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Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices pa
From: |
Alexander Graf |
Subject: |
Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF |
Date: |
Fri, 5 Oct 2012 16:13:20 +0200 |
On 05.10.2012, at 16:00, Avik Sil <address@hidden> 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 <address@hidden> wrote:
>>>>
>>>>
>>>> On 05.10.2012, at 10:29, Avik Sil <address@hidden> 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
>
>
- [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Avik Sil, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Alexander Graf, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Nikunj A Dadhania, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Alexander Graf, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Avik Sil, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF,
Alexander Graf <=
- Re: [Qemu-ppc] [Qemu-devel] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Anthony Liguori, 2012/10/05
- Re: [Qemu-ppc] [Qemu-devel] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Alexander Graf, 2012/10/05
- Re: [Qemu-ppc] [Qemu-devel] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Nikunj A Dadhania, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Nikunj A Dadhania, 2012/10/05
- Re: [Qemu-ppc] [PATCH] Workaround to bypass default qemu boot devices passed to SLOF, Nikunj A Dadhania, 2012/10/05