远程桌面协议 SPICE 介绍
Spice for NewbiesDraft 2Copyright © 2009 Red Hat, Inc.Licensed under a Creative Commons Attribution-Share Alike 3.0United States License (see/licenses/by-sa/3.0/us/legalcode).Table of Contents1 Introduction (3)2 Basic Architecture (3)2.1 Graphic Commands Flow (3)2.2 Agent Commands Flow (4)2.3 Spice Client (5)2.3.1 Client Basic Structure (5)2.3.2 Client Classes (5)2.3.2.1 Channels (5)2.3.2.2 Screens and Windows (6)2.4 Spice Server (6)2.4.1 Server Structure (7)2.4.1.1 Red Server (reds.c) (7)2.4.1.2 Graphics subsystem (8)2.5 Spice Protocol (9)2.6 QXL Device (9)2.7 QXL Guest Drivers (9)2.8 Spice Agent (10)2.9 VDIPort Device and Driver (10)3 Features (10)3.1 Graphic Commands (10)3.2 Hardware Acceleration (10)3.3 Image Compression (10)3.4 Video Compression (11)3.5 Caching (11)3.6 Mouse Modes (11)3.7 Multiple Monitors (12)3.8 2-way Audio and Lip-sync (12)3.9 Hardware Cursor (12)3.10 Live Migration (12)4 References (12)1 IntroductionSpice is an open remote computing solution, providing client access to remote machine display and devices (e.g., keyboard, mouse, audio). Spice achieves a user experience similar to an interaction with a local machine, while trying to offload most of the intensive CPU and GPU tasks to the client. Spice is suitable for both LAN and WAN usage, without compromising on the user experience.2 Basic ArchitectureSpice basic building blocks are the Spice protocol, Spice server and Spice client. Spice-related components include the QXL device and guest QXL driver.2.1 Graphic Commands FlowThe above figure shows the basic Spice architecture and guest-to-client data flow of graphic commands, when using libspice with QEMU. libspice can be used by any other VDI[2] compatible host application as well. Graphic commands data flow starts by a user application requesting the OS graphic engine(X or GDI)to perform a rendering operation.The graphic engine passes the commands to the QXL driver, which translates the OS commands to QXL commands and pushes them into a command ring. The command ring resides in the device memory. libspice pulls the commands from the ring and adds them to graphic commands tree. The graphic commands tree contains the set of commands, whose execution will reproduce the display content. The tree is used by libspice to optimize commands transmission to the client by dropping commands hidden by other commands.The commands tree is also used for video stream detection.libspice also maintains a queue of commands to be sent to the client, for updating its display. When a command is pulled from the queue for transmission to the client, it is translated into Spice protocol messages. Commands removed from the tree, are removed from the send queue as well. When a command is no longer required by libspice, it is pushed into the device release ring. The driver uses this ring for releasing commands resources. When a client receives a graphic command it uses the command to update the display.2.2 Agent Commands FlowSpice agent is a software module executed in the guest. Spice server and client use the agent for tasks that need to be performed in the guest context, such as configuring the guest display settings. The figure above shows the Spice client and server communication with the agent using VDIPort device and guest driver. Messages can be generated by the client (e.g., configuration of the guest display settings), the server (e.g., mouse motion), and the agent (e.g., configuration ack). The driver communicates with the device using its input and output rings.Client and server generated messages are written to the same write queue in the server and are later written to the device output ring. Messages are read from the device input ring to the server read buffer. The message port determines whether the message should be handled by the server or forwarded to the client.2.3 Spice ClientSpice cross-platform (Linux & Windows) client