I recently tried to run Minix 3.3 in a virtual machine, but it kept hanging at copying files during installation (and after it installed one, it hung at "starting daemons: update")

To fix this, add the following to your QEMU command-line:

-machine pc-i440fx-11.0,kernel-irqchip=split,hpet=off

or, if you are using libvirt, add this to your domain XML:

<qemu:commandline>
  <qemu:arg value="-machine"/>
  <qemu:arg value="pc-i440fx-11.0,kernel-irqchip=split,hpet=off"/>
</qemu:commandline>

For reference, here is the full domain XML of my Minix virtual machine (the minix.qcow2 drive is 1GB)

<domain xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0" type="kvm">
  <name>minix</name>
  <uuid>b5c5a7d0-77a2-4218-ace0-850a741150db</uuid>
  <title>Minix</title>
  <memory unit="KiB">262144</memory>
  <currentMemory unit="KiB">262144</currentMemory>
  <vcpu placement="static">2</vcpu>
  <os>
    <type arch="i686" machine="pc-i440fx-11.0">hvm</type>
  </os>
  <features>
    <acpi/>
    <apic/>
    <vmport state="off"/>
  </features>
  <cpu mode="custom" match="exact" check="none">
    <model fallback="allow">qemu32</model>
  </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>/run/libvirt/nix-emulators/qemu-system-x86_64</emulator>
    <disk type="file" device="cdrom">
      <driver name="qemu" type="raw"/>
      <source file="/share/aquired/isos/minix_R3.3.0-588a35b.iso"/>
      <target dev="hdb" bus="ide"/>
      <readonly/>
      <address type="drive" controller="0" bus="0" target="0" unit="1"/>
    </disk>
    <disk type="file" device="disk">
      <driver name="qemu" type="qcow2" discard="unmap"/>
      <source file="/var/lib/libvirt/images/minix.qcow2"/>
      <target dev="hdc" bus="ide"/>
      <boot order="1"/>
      <address type="drive" controller="0" bus="1" 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="ide" index="0">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x1"/>
    </controller>
    <controller type="virtio-serial" index="0">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x06" function="0x0"/>
    </controller>
    <controller type="sata" index="0">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x08" function="0x0"/>
    </controller>
    <interface type="network">
      <mac address="52:54:00:4f:a0:00"/>
      <source network="default"/>
      <model type="e1000"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" 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="tablet" bus="usb">
      <address type="usb" bus="0" port="1"/>
    </input>
    <input type="mouse" bus="ps2"/>
    <input type="keyboard" bus="ps2"/>
    <graphics type="spice" autoport="yes" listen="0.0.0.0">
      <listen type="address" address="0.0.0.0"/>
      <image compression="off"/>
    </graphics>
    <sound model="ich6">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x04" function="0x0"/>
    </sound>
    <audio id="1" type="spice"/>
    <video>
      <model type="qxl" ram="65536" vram="65536" vgamem="16384" 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="2"/>
    </redirdev>
    <redirdev bus="usb" type="spicevmc">
      <address type="usb" bus="0" port="3"/>
    </redirdev>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x07" function="0x0"/>
    </memballoon>
  </devices>
  <qemu:commandline>
    <qemu:arg value="-machine"/>
    <qemu:arg value="pc-i440fx-11.0,kernel-irqchip=split,hpet=off"/>
  </qemu:commandline>
</domain>