On 10/29/24 04:39, Borislav Petkov wrote: > 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. > Will do.
