[Qemu-devel] [RFC PATCH v2 2/2] VFIO: Clear stale MSIx table during EEH reset

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

The PCI device MSIx table is cleaned out in hardware after EEH PE
reset. However, we still hold the stale MSIx entries in QEMU, which
should be cleared accordingly. Otherwise, we will run into another
(recursive) EEH error and the PCI devices contained in the PE have
to be offlined exceptionally.

The patch clears stale MSIx table before EEH PE reset so that MSIx
table could be restored properly after EEH PE reset.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 hw/misc/vfio.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 1a3e7eb..1f55051 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -2724,6 +2724,17 @@ static void vfio_disable_interrupts(VFIODevice *vdev)
     }
 }
 
+static void vfio_disable_and_reset_interrupts(VFIODevice *vdev)
+{
+    vfio_disable_interrupts(vdev);
+
+    switch (vdev->interrupt) {
+    case VFIO_INT_MSIX:
+        msix_reset(&vdev->pdev);
+        break;
+    }
+}
+
 static int vfio_setup_msi(VFIODevice *vdev, int pos)
 {
     uint16_t ctrl;
@@ -4442,8 +4453,27 @@ int vfio_container_ioctl(AddressSpace *as, int32_t groupid,
     switch (req) {
     case VFIO_CHECK_EXTENSION:
     case VFIO_IOMMU_SPAPR_TCE_GET_INFO:
-    case VFIO_EEH_PE_OP:
         break;
+    case VFIO_EEH_PE_OP: {
+        VFIODevice *vdev;
+        struct vfio_eeh_pe_op *arg = (struct vfio_eeh_pe_op *)param;
+
+        switch (arg->op) {
+        case VFIO_EEH_PE_RESET_HOT:
+        case VFIO_EEH_PE_RESET_FUNDAMENTAL:
+            /*
+             * The MSIx table will be cleaned out by reset. We need
+             * disable it so that it can be reenabled properly. Also,
+             * the cached MSIx table should be cleared as it's not
+             * reflecting the contents in hardware.
+             */
+            QLIST_FOREACH(vdev, &group->device_list, next) {
+                vfio_disable_and_reset_interrupts(vdev);
+            }
+        }
+
+        break;
+    }
     default:
         /* Return an error on unknown requests */
         error_report("vfio: unsupported ioctl %X", req);
-- 
1.8.3.2