Re: [RFC PATCH 0/6] KVM: x86: async PF user

[Sean Christopherson]

On Thu, Feb 27, 2025, Nikita Kalyazin wrote:
> On 27/02/2025 16:44, Sean Christopherson wrote:
> > When it comes to uAPI, I want to try and avoid statements along the lines of
> > "IF 'x' holds true, then 'y' SHOULDN'T be a problem".  If this didn't impact uAPI,
> > I wouldn't care as much, i.e. I'd be much more willing iterate as needed.
> > 
> > I'm not saying we should go straight for a complex implementation.  Quite the
> > opposite.  But I do want us to consider the possible ramifications of using a
> > single bit for all userfaults, so that we can at least try to design something
> > that is extensible and won't be a pain to maintain.
> 
> So you would've liked more the "two-bit per gfn" approach as in: provide 2
> interception points, for sync and async exits, with the former chosen by
> userspace when it "knows" that the content is already in memory? 

No, all I'm saying is I want people think about what the future will look like,
to minimize the chances of ending up with a mess.