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

[Jiri Kosina]

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@xxxxxxx> (on x86)
Reviewed-by: Jiri Kosina <jkosina@xxxxxxx>

Thanks,

-- 
Jiri Kosina
SUSE Labs