Description of problem:
After installed viogpudo driver on win10-like guest iommu_platform=on, desktop display no response while click on the program in the taskbar. and even the cursor disappear for a few seconds when you click too much.

Version-Release number of selected component (if applicable):
qemu-kvm-4.2.0-40.module+el8.4.0+9278+dd53883d.x86_64
virtio-win-prewhql-193
kernel-4.18.0-270.el8.x86_64

How reproducible:
100%

Steps to Reproduce:
1.boot up win10+ guest with iommu=on:
/usr/libexec/qemu-kvm \
    -name 'avocado-vt-vm1'  \
    -sandbox on  \
    -machine q35,kernel-irqchip=split \
    -device intel-iommu,intremap=on,device-iotlb=on \
    -device pcie-root-port,id=pcie-root-port-0,multifunction=on,bus=pcie.0,addr=0x1,chassis=1 \
    -device pcie-pci-bridge,id=pcie-pci-bridge-0,addr=0x0,bus=pcie-root-port-0  \
    -nodefaults \
    -monitor stdio \
    -m 2048  \
    -device virtio-vga,id=video0 \
    -smp 24,maxcpus=24,cores=12,threads=1,dies=1,sockets=2  \
    -cpu 'Skylake-Server',hv_stimer,hv_synic,hv_vpindex,hv_relaxed,hv_spinlocks=0xfff,hv_vapic,hv_time,hv_frequencies,hv_runtime,hv_tlbflush,hv_reenlightenment,hv_stimer_direct,hv_ipi,+kvm_pv_unhalt \
    -chardev socket,path=/tmp/avocado_adfijf889/monitor-qmpmonitor1-20210105-032815-BLpNoZnG,id=qmp_id_qmpmonitor1,nowait,server  \
    -mon chardev=qmp_id_qmpmonitor1,mode=control \
    -chardev socket,path=/tmp/avocado_adfijf889/monitor-catch_monitor-20210105-032815-BLpNoZnG,id=qmp_id_catch_monitor,nowait,server  \
    -mon chardev=qmp_id_catch_monitor,mode=control \
    -device pvpanic,ioport=0x505,id=idXAAXfN \
    -chardev socket,path=/tmp/avocado_adfijf889/serial-serial0-20210105-032815-BLpNoZnG,id=chardev_serial0,nowait,server \
    -device isa-serial,id=serial0,chardev=chardev_serial0 \
    -chardev socket,path=/tmp/avocado_adfijf889/serial-org.qemu.guest_agent.0-20210105-032815-BLpNoZnG,id=chardev_org.qemu.guest_agent.0,nowait,server \
    -device pcie-root-port,id=pcie-root-port-1,port=0x1,addr=0x1.0x1,bus=pcie.0,chassis=2 \
    -device virtio-serial-pci,id=virtio_serial_pci0,bus=pcie-root-port-1,addr=0x0 \
    -device virtserialport,id=org.qemu.guest_agent.0,name=org.qemu.guest_agent.0,chardev=chardev_org.qemu.guest_agent.0,bus=virtio_serial_pci0.0,nr=1  \
    -chardev socket,id=seabioslog_id_20210105-032815-BLpNoZnG,path=/tmp/avocado_adfijf889/seabios-20210105-032815-BLpNoZnG,server,nowait \
    -device isa-debugcon,chardev=seabioslog_id_20210105-032815-BLpNoZnG,iobase=0x402 \
    -device pcie-root-port,id=pcie-root-port-2,port=0x2,addr=0x1.0x2,bus=pcie.0,chassis=3 \
    -device qemu-xhci,id=usb1,bus=pcie-root-port-2,addr=0x0 \
    -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \
    -device pcie-root-port,id=pcie-root-port-3,port=0x3,addr=0x1.0x3,bus=pcie.0,chassis=4 \
    -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pcie-root-port-3,addr=0x0 \
    -blockdev node-name=file_image1,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=win10-32-virtio-scsi.qcow2,cache.direct=on,cache.no-flush=off \
    -blockdev node-name=drive_image1,driver=qcow2,read-only=off,cache.direct=on,cache.no-flush=off,file=file_image1 \
    -device scsi-hd,id=image1,drive=drive_image1,write-cache=on \
    -device pcie-root-port,id=pcie-root-port-4,port=0x4,addr=0x1.0x4,bus=pcie.0,chassis=5 \
    -device virtio-net-pci,mac=9a:53:3e:06:b0:47,id=idKpQvyY,netdev=idpFCo1s,bus=pcie-root-port-4,addr=0x0  \
    -netdev tap,id=idpFCo1s,vhost=on \
    -blockdev node-name=file_cd1,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=/home/kvm_autotest_root/iso/windows/winutils.iso,cache.direct=on,cache.no-flush=off \
    -blockdev node-name=drive_cd1,driver=raw,read-only=on,cache.direct=on,cache.no-flush=off,file=file_cd1 \
    -device scsi-cd,id=cd1,drive=drive_cd1,write-cache=on \
    -blockdev node-name=file_virtio,driver=file,auto-read-only=on,discard=unmap,aio=threads,filename=/home/kvm_autotest_root/iso/windows/virtio-win-prewhql-0.1-193.iso,cache.direct=on,cache.no-flush=off \
    -blockdev node-name=drive_virtio,driver=raw,read-only=on,cache.direct=on,cache.no-flush=off,file=file_virtio \
    -device scsi-cd,id=virtio,drive=drive_virtio,write-cache=on  \
    -device pcie-root-port,id=pcie-root-port-5,port=0x5,addr=0x1.0x5,bus=pcie.0,chassis=6 \
    -device virtio-gpu-pci,id=video1,bus=pcie-root-port-5,addr=0x0,iommu_platform=on,ats=on \
    -vnc :8  \
    -rtc base=localtime,clock=host,driftfix=slew  \
    -boot menu=off,order=cdn,once=c,strict=off \
    -enable-kvm \
2. install the gpu driver
right click "My computers"-->"properties"--->"device manager"---->choose
"video controller"
3.click any program in taskbar.

Actual results:
The whole desktop has no response.
Expected results:
desktop display works well
Additional info: