From nobody Wed Apr 9 22:09:13 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1606133063; cv=none; d=zohomail.com; s=zohoarc; b=DNtrTPaWUtTTnsGJbDH2qfd1h99JNObLzCAAUW8zvUsAI5+LRCvWfdh/gewGTyPVj5wKOdkS8ptAP0RsZYLgXGDIcrXCGiBb+XKu7HdZK/EHdlVX5LlXSkDt2rcUp8IX0icthgT0NXiupiskFazOAmoHWzOiWp9/ep8cl5LsCDY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1606133063; h=Content-Type:Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=n6PeSqD/L5FpOK5OB82HPwRlzjxhtNygqZgCFMpVmXg=; b=ClSQ+kXq44FkCDY5PeD4rNTtEqwHl2mZYTHHa729b88dVgzeH71l7Kr4oNyYX8TIgWvqja+uK54VuOgvAxTLaWYdyqO+S9hmo4MSuRwos5R5rI8hxEZj3U0Fl1lqKMt0D834BtOlLMDcmvQjy1l6CRhQI8aCwyXwJyGXTSOoWy4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 16061330633602.532288119657437; Mon, 23 Nov 2020 04:04:23 -0800 (PST) Received: from localhost ([::1]:55326 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1khAZy-0007Qt-3T for importer@patchew.org; Mon, 23 Nov 2020 07:04:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55820) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1khAFy-0004vn-Bu for qemu-devel@nongnu.org; Mon, 23 Nov 2020 06:43:42 -0500 Received: from mail-wr1-x42a.google.com ([2a00:1450:4864:20::42a]:35319) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1khAFw-0002mZ-9t for qemu-devel@nongnu.org; Mon, 23 Nov 2020 06:43:42 -0500 Received: by mail-wr1-x42a.google.com with SMTP id k2so18319985wrx.2 for ; Mon, 23 Nov 2020 03:43:39 -0800 (PST) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id g186sm50836495wma.1.2020.11.23.03.43.37 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Nov 2020 03:43:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=n6PeSqD/L5FpOK5OB82HPwRlzjxhtNygqZgCFMpVmXg=; b=TV7vvSDdi9c7OCHG5D1gkwC88h/xtpidWlhLVqf9vdXMV9nd6b8qU8ppA1Vc2kSgK9 lRl599ZzEXbX9XbYzh/Y03C/dht4q+V4ZRHnx8L9kc0ylNQumEaJ/eMMnspynWHWYye3 l6M0+1nC6ZA1Ux97iWzJjxylGjyosFbqUnxqZk19GrHkc+bxWgxQbZdZrLCCcTNzRPAK h65jisptEBupkMh8oyOaF2rAkze61aE0ve9MPA2cEZoSVx7xGJtlQ40qq9DVmzMCOPtW RTWstdv9TdzgGo4cBeGp9TIn6eTyjGD8igU0MRykEfywjif2RtUNoKlubUkMrVc7q5HP prmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=n6PeSqD/L5FpOK5OB82HPwRlzjxhtNygqZgCFMpVmXg=; b=B929uFEd9cU18RUnfAP+xCQ7ozYmZ3POtbcwzsLJFfrfP5FP12b5gdXGaGG7TtYn89 To2Xvk5Ps459RWzHKTkcWW8A+L81A/TCG9gasAQhi1d/T7rI2nETCanfvmk2zLIMoFY/ +CxbRuo1nAzZjJjGNaWag3P4jk4nYoxDvN6Uvlp240+piPjELZbtJzUz8eY0sKzIKMZR w6TWIbW5x3Peuc+57y+3Wa69clllvvGVmllFvEq3k/Uj78rsYkJN2YU2hoYTSvsFU3W5 AcYSgb/R0w3zhb9ruZv+w53m4yrO/TKk0mMQNQ1ihg/xkL5k89zseMes1HcYOsSkHJTU V9Tg== X-Gm-Message-State: AOAM532EO7yU1mDhxD6WMwt2GS5JvcV2bK8VHJKHfR2gTZoAi0UwOwV0 HQ4IrCAD3HOxsZ+t4xDNC9/V2hQKx+qHxQ== X-Google-Smtp-Source: ABdhPJw271mVAxUO+A5t7/gE1Urgt111BhwJGijZLT0tQdOiwO/IaNEvaiDtnBWUzu3OO9tQxpszwQ== X-Received: by 2002:a5d:5146:: with SMTP id u6mr31999524wrt.66.1606131818577; Mon, 23 Nov 2020 03:43:38 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PULL 19/24] docs/system/virtio-pmem.rst: Fix minor style issues Date: Mon, 23 Nov 2020 11:43:10 +0000 Message-Id: <20201123114315.13372-20-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201123114315.13372-1-peter.maydell@linaro.org> References: <20201123114315.13372-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::42a; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x42a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @linaro.org) The virtio-pmem documentation has some minor style issues we hadn't noticed since we weren't rendering it in our docs: * Sphinx doesn't complain about overlong title-underlining the way it complains about too-short underlining, but it looks odd; make the underlines of section headers the right length * Indent of paragraphs makes them render as blockquotes; remove the indent so they just render as normal text * Leading 'o' isn't rst markup, so it just renders as a literal "o"; reformat as a subsection heading instead * "QEMU" in the document title and section headings are a bit odd and unnecessary since this is the QEMU manual; delete or rephrase them * There's no need to specify what QEMU version the device first appeared in. Signed-off-by: Peter Maydell Reviewed-by: Alex Benn=C3=A9e Reviewed-by: Pankaj Gupta --- docs/system/virtio-pmem.rst | 60 ++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 