is the interface for the end user.2.3.1 Client Basic Structure2.3.2 Client ClassesFollowing is an introduction to the key classes of the Spice client. For having a clean cross-platform structure,Spice defines generic interfaces,keeping their platform-specific implementation in parallel directories. One such generic interface is the Platform class, defining many low-level services such as timer and cursor operations.Application is the main class, which contains and controls the client, monitors and screens. It handles general application functionality such as parsing command line arguments, running the main message loop, handling events (connection, disconnection, error, etc.), redirection of mouse events to input handler, toggling full screen mode, etc.2.3.2.1 ChannelsThe client and server communicate via channels. Each channel type is dedicated to a specific type of data. Each channel uses a dedicated TCP socket, and it can be secured (using SSL) or unsecured. On the client side each channel has a dedicated thread, so different QoS can be given to each one by differentiating their thread priority.RedClient serves as the main channel. It owns all the other instantiated channels and controls them (creating channels using their factory,connecting,disconnecting,etc.),and handles control, configuration and migration (using the Migrate class).The ancestors of all the channels are:o RedPeer – socket wrapper for secured and unsecured communication, providing infrastructures such as connect, disconnect, close, send, receive, and socket swapping for migration. It defines generic message classes: InMessages, CompoundInMessage and OutMessage. All messages include type, size and data.o RedChannelBase – inherits RedPeer, provides the basic functionality for establishing channel connectivity with the server and support for channel capability exchange with the server.o RedChannel – inherits RedChannelBase. This class is the parent of all instantiated channels.Handles sending outgoing messages and dispatching incoming messages. RedChannel thread runs an event loop with various event sources (e.g., send and abort triggers). The channel socket is added as an event source for triggering Spice messages sending and receiving.The available channels are:o Main - implemented by RedClient (see above).o DisplayChannel - handles graphic commands, images and video streams.o InputsChannel - keyboard and mouse inputs.o CursorChannel - pointer device position, visibility and cursor shape.o PlaybackChannel - audio received from the server to be played by the client .o RecordChannel - audio captured on the client side.ChannelFactory is the base class for all channel factories. Each channel registers its specific factory for enabling RedClient to create channels by channel type.2.3.2.2 Screens and Windowso ScreenLayer – screen layer is attached to specific screen, providing operations on rectangle areas (set, clear, update, invalidate, etc.). Layers are z-ordered (e.g., cursor is above display).o RedScreen – implements the screen logic and controls the window, using the screen layers (e.g., display, cursor) for displaying its content.o RedDrawable – platform-specific implementation of basic pixmap. It supports basic rendering operations (e.g., copy, blend, combine).o RedWindow_p – platform-specific window data and methods.o RedWindow – inherits RedDrawable and RedWindow_p. Cross-platform implementation of basic window state and functionality (e.g., show, hide, move, minimize, set title, set cursor etc.).2.4 Spice ServerSpice server is implemented in libspice, a Virtual Device Interface (VDI) pluggable library. VDI provides a standard way to publish interfaces of virtual devices by a software component. This enables other software components to interact with these devices. For more information, refer to [2]. From one side, the server communicates with a remote client using the Spice