GCC9.2/Python3.8/Libvirt6.0/QEMU4.2 编译/配置/安装

待我称王封你为后i 2023-07-05 10:27 4阅读 0赞

### 文章目录 ###

*  安装CentOS系统
 *   *  安装GCC 4.8
     *  安装wget/bzip2
 *  编译安装GCC 9.2
 *   *  卸载GCC4.8版本
 *  编译安装Python3
 *   *  获取configure时的设定参数
 *  安装Libvirt的依赖包
 *  下载libvirt源代码
 *  Libvirt 编译配置选项
 *  编译安装Libvirt
 *   *  检查Libvirt命令都链接到正确的动态库
 *  配置libvirt服务
 *   *  启用virtlogd服务
     *  启动virtlogd服务
     *  启用/启动virtlockd服务
     *  启用/启动libvirtd服务
     *  创建到/var/run/libvirt的软链接
     *  libvirt capabilities
 *  编译安装QEMU 4.2
 *   *  libvirt capabilities with QEMU
     *  使用QEMU
     *   *  启用KVM

# 安装CentOS系统 #

$ cat /etc/redhat-release
    CentOS Linux release 7.5.1804 (Core)
    
    $ uname -a
    Linux centos7 3.10.0-862.el7.x86_64 #1 SMP Fri Apr 20 16:44:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

## 安装GCC 4.8 ##

这个版本的编译器不适合编译Python3.8，在编译时会产生如下的错误。我们用这个老版本编译器编译一个新的GCC 9.2版。

Could not import runpy module
    Traceback (most recent call last):
      File "Python-3.8.1/Lib/runpy.py", line 15, in <module>
        import importlib.util
      File "Python-3.8.1/Lib/importlib/util.py", line 14, in <module>
        from contextlib import contextmanager
      File "Python-3.8.1/Lib/contextlib.py", line 4, in <module>
        import _collections_abc
    SystemError: <built-in function compile> returned NULL without setting an error
    generate-posix-vars failed
    make[1]: *** [pybuilddir.txt] Error 1
    make[1]: Leaving directory `Python-3.8.1'
    make: *** [profile-opt] Error 2

$ sudo yum install -y gcc
    $ sudo yum install -y gcc-c++
    
    $ gcc -v
    Using built-in specs.
    COLLECT_GCC=gcc
    ...
    Thread model: posix
    gcc version 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC)
    
    $ c++ --version
    c++ (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39)
    Copyright (C) 2015 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions.  There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

## 安装wget/bzip2 ##

# wget用于下载源代码
    $ sudo yum install -y wget
    
    # bzip2 用于解压
    $ sudo yum install -y bzip2

# 编译安装GCC 9.2 #

$ wget https://ftp.gnu.org/gnu/gcc/gcc-9.2.0/gcc-9.2.0.tar.xz
    $ tar xvf gcc-9.2.0.tar.xz
    $ cd gcc-9.2.0
    $ ./contrib/download_prerequisites
    
    $ mkdir build && cd build
    $ ../configure --prefix=/usr/local --disable-multilib --enable-languages=c,c++
    $ make && sudo make install
    
    $ /usr/local/bin/gcc --version
    gcc (GCC) 9.2.0
    Copyright (C) 2019 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions.  There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    
    $ /usr/local/bin/gcc -v
    Using built-in specs.
    COLLECT_GCC=gcc
    COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-pc-linux-gnu/9.2.0/lto-wrapper
    Target: x86_64-pc-linux-gnu
    Configured with: ../configure --prefix=/usr/local --disable-multilib --enable-languages=c,c++
    Thread model: posix
    gcc version 9.2.0 (GCC)
    
    # 有些程序会调用cc，将cc软链接到gcc
    $ cd /usr/local/bin
    $ sudo ln -sf gcc cc
    $ ls -l cc
    lrwxrwxrwx. 1 root root 3 Feb 14 02:45 cc -> gcc
    
