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=-18.3 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,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 DE0E6C4338F for ; Thu, 19 Aug 2021 16:37:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7AE2610A0 for ; Thu, 19 Aug 2021 16:37:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229521AbhHSQiN (ORCPT ); Thu, 19 Aug 2021 12:38:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229465AbhHSQiM (ORCPT ); Thu, 19 Aug 2021 12:38:12 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5548EC061575 for ; Thu, 19 Aug 2021 09:37:36 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id k19so6019041pfc.11 for ; Thu, 19 Aug 2021 09:37:36 -0700 (PDT) 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=113bVJbsP9diowruwEeCAKf5QQDoYra/E0SzbMOGGlY=; b=RzLmC+/Cy/M7zc24FvWrozMC1HWaWjizmEelwunmGWserl9ZC+HiwQ0F6/FLz9tXIL waRQHBGrsUV0dQ4dtGUxmxVAewowYAdxlCnoAPJVrXQED02XxeeXn2Gj7VtTr6DIqpM1 AtlAhjftCgk0UkHk6pnnwl61T0spE85LsZ+qmQAXIwy/Ns78N5eXRQzVngWfpo4tkK9t DdrTomYy3bSeR/f2iDDaUvhOn66sKjuyFzPcuklLdaGGArX1LuxX2BZMqZHi+Kr9Curg cYYyua2VwnNJLp78GQYZKQBxDUMhCFKd6Ph1CRc9em/GEOf3/61N27uy4Hwavwef3vFG ALIg== 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=113bVJbsP9diowruwEeCAKf5QQDoYra/E0SzbMOGGlY=; b=cnlVOC4OuQvXdykalO0ARI7tbrU68XzMMnV7pfopXX6bPHv6+geXSwWv8PrfYDsFRz nQgRh/qdR55p8lbzPRnEVQRfp+sJ4ckAhNmJyy7C64tObMrOS+L4099JIVTw1t/X9CNI pOe2rD9kPNZNpv+Q9FpjRskCKkyUyhkZUopWbzsdLjBwlUFTANUgvcfIPFAv91/BxRAn kBhzt4sQ8vjqFuHENnG/W4/KFEpGjGPqoXeTUvUIFkG/TJu94oMGB1I45FjaWO5V0T14 UuVvFW3SCEz3Tx7UGJL+hbFBw088rXzaERUcvQOgI1pluME8eLdqkb8htoEYGj4qFjrq yczw== X-Gm-Message-State: AOAM533lL+xU+/V0PR2u7CSWp+ZgurHZOGlA80ZNx+lghuXbCNMOBRWe sxQ/NFBFFa2VnfPsGfgYJbxsIg== X-Google-Smtp-Source: ABdhPJw94yPjz6lkpQeH4PMVXdutytK/se+SZVHyaKAXsf4M6GT/CAc6297WbxdZ5baSLbxGO3Hjdg== X-Received: by 2002:a63:b59:: with SMTP id a25mr14635125pgl.373.1629391055651; Thu, 19 Aug 2021 09:37:35 -0700 (PDT) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id b12sm4074197pff.63.2021.08.19.09.37.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Aug 2021 09:37:34 -0700 (PDT) Date: Thu, 19 Aug 2021 16:37:29 +0000 From: Sean Christopherson To: David Matlack Cc: Paolo Bonzini , kvm@vger.kernel.org, Ben Gardon , Joerg Roedel , Jim Mattson , Wanpeng Li , Vitaly Kuznetsov Subject: Re: [RFC PATCH 3/6] KVM: x86/mmu: Pass the memslot around via struct kvm_page_fault Message-ID: References: <20210813203504.2742757-1-dmatlack@google.com> <20210813203504.2742757-4-dmatlack@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210813203504.2742757-4-dmatlack@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Aug 13, 2021, David Matlack wrote: > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 3352312ab1c9..fb2c95e8df00 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -2890,7 +2890,7 @@ int kvm_mmu_max_mapping_level(struct kvm *kvm, > > void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > { > - struct kvm_memory_slot *slot; > + struct kvm_memory_slot *slot = fault->slot; > kvm_pfn_t mask; > > fault->huge_page_disallowed = fault->exec && fault->nx_huge_page_workaround_enabled; > @@ -2901,8 +2901,7 @@ void kvm_mmu_hugepage_adjust(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault > if (is_error_noslot_pfn(fault->pfn) || kvm_is_reserved_pfn(fault->pfn)) > return; > > - slot = gfn_to_memslot_dirty_bitmap(vcpu, fault->gfn, true); > - if (!slot) > + if (kvm_slot_dirty_track_enabled(slot)) This is unnecessarily obfuscated. It relies on the is_error_noslot_pfn() to ensure fault->slot is valid, but the only reason that helper is used is because it was the most efficient code when slot wasn't available. IMO, this would be better: if (!slot || kvm_slot_dirty_track_enabled(slot)) return; if (kvm_is_reserved_pfn(fault->pfn)) return; On a related topic, a good follow-up to this series would be to pass @fault into the prefetch helpers, and modify the prefetch logic to re-use fault->slot and refuse to prefetch across memslot boundaries. That would eliminate all users of gfn_to_memslot_dirty_bitmap() and allow us to drop that abomination.