protocol. From the other side, it interacts with the VDI host application (e.g., QEMU).For display remoting purposes the server maintains a commands queue and a tree for managing the current objects dependencies and hidings. QXL commands are processed and translated to Spice protocol commands sent to the client.Spice always attempts to pass the rendering tasks to the client,thus leveraging its hardware acceleration abilities. Rendering on the host side, by software or GPU, is done as a last result. TheSpice server keeps guest graphic commands that compose the current image. It releases a command only when it is completely covered by other commands and there are no dependencies on it, or when we need to render the command to the frame buffer. The two main reasons that trigger drawing to the frame buffer are (1) Running out of resources; (2) The guest needs to read from the frame buffer.2.4.1 Server StructureThe server communicates with the client via channels. Each channel type is dedicated to a specific type of data. Each channel uses a dedicated TCP socket, and it can be secured (using SSL) or unsecured. The server channels are analogous of the client channels: Main, Inputs, Display, Cursor, Playback, and Record (for more information see Channels 2.3.2.1)The main and input channels are controlled by handler functions (implemented in reds.c). The display and cursor channels are handled by a red worker thread per display. The audio playback and record channels have their own handlers (snd_worker.c). Libspice and the VDI host application (e.g.QEMU)communicate via interfaces defined for each functionality(e.g.,QXL,agent, keyboard, mouse, tablet, playback, record), as detailed in [2].As shown in the above figures, spice server consists of the following major components:2.4.1.1 Red Server (reds.c)The server itself, which listens for client connections, accepts them and communicates with them. Reds is responsible for:•Channels•Owns and manages the channels (register, unregister, shutdown)•Informs the client about active channels, so that client can create them•Main and input channel handling•Links establishment (both main and the others)•Socket operations and connections management•Handles SSL and ticketing•VDI interfaces (e.g., core, migration, keyboard, mouse, tablet, agent) addition and removal •Migration process coordination•Handling of user commands (e.g., from Qemu monitor)•Communication with guest agent•Statistics2.4.1.2 Graphics subsystemUnlike other subsystems in Spice server, the graphics subsystem runs in parallel to the server execution, on a dedicated thread (i.e, red worker).This structure enables independency between QEMU flow and the processing and rendering of incoming graphic commands, which can consume a lot of CPU resources. The figure above shows Spice server graphics subsystem structure. Red server initiates a dispatcher on a new QXL interface (i.e., VDI). The dispatcher creates red worker for that interface. The commands processed by the worker can originate from three sources: (1) Synchronized QXL device commands, (2) red server commands, both (1 and 2) delivered by the dispatcher using a socket (i.e., socket pair), (3) asynchronous QXL device commands, pulled by the worker from the QXL device rings using the interface.Red Worker (red_worker.c)Spice server holds a different instance of the red worker thread for each QXL device instance. The responsibilities of the red_worker are:•Processing QXL device commands (e.g. draw, update, cursor)•Handling messages received from the dispatcher•Channel pipes and pipe items•Display and cursor channels•Image compression (using quic, lz and glzencoding)•Video streaming – identification, encoding and stream creation•Cache – client shared pixmap cache, cursor cache, palette cache•Graphic items removal optimization – using item tree, containers, shadows, excluded regions, opaque items•Cairo and OpenGL (pbuf and pixmap) renderers – canvas, surfaces etc.