    # c++编译器版本
    $ /usr/local/bin/g++ -v
    Using built-in specs.
    COLLECT_GCC=g++
    COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-pc-linux-gnu/9.2.0/lto-wrapper
    Target: x86_64-pc-linux-gnu
    Configured with: ../configure --prefix=/usr/local --disable-multilib --enable-languages=c,c++
    Thread model: posix
    gcc version 9.2.0 (GCC)

## 卸载GCC4.8版本 ##

# 赤裸裸的新颜换旧人
    $ sudo yum remove gcc

# 编译安装Python3 #

`注意：`gcc 4.8.5不适用于编译Python3.8，但是可以编译Python 3.7。  
我们使用GCC9.2来编译Python3.8。

$ wget https://www.python.org/ftp/python/3.8.1/Python-3.8.1.tar.xz
    $ tar xvf Python-3.8.1.tar.xz
    $ cd Python-3.8.1
    
    # 安装Python依赖的包
    $ sudo yum install -y sqlite-devel tcl-devel tk-devel
    $ sudo yum install -y openssl-devel
    $ sudo yum install -y libcurl-devel
    $ sudo yum install -y zlib zlib-devel
    $ sudo yum install -y bzip2-devel
    $ sudo yum install -y ncurses-devel
    $ sudo yum install -y gdbm-devel
    $ sudo yum install -y readline-devel
    $ sudo yum --enablerepo="PowerTools" install -y bluez-libs-devel      
    $ sudo yum --enablerepo="PowerTools" install -y tix-devel       
    $ sudo yum install -y valgrind-devel
    $ sudo dnf install -y libffi-devel
    $ sudo dnf --enablerepo="PowerTools" install -y libnsl2-devel
    $ sudo dnf install -y xz-devel
    
    # 配置Python3 编译 Makefile
    $ ./configure --prefix=/usr/local --enable-optimizations --enable-shared --enable-ipv6
    
    # 编译并安装Python3
    $ make && sudo make install
    
    # 检查Python版本
    $ which python3
    /usr/local/bin/python3
    
    # 找不到动态链接库
    $ python3 --version
    python3: error while loading shared libraries: libpython3.8.so.1.0: cannot open shared object file: No such file or directory
    
    # 搜索一下libpython动态库
    $ find /usr/local -name "libpython3.8.so.1.0"
    /usr/local/lib/libpython3.8.so.1.0
    
    # 把/usr/local/lib加到库搜索目录中
    $ cd /etc/ld.so.conf.d/
    $ ls
    kernel-3.10.0-862.el7.x86_64.conf  mariadb-x86_64.conf  tix-x86_64.conf
    
    # 创建一个新的.conf文件，内容是/usr/local/lib目录
    $ sudo su -c "echo /usr/local/lib > local_lib-x86_64.conf"
    
    $ ls
    kernel-3.10.0-862.el7.x86_64.conf  local_lib-x86_64.conf  mariadb-x86_64.conf  tix-x86_64.conf
    
    $ cat local_lib-x86_64.conf
    /usr/local/lib
    
    # 刷新一下库搜索路径的缓存
    $ sudo ldconfig
    
    # python3可以正确执行了
    $ python3 --version
    Python 3.8.1
    
    # 确认正确地链接到libpython3.8.so.1.0动态库
    $ cd /usr/local/bin
    $ ldd python3
            linux-vdso.so.1 =>  (0x00007ffe533f9000)
            libpython3.8.so.1.0 => /usr/local/lib/libpython3.8.so.1.0 (0x00007fb1304c1000)
            libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007fb13028a000)
            libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fb13006e000)
            libdl.so.2 => /lib64/libdl.so.2 (0x00007fb12fe6a000)
            libutil.so.1 => /lib64/libutil.so.1 (0x00007fb12fc67000)
            libm.so.6 => /lib64/libm.so.6 (0x00007fb12f965000)
            libc.so.6 => /lib64/libc.so.6 (0x00007fb12f597000)
            libfreebl3.so => /lib64/libfreebl3.so (0x00007fb12f394000)
            /lib64/ld-linux-x86-64.so.2 (0x00007fb130ae4000)

