Re: [PATCH 3/3] KVM: VMX: Extend VMX's #AC interceptor to handle split lock #AC in guest

[Peter Zijlstra]

On Thu, Apr 02, 2020 at 10:07:07PM +0200, Thomas Gleixner wrote:

If we're doing wish lists, I have one more ;-)

> TBH, the more I learn about this, the more I tend to just give up on
> this whole split lock stuff in its current form and wait until HW folks
> provide something which is actually usable:
> 
>    - Per thread
>    - Properly distinguishable from a regular #AC via error code

   - is an actual alignment check.

That is, disallow all unaligned LOCK prefixed ops, not just those that
happen to straddle a cacheline.