•Ring operationsRed D ispatcher (red_dispatcher.c)•Dispatcher, one per QXL device instance•Encapsulates the worker internals from the QXL device and reds•Initiates a worker for a QXL device instance and creates a worker thread•Dispatches the worker using a socketpair channel•QXL devices use the QXLWorker interface, implemented and attached by the red dispatcher, which translates the device calls to messages transmitted through the red worker pipe. This way keeps the two separated and logically independent.•Reds uses the interface defined in red_dispatcher.h for dispatcher functions such as dispatcher initialization, image compression change, video streaming state change, mouse mode setting and renderer addition.2.5 Spice ProtocolSpice protocol is used for client-server communication, i.e., for transferring graphical objects, keyboard and mouse events, cursor information, audio playback and record chunks, and control commands. Detailed documentation of the Spice protocol can be found in [1].2.6 QXL DeviceSpice server supports QXL VDI interface. When libspice is used with QEMU, a specific QEMU QXL PCI device can be used for improving the remote display performance and enhancing the graphic capabilities of the guest graphic system. QXL device requires guest QXL drivers for full functionality. However, standard VGA is supported when no driver exists. This mode also enables active display from the virtual machine (VM) boot stage. The device interacts with the driver using command and cursor rings,interrupts for display and cursor events,and I/O ports.Other responsibilities of the device include:•Initializing and map the device ROM, RAM and VRAM to physical memory•Mapping the I/O ports and handle reads and writes for managing: area updates, command and cursor notifications, IRQ updates, mode set, device reset, logging, etc.•Rings - initialize and maintain command and cursor rings, get commands and cursor commands from rings and wait for notifications. Maintain resources ring.•Communicating with the corresponding red worker using the QXLWorker interface, implemented and attached by red dispatcher, which translates the device calls to messages written to and read from the red worker pipe.•Registering the QXLInterface for enabling the worker to communicate with the device. The interface includes PCI information and functions for attaching a worker, getting display and cursor commands from rings, display and cursor notifications, mode change notification, etc.•Defining supported qxl modes and enabling modification of the current mode, including vga mode, where all monitors mirror a single device (vga clients)•Handle display initialization, update, resize andrefresh in VGA mode2.7 QXL Guest DriversPlatform-specific guest drivers are used to enable and communicate with the QXL device(s). The Windows drivers consist of a display driver that works with the graphics device interface (GDI) calls and structures, and a miniport driver that handles memory mapping, ports, and interrupts.2.8 Spice AgentSpice agent is an optional component for enhancing user experience and performing guest-oriented tasks. For example, the agent injects mouse position and state to the guest when using client mouse mode. In addition, it is used for configuration of the guest display settings. Future features include copying and pasting objects from/to the guest. The Windows agent consistss of a system service and a user process.2.9 VDIPort Device and DriverSpice protocol supports a communication channel between the client and an agent on the server side. When using QEMU, Spice agent resides on the guest. VDI port is a QEMU PCI device used for communication with the agent. A specific agent protocol is employed for the communication.A Windows guest driver is already implemented. .3 Features3.1 Graphic CommandsSpice supports transmission and