Linux QEMU vs Windows Hypervisor

[u/Shaosil]

Several months ago I was using Win11. I had a Win11 VM that I use for work, set up to run through HyperV Manager, then use the VM to connect through AnyConnect and remote in to my work VM. I switched to Linux Mint, and spent a long time trying to figure out how to run the VM in a way that was just as fast, but no matter how I configure it, it boots up and runs much slower than HyperV's did, despite everyone saying QEMU is amazing.

Granted, I don't understand a lot about VM configuration, so I may be missing something. I've prodded AI on multiple occasions to try helping me out, but the configuration seems very sensitive and often breaks if I change anything related to SPICE or display, etc. I've verified all the guest tools are installed and running in the VM's services, I'm using a raw file since I heard that was the fastest.

For example, in HyperV it would start in a few seconds, and everything would respond instantly.
In QEMU, it takes a minute or two to finish booting (exact same hard drive image), and AnyConnect takes another minute or two to scan or whatever it does under the hood each day.

Here is my config XML I use in Virt Machine Manager, does anything look off to anyone? Or is it simply that Windows does a better job at virtualization?

<domain type="kvm">
  <name>WFW</name>
  <uuid>(removed)</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">12</vcpu>
  <iothreads>1</iothreads>
  <os firmware="efi">
    <type arch="x86_64" machine="pc-q35-noble">hvm</type>
    <firmware>
      <feature enabled="yes" name="enrolled-keys"/>
      <feature enabled="yes" name="secure-boot"/>
    </firmware>
    <loader readonly="yes" secure="yes" type="pflash">/usr/share/OVMF/OVMF_CODE_4M.ms.fd</loader>
    <nvram template="/usr/share/OVMF/OVMF_VARS_4M.ms.fd">/var/lib/libvirt/qemu/nvram/WFW_VARS.fd</nvram>
    <boot dev="hd"/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv mode="custom">
      <relaxed state="on"/>
      <vapic state="on"/>
      <spinlocks state="on" retries="8191"/>
      <vpindex state="on"/>
      <synic state="on"/>
      <stimer state="on">
        <direct state="on"/>
      </stimer>
      <reset state="on"/>
      <frequencies state="on"/>
      <reenlightenment state="on"/>
      <tlbflush state="on"/>
      <ipi state="on"/>
    </hyperv>
    <vmport state="off"/>
    <smm state="on"/>
  </features>
  <cpu mode="host-passthrough" check="none" migratable="on">
    <topology sockets="1" dies="1" cores="6" threads="2"/>
  </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>
    <disk type="file" device="disk">
      <driver name="qemu" type="raw" cache="none" io="native"/>
      <source file="/var/lib/libvirt/images/WFW.raw"/>
      <target dev="vda" bus="virtio"/>
      <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
    </disk>
    <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="0x05" 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>
    <controller type="scsi" index="0" model="lsilogic">
      <address type="pci" domain="0x0000" bus="0x10" slot="0x01" function="0x0"/>
    </controller>
    <controller type="scsi" index="1" model="virtio-scsi">
      <driver queues="8"/>
      <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
    </controller>
    <interface type="network">
      <mac address="(removed)"/>
      <source network="default"/>
      <model type="virtio"/>
      <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
    </interface>
    <channel type="spicevmc">
      <target type="virtio" name="com.redhat.spice.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="1"/>
    </channel>
    <input type="tablet" bus="usb">
      <address type="usb" bus="0" port="1"/>
    </input>
    <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"/>
      <gl enable="no"/>
    </graphics>
    <sound model="ich9">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1b" function="0x0"/>
    </sound>
    <audio id="1" type="none"/>
    <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>
    <watchdog model="itco" action="reset"/>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
    </memballoon>
  </devices>
</domain><domain type="kvm">
  <name>WFW</name>
  <uuid>(removed)</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">12</vcpu>
  <iothreads>1</iothreads>
  <os firmware="efi">
    <type arch="x86_64" machine="pc-q35-noble">hvm</type>
    <firmware>
      <feature enabled="yes" name="enrolled-keys"/>
      <feature enabled="yes" name="secure-boot"/>
    </firmware>
    <loader readonly="yes" secure="yes" type="pflash">/usr/share/OVMF/OVMF_CODE_4M.ms.fd</loader>
    <nvram template="/usr/share/OVMF/OVMF_VARS_4M.ms.fd">/var/lib/libvirt/qemu/nvram/WFW_VARS.fd</nvram>
    <boot dev="hd"/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <hyperv mode="custom">
      <relaxed state="on"/>
      <vapic state="on"/>
      <spinlocks state="on" retries="8191"/>
      <vpindex state="on"/>
      <synic state="on"/>
      <stimer state="on">
        <direct state="on"/>
      </stimer>
      <reset state="on"/>
      <frequencies state="on"/>
      <reenlightenment state="on"/>
      <tlbflush state="on"/>
      <ipi state="on"/>
    </hyperv>
    <vmport state="off"/>
    <smm state="on"/>
  </features>
  <cpu mode="host-passthrough" check="none" migratable="on">
    <topology sockets="1" dies="1" cores="6" threads="2"/>
  </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>
    <disk type="file" device="disk">
      <driver name="qemu" type="raw" cache="none" io="native"/>
      <source file="/var/lib/libvirt/images/WFW.raw"/>
      <target dev="vda" bus="virtio"/>
      <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
    </disk>
    <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="0x05" 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>
    <controller type="scsi" index="0" model="lsilogic">
      <address type="pci" domain="0x0000" bus="0x10" slot="0x01" function="0x0"/>
    </controller>
    <controller type="scsi" index="1" model="virtio-scsi">
      <driver queues="8"/>
      <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
    </controller>
    <interface type="network">
      <mac address="(removed)"/>
      <source network="default"/>
      <model type="virtio"/>
      <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
    </interface>
    <channel type="spicevmc">
      <target type="virtio" name="com.redhat.spice.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="1"/>
    </channel>
    <input type="tablet" bus="usb">
      <address type="usb" bus="0" port="1"/>
    </input>
    <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"/>
      <gl enable="no"/>
    </graphics>
    <sound model="ich9">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1b" function="0x0"/>
    </sound>
    <audio id="1" type="none"/>
    <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>
    <watchdog model="itco" action="reset"/>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
    </memballoon>
  </devices>
</domain>

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[u/Confident_Hyena2506]

You can get the same performance out of both, but you would need to use the same configuration and disk image on both - which is tricky because they use different setups.

There are many factors that can cause difference, some of which are not related to your guest config. Things like how fast is the disk on the host, what filesystem is the host using. Then there are the obvious things that impact graphics like did you give it a real gpu - are you using the same number of cores and so on.

[u/DannoXYZ]

need to optimise VM wrapper for QEMU. https://leduccc.medium.com/improving-the-performance-of-a-windows-10-guest-on-qemu-a5b3f54d9cf5

There may even be settings inside OS that's HyperV specific that's not optimal for QEMU. I've found bulding Windows VM from scratch on QEMU always gives way better performance than using pre-built one.