[Qemu-devel] [PATCH] hw/arm/boot: allow using a command line specified dtb without a kernel

[Michael Olbrich <m.olbrich@pengutronix.de>]

When kernel and device tree are specified in the QEMU commandline, then
this device tree may be modified e.g. to add virtio_mmio devices.
With a bootloader e.g. on a flash device these extra devices are not
available.
With this change, the device tree can be specified at the QEMU commandline.
The modified device tree made available to the bootloader with the same
mechanism already supported by device trees fully generated by QEMU.

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
---
 hw/arm/boot.c | 4 ++--
 vl.c          | 5 -----
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 1b913a43ca65..942416d95a6f 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -773,6 +773,8 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data)
      */
     assert(!(info->secure_board_setup && kvm_enabled()));
 
+    info->dtb_filename = qemu_opt_get(qemu_get_machine_opts(), "dtb");
+
     /* Load the kernel.  */
     if (!info->kernel_filename || info->firmware_loaded) {
 
@@ -833,8 +835,6 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data)
         elf_machine = EM_ARM;
     }
 
-    info->dtb_filename = qemu_opt_get(qemu_get_machine_opts(), "dtb");
-
     if (!info->secondary_cpu_reset_hook) {
         info->secondary_cpu_reset_hook = default_reset_secondary;
     }
diff --git a/vl.c b/vl.c
index ee557a1d3f8a..bbea51e0ce7d 100644
--- a/vl.c
+++ b/vl.c
@@ -4335,11 +4335,6 @@ int main(int argc, char **argv, char **envp)
         exit(1);
     }
 
-    if (!linux_boot && qemu_opt_get(machine_opts, "dtb")) {
-        error_report("-dtb only allowed with -kernel option");
-        exit(1);
-    }
-
     if (semihosting_enabled() && !semihosting_get_argc() && kernel_filename) {
         /* fall back to the -kernel/-append */
         semihosting_arg_fallback(kernel_filename, kernel_cmdline);
-- 
2.9.3