30 deletions(-) diff --git a/docs/system/virtio-pmem.rst b/docs/system/virtio-pmem.rst index 4bf5d004432..c82ac067315 100644 --- a/docs/system/virtio-pmem.rst +++ b/docs/system/virtio-pmem.rst @@ -1,38 +1,37 @@ =20 -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D -QEMU virtio pmem -=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +virtio pmem +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 - This document explains the setup and usage of the virtio pmem device - which is available since QEMU v4.1.0. - - The virtio pmem device is a paravirtualized persistent memory device - on regular (i.e non-NVDIMM) storage. +This document explains the setup and usage of the virtio pmem device. +The virtio pmem device is a paravirtualized persistent memory device +on regular (i.e non-NVDIMM) storage. =20 Usecase --------- +------- =20 - Virtio pmem allows to bypass the guest page cache and directly use - host page cache. This reduces guest memory footprint as the host can - make efficient memory reclaim decisions under memory pressure. +Virtio pmem allows to bypass the guest page cache and directly use +host page cache. This reduces guest memory footprint as the host can +make efficient memory reclaim decisions under memory pressure. =20 -o How does virtio-pmem compare to the nvdimm emulation supported by QEMU? +How does virtio-pmem compare to the nvdimm emulation? +----------------------------------------------------- =20 - NVDIMM emulation on regular (i.e. non-NVDIMM) host storage does not - persist the guest writes as there are no defined semantics in the device - specification. The virtio pmem device provides guest write persistence - on non-NVDIMM host storage. +NVDIMM emulation on regular (i.e. non-NVDIMM) host storage does not +persist the guest writes as there are no defined semantics in the device +specification. The virtio pmem device provides guest write persistence +on non-NVDIMM host storage. =20 virtio pmem usage ----------------- =20 - A virtio pmem device backed by a memory-backend-file can be created on - the QEMU command line as in the following example:: +A virtio pmem device backed by a memory-backend-file can be created on +the QEMU command line as in the following example:: =20 -object memory-backend-file,id=3Dmem1,share,mem-path=3D./virtio_pmem.i= mg,size=3D4G -device virtio-pmem-pci,memdev=3Dmem1,id=3Dnv1 =20 - where: +where: =20 - "object memory-backend-file,id=3Dmem1,share,mem-path=3D, size= =3D" creates a backend file with the specified size. @@ -40,8 +39,8 @@ virtio pmem usage - "device virtio-pmem-pci,id=3Dnvdimm1,memdev=3Dmem1" creates a virtio p= mem pci device whose storage is provided by above memory backend device. =20 - Multiple virtio pmem devices can be created if multiple pairs of "-objec= t" - and "-device" are provided. +Multiple virtio pmem devices can be created if multiple pairs of "-object" +and "-device" are provided. =20 Hotplug ------- @@ -59,17 +58,18 @@ the guest:: Guest Data Persistence ---------------------- =20 - Guest data persistence on non-NVDIMM requires guest userspace applications - to perform fsync/msync. This is different from a real nvdimm backend where - no additional fsync/msync is required. This is to persist guest writes in - host backing file which otherwise remains in host page cache and there is - risk of losing the data in case of power failure. +Guest data persistence on non-NVDIMM requires guest userspace applications +to perform fsync/msync. This is different from a real nvdimm backend where +no additional fsync/msync is required. This is to persist guest writes in +host backing file which otherwise remains in host page cache and there is +risk of losing the data in case of power failure. =20 - With virtio pmem device, MAP_SYNC mmap flag is not supported. This provid= es - a hint to application to perform fsync for write persistence. +With virtio pmem device, MAP_SYNC mmap flag is not supported. This provides +a hint to application to perform fsync for write persistence. =20 Limitations ------------- +----------- + - Real nvdimm device backend is not supported. - virtio pmem hotunplug is not supported. - ACPI NVDIMM features like regions/namespaces are not supported. --=20 2.20.1