handling of 2D graphic commands (3D support is soon to come), as opposed to frame buffer updates, which are used in many other remote desktop solutions. The QXL device commands are generic and platform-independent, so both Windows and X drivers use them natively.3.2 Hardware AccelerationThe basic Spice client rendering is performed using Cairo, which is a cross-platform, device-independent library.Cairo provides vector graphics primitives for2-dimensional drawing. Hardware acceleration is an additional rendering mode in which the rendering is performed on hardware by the client GPU and not by software, using the client CPU. Hardware acceleration is implemented using OpenGL(experimental)in Linux,and GDI in Windows. .Hardware acceleration advantages are:●High performance rendering - using OpenGL the Spice client is able to render much fasterthan before. Heavy software operations such as stretching (used by video streaming) are much faster when preformed by hardware than by software. Therefore, Spice achieves a much smoother user experience.●Reducing client CPU usage - the client enjoys more CPU time, which can be used for othertasks like audio.Unlike Cairo, which is an independent software library, OpenGL is a hardware library that depends on the driver and hardware implementation.As a result,Spice might suffer from incorrect rendering, heavy CPU usage, or client or host crash in the worst case. In addition, although OpenGL is a global standard, the implementation of hardware and drivers changes dramatically between vendors. Thus, on different GPUs, Spice might display different rendering output, and different performance might be detected. In addition, there are devices which do not support OpenGL at all.The server also uses OpenGL for hardware acceleration, sharing the same code as the Linux client.3.3 Image CompressionSpice offers several image compression algorithms, which can be chosen on server initiation, and dynamically at run-time. Quic is Spice proprietary image compression utility which is based on the SFALIC algorithm [3]. The LZ (LZSS) [4] algorithm, adjusted to images, is another option. BothQuic and LZ are local algorithms, i.e., they encode each image independently. Global LZ (GLZ) is another Spice proprietary,that uses LZ with an history-based global dictionary.GLZ takes advantage of repeating patterns among images for shrinking the traffic and save bandwidth, which is critical in a WAN environment. Spice also offers an automatic mode for compression selection per-image,where the choice between LZ/GLZ and Quic is heuristically based on the image properties. Conceptually, artificial images are compressed better by LZ/GLZ, and real images are compressed better by Quic.3.4 Video CompressionSpice uses lossless compression for images sent to the client, and not lossy compression, in order to avoid disruption of important display objects . However, since (1) video streams can be major consumers of bandwith, as each video frame is an independent image, and (2) their content is mostly uncritical,Spice employs lossy video compression for such streams:Spice server heuristically identifies video areas by identifying regions that are updated with high rate. These areas updates are sent to the client as video streams coded using the loss-prone Motion JPEG algorithm(M-JPEG).This mechanism saves a lot of traffic,improving Spice performance, especially in WAN. Nevertheless, in some circumstances the heuristic behavior might cause low quality images (e.g., when identifying updated text area as a video stream). Video streaming can be chosen on server initiation and can be changed dynamically on run-time..3.5 CachingSpice implements client image caching in order to avoid redundant transmissions to the client. Caching applies to any kind of image data sent to the client, including pixmaps, palettes and cursors. Each image arrives from the driver with a