Re: [PATCH 0/3] AMD invpcid exception fix

[Bandan Das <bsd@redhat.com>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 12/02/21 21:56, Jim Mattson wrote:
>>> Not all, we intercept GPs only under a specific condition - just as we
>>> do for vmware_backdoor and for the recent amd errata. IMO, I think it's the right
>>> tradeoff to make to get guest exceptions right.
>> It sounds like I need to get you in my corner to help put a stop to
>> all of the incorrect #UDs that kvm is going to be raising in lieu of
>> #PF when narrow physical address width emulation is enabled!
>
> Ahah :)  Apart from the question of when you've entered diminishing
> returns, one important thing to consider is what the code looks
> like. This series is not especially pretty, and that's not your fault.
> The whole idea of special decoding for #GP is a necessary evil for the
> address-check errata, but is it worth extending it to the corner case
> of INVPCID for CPL>0?
>
Sure, no worries. I will have fond memories of the time I spent extra time
on a trivial patch to address Jim's concerns(ofcourse valid!) only to find out
now he has changed his mind.

Bandan

> Paolo