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 88C37ECAAD1 for ; Tue, 30 Aug 2022 05:35:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229983AbiH3Fe7 (ORCPT ); Tue, 30 Aug 2022 01:34:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229531AbiH3Fe6 (ORCPT ); Tue, 30 Aug 2022 01:34:58 -0400 Received: from mail-pg1-x532.google.com (mail-pg1-x532.google.com [IPv6:2607:f8b0:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D732D6399 for ; Mon, 29 Aug 2022 22:34:55 -0700 (PDT) Received: by mail-pg1-x532.google.com with SMTP id r69so9717598pgr.2 for ; Mon, 29 Aug 2022 22:34:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc; bh=dKOrthFlbnjVeVQ0rS6buD4uV0A0EXEatsTMiU6XtaU=; b=EneG2w1Rcvj9QqHKY9/WFAkOkqscs399/+OHsJihdU0gM711Fy51V2lIJOUqY1bJL8 aC1tUuR0gPSudQYrVS1g4BLoHJ+9bwIImBD+YbIyMwb2+pJkDxO+AvmJDJ05wJuC/KQ9 cpHmRczVotV13YofM7deeawyMFKPJV02RKbBnHT7f3DaaDYAkDObQVUVjhOuLNLU6bK0 loZ7wI4r3JXwCeFKYjT5klWVyEjFsm+tW+cdIRQV7/LJxRWIYj9G6P9oO+CETCYr0jD/ pHI4wILpEzZ4gdnbWht/009nPCxmsuSsuN+QOKg0tEcjmdOE3g9t0j0/Ec7TEeFVmqZ0 KqTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc; bh=dKOrthFlbnjVeVQ0rS6buD4uV0A0EXEatsTMiU6XtaU=; b=ex9ishoPH6aFkSK3NEO6LwFEuraC79zCH89+YFE6u+4CF3mxL1I8gHsOiEs8F9jmrP auQN4GzkrKm6XWCV+IS2xBFzLzx4E4FGcYe12V8WdXCmzVrNQeRYXIUbNnMT7jtT+9KK TZ0MeEDR0pIOGFchVXOfZEkHtBfU+Ur7MrytUyfbS2gvv3Nd7IBRlYhzOzqzgwEDmCIl 9JkHKQsw5/nezSyahfYXqnZ5TUJTq6IcTIxoqtimiDRC8d8yO5yY40KedNlGwvCSc3t/ KQIT1RRqOag8uWHuqcg8LZeDFTvt+jbCNGBTTM/o9lFqeQDCS77PSWI7eD9yy5JdxzH9 f7EQ== X-Gm-Message-State: ACgBeo0PvHJrNbU65kXVPjwbdkAk9FCJVMybeHKK1WiticSh1WrziDKH Wq/86Cc1EyCy+ZCqsFz5dkBeTbzE+I12JQ== X-Google-Smtp-Source: AA6agR7zW+i/d3NgK1mLET1x2R6V+hN2k+oA6fEFb9KkRNj8mpWXIajmR0Fou52TH6/Ak4p1W+Qh8Q== X-Received: by 2002:a63:fb4f:0:b0:42c:a1:43b4 with SMTP id w15-20020a63fb4f000000b0042c00a143b4mr7543916pgj.140.1661837695263; Mon, 29 Aug 2022 22:34:55 -0700 (PDT) Received: from google.com (7.104.168.34.bc.googleusercontent.com. [34.168.104.7]) by smtp.gmail.com with ESMTPSA id f12-20020a170902ce8c00b001749acb167csm4784285plg.27.2022.08.29.22.34.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Aug 2022 22:34:54 -0700 (PDT) Date: Tue, 30 Aug 2022 05:34:51 +0000 From: Sean Christopherson To: Alex Williamson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, david@redhat.com, lpivarc@redhat.com Subject: Re: [PATCH] vfio/type1: Unpin zero pages Message-ID: References: <166182871735.3518559.8884121293045337358.stgit@omen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <166182871735.3518559.8884121293045337358.stgit@omen> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Aug 29, 2022, Alex Williamson wrote: > There's currently a reference count leak on the zero page. We increment > the reference via pin_user_pages_remote(), but the page is later handled > as an invalid/reserved page, therefore it's not accounted against the > user and not unpinned by our put_pfn(). Heh, kvm_pfn_to_refcounted_page() all over again. is_zone_device_page() is the other known case where a PageReserved page is refcounted. But as KVM's comment calls out, KVM's list was built through trial and error.