Re: [RFC] KVM: mm: fd-based approach for supporting KVM guest private memory

[Andy Lutomirski]

On Thu, Aug 26, 2021, at 2:26 PM, David Hildenbrand wrote:
> On 26.08.21 19:05, Andy Lutomirski wrote:

> > Oof.  That's quite a requirement.  What's the point of the VMA once all
> > this is done?
> 
> You can keep using things like mbind(), madvise(), ... and the GUP code 
> with a special flag might mostly just do what you want. You won't have 
> to reinvent too many wheels on the page fault logic side at least.
> 

You can keep calling the functions.  The implementations working is a different story: you can't just unmap (pte_numa-style or otherwise) a private guest page to quiesce it, move it with memcpy(), and then fault it back in.

In any event, adding fd-based NUMA APIs would be quite nice.  Look at the numactl command.