## 获取configure时的设定参数 ##

$ python3 -c "import sysconfig; print(sysconfig.get_config_var('CONFIG_ARGS'))"

`'--prefix=/usr/local' '--enable-optimizations' '--enable-shared'`

# 安装Libvirt的依赖包 #

从源代码编译libvirt需要安装大量依赖的包。下面这些包是成功编译完libvirt后从我的机器上列取出来的，有些包是Python3依赖的，不想细区别了。

$ sudo yum install -y apr-devel apr-util-devel atk-devel bzip2-devel cairo-devel 
    $ sudo yum install -y cairo-gobject-devel cyrus-sasl-devel device-mapper-devel 
    $ sudo yum install -y elfutils-libelf-devel expat-devel fontconfig-devel 
    $ sudo yum install -y freetype-devel fribidi-devel gdbm-devel gdk-pixbuf2-devel 
    $ sudo yum install -y glib2-devel glibc-devel gmp-devel gnutls-devel 
    $ sudo yum install -y gobject-introspection-devel graphite2-devel gtk2-devel 
    $ sudo yum install -y harfbuzz-devel httpd-devel keyutils-libs-devel krb5-devel 
    $ sudo yum install -y libX11-devel libXau-devel libXcomposite-devel 
    $ sudo yum install -y libXcursor-devel libXdamage-devel libXext-devel 
    $ sudo yum install -y libXfixes-devel libXft-devel libXi-devel libXinerama-devel 
    $ sudo yum install -y libXrandr-devel libXrender-devel libXxf86vm-devel 
    $ sudo yum install -y libcom_err-devel libcurl-devel libdb-devel libdrm-devel 
    $ sudo yum install -y libevent-devel libffi-devel libgcrypt-devel 
    $ sudo yum install -y libglvnd-core-devel libglvnd-devel libgpg-error-devel 
    $ sudo yum install -y libicu-devel libjpeg-turbo-devel libnl3-devel 
    $ sudo yum install -y libpciaccess-devel libpng-devel libselinux-devel
    $ sudo yum install -y libsepol-devel libstdc++-devel libtasn1-devel 
    $ sudo yum install -y libuuid-devel libva-devel libverto-devel libvirt-devel 
    $ sudo yum install -y libxcb-devel libxml2-devel libxslt-devel libyaml-devel 
    $ sudo yum install -y mariadb-devel 
    $ sudo yum install -y mesa-khr-devel mesa-libEGL-devel mesa-libGL-devel 
    $ sudo yum install -y ncurses-devel nettle-devel numactl-devel
    $ sudo yum install -y openldap-devel openssl-devel p11-kit-devel pango-devel 
    $ sudo yum install -y pcre-devel perl-devel pixman-devel postgresql-devel 
    $ sudo yum install -y python-devel readline-devel sqlite-devel 
    $ sudo yum install -y systemd-devel systemtap-sdt-devel
    $ sudo yum install -y tcl-devel tk-devel wayland-devel 
    $ sudo yum install -y xorg-x11-proto-devel.noarch xz-devel yajl-devel zlib-devel
    
    # for rst2xml and rst2html command
    $ sudo yum install -y python-docutils

# 下载libvirt源代码 #

$ wget https://libvirt.org/sources/libvirt-6.0.0.tar.xz
    $ tar xvf libvirt-6.0.0.tar.xz
    $ cd libvirt-6.0.0

