Re: [PATCH] powerpc/pseries/dlpar: Search DRC index from ibm,drc-indexes for IO add

On 4/30/25 9:10 PM, Haren Myneni wrote:

IO hotplug add event is handled in the user space with drmgr tool.
After the device is enabled, the user space uses /sys/kerne/dlpar
interface with “dt add index <drc_index>” to update the device tree.
The kernel interface (dlpar_hp_dt_add()) finds the parent node for
the specified ‘drc_index’ from ibm,drc-info property. But old FW
provides ibm,drc-indexes property instead of ibm,drc-info.

If the ibm,drc-info is not available, this patch adds changes to
search ‘drc_index’ from the indexes array in ibm,drc-indexes
property to support old FW.

Fixes: 02b98ff44a57 ("powerpc/pseries/dlpar: Add device tree nodes for DLPAR IO add")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
---

My only comment would be maybe mentioning that this issue was discovered with a
KVM guest which would be using some version of SLOF firmware as opposed to
PowerVM's proprietary Open Firmware. Older Open Firmware using ibm,drc-indexes
would present the same issue, but is probably less likely to be encountered in
the wild as we got drc-info support showing up in the kernel as far back as 2017
which aligns with Power 7 that has since hit EOL.

Otherwise...

Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>