我已经设置了一个带有 NVIDIA 显卡直通的虚拟机，在安装了必要的驱动程序后，LightDM 会话没有启动（我可以看到欢迎程序，但用户会话没有启动）。
该机器在 libvirt 中的 XML 定义如下：
<domain type='kvm' id='8' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
<name>Ubuntu</name>
<uuid>63f0800e-73f8-27ac-59a0-791fc68f7e25</uuid>
<description>None</description>
<memory unit='KiB'>4194304</memory>
<currentMemory unit='KiB'>4194304</currentMemory>
<vcpu placement='static'>2</vcpu>
<resource>
<partition>/machine</partition>
</resource>
<os>
<type arch='x86_64' machine='pc-i440fx-xenial'>hvm</type>
<boot dev='hd'/>
<boot dev='cdrom'/>
<bootmenu enable='yes'/>
</os>
<features>
<acpi/>
<apic/>
<pae/>
</features>
<cpu mode='host-passthrough'>
<topology sockets='1' cores='2' threads='1'/>
<feature policy='require' name='abm'/>
<feature policy='require' name='pdpe1gb'/>
<feature policy='require' name='rdrand'/>
<feature policy='require' name='f16c'/>
<feature policy='require' name='osxsave'/>
<feature policy='require' name='pdcm'/>
<feature policy='require' name='xtpr'/>
<feature policy='require' name='tm2'/>
<feature policy='require' name='est'/>
<feature policy='require' name='vmx'/>
<feature policy='require' name='ds_cpl'/>
<feature policy='require' name='monitor'/>
<feature policy='require' name='dtes64'/>
<feature policy='require' name='pbe'/>
<feature policy='require' name='tm'/>
<feature policy='require' name='ht'/>
<feature policy='require' name='ss'/>
<feature policy='require' name='acpi'/>
<feature policy='require' name='ds'/>
<feature policy='require' name='vme'/>
</cpu>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<devices>
<emulator>/usr/bin/kvm-spice</emulator>
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2'/>
<source file='/virtualstorage/vms/Ubuntu.img'/>
<backingStore/>
<target dev='vda' bus='virtio'/>
<alias name='virtio-disk0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='qemu' type='raw'/>
<source file='/virtualstorage/iso/ubuntu-16.04.1-desktop-amd64.iso'/>
<backingStore/>
<target dev='hda' bus='ide'/>
<readonly/>
<alias name='ide0-1-1'/>
<address type='drive' controller='0' bus='1' target='0' unit='1'/>
</disk>
<controller type='ide' index='0'>
<alias name='ide'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
</controller>
<controller type='usb' index='0'>
<alias name='usb'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
</controller>
<controller type='pci' index='0' model='pci-root'>
<alias name='pci.0'/>
</controller>
<interface type='network'>
<mac address='52:54:00:40:2b:aa'/>
<source network='default' bridge='virbr0'/>
<target dev='vnet0'/>
<model type='virtio'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>
<serial type='pty'>
<source path='/dev/pts/0'/>
<target port='0'/>
<alias name='serial0'/>
</serial>
<console type='pty' tty='/dev/pts/0'>
<source path='/dev/pts/0'/>
<target type='serial' port='0'/>
<alias name='serial0'/>
</console>
<input type='tablet' bus='usb'>
<alias name='input0'/>
</input>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<graphics type='vnc' port='5900' autoport='yes' listen='0.0.0.0'>
<listen type='address' address='0.0.0.0'/>
</graphics>
<video>
<model type='cirrus' vram='16384' heads='1'/>
<alias name='video0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
</video>
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</source>
<alias name='hostdev0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0' multifunction='on'/>
</hostdev>
<hostdev mode='subsystem' type='pci' managed='yes'>
<driver name='vfio'/>
<source>
<address domain='0x0000' bus='0x01' slot='0x00' function='0x1'/>
</source>
<alias name='hostdev1'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x1'/>
</hostdev>
<memballoon model='none'>
<alias name='balloon0'/>
</memballoon>
</devices>
<qemu:commandline>
<qemu:arg value='-vga'/>
<qemu:arg value='none'/>
</qemu:commandline>
</domain>
安装的 NVIDIA 驱动程序是 NVIDIA-Linux-x86_64-367.57。
dmesg | grep -i NVIDIA:
[ 1.263194] nvidia: module license 'NVIDIA' taints kernel.
[ 1.266276] nvidia: module verification failed: signature and/or required key missing - tainting kernel
[ 1.330297] nvidia-nvlink: Nvlink Core is being initialized, major device number 247
[ 1.330312] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 367.57 Mon Oct 3 20:37:01 PDT 2016
[ 1.407850] nvidia-modeset: Loading NVIDIA Kernel Mode Setting Driver for UNIX platforms 367.57 Mon Oct 3 20:32:57 PDT 2016
[ 1.424992] [drm] [nvidia-drm] [GPU ID 0x00000006] Loading driver
[ 2.078662] input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:06.1/sound/card0/input6
[ 2.078733] input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:06.1/sound/card0/input7
[ 2.078794] input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:06.1/sound/card0/input8
[ 2.078832] input: HDA NVidia HDMI/DP,pcm=9 as /devices/pci0000:00/0000:00:06.1/sound/card0/input9
提前致谢。