Re: [PATCH 1/2] KVM: X86: Move ignore_msrs handling upper the stack

[Paolo Bonzini]

On 25/06/20 18:25, Sean Christopherson wrote:
> I get the "what" of the change, and even the "why" to some extent, but I
> dislike the idea of supporting/encouraging blind reads/writes to MSRs.
> Blind writes are just asking for problems, and suppressing warnings on reads
> is almost guaranteed to be suppressing a KVM bug.

Right, that's why this patch does not just suppress warnings: it adds a
different return value to detect the case.

> TSC_CTRL aside, if we insist on pointing a gun at our foot at some point,
> this should be a dedicated flavor of MSR access, e.g. msr_data.kvm_initiated,
> so that it at least requires intentionally loading the gun.

With this patch, __kvm_get_msr does not know about ignore_msrs at all,
that seems to be strictly an improvement; do you agree with that?  What
would you think about adding warn_unused_result to __kvm_get_msr?

Paolo