+ uint8_t pos;
+ struct virtio_pci_cap cap;
+ int ret;
+
+ if (rte_pci_map_device(dev)) {
+ PMD_INIT_LOG(DEBUG, "failed to map pci device!");
+ return -1;
+ }
+
+ ret = rte_pci_read_config(dev, &pos, 1, PCI_CAPABILITY_LIST);
+ if (ret < 0) {
+ PMD_INIT_LOG(DEBUG, "failed to read pci capability list");
+ return -1;
+ }
+
+ while (pos) {
+ ret = rte_pci_read_config(dev, &cap, sizeof(cap), pos);
+ if (ret < 0) {
+ PMD_INIT_LOG(ERR,
+ "failed to read pci cap at pos: %x", pos);
+ break;
+ }
+
+ if (cap.cap_vndr == PCI_CAP_ID_MSIX) {
+ /* Transitional devices would also have this capability,
+ * that's why we also check if msix is enabled.
+ * 1st byte is cap ID; 2nd byte is the position of next
+ * cap; next two bytes are the flags.
+ */
+ uint16_t flags = ((uint16_t *)&cap)[1];
+
+ if (flags & PCI_MSIX_ENABLE)
+ hw->use_msix = VIRTIO_MSIX_ENABLED;
+ else
+ hw->use_msix = VIRTIO_MSIX_DISABLED;
+ }
+
+ if (cap.cap_vndr != PCI_CAP_ID_VNDR) {
+ PMD_INIT_LOG(DEBUG,
+ "[%2x] skipping non VNDR cap id: %02x",
+ pos, cap.cap_vndr);
+ goto next;
+ }
+
+ PMD_INIT_LOG(DEBUG,
+ "[%2x] cfg type: %u, bar: %u, offset: %04x, len: %u",
+ pos, cap.cfg_type, cap.bar, cap.offset, cap.length);
+
+ switch (cap.cfg_type) {
+ case VIRTIO_PCI_CAP_COMMON_CFG:
+ hw->common_cfg = get_cfg_addr(dev, &cap);
+ break;
+ case VIRTIO_PCI_CAP_NOTIFY_CFG:
+ rte_pci_read_config(dev, &hw->notify_off_multiplier,
+ 4, pos + sizeof(cap));
+ hw->notify_base = get_cfg_addr(dev, &cap);
+ break;
+ case VIRTIO_PCI_CAP_DEVICE_CFG:
+ hw->dev_cfg = get_cfg_addr(dev, &cap);
+ break;
+ case VIRTIO_PCI_CAP_ISR_CFG:
+ hw->isr = get_cfg_addr(dev, &cap);
+ break;
+ }
+
+next:
+ pos = cap.cap_next;
+ }
+
+ if (hw->common_cfg == NULL || hw->notify_base == NULL ||
+ hw->dev_cfg == NULL || hw->isr == NULL) {
+ PMD_INIT_LOG(INFO, "no modern virtio pci device found.");
+ return -1;
+ }
+
+ PMD_INIT_LOG(INFO, "found modern virtio pci device.");
+
+ PMD_INIT_LOG(DEBUG, "common cfg mapped at: %p", hw->common_cfg);
+ PMD_INIT_LOG(DEBUG, "device cfg mapped at: %p", hw->dev_cfg);
+ PMD_INIT_LOG(DEBUG, "isr cfg mapped at: %p", hw->isr);
+ PMD_INIT_LOG(DEBUG, "notify base: %p, notify off multiplier: %u",
+ hw->notify_base, hw->notify_off_multiplier);
+
+ return 0;