linux-kernel - Re: [PATCH] KVM: x86/mmu: Use yield-safe TDP MMU root iter in MMU notifier unmapping

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Message-ID: <1f9722a5-9f8f-415f-88c7-29cee05831d0@redhat.com>
Date:   Fri, 26 Nov 2021 17:45:10 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: x86/mmu: Use yield-safe TDP MMU root iter in MMU
 notifier unmapping

On 11/20/21 02:50, Sean Christopherson wrote:
> Use the yield-safe variant of the TDP MMU iterator when handling an
> unmapping event from the MMU notifier, as most occurences of the event
> allow yielding.
> 
> Fixes: e1eed5847b09 ("KVM: x86/mmu: Allow yielding during MMU notifier unmap/zap, if possible")
> Cc: stable@...r.kernel.org
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>   arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 377a96718a2e..a29ebff1cfa0 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -1031,7 +1031,7 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
>   {
>   	struct kvm_mmu_page *root;
>   
> -	for_each_tdp_mmu_root(kvm, root, range->slot->as_id)
> +	for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, false)
>   		flush |= zap_gfn_range(kvm, root, range->start, range->end,
>   				       range->may_block, flush, false);
>   
> 

Queued, thanks.

Paolo