Comment 10 for bug 1414466

Hello, I'm also experiencing such a problem, using qemu-system-x86_64 (hence the retitling of this issue). More information and output is available at http://issues.guix.gnu.org/48739, but basically with the following QEMU command used to run a VM:

/gnu/store/vbjfas8smw260r0qw1d5bbnh5hz08haz-qemu-5.2.0/bin/qemu-system-x86_64 -kernel /gnu/store/0fylx9z8lzyrbdivqa2jzn574gk8lcjv-linux-libre-5.12.7/bzImage -initrd /gnu/store/76ikiyg6arhd40pmq6yyi0vgdszfl08w-system/initrd -append "--root=/dev/vda1 --system=/gnu/store/76ikiyg6arhd40pmq6yyi0vgdszfl08w-system --load=/gnu/store/76ikiyg6arhd40pmq6yyi0vgdszfl08w-system/boot modprobe.blacklist=usbmouse,usbkbd quiet" -enable-kvm -no-reboot -object rng-random,filename=/dev/urandom,id=guixsd-vm-rng -device virtio-rng-pci,rng=guixsd-vm-rng -virtfs local,path="/gnu/store",security_model=none,mount_tag="TAGjoptajej2oynju6yvboauz7pl6uj" -vga std -drive file=/gnu/store/gj50g71n2b7xa2s9lgcfijprvr4vj66y-qemu-image,if=virtio,cache=writeback,werror=report,readonly -m 512 -nic user,hostfwd=tcp::3333-:22

Trying to connect to the VM which has its sshd_config set to:
Port 22
PermitRootLogin yes
PermitEmptyPasswords yes
PasswordAuthentication yes
PubkeyAuthentication yes
X11Forwarding no
AllowAgentForwarding yes
AllowTcpForwarding yes
GatewayPorts no
PidFile /var/run/sshd.pi
ChallengeResponseAuthentication no
UsePAM yes
PrintLastLog yes
LogLevel DEBUG
AuthorizedKeysFile .ssh/authorized_keys .ssh/authorized_keys2 /etc/ssh/authorized_keys.d/%u
Subsytsem sftp internal-sftp

The SSH client would hang with its last debug output being:

debug1: Local version string SSH-2.0-OpenSSH_8.6

Inside the guest, /var/log/secure doesn't show any activity so itd oesn't seem to be reached.

Ideas?