0.准备工作&检查

显卡直通的前提条件是：

NVIDIA 独立显卡本身要具有视频输出功能
机身上至少有一个连接到独立显卡的视频接口
安装kvm虚拟机，具体步骤参照本博客archlinux安装或archlinux wiki

强烈建议阅读本文时参照下面几篇文章：
PCI_passthrough_via_OVMF_ARCHLINUX wiki
Optimus MUXed 笔记本上的 NVIDIA 虚拟机显卡直通
 vanities/GPU-Passthrough-Arch-Linux-to-Windows10 Public
KVM-GPU-Passthrough
Optimus笔记本虚拟机显卡直通 Linux低延遲在Windows虛擬機玩遊戲～ QEMU/KVM ＋ VFIO雙GPU直通＋ Looking Glass安裝過程

1.1开始

1.1隔离独显

1.1.1引导镜像的编辑

运行 lspci -nn | grep NVIDIA，获得类似如下输出,中括号里的八位是我们需要的

01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GA106M [GeForce RTX 3060 Mobile / Max-Q] [10de:2520] (rev a1)
01:00.1 Audio device [0403]: NVIDIA Corporation Device [10de:228e] (rev a1)

编辑或创建/etc/modprobe.d/vfio.conf，ids后面写上面得到的八位，并用逗号间隔(也可以添加内核参数 vfio-pci.ids=...)

options vfio-pci ids=10de:2520,10de:228e

修改/etc/mkinitcpio.conf，在MODULES里增加

vfio_pci vfio vfio_iommu_type1 vfio_virqfd

还需要确保/etc/mkinitcpio.conf之中有modconf
之后执行sudo mkinitcpio -P更新initramfs

1.1.2引导时内核参数的编辑

为了使iommu加载，还需要在引导选项中
修改/etc/default/grub
(注意：如果你是systemd-boot或者refind用户请自行编辑conf来应用内核参数)
对于intel用户：

GRUB_CMDLINE_LINUX_DEFAULT="quiet ... intel_iommu=on"

对于amd用户

GRUB_CMDLINE_LINUX_DEFAULT="quiet ... amd_iommu=on"

然后构建grub引导 sudo grub-mkconfig -o /boot/grub/grub.cfg

1.1.3重启后检查

运行lspci -nnk若输出中Kernel driver in use一行为vfio-pci则万事具备

01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GA106M [GeForce RTX 3060 Mobile / Max-Q] [10de:2520] (rev a1)
	DeviceName: NVIDIA Graphics Device
	Subsystem: Hewlett-Packard Company Device [103c:88d1]
	Kernel driver in use: vfio-pci
	Kernel modules: nouveau, nvidia_drm, nvidia
01:00.1 Audio device [0403]: NVIDIA Corporation Device [10de:228e] (rev a1)
	Subsystem: Hewlett-Packard Company Device [103c:88d1]
	Kernel driver in use: vfio-pci
	Kernel modules: snd_hda_intel

1.2准备一个虚拟机

之前文章已经说过了，在这不赘述了，在这里写一些可能遇到的问题

1.2.1 BIOS的选择

在bios上建议选择UEFI,对显卡的支持好一些
在安装前选择安装前配置，选择概览，芯片组选择Q35，固件选择/usr/share/edk2-ovmf/x64/OVMF_CODE.fd
接着进入安装windows,别忘了给windows打上virtio-win的驱动,再去红帽的spice-space下载spice-guest-tools

1.2.2 如果你已经给windows安装了上了传统legacy bios

进入windows,以管理员权限运行

mbr2gpt /convert /allowfullOS

之后将kvm的概览的xml中的os字段改为以下模样

<os>
    <type arch="x86_64" machine="pc-q35-6.2">hvm</type>
    <loader readonly="yes" type="pflash">/usr/share/edk2-ovmf/x64/OVMF_CODE.fd</loader>
    <nvram>/var/lib/libvirt/qemu/nvram/win10_VARS.fd</nvram>
    <boot dev="hd"/>
</os>

1.3 虚拟机上的操作

先不着急添加直通显卡，先进入虚拟机安装对应的显卡驱动，然后重启
在虚拟机上添加PCI主机设备把刚刚做过手脚的gpu选择上
不出意外的话重启你竟然发现原来丝滑的鼠标突然不能用了
已知的解决方法：

某宝购买kvm切换器，然后在 Virt-Manager 里选择添加硬件（Add Hardware） - USB 宿主设备（USB Host Device），选择你的鼠标键盘即可
Looking-glass或者scream,请自行参照官方文档安装配置
笔记本电脑有一套外接键鼠的话直接直通这一套键鼠，linux上使用触摸板和自带键盘

