Re: [PATCH v2 0/8] x86/PV: avoid speculation abuse through guest accessors

[Ian Jackson <iwj@xxxxxxxxxxxxxx>]

Jan Beulich writes ("Re: [PATCH v2 0/8] x86/PV: avoid speculation abuse through 
guest accessors"):
> On 19.02.2021 16:50, Ian Jackson wrote:
> > You say "consistency" but in practical terms, what will happen if the
> > code is not "conxistent" in this sense ?
> 
> Patches 4-6: The code is harder to understand with the mix of names.
> Backports from future versions to 4.15 may require more attention to
> get right (and then again the same level of attention when moving to
> 4.14).
> 
> Patches 7 is simply a minor improvement. Patch 8 is an equivalent
> of the one patch of the earlier version which has already gone in.
> Just like that other one it's more to avoid a latent issue than any
> active one.

Thank you for this clear explanation.

I think 4-6 and 8 are good candidates for the reasons you give, and
because they seem low risk to me.  Have you used any automatic
techniques to check that there is no unintentional codegen change ?
(Eg, binary diffs, diffing sedderied versions, or something.)

To my naive eye patch 7 looks scary because it might be moving the
scope of a critical section.  Am I wrong about that ?

Ian.