linux-kernel - Re: [PATCH 2/3] KVM: x86: Remove use of apicv_update

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Message-ID: <jhzyfv3t35zo43dhxjjuhgq2iz4gghr32ftsva3aeln5to5qns@iaunfm3qvqfd>
Date: Tue, 4 Feb 2025 18:40:59 +0530
From: Naveen N Rao <naveen@...nel.org>
To: Maxim Levitsky <mlevitsk@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	Suravee Suthikulpanit <suravee.suthikulpanit@....com>, Vasant Hegde <vasant.hegde@....com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>
Subject: Re: [PATCH 2/3] KVM: x86: Remove use of apicv_update_lock when
 toggling guest debug state

On Mon, Feb 03, 2025 at 09:00:05PM -0500, Maxim Levitsky wrote:
> On Mon, 2025-02-03 at 22:33 +0530, Naveen N Rao (AMD) wrote:
> > apicv_update_lock is not required when querying the state of guest
> > debug in all the vcpus. Remove usage of the same, and switch to
> > kvm_set_or_clear_apicv_inhibit() helper to simplify the code.
> 
> It might be worth to mention that the reason why the lock is not needed,
> is because kvm_vcpu_ioctl from which this function is called takes 'vcpu->mutex'
> and thus concurrent execution of this function is not really possible.
> 
> Besides this:
> 
> Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Sure, thanks for the review!


- Naveen