linux-kernel - Re: [PATCH v2 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU read lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4140362f-92d5-5c5e-de8e-4e1e3a65b317@redhat.com>
Date:   Fri, 2 Apr 2021 13:14:47 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Ben Gardon <bgardon@...gle.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.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 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to
 use MMU read lock

On 02/04/21 01:37, Ben Gardon wrote:
> To speed the process of disabling dirty logging, change the TDP MMU
> function which zaps collapsible SPTEs to run under the MMU read lock.

Technically it only reduces the impact on the running VM; it doesn't
speed it up right?  Something like:

     To reduce the impact of disabling dirty logging, change the TDP MMU
     function which zaps collapsible SPTEs to run under the MMU read lock.
     This way, page faults on zapped SPTEs can proceed in parallel with
     kvm_mmu_zap_collapsible_sptes.

Paolo