Re: [PATCH v2 0/5] cpu/speculation: Add 'mitigations=' cmdline option

Jiri Kosina
2019-04-16T07:53:29Z

On Fri, 12 Apr 2019, Josh Poimboeuf wrote:

> v2:
> - docs improvements: [Randy, Michael]
> - Rename to "mitigations=" [Michael]
> - Add cpu_mitigations_off() function wrapper [Michael]
> - x86: Simplify logic [Boris]
> - powerpc: Fix no_rfi_flush checking bug (use '&&' instead of '||')
> - arm64: Rebase onto Jeremy Linton's v7 patches [Will]
> - arm64: "kpti command line option" [Steve P]
> - arm64: Add nospectre_v2 support
>
> -----------
>
> Keeping track of the number of mitigations for all the CPU speculation
> bugs has become overwhelming for many users. It's getting more and more
> complicated to decide which mitigations are needed for a given
> architecture. Complicating matters is the fact that each arch tends to
> have its own custom way to mitigate the same vulnerability.
>
> Most users fall into a few basic categories:
>
> a) they want all mitigations off;
>
> b) they want all reasonable mitigations on, with SMT enabled even if
> it's vulnerable; or
>
> c) they want all reasonable mitigations on, with SMT disabled if
> vulnerable.
>
> Define a set of curated, arch-independent options, each of which is an
> aggregation of existing options:
>
> - mitigations=off: Disable all mitigations.
>
> - mitigations=auto: [default] Enable all the default mitigations, but
> leave SMT enabled, even if it's vulnerable.
>
> - mitigations=auto,nosmt: Enable all the default mitigations, disabling
> SMT if needed by a mitigation.
>
> Josh Poimboeuf (5):
> cpu/speculation: Add 'mitigations=' cmdline option
> x86/speculation: Support 'mitigations=' cmdline option
> powerpc/speculation: Support 'mitigations=' cmdline option
> s390/speculation: Support 'mitigations=' cmdline option
> arm64/speculation: Support 'mitigations=' cmdline option

Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86)
Reviewed-by: Jiri Kosina <jkosina@suse.cz>

Thanks,

--
Jiri Kosina
SUSE Labs