unique id and a cache hint. Non-identical images have different ids, while identical images share the same id. The cache hint recommends the server to cache the image. Pixmap cache is shared among all the displays. Cache is defined per connection and synchronized between the server and the client, i.e., in each moment the server knows exactly which images are in the client cache. Moreover, the server is the one to decide whether an item should be added or removed from the cache. The client cache size is set by the client and transferred to the server through the display channel initialization message. The server monitors the current cache capacity and when it lacks space it removes the least recently used cache items until there is enough available cache space. The server sends an invalidate command with these items and the client removes them.3.6 Mouse ModesSpice supports two mouse modes, server and client. The mode can change dynamically and is negotiated between the client and the server.●Server mouse - use the QEMU ps/2 mouse emulation for enabling mouse in the guest. Uponuser click inside the Spice client window, client mouse is captured and set invisible. The client sends mouse moves as delta coordinates to the server. Therefore, client mouse is returned to the window center after each move. In this mode, the server controls mouse position on display, so it is always synchronized between the client and the guest. However, it might be problematic on WAN or a loaded server, where mouse cursor might have some latency or non-responsiveness.●Client mouse - client mouse is used as the effective pointing device. It is not captured andguest cursor is set invisible. The client sends mouse moves as absolute coordinates to the server. Guest agent scales the coordinates for the guest virtual desktop and injects the appropriate cursor position. For a single monitor, client mouse can be used even without an agent if VDI host application registers an absolute pointing device (e.g., USB tablet in QEMU). In this case. the Spice server scales the coordinates. Client mode is appropriate forWAN or loaded server, since cursor has smooth motion and responsiveness. However, the cursor might loss sync (position and shape) for a while. The client mouse cursor is updated according to the guest mouse cursor.3.7 Multiple MonitorsSpice supports any number of monitors, constrained only by the guest, client, and server limitations. The number of monitors and their RAM size is set when launching the VM.Spice supports automatic configuration of the guest monitors resolution and display settings, according to the client machine settings. This is implemented by a client command to the guest agent.3.8 2-way Audio and Lip-syncSpice supports audio playback and recording.Playback is compressed using the CELT [5] algorithm. Lip-sync between video and audio is achieved by time-stamping the video frames in the QXL device and injecting them in the client side,synchronized with the audio,which is independent.3.9 Hardware CursorThe QXL device supports cursor hardware acceleration. Separating the cursor from the display enables prioritizing the cursor for better responsiveness. In addition, it reduces the network traffic.3.10 Live MigrationVM migration between servers is seamless to a connected client. The complete connection state, including the open channels and cursor, is saved on the source and restored on the destination.4 References[1] Spice remote computing protocol definition[2] Spice VD Interfaces documentation[3] Starosolski, R.: Simple Fast and Adaptive Lossless Image Compression Algorithm, Software–Practice and Experience, 2007, 37(1):65-91, DOI 10.1002/spe.746.[4] Lempel-Ziv-Storer-Szymanski:“Data compression via textual substitution"published in Journal of the ACM (pp. 928-951)[5] The CELT ultra-low delay audio codec.。
基于spice远程桌面协议-无人所武红杰20170502
KVM Qemu 之间的关系
