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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B79E0C433F5 for ; Wed, 16 Mar 2022 08:49:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350601AbiCPIu5 (ORCPT ); Wed, 16 Mar 2022 04:50:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235424AbiCPIu4 (ORCPT ); Wed, 16 Mar 2022 04:50:56 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 359B964BEB for ; Wed, 16 Mar 2022 01:49:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647420582; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=4icPmxzgJzoNfLGIPEaiu3EGs4DB/AfIqWIUwU4iOPM=; b=Sq4CeFH7dboTS4xLn78pzUBEGzIOPN7eQAF81MQ5LviDsPcFmG/ejGVF9cZ/uDH3ST7Ict rGgpG8prBmhxHN3wM8G18QeWeWhWqkYREaXTgIGMYPiC0Y7rhh+eEf6JjtE6k3+jNdF9nD un5b85Lym7KK/+6Ri2nIShXu7Kt9pMM= Received: from mail-pj1-f69.google.com (mail-pj1-f69.google.com [209.85.216.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-292-zuifonzFPcudVKQmnJctfQ-1; Wed, 16 Mar 2022 04:49:41 -0400 X-MC-Unique: zuifonzFPcudVKQmnJctfQ-1 Received: by mail-pj1-f69.google.com with SMTP id c7-20020a17090a674700b001beef0afd32so1329274pjm.2 for ; Wed, 16 Mar 2022 01:49:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=4icPmxzgJzoNfLGIPEaiu3EGs4DB/AfIqWIUwU4iOPM=; b=D8J7BgdCCxRwCjZTW/Lv953LfTw7uXodLOqZ11W+xD1P7bD9WIz4KXTqAKCYJopnm0 9lf268CSgc3rdGNdvJwKd5qnvScLtEUYRyiKediNiK1nQrMk4OwA9NPuu+xzUAi2Aqo8 e1rVpc4T/awS3B3N0KCj5bpI4y8UGRrO4XZI2N/JOfkYShC2D1SmG+Z6qPDiPkMe6kJK DeC0TihEkaKGusqpwqEDxBBpvqAWLoW6Bkts8XmgeqOnyRL3EYcWwh0DVhJOnus0KNpv rg8J64LG3eggeJqBKZwSvmwG8t+/1UKkcHe0H+rxubuzZjP6Ge3dou5KcYv5+OXGMO+g DFgA== X-Gm-Message-State: AOAM5309pPMNOkZoTtn0BfpMNrlA8ewVdvP5/e8BUPVdp90byBEUS9xQ NW7RxmuyFrwpFHLKz6ruxDD5Q2YXHGxAxUkFIksCH3XiNuC2yPmmwSaIsNTRimAfEZuXRc7iIe/ q/y+42xOmIIquONxmRYMihw== X-Received: by 2002:a17:90a:6903:b0:1c6:492:7cad with SMTP id r3-20020a17090a690300b001c604927cadmr8971470pjj.241.1647420579959; Wed, 16 Mar 2022 01:49:39 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxfu8xjnOwLJ2DUAYIdjwL8+oeBFXOUhILAgGJ8izXd1dK+cnJhjNgDsFw8fcJAqon+h3ZuZQ== X-Received: by 2002:a17:90a:6903:b0:1c6:492:7cad with SMTP id r3-20020a17090a690300b001c604927cadmr8971439pjj.241.1647420579692; Wed, 16 Mar 2022 01:49:39 -0700 (PDT) Received: from xz-m1.local ([191.101.132.128]) by smtp.gmail.com with ESMTPSA id ca9-20020a17090af30900b001c658fd7b47sm1716181pjb.36.2022.03.16.01.49.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Mar 2022 01:49:39 -0700 (PDT) Date: Wed, 16 Mar 2022 16:49:31 +0800 From: Peter Xu To: David Matlack Cc: Paolo Bonzini , Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner Subject: Re: [PATCH v2 18/26] KVM: x86/mmu: Zap collapsible SPTEs at all levels in the shadow MMU Message-ID: References: <20220311002528.2230172-1-dmatlack@google.com> <20220311002528.2230172-19-dmatlack@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220311002528.2230172-19-dmatlack@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On Fri, Mar 11, 2022 at 12:25:20AM +0000, David Matlack wrote: > Currently KVM only zaps collapsible 4KiB SPTEs in the shadow MMU (i.e. > in the rmap). This is fine for now KVM never creates intermediate huge > pages during dirty logging, i.e. a 1GiB page is never partially split to > a 2MiB page. > > However, this will stop being true once the shadow MMU participates in > eager page splitting, which can in fact leave behind partially split > huge pages. In preparation for that change, change the shadow MMU to > iterate over all necessary levels when zapping collapsible SPTEs. > > No functional change intended. > > Signed-off-by: David Matlack > --- > arch/x86/kvm/mmu/mmu.c | 26 +++++++++++++++++++------- > 1 file changed, 19 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 89a7a8d7a632..2032be3edd71 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -6142,18 +6142,30 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm, > return need_tlb_flush; > } > > +static void kvm_rmap_zap_collapsible_sptes(struct kvm *kvm, > + const struct kvm_memory_slot *slot) > +{ > + bool flush; > + > + /* > + * Note, use KVM_MAX_HUGEPAGE_LEVEL - 1 since there's no need to zap > + * pages that are already mapped at the maximum possible level. > + */ > + flush = slot_handle_level(kvm, slot, kvm_mmu_zap_collapsible_spte, > + PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL - 1, > + true); > + > + if (flush) > + kvm_arch_flush_remote_tlbs_memslot(kvm, slot); > + > +} Reviewed-by: Peter Xu IMHO it looks cleaner to write it in the old way (drop the flush var). Maybe even unwrap the helper? Thanks, -- Peter Xu