NOTES
=====

This image introduces bootflow changes. We use now OpenSBI -> U-Boot (S-mode)
[extlinux] -> kernel. The kernel and initramfs are wrapped in U-Boot container
for now. This should change later this year once kernel header patches are
merged in kernel and U-Boot.

This image will not work with libvirt v5.3.0 (or above) with QEMU 4.0.0 (or 
above) as in this setup libvirt defaults to PCI for attaching all devices
instead of MMIO. Use newer disk images, which contains requires changes in
U-Boot.

This image allows updating kernels via dnf + reboot.

This image does not contain out-of-tree patches for SiFive Unleashed board.

The disk image contains two partitions:
- sda1 (/boot) contains kernel, initramfs, extlinux configuration and firmware
  blobs.
- sdta2 contains rootfs.

    % virt-filesystems --long -h --all -a Fedora-Developer-Rawhide-20190506.n.0-sda.raw
    Name       Type        VFS   Label   MBR  Size  Parent
    /dev/sda1  filesystem  ext4  _/boot  -    488M  -
    /dev/sda2  filesystem  ext4  _/      -    7.2G  -
    /dev/sda1  partition   -     -       -    488M  /dev/sda
    /dev/sda2  partition   -     -       -    7.2G  /dev/sda
    /dev/sda   device      -     -       -    8.0G  -

To extract firmware blob install libguestfs-tools-c (Fedora/CentOS/RHEL), then:

    % mkdir a
    % guestmount -a $PWD/Fedora-Developer-Rawhide-*.raw -m /dev/sda1 $PWD/a
    % cp a/opensbi/unstable/fw_payload-uboot-qemu-virt-smode.elf .
    % guestunmount a

Use `fw_payload-uboot-qemu-virt-smode.elf` instead of the kernel.

libvirt (virt-instal):

    [..]
    --boot kernel=$PWD/fw_payload-uboot-qemu-virt-smode.elf \
    [..]

QEMU:

    [..]
    -kernel fw_payload-uboot-qemu-virt-smode.elf \
    [..]

You do not need to specify bootargs, initramfs or actual kernel images. U-Boot
will read /boot/extlinux/extlinux.conf (from sda1) to load that information.

Record from extlinux.conf:

    [..]
    label Fedora-Developer-Rawhide-20190506.n.0 (5.1.0-0.rc7.git4.1.1.riscv64.fc31.riscv64)
    	kernel /uImage-5.1.0-0.rc7.git4.1.1.riscv64.fc31.riscv64
    	append ro root=UUID=629b7cbb-e5f9-4d6a-b686-c427bd20075f rhgb quiet LANG=en_US.UTF-8
    	initrd /uInitrd-5.1.0-0.rc7.git4.1.1.riscv64.fc31.riscv64
    [..]