# Libvirt 编译配置选项 #

`注意：`libvirt编译需要Python3。

$ mkdir build && cd build
    $ ../configure --prefix=/usr/local --enable-debug=yes --with-numactl
    ...
    configure:               DTrace: yes
    configure:                numad: no
    configure:          Init script: systemd
    configure:    Char device locks: /var/lock
    configure:       Default Editor: vi
    configure:         Loader/NVRAM:
    configure:     virt-login-shell: yes
    configure:   virt-host-validate: yes
    configure:         TLS priority: NORMAL
    configure:
    configure: Developer Tools
    configure:
    configure:  wireshark_dissector: no
    configure:
    configure: Privileges
    configure:
    configure:    QEMU: root:root (!!! running QEMU as root is strongly discouraged !!!)
    configure:

# 编译安装Libvirt #

如果幸运的话，一次编译就能成功。

$ make
    
    # 在/usr/bin下创建一个/usr/local/bin/gcc的软链接
    # 否则在make install的时候会失败 - 提示无法找到 gcc。
    # 错误信息:
    # libvirt-6.0.0/build/libtool: line 10536: gcc: command not found
    # libtool: error: error: relink 'libvirt-qemu.la' with the above command 
    # before installing it
    # make[3]: *** [install-libLTLIBRARIES] Error 1
    # make[3]: Leaving directory `libvirt-6.0.0/build/src'
    # make[2]: *** [install-am] Error 2
    # make[2]: Leaving directory `libvirt-6.0.0/build/src'
    # make[1]: *** [install] Error 2
    # make[1]: Leaving directory `libvirt-6.0.0/build/src'
    # make: *** [install-recursive] Error 1
    $ sudo ln -s /usr/local/bin/gcc /usr/bin/
    $ sudo make install
    
    # 安装完毕后务必执行以下命令，更新动态库搜索路径, 否则libvirtd服务可能会启动失败
    $ sudo ldconfig

## 检查Libvirt命令都链接到正确的动态库 ##

$ ldd /usr/local/sbin/virtlogd
            linux-vdso.so.1 =>  (0x00007fffae1da000)
            libvirt.so.0 => /usr/local/lib/libvirt.so.0 (0x00007f5951241000)
            libm.so.6 => /lib64/libm.so.6 (0x00007f5950f3f000)
    		...
    
    $ ldd /usr/local/sbin/virtlockd
            linux-vdso.so.1 =>  (0x00007ffe67849000)
            libvirt.so.0 => /usr/local/lib/libvirt.so.0 (0x00007efe9ad75000)
    		...
    		
    $ ldd /usr/local/sbin/libvirtd
            linux-vdso.so.1 =>  (0x00007ffecdfef000)
            libvirt-lxc.so.0 => /usr/local/lib/libvirt-lxc.so.0 (0x00007f2eb2e3e000)
            libvirt-qemu.so.0 => /usr/local/lib/libvirt-qemu.so.0 (0x00007f2eb2c3a000)
            libvirt.so.0 => /usr/local/lib/libvirt.so.0 (0x00007f2eb2608000)
            ...

# 配置libvirt服务 #

## 启用virtlogd服务 ##

$ sudo systemctl enable virtlogd
    Created symlink from /etc/systemd/system/sockets.target.wants/virtlogd.socket to /usr/local/lib/systemd/system/virtlogd.socket.

这个命令将virtlogd.service注册到systemd中，然后创建一个辅助的socket软链接。

## 启动virtlogd服务 ##

$ sudo systemctl start virtlogd

`以下内容为猜测`  
查看一下 virtlogd.service的unit定义文件

$ sudo systemctl cat virtlogd
    # /usr/local/lib/systemd/system/virtlogd.service
    [Unit]
    Description=Virtual machine log manager
    Requires=virtlogd.socket
    Requires=virtlogd-admin.socket
    ...
    
