Dinar Valeev <dval...@suse.de> writes: > On 01/26/2015 10:11 AM, Markus Armbruster wrote: >> dval...@suse.de writes: >> >>> From: Dinar Valeev <dval...@suse.com> >>> >>> In order to use -boot once=X option we need to have default list >>> where restore to on reset. >> >> Really? What happens without this patch? >> > qemu segfaults on reset. > 0 > reset-all Segmentation fault
Next time, include a backtrace, please. Here's what I think happens. Boot order comes from --boot parameter once, order, or else the machine type's .default_boot_order. The latter is null for you. It gets passed via ppc_spapr_init() to spapr_create_fdt_skel(), which sets qemu,boot-device in the FDT to it, but only when it isn't null. If it comes from parameter once, we additionally register a reset handler to switch it to parameter order or else .default_boot_order on reset. If you specify once, but not order, this is null for you. On reset, reset handler restore_boot_order() runs. Unlike spapr_create_fdt_skel(), it doesn't check for null, and crashes in validate_bootdevices(). Correct? For me, a null .default_boot_order means "machine type does not support boot order" (this is how commit c165473 treats it). Arguably, --boot order and once should be rejected then. If I understand you correctly, your machine type does support boot order. Giving it a non-null .default_boot_order makes sense then. The appropriate value depends on firmware. It could even be "". The null check in spapr_create_fdt_skel() looks superfluous then. Consider dropping it. Makes sense?
