Re: [PATCH v7 02/10] x86/fred: Pass event data to the NMI entry point from KVM

[H. Peter Anvin]

On 2025-06-20 16:18, Sean Christopherson wrote:
> > So I was thinking about this, and wonder: how expensive is it to get the
> > event data exit information out of VMX? If it is not very expensive, it
> > would arguably be a good thing to future-proof by fetching that information,
> > even if it is currently always zero.
>
> It's trivially easy to do in KVM, and the cost of the VMREAD should be less than
> 20 cycles.  So quite cheap in the grand scheme.  If VMREAD is more costly than
> that, then we have bigger problems :-)

LOL. Since it is up to you, Paulo, etc. to decide how to do the 
tradeoffs formaintainability, debuggability and performance in KVM I am 
guessing this is a vote in favor? (You can always take it out if it is a 
performance problem, until such time that the kernel itself starts 
consuming this information for reasons currently unknown.)

	-hpa