由于启用looking-glass低延迟桌面需要独立显卡有输出信号，所以你需要保持显卡外接了屏幕或者使用了显卡欺骗器

虚拟机性能优化

cpu 优化

在“CPUs”部分，将您的 CPU 型号更改为host-passthrough 然后打开手动设置CPU拓扑，保持套接字为1（这是为了让cpu能够减少内存交换的次数）

接下来hugepage(按照wiki的来我没有成功，谨慎尝试)

首先查看cat /proc/meminfo | grep Hugetlb 是否启用Hugepage，若Hugetlb 0kb代表没启用
sudo $EDITOR /etc/sysctl.d/99-kvm.conf
预留8GB RAM (1 hugepage = 2mb)给虚拟机，添加以下内容

vm.nr_hugepages=4096
vm.hugetlb_shm_group=48

编辑XML,在<memory></memory>里添加

<memoryBacking>
  <hugepages/>
</memoryBacking>

接下来是cpu固定，同样编辑XML,在<vcpu></vcpu>字段下面添加需要独占的核心

  <cputune>
    <vcpupin vcpu="0" cpuset="0"/>
    <vcpupin vcpu="1" cpuset="1"/>
    <vcpupin vcpu="2" cpuset="2"/>
    <vcpupin vcpu="3" cpuset="3"/>
  </cputune>

调整hyper-v设置，在<features></features>里添加

  <hyperv mode="custom">
      <relaxed state="on"/>
      <vapic state="on"/>
      <spinlocks state="on" retries="8191"/>
      <vpindex state="on"/>
      <runtime state="on"/>
      <synic state="on"/>
      <stimer state="on"/>
      <reset state="on"/>
      <vendor_id state="on" value="123456789123"/>
      <frequencies state="on"/>
  </hyperv>

io 优化

这里提两点：

进入“添加硬件”并为“VirtIO SCSI”型号的SCSI驱动器添加控制器
然后然后将默认 SATA 磁盘更改为SCSI磁盘，该磁盘将绑定到所述控制器。
如果你电脑的其他硬盘上有一个winodws系统你可以直接把这个硬盘给直通进来，并在启动选项里面选择它，你就不需要虚拟硬盘了！！！这样你就拥有了接近ssd原生的读写速度！

去虚拟化/游戏

这一节将会配置looking-glass的低延迟桌面，让windows不把kvm当虚拟机等等一些重要提升体验的配置

looking-glass

在它的官网下载Windows Host Binary到windows虚拟机里面并安装
接下来在你的宿主机上安装looking-glass的客户端，arch用户应该paru -S looking-glass
编辑XML,在<device></device>里添加

<devices>
  <shmem name='looking-glass'>
    <model type='ivshmem-plain'/>
    <size unit='M'>32</size>
  </shmem>
</devices>

因为looking-glass是用过tmpfs来实现低延迟串流的，所以编辑sudo $EDITOR /etc/tmpfiles.d/10-looking-glass.conf 注意：user应当改成你的用户名！

# Type       Path        Mode UID       GID Age Argument
f /dev/shm/looking-glass 0660 user    kvm -

添加解决没有音频输出的问题

sudo $EDITOR /etc/libvirt/qemu.conf,找到这一行：user = "user",把双引号里的user改为你的用户名
在XML<device>中添加

    <sound model="ich6">
      <codec type="micro"/>
      <audio id="1"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1b" function="0x0"/>
    </sound>
    <audio id="1" type="spice">
      <input mixingEngine="yes" fixedSettings="yes" voices="1" bufferLength="100">
        <settings frequency="44100" channels="2" format="s16"/>
      </input>
      <output mixingEngine="yes" fixedSettings="yes" voices="2" bufferLength="100">
        <settings frequency="44100" channels="4" format="f32"/>
      </output>
    </audio>

去虚拟化

启动windows在任务管理器的性能-cpu里面会发现虚拟化：是
这个时候需要编辑XML：

<cpu mode='host-passthrough' check='none'>
<topology sockets='1' cores='6' threads='2'/>
<feature policy='disable' name='hypervisor'/>
</cpu>

首先获取你的机器信息

sudo dmidecode --type bios
sudo dmidecode --type baseboard
sudo dmidecode --type system
sudo dmidecode --type chassis

然后根据bios,baseboard,system,chassis信息对照填入vendor,manufacturer等信息，如下：

<sysinfo type="smbios">
    <bios>
      <entry name="vendor">AMI</entry>
    </bios>
    <system>
      <entry name="manufacturer">HP</entry>
      <entry name="product">OMEN Laptop 15-en1xxx</entry>
    </system>
    <baseBoard>
      <entry name="manufacturer">HP</entry>
      <entry name="product">88D1</entry>
      <entry name="version">75.75</entry>
      <entry name="serial">EFEA34756QWE</entry>
    </baseBoard>
    <chassis>
      <entry name="manufacturer">HP</entry>
      <entry name="version">Chassis Version</entry>
      <entry name="serial">6AD2345FF74</entry>
      <entry name="asset">Not Specified</entry>
      <entry name="sku">Not Specified</entry>
    </chassis>
    <oemStrings>
      <entry>myappname:some arbitrary data</entry>
      <entry>otherappname:more arbitrary data</entry>
    </oemStrings>
  </sysinfo>
  <os firmware="efi">
  ...

