On Thu, 27 Feb 2025, Greg A. Woods wrote:
So I reverted to IDE, which has been reliable, but seems about 1/3 the
speed of the SCSI emulation.
Don't use any emulated HW at all, is my recommendation. Use virtio wherever
you can, instead.
So, my main question is with the device emulations available in QEMU,
which do people have the most luck and performance with?
I use this for QEMU on Ubuntu:
```
$ cat ~/tmp/qemu/qemu.sh
#!/bin/sh
set -eu
cd ~/tmp/qemu
test -f netbsd.qcow2 || qemu-img create -f qcow2 netbsd.qcow2 10G
kvm -enable-kvm -machine ubuntu-q35,accel=kvm -device intel-iommu -m 4g \
-cpu host -smp cpus=4,cores=2,threads=2 -bios /usr/share/ovmf/OVMF.fd \
-drive file=netbsd.qcow2,if=none,id=hd0 -device
virtio-blk-pci,drive=hd0 \
-object rng-random,filename=/dev/urandom,id=viornd0 -device
virtio-rng-pci,rng=viornd0 \
-netdev user,id=net0,hostfwd=tcp::5555-:22 -device
virtio-net-pci,netdev=net0 \
"$@"
# -device virtio-gpu OR -device virtio-vga \
# -nographic -cdrom /tmp/NetBSD-10.1_STABLE-amd64.iso \
$
```
Since you're on -HEAD, also look at the MICROVM kernel:
https://github.com/NetBSD/src/blob/trunk/sys/arch/amd64/conf/MICROVM#L11
-RVP
