Re: [PATCH] ppc/fadump: collect dump if the collected size is lesser than reserved

[Sourabh Jain <sourabhjain@linux.ibm.com>]

On 29/07/26 12:30, Shivang Upadhyay wrote:
> On Wed, 2026-07-29 at 11:58 +0530, Sourabh Jain wrote:
>>> Yes, I made it this way by reading the dump_bytes and source_len
>>> relation. PAPR only says that dumped_bytes should not exceed the
>>> source_len. My change reflects the same restriction in sw. Also
>>> along
>>> with this lengths check, we have firmware reported error flag also,
>>> which should take care of overflow (Qemu handles it like this [1]).
>> But the firmware not copying the entire Real Mode memory is also a
>> problem for
>> the kernel, isn't it?
>>
> I think it should be fine. Firmware will report it status flags, right?

I don't know. Does PAPR says anything about the error code corresponds
to when memory to not copied completely?

> There are these valid flag values.
>
> Dump Error Flags (set by platform)
>   Bit mask
>   0x8000 = Invalid section data type
>   0x4000 = Invalid source address
>   0x2000 = Requested section length exceeds source
>   0x1000 = Invalid partition destination address
>   0x0800 = Partition memory destination too small