On Fri, Jun 1, 2012 at 11:56 AM, Peter Crosthwaite <peter.crosthwa...@petalogix.com> wrote: > On Fri, Jun 1, 2012 at 11:44 AM, Peter Maydell <peter.mayd...@linaro.org> > wrote: >> On 1 June 2012 02:16, Peter A. G. Crosthwaite >> <peter.crosthwa...@petalogix.com> wrote: >>> @@ -240,10 +241,13 @@ static int load_dtb(target_phys_addr_t addr, const >>> struct arm_boot_info *binfo) >>> fprintf(stderr, "couldn't set /memory/reg\n"); >>> } >>> >>> - rc = qemu_devtree_setprop_string(fdt, "/chosen", "bootargs", >>> - binfo->kernel_cmdline); >>> - if (rc < 0) { >>> - fprintf(stderr, "couldn't set /chosen/bootargs\n"); >>> + machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0); >>> + if (machine_opts && qemu_opt_get(machine_opts, "append")) { >>> + rc = qemu_devtree_setprop_string(fdt, "/chosen", "bootargs", >>> + binfo->kernel_cmdline); >>> + if (rc < 0) { >>> + fprintf(stderr, "couldn't set /chosen/bootargs\n"); >>> + } >>> } >> >> Can you just check for binfo->kernel_cmdline being NULL or not >> rather than rereading the option via qemu_opt_get? The latter >> seems pretty ugly. >> > > No, it wont work, > > vl.c will populate it with "\"\"": >
Correction, vl.c will populate it with an empty string. The problem still stands though that an empty string explicitly passed to -append should mean wipe out dtb command line. > if (machine_opts) { > ... > kernel_cmdline = qemu_opt_get(machine_opts, "append"); > } else { > kernel_filename = initrd_filename = kernel_cmdline = NULL; > } > > if (!kernel_cmdline) { > kernel_cmdline = ""; > } > > > binfo->kernel_cmdline will not be null on the omission of -append. > > I did it this way as its the only way I can see where you can > determine whether or not -apend happened. You could strcmp with "\"\"" > and use that as your condition, but then you have a possibly piece of > policy that an empty command means no update (i.e. you should still be > able to explictly -apend "\"\"" to wipe out the dtb command line). > > Regards, > > Peter > >> -- PMM