[Qemu-devel] [PATCH 2/3] VFIO: Clear INTx pending state on EEH reset

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

When Linux guest recovers from EEH error on the following Emulex
adapter, the MSIx interrupts are disabled and the INTx emulation
is enabled. One INTx interrupt is injected to the guest by host
because of detected pending INTx interrupts on the adapter. QEMU
disables mmap'ed BAR regions and starts a timer to enable those
regions at later point the INTx interrupt handler. Unfortunately,
"VFIOPCIDevice->intx.pending" isn't cleared, meaning those disabled
mapp'ed BAR regions won't be reenabled properly. It leads to EEH
recovery failure at guest side because of hanged MMIO access.

 # lspci | grep Emulex
 0000:01:00.0 Ethernet controller: Emulex Corporation \
              OneConnect 10Gb NIC (be3) (rev 02)
 0000:01:00.1 Ethernet controller: Emulex Corporation \
              OneConnect 10Gb NIC (be3) (rev 02)

The patch clears "VFIOPCIDevice->intx.pending" after EEH reset
is completed on the PE, which contains the adapter. In turn, the
mmap'ed BAR regions can be reenabled to avoid EEH recovery failure.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 hw/vfio/pci.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 8c4a8cb..55e0904 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3352,6 +3352,20 @@ int vfio_container_eeh_event(AddressSpace *as, int32_t groupid,
         }
 
         break;
+    case VFIO_EEH_PE_RESET_DEACTIVATE:
+        /*
+         * We might have INTx interrupt whose handler disabled the
+         * memory mapped BARs. Without clearing the INTx pending
+         * state, the timer kicked by the INTx interrupt handler
+         * won't enable those disabled memory mapped BARs, which
+         * leads EEH recovery failure.
+         */
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+            vdev->intx.pending = false;
+        }
+
+        break;
     }
 
     vfio_put_group(group);
-- 
1.8.3.2