[RFC v6 16/24] vfio/pci: Set up the DMA FAULT region

[Eric Auger <eric.auger@redhat.com>]

Set up the fault region which is composed of the actual fault
queue (mmappable) and a header used to handle it. The fault
queue is mmapped.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v4 -> v5:
- use a single DMA FAULT region. No version selection anymore
---
 hw/vfio/pci.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/pci.h |  1 +
 2 files changed, 65 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 7579f476b0..029652a507 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2530,11 +2530,67 @@ int vfio_populate_vga(VFIOPCIDevice *vdev, Error **errp)
     return 0;
 }
 
+static void vfio_init_fault_regions(VFIOPCIDevice *vdev, Error **errp)
+{
+    struct vfio_region_info *fault_region_info = NULL;
+    struct vfio_region_info_cap_fault *cap_fault;
+    VFIODevice *vbasedev = &vdev->vbasedev;
+    struct vfio_info_cap_header *hdr;
+    char *fault_region_name;
+    int ret;
+
+    ret = vfio_get_dev_region_info(&vdev->vbasedev,
+                                   VFIO_REGION_TYPE_NESTED,
+                                   VFIO_REGION_SUBTYPE_NESTED_DMA_FAULT,
+                                   &fault_region_info);
+    if (ret) {
+        goto out;
+    }
+
+    hdr = vfio_get_region_info_cap(fault_region_info,
+                                   VFIO_REGION_INFO_CAP_DMA_FAULT);
+    if (!hdr) {
+        error_setg(errp, "failed to retrieve DMA FAULT capability");
+        goto out;
+    }
+    cap_fault = container_of(hdr, struct vfio_region_info_cap_fault,
+                             header);
+    if (cap_fault->version != 1) {
+        error_setg(errp, "Unsupported DMA FAULT API version %d",
+                   cap_fault->version);
+        goto out;
+    }
+
+    fault_region_name = g_strdup_printf("%s DMA FAULT %d",
+                                        vbasedev->name,
+                                        fault_region_info->index);
+
+    ret = vfio_region_setup(OBJECT(vdev), vbasedev,
+                            &vdev->dma_fault_region,
+                            fault_region_info->index,
+                            fault_region_name);
+    g_free(fault_region_name);
+    if (ret) {
+        error_setg_errno(errp, -ret,
+                         "failed to set up the DMA FAULT region %d",
+                         fault_region_info->index);
+        goto out;
+    }
+
+    ret = vfio_region_mmap(&vdev->dma_fault_region);
+    if (ret) {
+        error_setg_errno(errp, -ret, "Failed to mmap the DMA FAULT queue");
+    }
+out:
+    g_free(fault_region_info);
+}
+
 static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)
 {
     VFIODevice *vbasedev = &vdev->vbasedev;
     struct vfio_region_info *reg_info;
     struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info) };
+    Error *err = NULL;
     int i, ret = -1;
 
     /* Sanity check device */
@@ -2598,6 +2654,12 @@ static void vfio_populate_device(VFIOPCIDevice *vdev, Error **errp)
         }
     }
 
+    vfio_init_fault_regions(vdev, &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+
     irq_info.index = VFIO_PCI_ERR_IRQ_INDEX;
 
     ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_GET_IRQ_INFO, &irq_info);
@@ -3200,6 +3262,7 @@ static void vfio_instance_finalize(Object *obj)
 
     vfio_display_finalize(vdev);
     vfio_bars_finalize(vdev);
+    vfio_region_finalize(&vdev->dma_fault_region);
     g_free(vdev->emulated_config_bits);
     g_free(vdev->rom);
     if (vdev->migration_blocker) {
@@ -3224,6 +3287,7 @@ static void vfio_exitfn(PCIDevice *pdev)
     vfio_unregister_req_notifier(vdev);
     vfio_unregister_err_notifier(vdev);
     vfio_unregister_ext_irq_notifiers(vdev);
+    vfio_region_exit(&vdev->dma_fault_region);
     pci_device_set_intx_routing_notifier(&vdev->pdev, NULL);
     if (vdev->irqchip_change_notifier.notify) {
         kvm_irqchip_remove_change_notifier(&vdev->irqchip_change_notifier);
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 56f0fabb33..c5a59a8e3d 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -141,6 +141,7 @@ typedef struct VFIOPCIDevice {
     EventNotifier err_notifier;
     EventNotifier req_notifier;
     VFIOPCIExtIRQ *ext_irqs;
+    VFIORegion dma_fault_region;
     int (*resetfn)(struct VFIOPCIDevice *);
     uint32_t vendor_id;
     uint32_t device_id;
-- 
2.20.1