linux-kernel - Re: [PATCH v2 15/20] kvm: x86/mmu: Support dirty logging for the TDP MMU

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Message-ID: <CANgfPd9UgKK6tr9ArQsDB9ys4Ne=RVkDccY_Za4r4SSHWV46cQ@mail.gmail.com>
Date:   Mon, 19 Oct 2020 10:07:37 -0700
From:   Ben Gardon <bgardon@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Cannon Matthews <cannonmatthews@...gle.com>,
        Peter Xu <peterx@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Peter Shier <pshier@...gle.com>,
        Peter Feiner <pfeiner@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Yulei Zhang <yulei.kernel@...il.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Xiao Guangrong <xiaoguangrong.eric@...il.com>
Subject: Re: [PATCH v2 15/20] kvm: x86/mmu: Support dirty logging for the TDP MMU

On Fri, Oct 16, 2020 at 9:18 AM Paolo Bonzini <pbonzini@...hat.com> wrote:
>
> On 14/10/20 20:26, Ben Gardon wrote:
> >
> > +     if (kvm->arch.tdp_mmu_enabled)
> > +             kvm_tdp_mmu_clear_dirty_pt_masked(kvm, slot,
> > +                             slot->base_gfn + gfn_offset, mask, true);
>
> This was "false" in v1, I need --verbose for this change. :)

I don't think this changed from v1. Note that there are two callers in
mmu.c - kvm_mmu_write_protect_pt_masked and
kvm_mmu_clear_dirty_pt_masked. One calls with wrprot = true and the
other with wrprot = false.

>
> >       while (mask) {
> >               rmap_head = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
>
> > +             spte_set = wrprot_gfn_range(kvm, root, slot->base_gfn,
> > +                             slot->base_gfn + slot->npages, min_level) ||
> > +                        spte_set;
>
> A few remaining instances of ||.

Gah, I thought I had gotten all of them. Thanks for catching these.

>
> Paolo
>