Re: [PATCH 3/4] KVM: x86: WARN and reject loading KVM if NX is supported but not enabled

[Paolo Bonzini]

On 16/06/21 00:39, Jim Mattson wrote:
> >          rdmsrl_safe(MSR_EFER, &host_efer);
> > +       if (WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_NX) &&
> > +                        !(host_efer & EFER_NX)))
> > +               return -EIO;
> Input/output error? Is that really the most appropriate error here?
> Why not, say, -ENOTSUP?
>
> I'm sure there's some arcane convention here that I'm not privy to.:-)
>
> Reviewed-by: Jim Mattson<jmattson@xxxxxxxxxx>

EIO often means "how the heck did we get here?" or "look in dmesg to get 
more info", both of which I think are appropriate after a WARN.

Paolo