While working on getting rid of CAS reboot, I realized that we currently
don't handle device hot unplug properly in the following situations:
1) if the device is unplugged between boot and CAS, SLOF doesn't handle
the even, which is a known limitation. The device hence stays around
forever (specifically, until some other event is emitted and the guest
eventually completes the unplug or a reboot). Until we can teach SLOF
to correctly process the full FDT at CAS, we should trigger a CAS reboot,
like we already do for hotplug.
2) if the guest is migrated after the even was emitted but before the
guest could process it, the destination is unaware of the pending
unplug operation and doesn't remove the device when the guests
releases it. The 'unplug_requested' field of the DRC is actually state
that should be migrated.
Changes since v1:
- new spapr_drc_transient() helper that covers pending plug and unplug
situations for both CAS and migration
- as a mechanical consequence, fix unplug for CAS an migration in the
same patch
--
Greg
---
Greg Kurz (2):
spapr: Don't use spapr_drc_needed() in CAS code
spapr: Fix handling of unplugged devices during CAS and migration
hw/ppc/spapr_drc.c | 43 ++++++++++++++++++++++++++++++++++++-------
hw/ppc/spapr_hcall.c | 14 +++++++++-----
include/hw/ppc/spapr_drc.h | 4 +++-
3 files changed, 48 insertions(+), 13 deletions(-)
