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Last active June 27, 2025 10:42
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Revisions

  1. houaq revised this gist Jun 27, 2025. 1 changed file with 7 additions and 48 deletions.
    55 changes: 7 additions & 48 deletions ubuntu-xenial-armfh-qemu.md
    View file
    Original file line number Diff line number Diff line change
    @@ -1,4 +1,4 @@
    # Running Ubuntu 16.04.1 armhf on Qemu
    # Running Ubuntu 16.04.1 armhf on Qemu 10.x under macOS

    This is a writeup about how to install [Ubuntu 16.04.1 Xenial Xerus](https://wiki.ubuntu.com/XenialXerus/ReleaseNotes) for the 32-bit hard-float ARMv7 (armhf) architecture on a Qemu VM via [Ubuntu netboot](http://cdimage.ubuntu.com/netboot/16.04.1/).

    @@ -21,48 +21,7 @@ wget -r -nH -nd -np -R "index.html*" --quiet http://ports.ubuntu.com/ubuntu-port
    The following command creates a image file that will be used as a disk for the Ubuntu system:

    ```bash
    qemu-img create -f qcow2 ubuntu.img 16G
    ```

    ## Setup networking

    Installing Ubuntu via netboot requires an Internet connection. Therefore the Ubuntu VM requires a network intefaces that can use the Internet connection of the host system. The host systems needs to create a tuntap device for the VM and a bridge that will connect the tuntap interface with the Internet-facing interface. The bridge is called `br0` and the tuntap device for the Ubuntu VM will be `tap0`.

    ```bash
    sudo ip tuntap add dev tap0 mode tap
    sudo ip link set up dev tap0
    sudo ip link set tap0 master br0
    ```

    Creating a bridge and adding the Internet-facing interface (e.g. `eth0`):

    ```bash
    sudo ip link add br0 type bridge
    sudo ip link set eth0 master br0
    ```

    Allow IP packet forwarding:

    ```bash
    sudo sysctl -w net.ipv4.ip_forward=1
    ```

    Start a DHCP server in the bridge so that the Ubuntu VM receives an IP address:

    ```bash
    echo "subnet 192.168.0.0 netmask 255.255.255.0 {
    range 192.168.0.10 192.168.0.100;
    option routers 192.168.0.1;
    option domain-name-servers 208.67.222.222, 208.67.220.220;
    }" > qemu-dhcpd.conf
    sudo dhcpd -cf qemu-dhcpd.conf br0
    ```

    Set router IP on bridge interface:

    ```bash
    ip addr add 192.168.0.1/24 dev br0
    ip link set up dev br0
    qemu-img create -f qcow2 ubuntu.qcow2 16G
    ```

    ## Start the netboot installation
    @@ -78,10 +37,10 @@ qemu-system-arm \
    -nographic \
    -m 1024 \
    -M virt \
    -serial stdio \
    -net nic \
    -net tap,ifname=tap0,script=no,downscript=no \
    -hda ubuntu.img
    -device virtio-blk-device,drive=hd0 \
    -drive if=none,file=ubuntu.qcow2,id=hd0 \
    -device virtio-net-device,netdev=usernet \
    -netdev user,id=usernet,hostfwd=tcp::5555-:22
    ```

    The kernel should now boot into the Ubuntu installer within the terminal window where the command has been executed.
    @@ -91,7 +50,7 @@ The kernel should now boot into the Ubuntu installer within the terminal window
    After the installation process has been finished, extract the kernel and initrd files from the new installed Ubuntu system. Mount the Ubuntu image:

