CVS commit: src

["Emile iMil Heitor" <imil%netbsd.org@localhost>]

Module Name:    src
Committed By:   imil
Date:           Wed Jan 15 13:16:23 UTC 2025

Modified Files:
        src/sys/arch/x86/pv: files.pv
Added Files:
        src/share/man/man4: virtio_mmio.4
        src/sys/arch/amd64/conf: MICROVM
        src/sys/dev/virtio/arch/x86: virtio_mmio_cmdline.c

Log Message:
Add support for command line MMIO devices, at least qemu and
Firecracker pass MMIO virtual devices mapping through the kernel
command line.
This driver is based on Colin Percival's FreeBSD virtio_mmio_cmdline.c
https://github.com/freebsd/freebsd-src/blob/main/sys/dev/virtio/mmio/virtio_mmio_cmdline.c

The following kernel options are needed

options MPBIOS
options MPTABLE_LINUX_BUG_COMPAT

As are these drivers

pv* at pvbus?
virtio* at pv?

Exemple qemu usage on a Linux host to boot a NetBSD guest:

qemu-system-x86_64 \
       -M microvm,x-option-roms=off,rtc=on,acpi=off,pic=off,accel=kvm \
       -m 256 -cpu host -kernel ${KERNEL} \
       -append "root=ld0a console=com rw -v" \
       -device virtio-blk-device,drive=hd0 \
       -drive file=${IMG},format=raw,id=hd0 \
       -device virtio-net-device,netdev=net0 \
       -netdev user,id=net0,ipv6=off,hostfwd=::2200-:22 \
       -global virtio-mmio.force-legacy=false -display none -serial stdio

A lightweight kernel configuration named MICROVM if available for this
use case.


To generate a diff of this commit:
cvs rdiff -u -r0 -r1.1 src/share/man/man4/virtio_mmio.4
cvs rdiff -u -r0 -r1.1 src/sys/arch/amd64/conf/MICROVM
cvs rdiff -u -r1.1 -r1.2 src/sys/arch/x86/pv/files.pv
cvs rdiff -u -r0 -r1.1 src/sys/dev/virtio/arch/x86/virtio_mmio_cmdline.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.