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

From: Sourabh Jain

Date: Wed Jul 29 2026 - 04:18:43 EST



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