    ```bash
    qemu-img convert -f qcow2 -O raw ubuntu.img ubuntu-raw.img
    qemu-img convert -f qcow2 -O raw ubuntu.qcow2 ubuntu-raw.img
    sudo losetup /dev/loop0 ubuntu-raw.img
    OFFSET=$(($(sudo fdisk -l /dev/loop0 |grep /dev/loop0p1 |awk '{print $3}')*512))
    sudo mount -o loop,offset=$OFFSET /dev/loop0 /mnt
  2. @takeshixx takeshixx revised this gist Sep 29, 2016. 1 changed file with 7 additions and 0 deletions.
    7 changes: 7 additions & 0 deletions ubuntu-xenial-armfh-qemu.md
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    Original file line number Diff line number Diff line change
    @@ -58,6 +58,13 @@ echo "subnet 192.168.0.0 netmask 255.255.255.0 {
    sudo dhcpd -cf qemu-dhcpd.conf br0
    ```

    Set router IP on bridge interface:

    ```bash
    ip addr add 192.168.0.1/24 dev br0
    ip link set up dev br0
    ```

    ## Start the netboot installation

    From the netboot directory (containing the netboot files `vmlinuz` and `initrd.gz`), run the following command:
  3. @takeshixx takeshixx created this gist Sep 29, 2016.
    173 changes: 173 additions & 0 deletions ubuntu-xenial-armfh-qemu.md
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,173 @@
    # Running Ubuntu 16.04.1 armhf on Qemu

    This is a writeup about how to install [Ubuntu 16.04.1 Xenial Xerus](https://wiki.ubuntu.com/XenialXerus/ReleaseNotes) for the 32-bit hard-float ARMv7 (armhf) architecture on a Qemu VM via [Ubuntu netboot](http://cdimage.ubuntu.com/netboot/16.04.1/).

    The setup will create a Ubuntu VM with [LPAE](https://www.arm.com/products/processors/technologies/virtualization-extensions.php) extensions (generic-lpae) enabled. However, this writeup should also work for non-LPAE (generic) kernels.

    The performance of the resulting VM is quite good, and it allows VMs with >1G ram (compared to 256M on `versatilepb` and 1G on `versatile-a9`/`versatile-a15`). It also supports `virtio` disks whereas `versatile-a9`/`versatile-a15` only support SD cards via the `-sd` argument.

    ## Get netboot files

    The netboot files are available on the official [Ubuntu mirror](http://ports.ubuntu.com/ubuntu-ports/dists/xenial/main/installer-armhf/current/images/generic-lpae/netboot/). The following commands will download the kernel (vmlinuz) and initrd (initrd.gz) in a new directory called `netboot`:

    ```bash
    mkdir netboot
    cd netboot
    wget -r -nH -nd -np -R "index.html*" --quiet http://ports.ubuntu.com/ubuntu-ports/dists/xenial/main/installer-armhf/current/images/generic-lpae/netboot/
    ```

    ## Create a image file

    The following command creates a image file that will be used as a disk for the Ubuntu system:

    ```bash
    qemu-img create -f qcow2 ubuntu.img 16G
    ```

    ## Setup networking

    Installing Ubuntu via netboot requires an Internet connection. Therefore the Ubuntu VM requires a network intefaces that can use the Internet connection of the host system. The host systems needs to create a tuntap device for the VM and a bridge that will connect the tuntap interface with the Internet-facing interface. The bridge is called `br0` and the tuntap device for the Ubuntu VM will be `tap0`.

    ```bash
    sudo ip tuntap add dev tap0 mode tap
    sudo ip link set up dev tap0
    sudo ip link set tap0 master br0
    ```

    Creating a bridge and adding the Internet-facing interface (e.g. `eth0`):

    ```bash
    sudo ip link add br0 type bridge
    sudo ip link set eth0 master br0
    ```

    Allow IP packet forwarding:

    ```bash
    sudo sysctl -w net.ipv4.ip_forward=1
    ```

    Start a DHCP server in the bridge so that the Ubuntu VM receives an IP address:

    ```bash
    echo "subnet 192.168.0.0 netmask 255.255.255.0 {
    range 192.168.0.10 192.168.0.100;
    option routers 192.168.0.1;
    option domain-name-servers 208.67.222.222, 208.67.220.220;
    }" > qemu-dhcpd.conf
    sudo dhcpd -cf qemu-dhcpd.conf br0
    ```