我的完整配置：

<domain type="kvm">
  <name>win11</name>
  <uuid>9806182e-c6cd-4855-ba84-626d953e0bdf</uuid>
  <metadata>
    <libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0">
      <libosinfo:os id="http://microsoft.com/win/11"/>
    </libosinfo:libosinfo>
  </metadata>
  <memory unit="KiB">8388608</memory>
  <currentMemory unit="KiB">8388608</currentMemory>
  <vcpu placement="static">8</vcpu>
  <cputune>
    <vcpupin vcpu="0" cpuset="0"/>
    <vcpupin vcpu="1" cpuset="1"/>
    <vcpupin vcpu="2" cpuset="2"/>
    <vcpupin vcpu="3" cpuset="3"/>
    <vcpupin vcpu="4" cpuset="4"/>
    <vcpupin vcpu="5" cpuset="5"/>
    <vcpupin vcpu="6" cpuset="6"/>
    <vcpupin vcpu="7" cpuset="7"/>
  </cputune>
  <sysinfo type="smbios">
    <bios>
      <entry name="vendor">AMI</entry>
    </bios>
    <system>
      <entry name="manufacturer">HP</entry>
      <entry name="product">OMEN Laptop 15-en1xxx</entry>
    </system>
    <baseBoard>
      <entry name="manufacturer">HP</entry>
      <entry name="product">88D1</entry>
      <entry name="version">75.75</entry>
      <entry name="serial">EFEA34756QWE</entry>
    </baseBoard>
    <chassis>
      <entry name="manufacturer">HP</entry>
      <entry name="version">Chassis Version</entry>
      <entry name="serial">6AD2345FF74</entry>
      <entry name="asset">Not Specified</entry>
      <entry name="sku">Not Specified</entry>
    </chassis>
    <oemStrings>
      <entry>myappname:some arbitrary data</entry>
      <entry>otherappname:more arbitrary data</entry>
    </oemStrings>
  </sysinfo>
  <os firmware="efi">
    <type arch="x86_64" machine="pc-q35-8.0">hvm</type>
    <firmware>
      <feature enabled="no" name="enrolled-keys"/>
      <feature enabled="no" name="secure-boot"/>
    </firmware>
    <loader readonly="yes" type="pflash">/usr/share/edk2/x64/OVMF_CODE.fd</loader>
    <nvram template="/usr/share/edk2/x64/OVMF_VARS.fd">/var/lib/libvirt/qemu/nvram/win11_VARS.fd</nvram>
    <bootmenu enable="no"/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv mode="custom">
      <relaxed state="on"/>
      <vapic state="on"/>
      <spinlocks state="on" retries="8191"/>
      <vpindex state="on"/>
      <runtime state="on"/>
      <synic state="on"/>
      <stimer state="on"/>
      <reset state="on"/>
      <vendor_id state="on" value="123456789123"/>
      <frequencies state="on"/>
    </hyperv>
    <kvm>
      <hidden state="on"/>
    </kvm>
    <vmport state="off"/>
    <smm state="on"/>
    <ioapic driver="kvm"/>
  </features>
  <cpu mode="host-passthrough" check="none" migratable="on">
    <topology sockets="1" dies="1" cores="8" threads="1"/>
    <feature policy='disable' name='hypervisor'/>
  </cpu>
  <clock offset="localtime">
    <timer name="rtc" tickpolicy="catchup"/>
    <timer name="pit" tickpolicy="delay"/>
    <timer name="hpet" present="no"/>
    <timer name="hypervclock" present="yes"/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <pm>
    <suspend-to-mem enabled="no"/>
    <suspend-to-disk enabled="no"/>
  </pm>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <controller type="usb" index="0" model="qemu-xhci" ports="15">
      <address type="pci" domain="0x0000" bus="0x02" slot="0x00" function="0x0"/>
    </controller>
    <controller type="pci" index="0" model="pcie-root"/>
    <controller type="pci" index="1" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="1" port="0x10"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0" multifunction="on"/>
    </controller>
    <controller type="pci" index="2" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="2" port="0x11"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x1"/>
    </controller>
    <controller type="pci" index="3" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="3" port="0x12"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x2"/>
    </controller>
    <controller type="pci" index="4" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="4" port="0x13"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x3"/>
    </controller>
    <controller type="pci" index="5" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="5" port="0x14"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x4"/>
    </controller>
    <controller type="pci" index="6" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="6" port="0x15"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x5"/>
    </controller>
    <controller type="pci" index="7" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="7" port="0x16"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x6"/>
    </controller>
    <controller type="pci" index="8" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="8" port="0x17"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x7"/>
    </controller>
    <controller type="pci" index="9" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="9" port="0x18"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x0" multifunction="on"/>
