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From:   Mingwei Zhang <mizhang@google.com>
Date:   Tue, 26 Apr 2022 11:48:36 -0700
Message-ID: <CAL715WK8-cOJWK+iai=ygdOTzPb-QUvEwa607tVEkmGOu3gyQA@mail.gmail.com>
Subject: Re: [PATCH] KVM: x86/mmu: add lockdep check before lookup_address_in_mm()
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 <kvm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Ben Gardon <bgardon@google.com>,
        David Matlack <dmatlack@google.com>
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> I completely agree that lookup_address() and friends are unnecessarily fragile,
> but I think that attempting to harden them to fix this KVM bug will open a can
> of worms and end up delaying getting KVM fixed.

So basically, we need to:
 - choose perf_get_page_size() instead of using any of the
lookup_address*() in mm.
 - add a wrapper layer to adapt: 1) irq disabling/enabling and 2) size
-> level translation.

Agree?