Como obter um desempenho gráfico 2D melhor com o Android-x86 em execução no KVM?

Question

Estou executando o Android-x86 no QEMU / KVM por meio do Virtual Machine Manager. Esta é uma máquina virtual que eu anteriormente corri de um host do Windows com VMWare. Eu consegui executá-lo no Linux QEMU / KVM por enquanto, mas o desempenho 2D é muito muito ruim.

Aqui está o código vm ( /etc/libvirt/qemu/generic.xml ):

<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
  virsh edit generic
or other application using the libvirt API.
-->

<domain type='kvm'>
  <name>generic</name>
  <uuid>386c966a-0cdf-427d-aa24-7fe71583ab85</uuid>
  <memory unit='KiB'>2097152</memory>
  <currentMemory unit='KiB'>2097152</currentMemory>
  <vcpu placement='static'>4</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-2.9'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <vmport state='off'/>
  </features>
  <cpu mode='host-model' check='partial'>
    <model fallback='allow'/>
  </cpu>
  <clock offset='utc'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </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/sbin/qemu-system-x86_64</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='vmdk'/>
      <source file='/vms/android-x86-6.0-rc1.vmdk'/>
      <target dev='sda' bus='sata'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <controller type='usb' index='0' model='ich9-ehci1'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x7'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci1'>
      <master startport='0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0' multifunction='on'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci2'>
      <master startport='2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x1'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci3'>
      <master startport='4'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='sata' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </controller>
    <controller type='virtio-serial' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </controller>
    <interface type='direct'>
      <mac address='52:54:00:06:96:fd'/>
      <source dev='enp10s0' mode='bridge'/>
      <model type='rtl8139'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target port='0'/>
    </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'/>
    <graphics type='spice' autoport='yes'>
      <listen type='address'/>
      <gl enable='no' rendernode='/dev/dri/by-path/pci-0000:01:00.0-render'/>
    </graphics>
    <sound model='ich6'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </sound>
    <video>
      <model type='qxl' ram='131072' vram='131072' vgamem='131072' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='1'/>
    </redirdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='2'/>
    </redirdev>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
    </memballoon>
  </devices>
</domain>

Eu tentei um cartão VMVGA anteriormente, mas depois de ler aqui , mudei para QXL e ativado Spice, conforme indicado no código. Também atribuí manualmente 128 MB de memória gráfica virtual e reiniciei o host.

Ainda assim, os gráficos 2D são muito lentos. Existe alguma solução, além de instalar o VMWare ou comprar uma segunda placa gráfica?

[Editar]: Meu hardware tem 8 GB de RAM e o GPU R9 280x (AMD GCN 1.0, 1070 MHz, 3 GB GDDR5). Também desde que o desempenho foi muito bom no VMWare, estou convencido de que este é um problema de software. Estou usando o Arch Linux 64 bits como host com os drivers AMDGPU de código aberto.