    </controller>
    <controller type="pci" index="10" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="10" port="0x19"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x1"/>
    </controller>
    <controller type="pci" index="11" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="11" port="0x1a"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x2"/>
    </controller>
    <controller type="pci" index="12" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="12" port="0x1b"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x3"/>
    </controller>
    <controller type="pci" index="13" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="13" port="0x1c"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x4"/>
    </controller>
    <controller type="pci" index="14" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="14" port="0x1d"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x5"/>
    </controller>
    <controller type="pci" index="15" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="15" port="0x1e"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x6"/>
    </controller>
    <controller type="pci" index="16" model="pcie-to-pci-bridge">
      <model name="pcie-pci-bridge"/>
      <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
    </controller>
    <controller type="sata" index="0">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1f" function="0x2"/>
    </controller>
    <controller type="virtio-serial" index="0">
      <address type="pci" domain="0x0000" bus="0x03" slot="0x00" function="0x0"/>
    </controller>
    <interface type="network">
      <mac address="52:54:00:23:03:75"/>
      <source network="default"/>
      <model type="e1000e"/>
      <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
    </interface>
    <serial type="pty">
      <target type="isa-serial" port="0">
        <model name="isa-serial"/>
      </target>
    </serial>
    <console type="pty">
      <target type="serial" port="0"/>
    </console>
    <channel type="spicevmc">
      <target type="virtio" name="com.redhat.spice.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="1"/>
    </channel>
    <input type="mouse" bus="ps2"/>
    <input type="keyboard" bus="ps2"/>
    <tpm model="tpm-crb">
      <backend type="emulator" version="2.0"/>
    </tpm>
    <graphics type="spice" port="-1" autoport="no">
      <listen type="address"/>
      <image compression="off"/>
    </graphics>
    <sound model="ich6">
      <codec type="micro"/>
      <audio id="1"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1b" function="0x0"/>
    </sound>
    <audio id="1" type="spice">
      <input mixingEngine="yes" fixedSettings="yes" voices="1" bufferLength="100">
        <settings frequency="44100" channels="2" format="s16"/>
      </input>
      <output mixingEngine="yes" fixedSettings="yes" voices="2" bufferLength="100">
        <settings frequency="44100" channels="4" format="f32"/>
      </output>
    </audio>
    <video>
      <model type="qxl" ram="65536" vram="65536" vgamem="16384" heads="1" primary="yes"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0"/>
    </video>
    <hostdev mode="subsystem" type="pci" managed="yes">
      <source>
        <address domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
      </source>
      <address type="pci" domain="0x0000" bus="0x05" slot="0x00" function="0x0"/>
    </hostdev>
    <hostdev mode="subsystem" type="pci" managed="yes">
      <source>
        <address domain="0x0000" bus="0x01" slot="0x00" function="0x1"/>
      </source>
      <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
    </hostdev>
    <hostdev mode="subsystem" type="pci" managed="yes">
      <source>
        <address domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
      </source>
      <boot order="1"/>
      <address type="pci" domain="0x0000" bus="0x08" slot="0x00" function="0x0"/>
    </hostdev>
    <redirdev bus="usb" type="spicevmc">
      <address type="usb" bus="0" port="2"/>
    </redirdev>
    <watchdog model="itco" action="reset"/>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
    </memballoon>
    <shmem name="looking-glass">
      <model type="ivshmem-plain"/>
      <size unit="M">32</size>
      <address type="pci" domain="0x0000" bus="0x10" slot="0x01" function="0x0"/>
    </shmem>
  </devices>
</domain>

/etc/modprobe.d/kvm.conf

options iommu=pt amd_iommu=on   
options vfio-pci ids=10de:2520,10de:228e disable_vga=1
options kvm ignore_msrs=1 report_ignored_msrs=0
options vfio_iommu_type1 allow_unsafe_interrupts=1

0.准备工作&检查#

1.1开始#

1.1隔离独显#

1.1.1引导镜像的编辑#

1.1.2引导时内核参数的编辑#

1.1.3重启后检查#

1.2准备一个虚拟机#

1.2.1 BIOS的选择#

1.2.2 如果你已经给windows安装了上了传统legacy bios#

1.3 虚拟机上的操作#

虚拟机性能优化#

cpu 优化#

io 优化#

去虚拟化/游戏#

looking-glass#

添加解决没有音频输出的问题#

去虚拟化#

我的完整配置：#