Windows 10 qemu/kvm optimizations CPU usage #virt-manager

Windows-qemu-KVM.10.xml

<domain type="kvm">
  <!-- https://www.reddit.com/r/VFIO/comments/80p1q7/high_kvmqemu_cpu_utilization_when_windows_10/ -->

  <!-- https://github.com/duncanthrax/scream -->

  <!-- https://gitlab.com/YuriAlek/vfio -->
  <!-- https://github.com/PiMaker/Win10-VFIO -->
  <!-- https://gitlab.com/YuriAlek/vfio -->
  <!-- https://github.com/sk1080/nvidia-kvm-patcher -->
  <!-- https://github.com/T-vK/MobilePassThrough -->

  <!-- https://techrevelations.de/2019/01/27/kvm-qemu-selinux-and-shared-folders-in-fedora-29/ -->
  <!-- https://github.com/virt-manager/virt-manager/issues/127 -->

  <os>
    <type arch="x86_64" machine="pc-q35-5.0">hvm</type>
    <!-- ... -->
  </os>
  <!-- ... -->
  <features>
    <acpi/>
    <apic/>
    <hyperv>
      <relaxed state="on"/>
      <vapic state="on"/>
      <spinlocks state="on" retries="8191"/>
      <vpindex state="on"/>
      <runtime state="on"/>
      <synic state="on"/>
      <stimer state="on">
        <direct state="on"/>
      </stimer>
      <reset state="on"/>
      <vendor_id state="on" value="1234567890ab"/>
      <frequencies state="on"/>
      <ipi state="on"/>
      <evmcs state="on"/>
    </hyperv>
    <kvm>
      <hidden state="off"/>
    </kvm>
    <vmport state="off"/>
    <smm state="on"/>
  </features>

  <cpu mode="custom" match="exact" check="partial">
    <model fallback="allow">Skylake-Client-IBRS</model>
    <feature policy="require" name="ibpb"/>
    <feature policy="require" name="md-clear"/>
    <feature policy="require" name="spec-ctrl"/>
    <feature policy="require" name="ssbd"/>
  </cpu>

  <clock offset="localtime">
    <timer name="rtc" present="yes" tickpolicy="catchup" track="guest"/>
    <timer name="pit" present="yes" tickpolicy="delay"/>
    <timer name="hpet" present="no"/>
    <timer name="hypervclock" present="yes"/>
  </clock>

  <devices>
    <disk type="file" device="disk">
      <driver name="qemu" type="qcow2"/>
      <!--source file="...../win10.qcow2"/-->
      <target dev="vda" bus="virtio"/>
    </disk>

    <channel type="spicevmc">
      <target type="virtio" name="com.redhat.spice.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="1"/>
    </channel>

    <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>
    <redirdev bus="usb" type="spicevmc">
      <address type="usb" bus="0" port="2"/>
    </redirdev>
    <redirdev bus="usb" type="spicevmc">
      <address type="usb" bus="0" port="3"/>
    </redirdev>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x05" slot="0x00" function="0x0"/>
    </memballoon>

    <rng model="virtio">
      <backend model="random">/dev/urandom</backend>
      <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
    </rng>
    <panic model="hyperv"/>
  </devices>

</domain>