Maybe this help, but have zero idea about how to fix.
-blockdev '{"driver":"file","filename":"/mnt/user/domains/W7/vdisk1.img","node-name":"libvirt-3-storage","cache":{"direct":false,"no-flush":false},"auto-read-only":true,"discard":"unmap"}' \
-blockdev '{"node-name":"libvirt-3-format","read-only":false,"cache":{"direct":false,"no-flush":false},"driver":"raw","file":"libvirt-3-storage"}' \
-device virtio-blk-pci,bus=pci.0,addr=0x5,drive=libvirt-3-format,id=virtio-disk2,bootindex=1,write-cache=on \
-blockdev '{"driver":"file","filename":"/mnt/user/isos/Windows 7 Todas as Versões 7 SP1 Outubro 2017 X64.ISO","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}' \
-blockdev '{"node-name":"libvirt-2-format","read-only":true,"driver":"raw","file":"libvirt-2-storage"}' \
-device ide-cd,bus=ide.0,unit=0,drive=libvirt-2-format,id=ide0-0-0,bootindex=2 \
-blockdev '{"driver":"file","filename":"/mnt/user/isos/virtio-win-0.1.189-1.iso","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
-blockdev '{"node-name":"libvirt-1-format","read-only":true,"driver":"raw","file":"libvirt-1-storage"}'