    [Service]
    EnvironmentFile=-/usr/local/etc/sysconfig/virtlogd
    ExecStart=/usr/local/sbin/virtlogd $VIRTLOGD_ARGS
    ExecReload=/bin/kill -USR1 $MAINPID
    ...
    LimitNOFILE=16384
    
    [Install]
    Also=virtlogd.socket

从这个文件中可以看出：

1.  \[unit\]一节的设定，virtlogd.service 服务还需要virtlogd.socket和virtlogd-admin.socket这两个辅助socket类型的unit。所以注册virtlogd.service时，同时将virtlogd.socket与virtlogd-admin.socket一起注册到systemd。

$ sudo systemctl | grep virtlogd
    virtlogd.service      loaded active running   Virtual machine log manager
    virtlogd-admin.socket loaded active running   Virtual machine log manager socket
    virtlogd.socket       loaded active running   Virtual machine log manager socket

1.  \[Install\]节的设定，还需要注册并安装virtlogd.socket — systemd创建了一个软链接。注意：并没有创建到virtlogd-admin.socket的软链接；可能是因为它不在\[Install\]节中。

$ find /etc/systemd -name "virtlogd*" -exec ls -l { } \;
    lrwxrwxrwx. 1 root root 45 Feb 14 03:41 /etc/systemd/system/sockets.target.wants/virtlogd.socket -> /usr/local/lib/systemd/system/virtlogd.socket

1.  当virtlogd服务运行后，在/usr/local/var/run/libvirt目录会创建两个socket文件。这两个文件是由virtlogd.socket和virtlogd-admin.socket创建的。

$ ls -l /usr/local/var/run/libvirt/virtlogd*
    srw-------. 1 root root 0 Feb 14 03:48 /usr/local/var/run/libvirt/virtlogd-admin-sock
    srw-------. 1 root root 0 Feb 14 03:48 /usr/local/var/run/libvirt/virtlogd-sock

1.  查看一下virtlogd-admin.socket的unit定义文件。可以看到virtlogd-admin-sock文件的位置以及关联的服务。

$ sudo systemctl cat virtlogd-admin.socket
    # /usr/local/lib/systemd/system/virtlogd-admin.socket
    [Unit]
    Description=Virtual machine log manager socket
    Before=libvirtd.service
    BindsTo=virtlogd.socket
    After=virtlogd.socket
    
    [Socket]
    ListenStream=/usr/local/var/run/libvirt/virtlogd-admin-sock
    Service=virtlogd.service
    SocketMode=0600
    
    [Install]
    WantedBy=sockets.target

## 启用/启动virtlockd服务 ##

$ sudo systemctl enable virtlockd
    Created symlink from /etc/systemd/system/sockets.target.wants/virtlockd.socket to /usr/local/lib/systemd/system/virtlockd.socket.
    
    $ sudo systemctl start virtlockd

$ sudo systemctl status virtlockd
    ● virtlockd.service - Virtual machine lock manager
       Loaded: loaded (/usr/local/lib/systemd/system/virtlockd.service; indirect; vendor preset: disabled)
       Active: active (running) since Fri 2020-02-14 04:15:15 EST; 5s ago
         Docs: man:virtlockd(8)
               https://libvirt.org
     Main PID: 5680 (virtlockd)
        Tasks: 1
       CGroup: /system.slice/virtlockd.service
               └─5680 /usr/local/sbin/virtlockd
    
    Feb 14 04:15:15 centos7 systemd[1]: Started Virtual machine lock manager.

## 启用/启动libvirtd服务 ##

$ sudo systemctl enable libvirtd
    Created symlink from /etc/systemd/system/multi-user.target.wants/libvirtd.service to /usr/local/lib/systemd/system/libvirtd.service.
    Created symlink from /etc/systemd/system/sockets.target.wants/libvirtd.socket to /usr/local/lib/systemd/system/libvirtd.socket.
    Created symlink from /etc/systemd/system/sockets.target.wants/libvirtd-ro.socket to /usr/local/lib/systemd/system/libvirtd-ro.socket.
    
