The arm_boot_info struct has a skip_dtb_autoload flag: if this is set to true by the board code then arm_load_kernel() will not load the DTB itself, but will leave this for the board code to do itself later. However, the check for this is done in a code path which is only executed for the case where we load a kernel image file. If we're taking the "boot via firmware" code path then the flag isn't honoured and the DTB is never loaded. We didn't notice this because the only real user of "boot via firmware" that cares about the DTB is the virt board (for UEFI boot), and that always wants skip_dtb_autoload anyway. But the SBSA reference board model we're planning to add will want the flag to behave correctly.
The first four patches in this set are just refactoring, splitting the code in arm_load_kernel() out into a couple of sub-functions for "direct kernel boot" and "firmware boot". The last patch that fixes the issue is then just a one-liner. (Without the refactoring we'd need to use a goto, which is what I wanted to avoid.) thanks -- PMM Peter Maydell (5): hw/arm/boot: Fix block comment style in arm_load_kernel() hw/arm/boot: Factor out "direct kernel boot" code into its own function hw/arm/boot: Factor out "set up firmware boot" code hw/arm/boot: Clarify why arm_setup_firmware_boot() doesn't set env->boot_info hw/arm/boot: Support DTB autoload for firmware-only boots hw/arm/boot.c | 166 +++++++++++++++++++++++++++++--------------------- 1 file changed, 96 insertions(+), 70 deletions(-) -- 2.20.1