[Qemu-arm] [RFC v3 25/27] vfio-pci: register handler for iommu fault

[Eric Auger]

We use the VFIO_PCI_DMA_FAULT_IRQ_INDEX "irq" index to set/unset
a notifier for physical DMA faults. The associated eventfd is
triggered, in nested mode, whenever a fault is detected at IOMMU
physical level.

The actual handler will be implemented in subsequent patches.

Signed-off-by: Eric Auger <address@hidden>

---
---
 hw/vfio/pci.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/pci.h |  1 +
 2 files changed, 46 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index aeb4dfa388..91714cea84 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2722,6 +2722,49 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice 
*vdev)
     vdev->req_enabled = false;
 }
 
+static void vfio_dma_fault_notifier_handler(void *opaque)
+{
+    VFIOPCIDevice *vdev = opaque;
+
+    if (!event_notifier_test_and_clear(&vdev->dma_fault_notifier)) {
+        return;
+    }
+}
+
+static void vfio_register_dma_fault_notifier(VFIOPCIDevice *vdev)
+{
+    Error *err = NULL;
+    int32_t fd;
+
+    if (event_notifier_init(&vdev->dma_fault_notifier, 0)) {
+        error_report("vfio: Unable to init event notifier for dma fault");
+        return;
+    }
+
+    fd = event_notifier_get_fd(&vdev->dma_fault_notifier);
+    qemu_set_fd_handler(fd, vfio_dma_fault_notifier_handler, NULL, vdev);
+
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_DMA_FAULT_IRQ_INDEX, 
0,
+                           VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
+        qemu_set_fd_handler(fd, NULL, NULL, vdev);
+        event_notifier_cleanup(&vdev->dma_fault_notifier);
+    }
+}
+
+static void vfio_unregister_dma_fault_notifier(VFIOPCIDevice *vdev)
+{
+    Error *err = NULL;
+
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_DMA_FAULT_IRQ_INDEX, 
0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, -1, &err)) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
+    }
+    qemu_set_fd_handler(event_notifier_get_fd(&vdev->dma_fault_notifier),
+                        NULL, NULL, vdev);
+    event_notifier_cleanup(&vdev->dma_fault_notifier);
+}
+
 static void vfio_realize(PCIDevice *pdev, Error **errp)
 {
     VFIOPCIDevice *vdev = PCI_VFIO(pdev);
@@ -3007,6 +3050,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
 
     vfio_register_err_notifier(vdev);
     vfio_register_req_notifier(vdev);
+    vfio_register_dma_fault_notifier(vdev);
     vfio_setup_resetfn_quirk(vdev);
 
     return;
@@ -3045,6 +3089,7 @@ static void vfio_exitfn(PCIDevice *pdev)
 
     vfio_unregister_req_notifier(vdev);
     vfio_unregister_err_notifier(vdev);
+    vfio_unregister_dma_fault_notifier(vdev);
     pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
     vfio_disable_interrupts(vdev);
     if (vdev->intx.mmap_timer) {
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index c11c3f1670..55b14a1ece 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -135,6 +135,7 @@ typedef struct VFIOPCIDevice {
     PCIHostDeviceAddress host;
     EventNotifier err_notifier;
     EventNotifier req_notifier;
+    EventNotifier dma_fault_notifier;
     int (*resetfn)(struct VFIOPCIDevice *);
     uint32_t vendor_id;
     uint32_t device_id;
-- 
2.20.1