Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 00/22] Introduce the TDP MMU
To:     Ben Gardon <bgardon@google.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     Cannon Matthews <cannonmatthews@google.com>,
        Peter Xu <peterx@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Peter Shier <pshier@google.com>,
        Peter Feiner <pfeiner@google.com>,
        Junaid Shahid <junaids@google.com>,
        Jim Mattson <jmattson@google.com>,
        Yulei Zhang <yulei.kernel@gmail.com>,
        Wanpeng Li <kernellwp@gmail.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Xiao Guangrong <xiaoguangrong.eric@gmail.com>
References: <20200925212302.3979661-1-bgardon@google.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <425b098c-dbe0-d614-8e62-1f50b2f63272@redhat.com>
Date:   Mon, 28 Sep 2020 19:31:10 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.11.0
MIME-Version: 1.0
In-Reply-To: <20200925212302.3979661-1-bgardon@google.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 25/09/20 23:22, Ben Gardon wrote:
> This series is the first of two. In this series we add a basic
> implementation of the TDP MMU. In the next series we will improve the
> performance of the TDP MMU and allow it to execute MMU operations
> in parallel.

I have finished rebasing and adding a few cleanups on top, but I don't
have time to test it today.  I think the changes shouldn't get too much
in the way of the second series, but I've also pushed your v1 unmodified
to kvm/tdp-mmu for future convenience.  I'll await for your feedback in
the meanwhile!

One feature that I noticed is missing is the shrinker.  What are your
plans (or opinions) around it?

Also, the code generally assume a 64-bit CPU (i.e. that writes to 64-bit
PTEs are atomic).  That is not a big issue, it just needs a small change
on top to make the TDP MMU conditional on CONFIG_X86_64.

Thanks,

Paolo