On Mon, Oct 28, 2024 at 04:50:34PM -0700, Daniel Sneddon wrote:
> There are currently 4 mitigations that use VERW: MDS, TAA,
> MMIO Stale Data, and Register File Data Sampling. Because
> all 4 use the same mitigation path, if any one of them is
> enabled, they're all enabled. Normally, this is what is
> wanted. However, if a user wants to disable the mitigation,
> this can cause problems. If the user misses disabling even
> one of these mitigations, then none of them will be
> disabled. This can cause confusion as the user expects to
> regain the performance lost to the mitigation but isn't
> seeing any improvement. Since there are already 4 knobs for
> controlling it, adding a 5th knob that controls all 4
> mitigations together would just overcomplicate things.
> Instead, let the user know their mitigations are out of sync
> when at least one of these mitigations is disabled but not
> all 4.
Please split this commit message into smaller chunks for better readability.
For example:
There are currently 4 mitigations that use VERW: MDS, TAA, MMIO Stale Data,
and Register File Data Sampling. Because all 4 use the same mitigation path,
if any one of them is enabled, they're all enabled.
Normally, this is what is wanted. However, if a user wants to disable the
mitigation, this can cause problems. If the user misses disabling even one of
these mitigations, then none of them will be disabled.
This can cause confusion as the user expects to regain the performance lost to
the mitigation but isn't seeing any improvement. Since there are already
4 knobs for controlling it, adding a 5th knob that controls all 4 mitigations
together would just overcomplicate things.
Instead, let the user know their mitigations are out of sync when at least one
of these mitigations is disabled but not all 4.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
