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

[Jürgen Groß]

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. 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".


Juergen

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