Re: vio.c:__vio_register_driver && LPAR Migration issue

On 08/02/2018 11:15 AM, Michael Bringmann wrote:

Hello:
    I have been observing an anomaly during LPAR migrations between
a couple of P8 systems.

This is the problem.  After migrating an LPAR, the PPC mobility code
receives RTAS requests to delete nodes with platform-/hardware-specific
attributes when restarting the kernel after a migration.  My example is
for migration between a P8 Alpine and a P8 Brazos.  Among the nodes
that I see being deleted are 'ibm,random-v1', 'ibm,compression-v1',
'ibm,platform-facilities', and 'ibm,sym-encryption-v1'.  Of these
nodes, the following are created during initial boot by calls to
vio_register_driver:

drivers/char/hw_random/pseries-rng.c
        ibm,random-v1

drivers/crypto/nx/nx-842-pseries.c
        ibm,compression-v1

drivers/crypto/nx/nx.c
        ibm,sym-encryption-v1

After the migration, these nodes are deleted, but nothing recreates
them.  If I boot the LPAR on the target system, the nodes are added
again.

My question is how do we recreate these nodes after migration?

Hmm, I'd have to see the scenario in action, but these should be added back by ibm,update-nodes RTAS call. There is some debug code in driver/of/dynamic.c that can be enabled that will log node/property dynamic reconfiguration events.

-Tyrel

Thanks.