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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 0930CC072B3 for ; Thu, 21 Jan 2021 01:47:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C30B623788 for ; Thu, 21 Jan 2021 01:47:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729332AbhAUBoh (ORCPT ); Wed, 20 Jan 2021 20:44:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728665AbhAUA4x (ORCPT ); Wed, 20 Jan 2021 19:56:53 -0500 Received: from mail-pf1-x435.google.com (mail-pf1-x435.google.com [IPv6:2607:f8b0:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A2FFC061793 for ; Wed, 20 Jan 2021 16:56:00 -0800 (PST) Received: by mail-pf1-x435.google.com with SMTP id i63so394378pfg.7 for ; Wed, 20 Jan 2021 16:56:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=q+sTlfHUdpFVsp7Fzw5vyE8GQzeyLMw9GCNbrTB8/LI=; b=j++IUpn6j1YjY0jaRYpasY0t7mWxbprI/uufZaqvRpzXY7SfRQBXrkesPaHK5LfAje 9eZTc7RJS4BrgtC8qKKBMdjihNBmzgkJ3GayOGCBhSnczTDdxc0jR+/LAP7T69F9bPV5 +JlNEqdzDeKkhE5qtCSH2XFrXQ/9EARog181f10bDQsfuJPHiRYvQ9ed6fzniodqkQOx kQGPu3ybQtoUCafVUY4bKv6O+VZvHGLcIa+zAbUHNJf8gCNYWHaPHcXc0pKAjpPdotG6 j4e78F3hql0oeS2t3MqJKF6eVA7xItM57hmKMaAcrkMV5ruvXqhdDltnv3STtpucnLW/ idDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=q+sTlfHUdpFVsp7Fzw5vyE8GQzeyLMw9GCNbrTB8/LI=; b=byYuFcBKaxOvM3LIn8isAGxxxJJZSh20VCF4kPx6XmhUytpQffkeAqDva9ZNPnggNx Ay4/LVOu3YIctmMCxivDmRrrGpmu4bJwCB42K2A667EjCFDVj4YaRXDP7JVEuVbhxrKm thxIu3Y6BW43Xt/wN327Om7BdRocOW+DNA/870DpjoYJC8iLSOopn9l4Wg/yBt/tY/e1 gQnB2IaquCawCoxvjYPxdnwgtopetoG9dGlJcGcfhGrJYqfVt5NnxMN+jotE3xEhU0i3 ayUgzirXB2Nng7hvx+wSH9UmzRLY576+kukEWqiRE08jdTnyPpWsWzrkythwDEWYrQFe c6aQ== X-Gm-Message-State: AOAM531rPfpF3ySjI2mEM2mnQB5adGVDdvHAf6aj0LDQHN38X2FjV29j FWfTbSGQ+C5kyg5UN+sWgBMAsQ== X-Google-Smtp-Source: ABdhPJxq2YQ42sEdEfikrjIe/ByaxfW6cpKWSBURUQhCc3OJthAG57W63TewMsqRe6hAoWPI0TpIRw== X-Received: by 2002:a62:1b95:0:b029:19b:178f:84d7 with SMTP id b143-20020a621b950000b029019b178f84d7mr11918516pfb.70.1611190559429; Wed, 20 Jan 2021 16:55:59 -0800 (PST) Received: from google.com ([2620:15c:f:10:1ea0:b8ff:fe73:50f5]) by smtp.gmail.com with ESMTPSA id z11sm3714996pjn.5.2021.01.20.16.55.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Jan 2021 16:55:58 -0800 (PST) Date: Wed, 20 Jan 2021 16:55:52 -0800 From: Sean Christopherson To: Ben Gardon Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Peter Xu , Peter Shier , Peter Feiner , Junaid Shahid , Jim Mattson , Yulei Zhang , Wanpeng Li , Vitaly Kuznetsov , Xiao Guangrong Subject: Re: [PATCH 24/24] kvm: x86/mmu: Allow parallel page faults for the TDP MMU Message-ID: References: <20210112181041.356734-1-bgardon@google.com> <20210112181041.356734-25-bgardon@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210112181041.356734-25-bgardon@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Jan 12, 2021, Ben Gardon wrote: > Make the last few changes necessary to enable the TDP MMU to handle page > faults in parallel while holding the mmu_lock in read mode. > > Reviewed-by: Peter Feiner > > Signed-off-by: Ben Gardon > --- > arch/x86/kvm/mmu/mmu.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 280d7cd6f94b..fa111ceb67d4 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -3724,7 +3724,12 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, > return r; > > r = RET_PF_RETRY; > - kvm_mmu_lock(vcpu->kvm); > + > + if (is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)) Off topic, what do you think about rewriting is_tdp_mmu_root() to be both more performant and self-documenting as to when is_tdp_mmu_root() != kvm->arch.tdp_mmu_enabled? E.g. key off is_guest_mode() and then do a thorough audit/check when CONFIG_KVM_MMU_AUDIT=y? #ifdef CONFIG_KVM_MMU_AUDIT bool is_tdp_mmu_root(struct kvm *kvm, hpa_t hpa) { struct kvm_mmu_page *sp; if (!kvm->arch.tdp_mmu_enabled) return false; if (WARN_ON(!VALID_PAGE(hpa))) return false; sp = to_shadow_page(hpa); if (WARN_ON(!sp)) return false; return sp->tdp_mmu_page && sp->root_count; } #endif bool is_tdp_mmu(struct kvm_vcpu *vcpu) { bool is_tdp_mmu = kvm->arch.tdp_mmu_enabled && !is_guest_mode(vcpu); #ifdef CONFIG_KVM_MMU_AUDIT WARN_ON(is_tdp_mmu != is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)); #endif return is_tdp_mmu; } > + kvm_mmu_lock_shared(vcpu->kvm); > + else > + kvm_mmu_lock(vcpu->kvm); > + > if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) > goto out_unlock; > r = make_mmu_pages_available(vcpu); > @@ -3739,7 +3744,10 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, > prefault, is_tdp); > > out_unlock: > - kvm_mmu_unlock(vcpu->kvm); > + if (is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)) > + kvm_mmu_unlock_shared(vcpu->kvm); > + else > + kvm_mmu_unlock(vcpu->kvm); > kvm_release_pfn_clean(pfn); > return r; > } > -- > 2.30.0.284.gd98b1dd5eaa7-goog >