Re: [PATCH v2 0/6] KVM/x86: Drop "1" as MSR emulation return value

[Sean Christopherson]

On Thu, May 28, 2026, Jürgen Groß wrote:
> On 28.05.26 15:09, Sean Christopherson wrote:
> > On Thu, May 28, 2026, Juergen Gross wrote:
> > > Please disregard this series, there is one complication sashiko made me
> > > aware of.
> > 
> > Sashiko beat me to the punch. :-)
> > 
> > See commit 2368048bf5c2 ("KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS)")
> > for a real world example of how things can and will go wrong.
> 
> Yeah, with Sashiko's pointer it was easy to spot.
> 
> Question now is whether the already existing cases of -errno passed as return
> value are wrong or on purpose. 

What are the existing cases?

> If the latter, there should be a comment for
> that, otherwise they need to be fixed..
> 
> Disentangling the MSR emulation return values from the "normal" ones ("return
> to guest"/"return to user mode") will be quite interesting with the overloaded
> semantics of "1".

LOL, "interesting".