On 01/26/2015 01:57 PM, Dinar Valeev wrote:
On 01/26/2015 01:37 PM, Markus Armbruster wrote:
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.
Ok, sorry for that.
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?
Yes
qemu_register_boot_set is implemented in PATCH 2/2. on reset
boot_device is restored to NULL
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.
AFICS SLOF handles qemu,boot-device as boot device, if nothing passed
then it goes disk, cdrom, network. Which is the same as "cdn" list.
That's not entirely true. If SLOF doesn't see qemu,boot-device, it first
goes via its NVRAM configured boot list and only if nothing is there it
falls back to "cdn".
Maybe the actual appropriate thing would be "mcdn" with m meaning "NVRAM".
Alex
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?