    ## Start the netboot installation

    From the netboot directory (containing the netboot files `vmlinuz` and `initrd.gz`), run the following command:

    ```bash
    qemu-system-arm \
    -kernel vmlinuz \
    -initrd initrd.gz \
    -append "root=/dev/ram" \
    -no-reboot \
    -nographic \
    -m 1024 \
    -M virt \
    -serial stdio \
    -net nic \
    -net tap,ifname=tap0,script=no,downscript=no \
    -hda ubuntu.img
    ```

    The kernel should now boot into the Ubuntu installer within the terminal window where the command has been executed.

    ## Extract the new kernel

    After the installation process has been finished, extract the kernel and initrd files from the new installed Ubuntu system. Mount the Ubuntu image:

    ```bash
    qemu-img convert -f qcow2 -O raw ubuntu.img ubuntu-raw.img
    sudo losetup /dev/loop0 ubuntu-raw.img
    OFFSET=$(($(sudo fdisk -l /dev/loop0 |grep /dev/loop0p1 |awk '{print $3}')*512))
    sudo mount -o loop,offset=$OFFSET /dev/loop0 /mnt
    ```

    Create a new directory `boot` for the new kernel and initrd files and copy them into it:

    ```bash
    mkdir boot
    cp /mnt/initrd.img-4.4.0-38-generic-lpae
    cp /mnt/vmlinuz-4.4.0-38-generic-lpae boot
    ```

    Cleanup:

    ```bash
    sudo umount /mnt
    sudo losetup -d /dev/loop0
    rm ubuntu-raw.img
    ```

    *TODO*: Add working solution that does not require to convert the image file.

    ## Start the Ubuntu VM

    The Ubuntu VM directory should now have the following structure:

    ```bash
    ├── boot
    │   ├── initrd.img-4.4.0-38-generic-lpae
    │   └── vmlinuz-4.4.0-38-generic-lpae
    ├── netboot
    │   ├── initrd.gz
    │   └── vmlinuz
    └── ubuntu.img
    ```

    Start Qemu:

    ```bash
    qemu-system-arm \
    -kernel boot/vmlinuz-4.4.0-38-generic-lpae \
    -initrd boot/initrd.img-4.4.0-38-generic-lpae \
    -append "root=/dev/vda2 rootfstype=ext4" \
    -no-reboot \
    -nographic \
    -m 1024 \
    -M virt \
    -serial stdio \
    -monitor telnet:127.0.0.1:9000,server,nowait \
    -net nic \
    -net tap,ifname=tap0,script=no,downscript=no \
    -drive file=ubuntu.img,if=virtio
    ```

    The following script can be used for starting the VM:

    ```bash
    #!/bin/sh
    NET_IF=tap0
    BRIDGE=br0
    if ! grep --quiet $NET_IF /proc/net/dev;then
    echo "Creating ${NET_IF} device"
    sudo ip tuntap add dev $NET_IF mode tap
    sudo ip l s up dev $NET_IF
    fi
    if grep --quiet $BRIDGE /proc/net/dev;then
    sudo ip l s $NET_IF master $BRIDGE
    else
    echo "${BRIDGE} does not exist!"
    exit
    fi
    qemu-system-arm \
    -kernel boot/vmlinuz-4.4.0-38-generic-lpae \
    -initrd boot/initrd.img-4.4.0-38-generic-lpae \
    -append "root=/dev/vda2 rootfstype=ext4" \
    -no-reboot \
    -nographic \
    -m 1024 \
    -M virt \
    -serial stdio \
    -monitor telnet:127.0.0.1:9000,server,nowait \
    -net nic \
    -net tap,ifname=tap0,script=no,downscript=no \
    -drive file=ubuntu.img,if=virtio
    ```