Re: [PATCH] KVM: x86: Deflect unknown MSR accesses to user space

[Alexander Graf]

On 29.07.20 10:23, Vitaly Kuznetsov wrote:
> Jim Mattson <jmattson@xxxxxxxxxx> writes:
>
> > On Tue, Jul 28, 2020 at 5:41 AM Alexander Graf <graf@xxxxxxxxxx> wrote:
> > >
>
> ...
>
> > > While it does feel a bit overengineered, it would solve the problem that
> > > we're turning in-KVM handled MSRs into an ABI.
> >
> > It seems unlikely that userspace is going to know what to do with a
> > large number of MSRs. I suspect that a small enumerated list will
> > suffice.
>
> The list can also be 'wildcarded', i.e.
> {
>   u32 index;
>   u32 mask;
>   ...
> }
>
> to make it really short.

I like the idea of wildcards, but I can't quite wrap my head around how 
we would implement ignore_msrs in user space with them?


Alex



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