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References: <20211120045046.3940942-1-seanjc@google.com> <20211120045046.3940942-2-seanjc@google.com>
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From:   Ben Gardon <bgardon@google.com>
Date:   Mon, 22 Nov 2021 11:48:33 -0800
Message-ID: <CANgfPd-LdHPySzoL3_e4q2fHOzjdXe-Z=4j01Sw1f7A8bdhOOw@mail.gmail.com>
Subject: Re: [PATCH 01/28] KVM: x86/mmu: Use yield-safe TDP MMU root iter in
 MMU notifier unmapping
To:     Sean Christopherson <seanjc@google.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Hou Wenlong <houwenlong93@linux.alibaba.com>
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Precedence: bulk

On Fri, Nov 19, 2021 at 8:50 PM Sean Christopherson <seanjc@google.com> 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@vger.kernel.org
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Reviewed-by: Ben Gardon <bgardon@google.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);
>
> --
> 2.34.0.rc2.393.gf8c9666880-goog
>