linux-kernel - Re: [PATCH] KVM: x86/MMU: Zap non-leaf SPTEs when disabling dirty logging

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Message-ID: <a3ea7446-901f-1d33-47a9-35755b4d86d5@redhat.com>
Date:   Thu, 26 May 2022 14:01:43 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Ben Gardon <bgardon@...gle.com>, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        David Dunn <daviddunn@...gle.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        Junaid Shahid <junaids@...gle.com>
Subject: Re: [PATCH] KVM: x86/MMU: Zap non-leaf SPTEs when disabling dirty
 logging

On 5/26/22 01:09, Ben Gardon wrote:
> +		WARN_ON(max_mapping_level < iter.level);
> +
> +		/*
> +		 * If this page is already mapped at the highest
> +		 * viable level, there's nothing more to do.
> +		 */
> +		if (max_mapping_level == iter.level)
> +			continue;
> +
> +		/*
> +		 * The page can be remapped at a higher level, so step
> +		 * up to zap the parent SPTE.
> +		 */
> +		while (max_mapping_level > iter.level)
> +			tdp_iter_step_up(&iter);
> +
>   		/* Note, a successful atomic zap also does a remote TLB flush. */
> -		if (tdp_mmu_zap_spte_atomic(kvm, &iter))
> -			goto retry;
> +		tdp_mmu_zap_spte_atomic(kvm, &iter);
> +

Can you make this a sparate function (for example 
tdp_mmu_zap_collapsible_spte_atomic)?  Otherwise looks great!

Paolo