On 10 September 2016 at 16:07, Michael Olbrich <m.olbr...@pengutronix.de> wrote: > 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.
Would you mind explaining your usecase in a little more detail (for instance which machine model are you using) ? > Signed-off-by: Michael Olbrich <m.olbr...@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; > } This change definitely makes sense -- we check info->dtb_filename in have_dtb() so we need to set it before we call that function, not afterwards. > 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); > - } > - I can see why you want this change, but what worries me a little is that this is changing the behaviour of -dtb for all QEMU target architectures, not just ARM (they no longer get a helpful message on user error). I'm not sure how to address that, though. thanks -- PMM