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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 BE9F2C4363D for ; Wed, 30 Sep 2020 23:24:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E34E2076A for ; Wed, 30 Sep 2020 23:24:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732219AbgI3XYg (ORCPT ); Wed, 30 Sep 2020 19:24:36 -0400 Received: from mga02.intel.com ([134.134.136.20]:4791 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730310AbgI3XYg (ORCPT ); Wed, 30 Sep 2020 19:24:36 -0400 IronPort-SDR: G+gNLcF+Ob1QJ2Jq5/VInePf+rntLQqHBQKZeMztNBxPPpU645gkSw01JyxET6ZLALXwyMVZMm WyWKtfJ+Wv0Q== X-IronPort-AV: E=McAfee;i="6000,8403,9760"; a="150220233" X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="150220233" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 16:24:33 -0700 IronPort-SDR: f4b3ZziJaIx737s5hskNUAVyiWNqYThsApyflfAtet9h4bdzWOQNiDs1XeQdZUy79iHENLWkjb k0fUdIsQRbNg== X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="500081380" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.160]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 16:24:32 -0700 Date: Wed, 30 Sep 2020 16:24:29 -0700 From: Sean Christopherson To: Ben Gardon 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 Subject: Re: [PATCH 13/22] kvm: mmu: Support invalidate range MMU notifier for TDP MMU Message-ID: <20200930232429.GA2988@linux.intel.com> References: <20200925212302.3979661-1-bgardon@google.com> <20200925212302.3979661-14-bgardon@google.com> <20200930170354.GF32672@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.