Re: [PATCH 0/2] handle premature return from H_JOIN in pseries mobility code

Excerpts from Nathan Lynch's message of March 15, 2021 6:00 pm:

pseries VMs in shared processor mode are susceptible to failed
migrations becasue stray H_PRODs from the paravirt spinlock
implementation can bump threads out of joining state before the
suspend has occurred. Fix this by adding a small amount of shared
state and ordering accesses to it with respect to H_PROD and H_JOIN.

Oh, tricky problem. Nice work on finding and fixing it.

The patches seem okay to me.

Thanks,
Nick