Kernel with Networking

1. Obtain buildroot and build it

   git clone git://git.buildroot.net/buildroot
   cd buildroot
   make snps_archs38_hsdk_defconfig
   make menuconfig
    #Target options --> Target Architecture --> ARC (little endian)
    #                   Target CPU          --> ARC HS38
    #Filesystem images --> cpio the root filesystem
    #Save
   make BR2_JLEVEL=4
   

   Note: You will need cpio package installed.

2. Grab the latest kernel for qemu-arc and build

   git clone --single-branch --branch qemu-5.0 --depth 1 https://github.com/abrodkin/linux.git
   cd linux
   export ARCH=arc
   export CROSS_COMPILE=arc-elf32-             # make sure you have arc-elf32-gcc in PATH
   make hsdk_defconfig           
   make menuconfig
    # Ensure CONFIG_VIRTIO=y, CONFIG_VIRTIO_NET=y, CONFIG_VIRTIO_MENU=y, CONFIG_VIRTIO_MMIO=y
    # General setup --> Init ramfs source file(s) -->
    #  /path/to/buildroot/output/images/rootfs.cpio
   cat .config
    #CONFIG_INITRAMFS_SOURCE="/path/to/buildroot/output/images/rootfs.cpio"
   make -j4
   

3. Run the kernel with the following QEMU command

   qemu-system-arc -M virt                                                        \
                   -nographic                                                      \
                   -no-reboot                                                      \
                   -serial stdio                                                   \
                   -monitor none                                                   \
                   -cpu archs                                                      \
                   -netdev user,id=net,hostfwd=tcp::5555-:23,hostfwd=tcp::5556-:21 \
                   -device virtio-net-device,netdev=net0                           \
                   -device virtio-rng-pci                                          \
                   -kernel vmlinux
   

See QEMU's VirtIORNG for -device virtio-rng-pci.

1. Once booted

   ifconfig eth0 up
   udhcpc
   

Shared folder

If you need shared folder access, add the following arguments to QEMU's command line:

... -drive format=vvfat,id=hd0,file=fat:rw:FOLDER -device virtio-blk-device,drive=hd0 ...

and then in the guest:

# mount /dev/vda1
# mount /dev/vda1 /mnt
# touch /mnt/test.txt

Note:

1. Target will see contents on your __FOLDER__ as if it's a FAT partition on some drive so I guess no symlinks, no special attributes etc.
2. Target may do changes to the contents of this folder (with rw permissions above)
3. Host MUST NOT do any changes to the folder while target is using this share, otherwise things will go seriously wrong (QEMU creates FAT table on start and then it's target which manipulates it but not host).