linux-kernel - Re: [PATCH] KVM: selftests: Relax assertion on HLT exits if CPU supports Idle HLT

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Message-ID: <174078621049.3857714.9685413190678445101.b4-ty@google.com>
Date: Tue,  4 Mar 2025 17:05:16 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Manali Shukla <Manali.Shukla@....com>
Subject: Re: [PATCH] KVM: selftests: Relax assertion on HLT exits if CPU
 supports Idle HLT

On Wed, 26 Feb 2025 15:18:09 -0800, Sean Christopherson wrote:
> If the CPU supports Idle HLT, which elides HLT VM-Exits if the vCPU has an
> unmasked pending IRQ or NMI, relax the xAPIC IPI test's assertion on the
> number of HLT exits to only require that the number of exits is less than
> or equal to the number of HLT instructions that were executed.  I.e. don't
> fail the test if Idle HLT does what it's supposed to do.
> 
> Note, unfortunately there's no way to determine if *KVM* supports Idle HLT,
> as this_cpu_has() checks raw CPU support, and kvm_cpu_has() checks what can
> be exposed to L1, i.e. the latter would check if KVM supports nested Idle
> HLT.  But, since the assert is purely bonus coverage, checking for CPU
> support is good enough.
> 
> [...]

Applied to kvm-x86 selftests, thanks!

[1/1] KVM: selftests: Relax assertion on HLT exits if CPU supports Idle HLT
      https://github.com/kvm-x86/linux/commit/62838fa5eade

--
https://github.com/kvm-x86/linux/tree/next