• KVM是内核的模块，采用硬件辅助虚拟化技术Intel-VT，AMD-V • 使用KVM，Guest OS的CPU指令不用经过Qemu转译，直接运行，大
大提高了速度 • KVM通过/dev/kvm暴露接口，用户态程序可以通过ioctl来访问这个接口
open("/dev/kvm") ioctl(KVM_CREATE_VM) ioctl(KVM_CREATE_VCPU) for (;;) {
基于spice远程桌面协议
无人装备所 武红杰 2017.4
目录
• 虚拟化基本类型 • KVM QEMU关系 • 为什么是spice • 架构 • Spice client • spice客户端优化 • 搭建
虚拟化的基本类型
• 无虚拟化
▫ CPU一般设为四个Ring ▫ Kernel Mode一般跑在Ring 0上 ▫ User Mode一般跑在Ring 3上 ▫ 对于一个普通的传统的Linux系统没有问题
▫ Hypervisor运行在Kernel Mode, Ring 0 ▫ Guest OS不能直接运行在Ring 0，而是
需要对Kernel进行修改，将运行在Ring 0上的指令转为调用Hypervisor ▫ Guest OS上的APP运行在Ring 3
虚拟化的基本类型
• Full Virtualization without Hardware Assist非硬件辅助 全虚拟化 ▫ Hypervisor运行在Ring 0 ▫ Hypervisor对Guest OS提供CPU模拟，由Hypervisor 模拟一个CPU给VM，VM不直接使用真实的CPU ▫ Guest OS不做修改，还是试图运行在Ring 0上，只不 过是模拟CPU的Ring 0 ▫ Hypervisor对Guest OS的Ring 0上的指令进行转译， 变成真实CPU的指令，只能运行在Ring 1上
基于SPICE协议的桌面虚拟化技术研究与改进方案
计算机工程与科学
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桌面虚拟化与传统的远程桌面的关键不同之处在于远程桌面技术是接入到一个真正安装在物理机上的操作系统如果要大面积作为企业应用技术不仅需要一个个pc运行操作系统还需要投入相应的很多终端所以远程桌面仅作为远程控制和远程访问的一种方式
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红帽桌面虚拟化：SPICE协议的优势
红帽桌面虚拟化：SPICE协议的优势导读：红帽解决虚拟桌面性能问题的答案是SPICE，这个开源的协议能以低价交付高性能的虚拟桌面。
关键词：虚拟桌面性能 SPICE协议【TechTarget中国原创】红帽的桌面虚拟化软件和其受欢迎的远程桌面协议能尽可能复制原生的桌面体验，从多媒体播放到本地连通硬件。
尽管，这家开源公司的创新能走到多远是另外一回事，但竞争对手交付类似的方案，有更广泛的用户基础。
红帽的虚拟桌面愿景Red Hat Enterprise Virtualization（RHEV）的理念很简单，这也是部署虚拟桌面的IT人士的目的，那就是随时随地通过任何设备访问桌面。
服务器运行操作系统的虚拟实例，包括Windows与各种版本的Linux，并将虚拟桌面播送到网络上的客户端。
在桌面使用RHEV的优势与使用其他桌面虚拟化产品相同。
可按需部署桌面系统，不仅限于用户系统的某个位置，所有虚拟系统都可集中管理。
终端用户机器也可完全在后端服务器隔离，红帽使用page-sharing和其他资源优化算法，让同个硬件上并列运行多台虚拟机。
服务器宿主桌面的缺陷也不能忽视。
通常，终端用户体验非常有限（视频与声音惨不忍睹啊），本地硬件一般连接到远程服务器，这让用户很痛苦，整个的体验由于带宽限制和网络延迟而杯具。
红帽的秘密武器：SPICE红帽解决虚拟桌面性能问题的答案是SPICE，这是由Qumranet开发的开源网络协议，2008年红帽收购了Qumranet获得了这个协议。
SPICE是红帽在虚拟化领域除了KVM的又一“新兴技术”，投入很多精力开发这个技术。
SPICE的工作原理是创建几个通用接口或“通道”，每样都会获得不同的用户体验，它们都高度抽象，所以能在各种平台上使用。
播放功能、用户接口设备插入、光标移动、音频播放和录像，每个都有自己专门的通道。
子操作系统需要安装专门的驱动，通过SPICE转播并接受事件，但这与操作系统中的每个虚拟实例安装的“子扩展”没有多大区别。
《spice应用》课件
目前，Spice已经成为了许多虚拟化解决方案的默认 图形协议。
Spice的应用领域
虚拟化平台
Spice常用于虚拟化平台，提供虚 拟机的图形界面，使得用户可以 在远程访问虚拟机时获得与本地 访问相似使用虚拟化技术 来提供计算服务，Spice可以用于 提供虚拟机的图形界面，使得用 户可以在云端运行图形应用程序 。
远程桌面
Spice可以用于远程桌面解决方案 ，使得用户可以在远程访问桌面 时获得与本地访问相似的体验。
Spice的优点和特性
跨平台 高性能 安全性 兼容性
Spice支持多种操作系统和虚拟化平台，可以在不同的平台上使 用。
Spice提供了高效的图形渲染和数据传输机制，使得远程访问虚 拟机的图形界面可以获得较高的性能。
Spice应用
contents
目录
• Spice简介 • Spice的基本原理 • Spice的应用实例 • Spice的未来发展 • 总结与展望
Spice简介
01
Spice的起源和历史
01
Spice起源于20世纪80年代，最初是为了解决远程终 端用户访问主机的图形界面问题而开发的。
02
随着技术的发展，Spice逐渐发展成为一个开源的虚 拟化标准，用于提供虚拟机的图形界面。
扩大应用范围
开源和社区发展有助于扩大Spice的应用范 围，推动其在学术研究、产业应用等领域的 发展。
总结与展望
05
Spice的重要性和影响
技术革新
Spice技术为音频处理领域带来了革新，提供了更高 效、更灵活的音频处理方式。
产业影响
Spice的应用推动了音频处理行业的进步，提高了音 频处理的质量和效率。
Spice技术的标准化和与其他系统的兼容性有待提高。
spice协议原理
竭诚为您提供优质文档/双击可除spice协议原理篇一：spice学习文档spice学习文档spice简介spice(simpleprotocolforindependentcomputingenvironm ent独立计算环境简单协议)是一项高性能、动态的自适应远程呈现技术，能为终端用户带来和物理桌面个人计算机难以区分的体验。
spice是为远程访问虚拟化桌面而专门设计和创建，它是使用redhat企业虚拟化桌面版时，将用户连接至虚拟化桌面的协议。
与microsoft的Rdp和citrix的ica旧协议不同，spice 是以多层架构为基础，旨在满足目前桌面用户的丰富多媒体需求。
设计的核心是实现对用户端设备(cpu、Ram等)或主机虚拟服务器上可用系统资源的智能访问。
作为访问的结果，协议会以动态方式判定是在客户端设备上还是在主机服务器上对桌面应用程序进行呈现，从而在任何网络条件下都能生成最佳用户体验。
优势：1.超群的用户体验spice可充分利用终端用户客户端设备的系统资源以呈现资源密集型应用程序、远程桌面可实现近似于在本地安装环境时的功能。
这种方式产生了极佳效果，尤其是在更具挑战性应用方面，如音频、视频和其他形式多媒体，这些一度曾是效果较差或甚至无法利用虚拟桌面解决方案进行观看。
2.降低部署成本和支出费用通过利用本地客户端的系统资源，在可用情况下，它可即时释放主机虚拟服务器上的重要系统资源。
其结果是实现主机服务器上最高的虚拟机密度，极大地释放了主机服务器系统资源，并可运行更多虚拟机，和其他备选解决方案相比，使企业只需要购买和支持较少的服务器硬件。
3.确保数据安全性红帽企业虚拟化桌面版具有一项可选功能，可充分加密spice连接终端用户的客户端设备与桌面虚拟机之间的端对端ssl（安全套接层）通道。
这一安全通道确保无论客户端设备用户在何处对其桌面进行访问，客户端和主机服务器之间的数据链接都能受到保护。
4.连接任何usb设备今天大多数桌面用户在他们的本地桌面pc上连接各种各样的usb设备。
基于SPICE协议的虚拟云桌面访问技术的研究与应用
科技资讯2016 NO.30SCIENCE & TECHNOLOGY INFORMATION7科 技 前 沿1科技资讯 SCIENCE & TECHNOLOGY INFORMATION 随着2015年国家“互联网+”行动计划的逐步实施，移动互联网、云计算和大数据等新技术的不断推进，很多传统的信息框架和观念被淘汰或更新，国家信息化和现代化的发展日新月异。
但是长期以来一些信息化基础设施的建设却比较落后，尤其是传统桌面终端的管理存在安全性差、设备不稳定、维护成本较高等问题，这些问题不仅限制了人们的使用，也阻碍了信息化的发展。
而以RDP、VNC和SPICE等技术为基础的虚拟云桌面的发展将操作系统和应用数据集中于数据中心统一管理，这种系统运行方式的变革提升了数据的安全和用户的体验，有效地解决了传统构架带来的复杂管理和高耗能等问题，是未来桌面终端应用发展的趋势。
1 SPICE(1)协议简介。
