In addition to bug #1916775, my Win10 Home guest freezes randomly and infrequently. Unlike bug #1916775, this is unrecoverable and I see on the host (Debian 4.19.171-2) via iotop that all disk IO has stopped. My only recourse is a hard reset of the guest.
My setup uses PCI-pass-through graphics (GTX 1650), host cpu (Ryzen 7 3800XT). It seems to occur more frequently (every few hours) after switching from "kvm=off,vendor=GenuineIntel" to "kvm=on" and maybe using 3 monitors rather than 2 on the pass-through graphics card further increases frequency. The switch to "kvm=on" was necessary to enable nested virtualization, which now works. It occurs whether or not I use the qcow disk drive.
qemu-system-x86_64
-cpu host,kvm=on,l3-cache=on,hv_relaxed,hv_vapic,hv_time,hv_spinlocks=0x1fff,hv_vendor_id=hv_dummy
-smp 8
-rtc clock=host,base=localtime
-machine type=q35,accel=kvm,kernel_irqchip=on
-enable-kvm
-drive if=pflash,format=raw,readonly,file=/usr/share/OVMF/OVMF_CODE.fd
-drive if=pflash,format=raw,file=/tmp/OVMF_VARS.fd
-m 32G
-usb
-device usb-tablet
-vga none
-serial none
-parallel none
-boot cd
-nographic
-device usb-host,vendorid=0x045e,productid=0x00db
-device usb-host,vendorid=0x1bcf,productid=0x0005
-drive id=disk0,index=0,format=qcow2,if=virtio,cache=off,file=./win10_boot_priv.qcow2
-drive id=disk2,index=2,aio=native,cache.direct=on,if=virtio,cache=off,format=raw,discard=unmap,detect-zeroes=unmap,file=/dev/vg0/win10_hdpriv
-device vfio-pci,host=09:00.0,addr=0x02.0x0,multifunction=on
-device vfio-pci,host=09:00.1,addr=0x02.0x1
-device vfio-pci,host=09:00.2,addr=0x02.0x2
-device vfio-pci,host=09:00.3,addr=0x02.0x3
-netdev tap,id=netid,ifname=taplan,script=no,downscript=no
-device e1000,netdev=netid,mac=52:54:00:01:02:03
The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting the bug state to "Incomplete" now.
If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".
If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:
1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:
https:/
and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.
2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" or "Confirmed" within the next 60 days (other-
wise it will get closed as "Expired"). We will then eventually migrate
the ticket automatically to the new system (but you won't be the reporter
of the bug in the new system and thus you won't get notified on changes
anymore).
Thank you and sorry for the inconvenience.