[PATCH 3/3] powerpc/eeh: Synchronize recovery in host/guest

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

When passing through SRIOV VFs to guest, we possibly encounter EEH
error on PF. In this case, the VF PEs are put into frozen state.
The error could be reported to guest before it's captured by the
host. That means the guest could attempt to recover errors on VFs
before host gets chance to recover errors on PFs. The VFs won't be
recovered successfully.

This enforces the recovery order for above case: the recovery on
child PE in guest is hold until the recovery on parent PE in host
is completed.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/eeh.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index fd9c782..42bd546 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1541,6 +1541,17 @@ int eeh_pe_get_state(struct eeh_pe *pe)
 	if (!eeh_ops || !eeh_ops->get_state)
 		return -ENOENT;
 
+	/*
+	 * If the parent PE, which is owned by host kernel, is experiencing
+	 * error recovery. We should return temporarily unavailable PE state
+	 * so that the recovery on guest side is suspended until the error
+	 * recovery is completed on host side.
+	 */
+	if (pe->parent &&
+	    !(pe->state & EEH_PE_REMOVED) &&
+	    (pe->parent->state & (EEH_PE_ISOLATED | EEH_PE_RECOVERING)))
+		return EEH_PE_STATE_UNAVAIL;
+
 	result = eeh_ops->get_state(pe, NULL);
 	rst_active = !!(result & EEH_STATE_RESET_ACTIVE);
 	dma_en = !!(result & EEH_STATE_DMA_ENABLED);
-- 
2.1.0