SPICE （Simple Protocol for independent Computing Environment/独立计算环境的简单协议）是基于虚拟云桌面的一种虚拟化框架，也是一个桌面服务展示协议，与RDP(Remote Desktop Protocol/远程桌面协议)和VNC(Virtual Network Console/虚拟网络控制台)类似。
通过SPICE人们可以像使用本地计算机一样访问远程PC，这样可以将需要进行高强度和长时间计算的工作移交给数据中心服务器，有效地提高运行效率，降低企业开支，用户身边只要有可以上网的设备就可以方便地与远程虚拟桌面进行交互，并且整个方案是开源构架的。
(2)协议组件。
作为REDHAT公司重要的虚拟化桌面组件之一，SPICE具有很强的自适应能力，能够让用户获得与真实PC相同的体验，它主要包含以下3个组件：SPICE Driver （SPICE驱动器）,每个虚拟桌面都具备的基础组件;SPICE Device （SPICE设备）,REDHAT企业虚拟化Hypervisor设备内存在的组件;SPICE Client （SPICE客户端）,终端组件，终端可以是个人电脑、平板电脑、瘦客户端甚至是ipad等设备，用于接入虚拟桌面。
Spice学习文档
Spice学习文档SPICE简介SPICE(Simple Protocol for Independent Computing Environment独立计算环境简单协议)是一项高性能、动态的自适应远程呈现技术，能为终端用户带来和物理桌面个人计算机难以区分的体验。
SPICE是为远程访问虚拟化桌面而专门设计和创建，它是使用redhat企业虚拟化桌面版时，将用户连接至虚拟化桌面的协议。
与Microsoft的RDP和Citrix的ICA旧协议不同，SPICE是以多层架构为基础，旨在满足目前桌面用户的丰富多媒体需求。
设计的核心是实现对用户端设备(CPU、RAM等)或主机虚拟服务器上可用系统资源的智能访问。
作为访问的结果，协议会以动态方式判定是在客户端设备上还是在主机服务器上对桌面应用程序进行呈现，从而在任何网络条件下都能生成最佳用户体验。
优势：1.超群的用户体验SPICE 可充分利用终端用户客户端设备的系统资源以呈现资源密集型应用程序、远程桌面可实现近似于在本地安装环境时的功能。
这种方式产生了极佳效果，尤其是在更具挑战性应用方面，如音频、视频和其他形式多媒体，这些一度曾是效果较差或甚至无法利用虚拟桌面解决方案进行观看。
2.降低部署成本和支出费用通过利用本地客户端的系统资源，在可用情况下，它可即时释放主机虚拟服务器上的重要系统资源。
其结果是实现主机服务器上最高的虚拟机密度，极大地释放了主机服务器系统资源，并可运行更多虚拟机，和其他备选解决方案相比，使企业只需要购买和支持较少的服务器硬件。
3.确保数据安全性红帽企业虚拟化桌面版具有一项可选功能，可充分加密SPICE 连接终端用户的客户端设备与桌面虚拟机之间的端对端SSL（安全套接层）通道。
这一安全通道确保无论客户端设备用户在何处对其桌面进行访问，客户端和主机服务器之间的数据链接都能受到保护。
4.连接任何USB 设备今天大多数桌面用户在他们的本地桌面PC 上连接各种各样的USB 设备。
spice协议书
spice协议书SPICE协议（Simulation Program with Integrated Circuit Emphasis）是一种模拟电子电路的软件工具。
它提供了一种方法，能够对电路的行为进行精确地建模和仿真，以帮助工程师在设计过程中进行验证和优化。
SPICE协议由美国加利福尼亚大学伯克利分校的计算机科学实验室（CSL）于1972年开发出来。
它是业界最早最受欢迎的电路仿真工具之一，并且至今仍然在广泛使用。
SPICE协议提供了许多不同版本，如PSPICE、HSPICE和LTspice等。
SPICE协议的主要特点是其强大的模拟功能。
它可以准确地描述各种电子器件和电路元件的特性，如电阻、电容、电感、二极管、晶体管等。
此外，SPICE还可以模拟各种非线性和时变电路。
通过使用数学模型和方程，SPICE能够计算电流、电压和功率等关键参数，并通过图形显示结果。
SPICE协议的使用非常灵活。
它可以接受用户提供的电路描述文件，通常是一个简单的文本文件，其中包含了电路的拓扑结构、元件类型和模型参数等信息。
用户可以通过添加或修改这些信息来模拟不同的电路和器件。
此外，SPICE还提供了一些简便的快捷命令，使得用户能够轻松地执行模拟和分析任务。
SPICE协议除了提供基本的直流和交流分析外，还提供了更高级的功能，如传输函数分析、傅里叶变换、噪声分析和蒙特卡洛分析等。
这些功能使得工程师能够更深入地了解电路的性能，从而做出更明智的设计决策。
此外，SPICE还可以与其他软件工具进行集成，如MATLAB和Python等，以提供更全面的仿真环境。
SPICE协议在电子工程领域的应用非常广泛。
它被用于各种设计阶段，从电路原理图的初步验证到PCB布局的最终确认。
SPICE的模拟结果可以帮助工程师分析电路的性能、稳定性和可靠性，并找出潜在的问题和改进的空间。
此外，SPICE还被用于教育和研究领域，以帮助学生和学者深入理解电子电路的原理和特性。
ZStack V2.6.0 SPICE协议 使用指南说明书
图 3: zstaak-cli设置QXL显卡设置
• 使用UI设置QXL显卡 在ZStack系统菜单栏点击设置 > 全局设置按钮，然后在全局设置界面，更改显卡类型为qxl ，点击确定按钮保存。如图 4: 使用UI设置QXL显卡所示：
图 4: 使用UI设置QXL显卡
Spice协议 使用指南
产品版本：ZStack 2.6.0 文档版本：V2.6.0
Spice协议 使用指南 / 版权声明
版权声明
版权所有©上海云轴信息科技有限公司 2018。保留一切权利。 非经本公司书面许可，任何单位和个人不得擅自摘抄、复制本文档内容的部分或全部，并不得以任 何形式传播。 商标说明 ZStack商标和其他云轴商标均为上海云轴信息科技有限公司的商标。 本文档提及的其他所有商标或注册商标，由各自的所有人拥有。 注意 您购买的产品、服务或特性等应受上海云轴公司商业合同和条款的约束，本文档中描述的全部或部 分产品、服务或特性可能不在您的购买或使用范围之内。除非合同另有约定，上海云轴公司对本文 档内容不做任何明示或暗示的声明或保证。 由于产品版本升级或其他原因，本文档内容会不定期进行更新。除非另有约定，本文档仅作为使用 指导，本文档中的所有陈述、信息和建议不构成任何明示或暗示的担保。
2. 设置QXL显卡 ZStack云主机支持三种显卡类型：cirrus，vga，QXL，在使用Spice协议时推荐使用QXL显 卡，能够让Windows虚拟机图形页面更加流畅。以下是修改QXL的两种方法： • 使用zstack-cli设置QXL显卡模式：
[root@localhost ~]# zstack-cli UpdateGlobalConfig category=vm name=videoType value=qxl
桌面云的四大协议解析
桌面云的四大协议解析发表于 2013-8-7 15:18 |来自51CTO网页[只看他]楼主显示协议是桌面虚拟化厂商必争之地。
协议效率决定了虚拟桌面使用的用户体验，而用户体验是决定了桌面产品生命力的关键。
目前提供虚拟化解决方案的主要国外厂商都有自己的协议，Microsoft使用RDP协议，Citrix用的是ICA协议，Vmware开发了自己的PCoIP协议，Redhat发布了SPICE协议。
下面随小编了解一下这四种在市场占主导的协议。
1.RDP协议RDP是微软终端服务应用的协议，服务端基于win2000/winNT。
协议基于T.128（T.120协议族）提供多通道通信。
RDP早期由Citrix开发的，后来被微软购买并集成在Windows中，VMware虚拟化平台早期也运用RDP协议。
RDP协议中，终端服务使任何一台有权限的终端机，用已知的账号登录服务器，可以使用账号内的资源，包括软件、硬件资源；同时，在协议升级后，客户端连接后可以使用本地的资源，包括本地打印机、声音本地回放、本地磁盘资源和本地硬件接口。
所有的计算都在服务器端进行，客户端只需要处理网络连接、接收数据、界面显示和设备数据输出。
国内基于RDP协议开发的虚拟化厂商有北京方物、西安瑞友天翼等。
2.ICA协议Citrix自己开发独有的ICA协议，Citrix将这种协议使用到其应用虚拟化产品与桌面虚拟化产品中。
CitrixICA具有平台独立的特性，它的不同模块使其很容易适应不同的客户端操作系统的需要，包括UNIX、Macintosh、Java和MS-DOS，而不需考虑用户的位置、客户端硬件设备或者可用带宽的限制，让多名用户得以共享同一台主机。
相对于传统RDP协议，ICA协议稳定性更好，支持各种类型的客户端设备，ICA协议能够支持音频、视频和多媒体带宽控制，在视频观看、Flash播放、3D设计等应用上，ICA的用户体验会很流畅。
3.PCoIP协议近年来VMware推出了其自有的PCoIP协议，用于提供高质量的虚拟桌面用户体验，目前已经成为最为流行的桌面虚拟化协议和标准。