Re: RISC-V virtual machine does not boot anymore

[Mitsuya Shibata <mty.shibata@gmail.com>]

Hi all,

What is the content of /boot/extlinux/extlinux.conf?

On my environment (Ubuntu 19.10 with amd64),
I need to set 'U_BOOT_FDT_DIR="noexist"' in /etc/default/u-boot,
then execute "u-boot-update".

As following commit, v5.3 kernel of debain enabled CONFIG_SOC_SIFIVE.

  https://salsa.debian.org/kernel-team/linux/commit/263ffea1717c37378581c991a43278de085a9033

By CONFIG_SOC_SIFIVE, DTB for sifive is built and installed to
/usr/lib/linux-image-5.3.0-3-riscv64/sifive/hifive-unleashed-a00.dtb.

u-boot-update command of u-boot-menu package will add "fdtdir" in extlinux.conf
automatically.

  ref: https://github.com/suihkulokki/u-boot-menu/blob/master/u-boot-update#L162-L167

u-boot try to load DTB file from
/usr/lib/linux-image-5.3.0-3-riscv64/<DTB FILE NAME>.

However <DTB FILE NAME> should not be "sifive/hifive-unleashed-a00.dtb"
for QEMU instance.

---

Another perspective, Linux 5.3 introduced new image header for RISC-V.

  RISC-V: Add an Image header that boot loader can parse.
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0f327f2aaad6a87356cbccfa390d4d3b64d0d3b6

For this, following patch will be needed which is committed after v2019.10.

  https://gitlab.denx.de/u-boot/u-boot/commit/70d64a4c7646aa51c0334618ccb9af0132d9d834

However, at least on my environment, v5.3 kernel can boot from U-Boot v2019.10
without above patch.

Regards,
-- 
Mitsuya Shibata
mty.shibata@gmail.com