From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.1 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACA73C4363D for ; Wed, 30 Sep 2020 23:28:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E94E2076A for ; Wed, 30 Sep 2020 23:28:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="csWJ/JkK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731678AbgI3X2T (ORCPT ); Wed, 30 Sep 2020 19:28:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730548AbgI3X2I (ORCPT ); Wed, 30 Sep 2020 19:28:08 -0400 Received: from mail-io1-xd41.google.com (mail-io1-xd41.google.com [IPv6:2607:f8b0:4864:20::d41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B723C061755 for ; Wed, 30 Sep 2020 16:28:07 -0700 (PDT) Received: by mail-io1-xd41.google.com with SMTP id z13so4482531iom.8 for ; Wed, 30 Sep 2020 16:28:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=2zNPnMDwSH/evHHtODPlaoouseFTp99pPVZGDDgyGhY=; b=csWJ/JkKF1QDPuiE2UlASPtZozKxHAy9twR4BpV/CVlBp3NNqfb7MaHWD+Y/2icij0 N/Bj3Zg90314vTClj/ISg9iAfKZ4Y9ZfI+ZMQLGVZ8KHCst0NjVmg3HXngQ1Dgee9uoe HXjlYMSTvosxHGdfVpcRtIzdCV4f+8/JjKWNBsOv36BJ2nZxOLoHCJHKGfEAFtPclgUf vcNFZXE6/z3CZ6hTHf0bdAgjpoKyOZ4s4lJ9JvzrUhFAauxmZVyPTxaOeDX06PlzLGg8 vrE09LjaLrLUvrIbKHWTzd+j4FjjxrMhDcdIRocMSXyIcb5E877goKN10xxB+MQ6amOf gdjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=2zNPnMDwSH/evHHtODPlaoouseFTp99pPVZGDDgyGhY=; b=aLLXKIGdaUsfbdRbQganMlWmznNIPnbYZFlo+ednldUVH0ZLvDEUWTz5PCPV9pMQjh tKkCGBggGTuEVPftVw7g7POWUHrxfbZC3wr/lDOX20bLaDz5AK6JQbeewr3wlhMbYNq+ 5Iqv/kOf5xkxkArVlxVDFcWDnMCxdLLvpzTundrVCMRwnQHnm0a5fL3PC2N8csOcZCmp EHygR1mNeMFElPtcpGUj58oJYzEEi2arOEcIJ2kJj6SocVkS5oBzuEH51GyVU+boYJh4 30nee9LTtwGV+L62d8XnbCwUmPhCazVxNwUxZICnCp2qW8DFsDezcLoAgiaFN2csXi9n lu1g== X-Gm-Message-State: AOAM530eKzGxbqALOKpz15U1yx2i5qSxHjt5elPGTc7190yVZSSWMdGj uxGtqOkGb4ZG+ryPj96EaqU1Aoab892WpyfAOX8uqw== X-Google-Smtp-Source: ABdhPJyV65yYiiq0KobGlnIOzHQWS7SawVm798cnYHga5XG0xk5hDJx4jkkXKyOlo1sSu3e66a/2DgL/9XUAbUvXk4U= X-Received: by 2002:a05:6602:2d55:: with SMTP id d21mr3333082iow.134.1601508486309; Wed, 30 Sep 2020 16:28:06 -0700 (PDT) MIME-Version: 1.0 References: <20200925212302.3979661-1-bgardon@google.com> <20200925212302.3979661-14-bgardon@google.com> <20200930170354.GF32672@linux.intel.com> <20200930232429.GA2988@linux.intel.com> In-Reply-To: <20200930232429.GA2988@linux.intel.com> From: Ben Gardon Date: Wed, 30 Sep 2020 16:27:55 -0700 Message-ID: Subject: Re: [PATCH 13/22] kvm: mmu: Support invalidate range MMU notifier for TDP MMU To: Sean Christopherson Cc: LKML , kvm , Cannon Matthews , Paolo Bonzini , Peter Xu , Peter Shier , Peter Feiner , Junaid Shahid , Jim Mattson , Yulei Zhang , Wanpeng Li , Vitaly Kuznetsov , Xiao Guangrong Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Sep 30, 2020 at 4:24 PM Sean Christopherson wrote: > > On Wed, Sep 30, 2020 at 04:15:17PM -0700, Ben Gardon wrote: > > On Wed, Sep 30, 2020 at 10:04 AM Sean Christopherson > > wrote: > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > > > index 52d661a758585..0ddfdab942554 100644 > > > > --- a/arch/x86/kvm/mmu/mmu.c > > > > +++ b/arch/x86/kvm/mmu/mmu.c > > > > @@ -1884,7 +1884,14 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva, > > > > int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end, > > > > unsigned flags) > > > > { > > > > - return kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); > > > > + int r; > > > > + > > > > + r = kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); > > > > + > > > > + if (kvm->arch.tdp_mmu_enabled) > > > > + r |= kvm_tdp_mmu_zap_hva_range(kvm, start, end); > > > > > > Similar to an earlier question, is this intentionally additive, or can this > > > instead by: > > > > > > if (kvm->arch.tdp_mmu_enabled) > > > r = kvm_tdp_mmu_zap_hva_range(kvm, start, end); > > > else > > > r = kvm_handle_hva_range(kvm, start, end, 0, kvm_unmap_rmapp); > > > > > > > It is intentionally additive so the legacy/shadow MMU can handle nested. > > Duh. Now everything makes sense. I completely spaced on nested EPT. > > I wonder if would be worth adding a per-VM sticky bit that is set when an > rmap is added so that all of these flows can skip the rmap walks when using > the TDP MMU without a nested guest. We actually do that in the full version of this whole TDP MMU scheme. It works very well. I'm not sure why I didn't include that in this patch set - probably just complexity. I'll definitely include that as an optimization along with the lazy rmap allocation in the followup patch set.