wolfyportal

I now actually see after some more reading and checking other SoC's that the CPU's in the A733 must start the kernel at EL2. See also ARM reference doc:  102412_0103_01_en
 
So also 5.x kernel should work if EL2 I think
 
If the A733 has not implemented EL2 and EL3 as could be the case as suggested in ARM reference doc, no KVM. See chapter6:
 
As it is Allwinner, I won't be surprised, but wait and see what Radxa will come up with.

Radxa staff actually does not answer the original question w.r.t. Allwinner A733 HW virtualization, it is just that kernel config has it.
 
But I see from releases 'bullseye', that does not look good at all. In theory, that means 5.10 kernel, and oldoldstable libvirtd/KVM/QEMU etc. As this SoC is bigLITTLE, (Cortex-A76 Cortex-A55), starting a qemu-system-aarch64 process will pick some of those cores randomly, assuming you have more than 1 vCore (smp option > 1) . Kernel older than 6.8 or so does not support moving between an A76 and an A55.
That is the same for Rockchips (RK3588). It took me quite a while before I discovered that this is known behavior. So on for example on vendor rk35xx 6.1.115, I pin vCPUs, can be done in virt-manager GUI xml config or cmdline via taskset. As easy test, use -smp 1, then it should work. mainline kernel CPU numbers are such that simplest/lowest CPU's get lowest number. That might be the other way around on 6.1 or older downstream/vendor/BSP kernels.
On an RK3588, a 2-core VM with 2x A76  and 512MiB is done by:
taskset --cpu-list 6-7 qemu-system-aarch64 -M virt -cpu host -enable-kvm -m 512 -smp 2 \ -bios u-boot.bin \ -drive if=none,file=armbian.img,format=raw,id=hd0 \ -device virtio-blk-device,drive=hd0 \ -netdev bridge,id=hn1 -device virtio-net,netdev=hn1 \ -nographic Same should work on A733

Thank you Wolfypotal for the update,
 
The recent days I was also test the official image, Nick A's 0.4, but no good luck for the kvm, which actrally the big reason I purchase this cute small soc. I even upgrade the broad to have 8GB ram and 256 UFS, to use the kvm qemu...