linux-kernel - Re: [RFC PATCH v3 12/59] KVM: x86/mmu: Zap only leaf SPTEs for deleted/moved memslot by default

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Date:   Thu, 25 Nov 2021 20:04:57 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     isaku.yamahata@...el.com, Ingo Molnar <mingo@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, erdemaktas@...gle.com,
        Connor Kuehl <ckuehl@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: Re: [RFC PATCH v3 12/59] KVM: x86/mmu: Zap only leaf SPTEs for
 deleted/moved memslot by default

On Wed, Nov 24 2021 at 16:19, isaku yamahata wrote:
> From: Sean Christopherson <sean.j.christopherson@...el.com>
>
> Zap only leaf SPTEs when deleting/moving a memslot by default, and add a
> module param to allow reverting to the old behavior of zapping all SPTEs
> at all levels and memslots when any memslot is updated.

This changelog describes WHAT the change is doing, which can be seen in
the patch itself, but it gives zero justification neither for the change
nor for the existance of the module parameter.

Thanks,

        tglx