On 05.10.2012, at 16:00, Avik Sil <avik...@linux.vnet.ibm.com> wrote:
> On 10/05/2012 05:39 PM, Alexander Graf wrote: >> >> On 05.10.2012, at 13:41, Nikunj A Dadhania wrote: >> >>> On Fri, 5 Oct 2012 12:24:47 +0200, Alexander Graf <ag...@suse.de> wrote: >>>> >>>> >>>> On 05.10.2012, at 10:29, Avik Sil <avik...@linux.vnet.ibm.com> wrote: >>>> >>>>> Hi David, >>>>> >>>>> Please find below the patch for working around the default boot device >>>>> issue currently being discussed on the list. >>>>> >>>>> Regards, >>>>> Avik >>>>> --- >>>>> >>>>> The default qemu boot_devices string passed to firmware is "cad" >>>>> which creates a confusion whether -boot oprion is specified or >>>>> not. This patch handles this issue by setting a global flag when >>>>> no -boot option is specified. >>>> >>>> Hrm. How does x86 distinguish between -boot and bootindex=? >>> >>> IMHO, that behaviour is not changed with this patch. Not sure how >>> seabios is taking care of this. >> >> I don't care about what you change with the patch. I care about consistency. >> And we shouldn't differ from x86 in that respect. >> >> So please try and figure out how x86 knows that bootindex= is supposed to be >> used instead of -boot. We want the same logic for ppc. >> >>> >>>> Also, we could just map -boot c to "nvram given boot device or first >>>> automatically found disk". Then there's no need to know whether a >>>> default was given. If you specify -boot you most likely want to force >>>> cd-rom or network boot anyway and there is no way to tell which disk >>>> 'c' would reflect. >>> >>> We do want to use -boot [cad], but not for the nvram saved >>> boot-device. That is done automatically in SLOF. If there is a property >>> saved named boot-device, its going to use that for booting. >> >> Hrm. Ok, how about we change the default string to >> >> xcad >> >> with x meaning "device stored in nvram". Then any time you specify -boot it >> would override the nvram device, but you could also manually specify "I want >> to only boot from the nvram device, no fallbacks". >> > Setting default string to "xcad" might jeopardize behavior of other machines > (about hundred of them) that are passed boot_devices through machine->init() Ugh. I only realized just now that qemu-devel is not CC'ed. Let's ask the non-ppc guys what they think. I would really like to make "boot from nvram default device" just yet another -boot drive option. That would scale a lot better. Alex >> >> Alex >> >>> The point here is when we really want to over-ride the boot-device >>> setting in nvram(say the boot-device specified got corrupted), we need >>> help from -boot and corresponding disk provided in the qemu >>> command-line. >>> >>> At present, if there is boot-device specified there is now way to >>> over-ride it using qemu command line as "cad" is passed by >>> default. Which is the cause of all the pain. >>> >>> Regards, >>> Nikunj >>> > > Regards, > Avik > >