    $ sudo systemctl start libvirtd
    
    $ systemctl | grep libvirtd
    libvirtd.service       loaded active running   Virtualization daemon
    libvirtd-admin.socket  loaded active running   Libvirt admin socket
    libvirtd-ro.socket     loaded active running   Libvirt local read-only socket
    libvirtd.socket        loaded active running   Libvirt local socket
    
    $ pwd
    /usr/local/var/run/libvirt
    $ ls -l *sock
    srw-------. 1 root root 0 Feb 14 04:28 libvirt-admin-sock
    srw-rw-rw-. 1 root root 0 Feb 14 04:28 libvirt-sock
    srw-------. 1 root root 0 Feb 14 04:15 virtlockd-admin-sock
    srw-------. 1 root root 0 Feb 14 04:15 virtlockd-sock
    srw-------. 1 root root 0 Feb 14 03:48 virtlogd-admin-sock
    srw-------. 1 root root 0 Feb 14 03:48 virtlogd-sock

## 创建到/var/run/libvirt的软链接 ##

有些程序在与libvirt通信时，似乎只会到/var/run/libvirt目录下找那些socket文件。  
这样就需要在/var/run目录下创建一个到/usr/loca/var/run/libvirt目录的软链接 `“欺骗”`一下这些蠢程序。

$ sudo ln -s /usr/local/var/run/libvirt /var/run

## libvirt capabilities ##

因为没有安装qemu，`virsh capabilities`显示不出emulator信息，此时也就不能创建虚拟机。

$ which virsh
    /usr/local/bin/virsh
    
    $ virsh --version
    6.0.0
    
    $ virsh capabilities
    <capabilities>
    
      <host>
        <uuid>b78de1f0-ab44-4c08-9171-46bbb78f0c21</uuid>
        <cpu>
          <arch>x86_64</arch>
          <model>Haswell-noTSX-IBRS</model>
          <vendor>Intel</vendor>
          <microcode version='37'/>
          <counter name='tsc' frequency='3499997000'/>
          <topology sockets='1' cores='4' threads='1'/>
          <feature name='vme'/>
    	  ...
          <feature name='invtsc'/>
          <pages unit='KiB' size='4'/>
          <pages unit='KiB' size='2048'/>
          <pages unit='KiB' size='1048576'/>
        </cpu>
        <power_management/>
        <iommu support='no'/>
        <migration_features>
          <live/>
          <uri_transports>
            <uri_transport>tcp</uri_transport>
            <uri_transport>rdma</uri_transport>
          </uri_transports>
        </migration_features>
        <topology>
          <cells num='1'>
            <cell id='0'>
              <memory unit='KiB'>12713396</memory>
              <pages unit='KiB' size='4'>3178349</pages>
              <pages unit='KiB' size='2048'>0</pages>
              <pages unit='KiB' size='1048576'>0</pages>
              <distances>
                <sibling id='0' value='10'/>
              </distances>
              <cpus num='4'>
                <cpu id='0' socket_id='0' core_id='0' siblings='0'/>
                <cpu id='1' socket_id='0' core_id='1' siblings='1'/>
                <cpu id='2' socket_id='0' core_id='2' siblings='2'/>
                <cpu id='3' socket_id='0' core_id='3' siblings='3'/>
              </cpus>
            </cell>
          </cells>
        </topology>
        <cache>
          <bank id='0' level='3' type='both' size='8' unit='MiB' cpus='0-3'/>
        </cache>
        <secmodel>
          <model>selinux</model>
          <doi>0</doi>
          <baselabel type='kvm'>system_u:system_r:svirt_t:s0</baselabel>
          <baselabel type='qemu'>system_u:system_r:svirt_tcg_t:s0</baselabel>
        </secmodel>
      </host>
    
    </capabilities>

# 编译安装QEMU 4.2 #

# Install dependent packages
    $ sudo yum install -y gtk3-devel
    $ sudo yum install -y spice-server spice-protocol spice-server-devel
    
    
    $ wget https://download.qemu.org/qemu-4.2.0.tar.xz
    $ tar xvf qemu-4.2.0.tar.xz
    $ cd qemu-4.2.0
    $ mkdir build && cd build
    $ CC=gcc ../configure --prefix=/usr/local --target-list=x86_64-softmmu --enable-vnc --enable-gtk --enable-kvm --enable-numa --enable-tools --enable-spice
    $ make && sudo make install
    
