 6.4), MDS and TAA mitigations are not disabled when CONFIG_SPECULATION_MITIGATIONS=n. MDS and TAA mitigations are disabled when `mitigations=off` parameter is passed, tho.
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