Steps to reproduce
1. Create image file
/usr/bin/qemu-img create --object secret,id=image1_encrypt0,data=redhat -f luks -o key-secret=image1_encrypt0 /home/kvm_autotest_root/images/rhel950-64-virtio.luks 20G 

2.Boot VM, enable two iothreads on disk.

 /usr/libexec/qemu-kvm \
     -name 'avocado-vt-vm1'  \
     -sandbox on,elevateprivileges=deny,obsolete=deny,resourcecontrol=deny,spawn=deny \
     -machine q35,memory-backend=mem-machine_mem \
     -device '{"id": "pcie-root-port-0", "driver": "pcie-root-port", "multifunction": true, "bus": "pcie.0", "addr": "0x1", "chassis": 1}' \
     -device '{"id": "pcie-pci-bridge-0", "driver": "pcie-pci-bridge", "addr": "0x0", "bus": "pcie-root-port-0"}'  \
     -nodefaults \
     -device '{"driver": "VGA", "bus": "pcie.0", "addr": "0x2"}' \
     -m 7168 \
     -object '{"size": 7516192768, "id": "mem-machine_mem", "qom-type": "memory-backend-ram"}'  \
     -smp 8,maxcpus=8,cores=4,threads=1,dies=1,sockets=2  \
     -cpu 'Skylake-Server',+kvm_pv_unhalt \
\
     -device '{"id": "pcie-root-port-1", "port": 1, "driver": "pcie-root-port", "addr": "0x1.0x1", "bus": "pcie.0", "chassis": 2}' \
     -device '{"driver": "qemu-xhci", "id": "usb1", "bus": "pcie-root-port-1", "addr": "0x0"}' \
     -device '{"driver": "usb-tablet", "id": "usb-tablet1", "bus": "usb1.0", "port": "1"}' \
     -object '{"qom-type": "iothread", "id": "iothread0"}' \
     -object '{"qom-type": "iothread", "id": "iothread1"}' \
     -object '{"qom-type": "secret", "id": "image1_encrypt0", "data": "redhat"}' \
     -blockdev '{"node-name": "file_image1", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/kvm_autotest_root/images/rhel950-64-virtio.luks", "cache": {"direct": true, "no-flush": false}}' \
     -blockdev '{"node-name": "drive_image1", "driver": "luks", "read-only": false, "key-secret": "image1_encrypt0", "cache": {"direct": true, "no-flush": false}, "file": "file_image1"}' \
     -device '{"id": "pcie-root-port-2", "port": 2, "driver": "pcie-root-port", "addr": "0x1.0x2", "bus": "pcie.0", "chassis": 3}' \
     -device '{"driver": "virtio-blk-pci", "id": "image1", "drive": "drive_image1", "bootindex": 1, "write-cache": "on", "iothread-vq-mapping": [{"iothread": "iothread0"}, {"iothread": "iothread1"}], "bus": "pcie-root-port-2", "addr": "0x0"}' \
     -device '{"id": "pcie-root-port-3", "port": 3, "driver": "pcie-root-port", "addr": "0x1.0x3", "bus": "pcie.0", "chassis": 4}' \
     -device '{"driver": "virtio-net-pci", "mac": "9a:74:e5:6b:7b:e2", "id": "idwEe6Et", "netdev": "idki94xH", "bus": "pcie-root-port-3", "addr": "0x0"}' \
     -netdev  '{"id": "idki94xH", "type": "tap", "vhost": true, "vhostfd": "16", "fd": "12"}' \
     -blockdev '{"node-name": "file_cd1", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/kvm_autotest_root/iso/linux/RHEL-9.5.0-20240512.8-x86_64-dvd1.iso", "cache": {"direct": true, "no-flush": false}}' \
     -blockdev '{"node-name": "drive_cd1", "driver": "raw", "read-only": true, "cache": {"direct": true, "no-flush": false}, "file": "file_cd1"}' \
     -device '{"driver": "ide-cd", "id": "cd1", "drive": "drive_cd1", "bootindex": 2, "write-cache": "on", "bus": "ide.0", "unit": 0}' \
     -blockdev '{"node-name": "file_unattended", "driver": "file", "auto-read-only": true, "discard": "unmap", "aio": "threads", "filename": "/home/kvm_autotest_root/images/rhel950-64/ks.iso", "cache": {"direct": true, "no-flush": false}}' \
     -blockdev '{"node-name": "drive_unattended", "driver": "raw", "read-only": true, "cache": {"direct": true, "no-flush": false}, "file": "file_unattended"}' \
     -device '{"driver": "ide-cd", "id": "unattended", "drive": "drive_unattended", "bootindex": 3, "write-cache": "on", "bus": "ide.1", "unit": 0}'  \
     -kernel '/home/kvm_autotest_root/images/rhel950-64/vmlinuz'  \
     -append 'inst.sshd inst.repo=cdrom inst.ks=cdrom:/ks.cfg net.ifnames=0 console=ttyS0,115200'  \
     -initrd '/home/kvm_autotest_root/images/rhel950-64/initrd.img'  \
     -vnc :1  \
     -rtc base=utc,clock=host,driftfix=slew  \
     -boot menu=off,order=cdn,once=d,strict=off  \
     -no-shutdown \
     -enable-kvm \
     -device '{"id": "pcie_extra_root_port_0", "driver": "pcie-root-port", "multifunction": true, "bus": "pcie.0", "addr": "0x3", "chassis": 5}'

3.