    $ which qemu-system-x86_64
    /usr/local/bin/qemu-system-x86_64
    
    $ qemu-system-x86_64 --version
    QEMU emulator version 4.2.0
    Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers

## libvirt capabilities with QEMU ##

$ sudo /usr/local/bin/virsh capabilities | grep emulator
          <emulator>/usr/local/bin/qemu-system-alpha</emulator>
          <emulator>/usr/local/bin/qemu-system-arm</emulator>
          <emulator>/usr/local/bin/qemu-system-arm</emulator>
          <emulator>/usr/local/bin/qemu-system-aarch64</emulator>
          <emulator>/usr/local/bin/qemu-system-cris</emulator>
          <emulator>/usr/local/bin/qemu-system-i386</emulator>
          <emulator>/usr/local/bin/qemu-system-lm32</emulator>
          <emulator>/usr/local/bin/qemu-system-m68k</emulator>
          <emulator>/usr/local/bin/qemu-system-microblaze</emulator>
          <emulator>/usr/local/bin/qemu-system-microblazeel</emulator>
          <emulator>/usr/local/bin/qemu-system-ppc</emulator>
          <emulator>/usr/local/bin/qemu-system-ppc64</emulator>
          <emulator>/usr/local/bin/qemu-system-ppc64</emulator>
          <emulator>/usr/local/bin/qemu-system-riscv32</emulator>
          <emulator>/usr/local/bin/qemu-system-riscv64</emulator>
          <emulator>/usr/local/bin/qemu-system-s390x</emulator>
          <emulator>/usr/local/bin/qemu-system-sh4</emulator>
          <emulator>/usr/local/bin/qemu-system-sh4eb</emulator>
          <emulator>/usr/local/bin/qemu-system-sparc</emulator>
          <emulator>/usr/local/bin/qemu-system-sparc64</emulator>
          <emulator>/usr/local/bin/qemu-system-unicore32</emulator>
          <emulator>/usr/local/bin/qemu-system-x86_64</emulator>
          <emulator>/usr/local/bin/qemu-system-xtensa</emulator>
          <emulator>/usr/local/bin/qemu-system-xtensaeb</emulator>

## 使用QEMU ##

# 下载cirros image文件
    $ wget http://download.cirros-cloud.net/0.4.0/cirros-0.4.0-x86_64-disk.img
    $ qemu-system-x86_64 ./cirros-0.4.0-x86_64-disk.img
    VNC server running on ::1:5900
    $ vncviewer localhost:0

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDAxODA4_size_16_color_FFFFFF_t_70]

### 启用KVM ###

执行`qemu-system-x86_64`命令时，加上`-enable-kvm`可以启用KVM。

# 如果这个命令失败，提示 权限不足(permission denied)，参看下注。
    $ qemu-system-x86_64 -enable-kvm ./cirros-0.4.0-x86_64-disk.img
    VNC server running on ::1:5900

`注：可以检查 /dev/kvm的文件权限设置，并将其改成666（此时没有考虑安全性）`

$ ls -l /dev/kvm
    crw-------+ 1 root root 10, 232 Feb 21 00:01 /dev/kvm
    
    $ sudo chmod 666 /dev/kvm
    
    $ ls -l /dev/kvm
    crw-rw-rw-+ 1 root root 10, 232 Feb 21 00:01 /dev/kvm

在VNC控制台中，键入<CTRL+ALT>+2，可以切换到QEMU命令行窗口，输入`info kvm`可以看到 `kvm support: enabled`，说明已经启用KVM了。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDAxODA4_size_16_color_FFFFFF_t_70 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDAxODA4_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/2020022112571924.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDAxODA4,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDAxODA4_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200221130055185.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQzNDAxODA4,size_16,color_FFFFFF,t_70