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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 59CFDC433E6 for ; Thu, 18 Feb 2021 18:40:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C65464EE0 for ; Thu, 18 Feb 2021 18:40:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232853AbhBRSiK (ORCPT ); Thu, 18 Feb 2021 13:38:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233248AbhBRQP6 (ORCPT ); Thu, 18 Feb 2021 11:15:58 -0500 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 046BDC0613D6 for ; Thu, 18 Feb 2021 08:15:18 -0800 (PST) Received: by mail-pj1-x1036.google.com with SMTP id lw17so3053990pjb.0 for ; Thu, 18 Feb 2021 08:15:17 -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=A+5Mc6ykPR3IfEGP3VJhjfuAa6Mt0cwNEOHk30v0jf0=; b=fB/FEapaxzigjjLl4zCOhSefLUVMNN8EIBtfR3LcJMrIBiN1ygW37Yp90vjur8e2l/ Rr67H0uSayNyzQvc5iqeWMHIF97c3L4gAn/rpoljICsBWcQRri2t71UkFqDh5RxIWziF 3szYWiawplZ+b9mPuUh/g5KKqNl2S5whlTKyQBFQwuz6yZ5dXXGh0yLJDFqEbdNa3Xdg 2o7kwGpImm9612ADEZ93vAgOblfdr9d4hNfiwowyKvcY4/6kAGgGVa+5M+NLNJgy5lzE 4lCrwXeniJcjgTaqVRxnIwZRC/pgETc51xEX+U7l7hgd55HHA5GtGGuud84uZu02j7fB 2ypg== 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=A+5Mc6ykPR3IfEGP3VJhjfuAa6Mt0cwNEOHk30v0jf0=; b=QEjshvW0Ju0Eb6LbeFOofOVDlArSCGAJDV3xQwqjCqwI2STNXpqKaNMr8OQBbygz/2 INOXqy4gb57K5uTDIqhX+QqDgv/Rl9rFtGJ52R/4cDQR0LUtfzGk859mRsEeLl9nDHga FcZY/EM2A+MSLpQtk6gtd7VmxtAxXib6OgxbeYDWwMZgC9UYO3BDkVzSrVWkAOqpjfSB 5rishh1WV4v5wDqlnqZQElRnZRVJiHj4Iuj5X5GJl1JIwf7tB1Qz454L6O18UwOHX4vU kwGudSiLXu1Vav5yRSxSaZbhm5+397g8bcWiLrhndMW9qXLcM4asZPOnISdNcPzeRMJc GS3w== X-Gm-Message-State: AOAM5307CDfV3EKePiuUudGTOCS+/Tu9yXr1+usUS08dHHIprbQZmDh4 xdowGQnx/PWQwQ5m/aYYP1q3Ug== X-Google-Smtp-Source: ABdhPJw7zrGsk3lH2nKUm+BUZrpwqWXxQ9G6LFBM6DAkMYfBsxP0EaJZZuH7PLr/Hwh8lSeUWEHqAw== X-Received: by 2002:a17:90b:3886:: with SMTP id mu6mr4574793pjb.153.1613664917480; Thu, 18 Feb 2021 08:15:17 -0800 (PST) Received: from google.com ([2620:15c:f:10:dc76:757f:9e9e:647c]) by smtp.gmail.com with ESMTPSA id dw4sm6227643pjb.13.2021.02.18.08.15.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Feb 2021 08:15:16 -0800 (PST) Date: Thu, 18 Feb 2021 08:15:10 -0800 From: Sean Christopherson To: Paolo Bonzini Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ben Gardon , Makarand Sonare Subject: Re: [PATCH 10/14] KVM: x86: Further clarify the logic and comments for toggling log dirty Message-ID: References: <20210213005015.1651772-1-seanjc@google.com> <20210213005015.1651772-11-seanjc@google.com> <2d455c2e-1db4-5aff-45eb-529e68127fe7@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2d455c2e-1db4-5aff-45eb-529e68127fe7@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 18, 2021, Paolo Bonzini wrote: > On 13/02/21 01:50, Sean Christopherson wrote: > > > > - * Nothing to do for RO slots or CREATE/MOVE/DELETE of a slot. > > - * See comments below. > > + * Nothing to do for RO slots (which can't be dirtied and can't be made > > + * writable) or CREATE/MOVE/DELETE of a slot. See comments below. > > */ > > if ((change != KVM_MR_FLAGS_ONLY) || (new->flags & KVM_MEM_READONLY)) > > return; > > + /* > > + * READONLY and non-flags changes were filtered out above, and the only > > + * other flag is LOG_DIRTY_PAGES, i.e. something is wrong if dirty > > + * logging isn't being toggled on or off. > > + */ > > + if (WARN_ON_ONCE(!((old->flags ^ new->flags) & KVM_MEM_LOG_DIRTY_PAGES))) > > + return; > > + > > What about readonly -> readwrite changes? Not allowed without first deleting the memslot. See commit 75d61fbcf563 ("KVM: set_memory_region: Disallow changing read-only attribute later"). RW->RO is also not supported. if (!old.npages) { change = KVM_MR_CREATE; new.dirty_bitmap = NULL; memset(&new.arch, 0, sizeof(new.arch)); } else { /* Modify an existing slot. */ if ((new.userspace_addr != old.userspace_addr) || (new.npages != old.npages) || ((new.flags ^ old.flags) & KVM_MEM_READONLY)) return -EINVAL;