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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 89B60C43218 for ; Tue, 11 Jun 2019 11:29:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 677862089E for ; Tue, 11 Jun 2019 11:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389546AbfFKL3s (ORCPT ); Tue, 11 Jun 2019 07:29:48 -0400 Received: from mail-wr1-f43.google.com ([209.85.221.43]:38176 "EHLO mail-wr1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389269AbfFKL3s (ORCPT ); Tue, 11 Jun 2019 07:29:48 -0400 Received: by mail-wr1-f43.google.com with SMTP id d18so12602541wrs.5 for ; Tue, 11 Jun 2019 04:29:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=8qwW4QLFfBtKgDafCW+DM4bjjPQdr1v0w8rEMFQF8Nc=; b=MMAVuyk/JO9uwMuwoLnCVe07m3Hn5bw+s4ZKbVSnEHy19XII9+0KCp/LiKdBzRKwhn uFnjaUe0CbuOFu94/k67MHJZV24eUHGuh4f3TJSTT1CNYeY8jeT6Hw3UByYgYRFfetWy b5ytAfgj4k4/B8SA0iORwrIYNOTtdVvtu0kIGNd0Ztk8Ce+lX0JPDlpfiVVoxY1KkSmj xmlTvyVZHqsegNepx07AxJoGT0XAq589HsxbuIw/djwNDL4qEAsqFQq2nOhuUUVb8Lf4 ihE4vOs8pmJ5Q55UPOKYXMWIIKjQgLdflEa7SGqsSrxZKMbX2kZXLwRchESwhJFYN48g ZUMg== X-Gm-Message-State: APjAAAXuHLMyYm2Ft6bUPB+YvVi7OH1cIw5nQNhtmggZ3li9S69VHa6R xXn2px2ElcVshRWVSaUUP4rE9g== X-Google-Smtp-Source: APXvYqxRkhZhFVuzHilj+D+oNIN0jm/MbCPNStvK6j2mqgYSwuEvx4QZFVySkwECNpCx/N73T3wteA== X-Received: by 2002:adf:e9cc:: with SMTP id l12mr1943923wrn.29.1560252586574; Tue, 11 Jun 2019 04:29:46 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:8cc3:8abd:4519:2cd6? ([2001:b07:6468:f312:8cc3:8abd:4519:2cd6]) by smtp.gmail.com with ESMTPSA id n1sm13073990wrx.39.2019.06.11.04.29.45 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Tue, 11 Jun 2019 04:29:45 -0700 (PDT) Subject: Re: Reference count on pages held in secondary MMUs To: Christoffer Dall Cc: kvm@vger.kernel.org, aarcange@redhat.com, kvmarm@lists.cs.columbia.edu References: <20190609081805.GC21798@e113682-lin.lund.arm.com> <3ca445bb-0f48-3e39-c371-dd197375c966@redhat.com> <20190611112158.GA5318@e113682-lin.lund.arm.com> From: Paolo Bonzini Message-ID: Date: Tue, 11 Jun 2019 13:29:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190611112158.GA5318@e113682-lin.lund.arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 11/06/19 13:21, Christoffer Dall wrote: >> If I understand correctly, I think the MMU notifier would not fire if >> you took an actual reference; the page would be pinned in memory and >> could not be swapped out. >> > That was my understanding too, but I can't find the code path that would > support this theory. Yeah, as Andrea said you could drop the reference in the invalidate callback too. Paolo