sPAPR: Reenable EEH functionality on reboot

When rebooting the guest, some PEs might be in frozen state. The
contained PCI devices won't work properly if their frozen states
aren't cleared in time. One case running into this situation would
be maximal EEH error times encountered in the guest.

The patch reenables the EEH functinality on PEs on PHB's reset
callback, which will clear their frozen states if needed.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>

hw/ppc/spapr_pci_vfio.c

@@ -71,9 +71,26 @@ static void spapr_phb_vfio_finish_realize(sPAPRPHBState *sphb, Error **errp)
                                 spapr_tce_get_iommu(tcet));
 }
 
+static void spapr_phb_vfio_eeh_reenable(sPAPRPHBVFIOState *svphb)
+{
+    struct vfio_eeh_pe_op op = {
+        .argsz = sizeof(op),
+        .op    = VFIO_EEH_PE_ENABLE
+    };
+
+    vfio_container_ioctl(&svphb->phb.iommu_as,
+                         svphb->iommugroupid, VFIO_EEH_PE_OP, &op);
+}
+
 static void spapr_phb_vfio_reset(DeviceState *qdev)
 {
-    /* Do nothing */
+    /*
+     * The PE might be in frozen state. To reenable the EEH
+     * functionality on it will clean the frozen state, which
+     * ensures that the contained PCI devices will work properly
+     * after reboot.
+     */
+    spapr_phb_vfio_eeh_reenable(SPAPR_PCI_VFIO_HOST_BRIDGE(qdev));
 }
 
 static int spapr_phb_vfio_eeh_set_option(sPAPRPHBState *sphb,