Function pci_vfio_setup_interrupts

dpdk/drivers/bus/pci/linux/pci_vfio.c:180–288

set up interrupt support (but not enable interrupts) */

/* set up interrupt support (but not enable interrupts) */
static int
pci_vfio_setup_interrupts(struct rte_pci_device *dev, int vfio_dev_fd)
{
	int i, ret, intr_idx;
	enum rte_intr_mode intr_mode;

	/* default to invalid index */
	intr_idx = VFIO_PCI_NUM_IRQS;

	/* Get default / configured intr_mode */
	intr_mode = rte_eal_vfio_intr_mode();

	/* get interrupt type from internal config (MSI-X by default, can be
	 * overridden from the command line
	 */
	switch (intr_mode) {
	case RTE_INTR_MODE_MSIX:
		intr_idx = VFIO_PCI_MSIX_IRQ_INDEX;
		break;
	case RTE_INTR_MODE_MSI:
		intr_idx = VFIO_PCI_MSI_IRQ_INDEX;
		break;
	case RTE_INTR_MODE_LEGACY:
		intr_idx = VFIO_PCI_INTX_IRQ_INDEX;
		break;
	/* don't do anything if we want to automatically determine interrupt type */
	case RTE_INTR_MODE_NONE:
		break;
	default:
		RTE_LOG(ERR, EAL, "Unknown default interrupt type!\n");
		return -1;
	}

	/* start from MSI-X interrupt type */
	for (i = VFIO_PCI_MSIX_IRQ_INDEX; i >= 0; i--) {
		struct vfio_irq_info irq = { .argsz = sizeof(irq) };
		int fd = -1;

		/* skip interrupt modes we don't want */
		if (intr_mode != RTE_INTR_MODE_NONE &&
				i != intr_idx)
			continue;

		irq.index = i;

		ret = ioctl(vfio_dev_fd, VFIO_DEVICE_GET_IRQ_INFO, &irq);
		if (ret < 0) {
			RTE_LOG(ERR, EAL, "Cannot get VFIO IRQ info, error "
					"%i (%s)\n", errno, strerror(errno));
			return -1;
		}

		/* if this vector cannot be used with eventfd, fail if we explicitly
		 * specified interrupt type, otherwise continue */
		if ((irq.flags & VFIO_IRQ_INFO_EVENTFD) == 0) {
			if (intr_mode != RTE_INTR_MODE_NONE) {
				RTE_LOG(ERR, EAL,
					"Interrupt vector does not support eventfd!\n");