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

[Shivang Upadhyay <shivangu@linux.ibm.com>]

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?
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

I think these should cover all our error cases.

~Shivang.