Re: [dpdk-dev] [PATCH v2 4/5] eal: add per rx queue interrupt handling based on VFIO

["Liang, Cunming" <cunming.liang@intel.com>]

Hi,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Zhou Danny
> Sent: Tuesday, February 03, 2015 4:19 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v2 4/5] eal: add per rx queue interrupt handling
> based on VFIO
> 
[...]
>  #include "eal_private.h"
>  #include "eal_vfio.h"
> @@ -127,6 +128,7 @@ static pthread_t intr_thread;
>  #ifdef VFIO_PRESENT
> 
>  #define IRQ_SET_BUF_LEN  (sizeof(struct vfio_irq_set) + sizeof(int))
> +#define MSIX_IRQ_SET_BUF_LEN (sizeof(struct vfio_irq_set) + sizeof(int) *
> (VFIO_MAX_QUEUE_ID + 1))
[LCM] Does it better to add comment for '+1' which is the max other interrupts besides rxtx.
> 
>  /* enable legacy (INTx) interrupts */
>  static int
> @@ -221,7 +223,7 @@ vfio_disable_intx(struct rte_intr_handle *intr_handle) {
>  /* enable MSI-X interrupts */
[LCM] typo on comment. 'enable MSI interrupts' ?

> 
> @@ -292,8 +284,8 @@ vfio_disable_msi(struct rte_intr_handle *intr_handle) {
>  /* enable MSI-X interrupts */
>  static int
>  vfio_enable_msix(struct rte_intr_handle *intr_handle) {
> -	int len, ret;
> -	char irq_set_buf[IRQ_SET_BUF_LEN];
> +	int len, ret, max_intr;
> +	char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
>  	struct vfio_irq_set *irq_set;
>  	int *fd_ptr;
> 
> @@ -301,12 +293,19 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle)
> {
> 
>  	irq_set = (struct vfio_irq_set *) irq_set_buf;
>  	irq_set->argsz = len;
> -	irq_set->count = 1;
> +	if ((!intr_handle->max_intr) ||
> +		(intr_handle->max_intr > VFIO_MAX_QUEUE_ID))
> +		max_intr = VFIO_MAX_QUEUE_ID + 1;
> +	else
> +		max_intr = intr_handle->max_intr;
> +
> +	irq_set->count = max_intr;
>  	irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
> VFIO_IRQ_SET_ACTION_TRIGGER;
>  	irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
>  	irq_set->start = 0;
>  	fd_ptr = (int *) &irq_set->data;
> -	*fd_ptr = intr_handle->fd;
> +	memcpy(fd_ptr, intr_handle->queue_fd, sizeof(intr_handle-
> >queue_fd));
> +	fd_ptr[max_intr - 1] = intr_handle->fd;
> 
>  	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
> 
> @@ -316,22 +315,6 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
>  		return -1;
>  	}
> 
> -	/* manually trigger interrupt to enable it */
> -	memset(irq_set, 0, len);
> -	len = sizeof(struct vfio_irq_set);
> -	irq_set->argsz = len;
> -	irq_set->count = 1;
> -	irq_set->flags = VFIO_IRQ_SET_DATA_NONE |
> VFIO_IRQ_SET_ACTION_TRIGGER;
> -	irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
> -	irq_set->start = 0;
> -
> -	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
> -
> -	if (ret) {
> -		RTE_LOG(ERR, EAL, "Error triggering MSI-X interrupts for fd %d\n",
> -						intr_handle->fd);
> -		return -1;
> -	}
>  	return 0;
>  }
> 
> @@ -339,7 +322,7 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
>  static int
>  vfio_disable_msix(struct rte_intr_handle *intr_handle) {
>  	struct vfio_irq_set *irq_set;
> -	char irq_set_buf[IRQ_SET_BUF_LEN];
> +	char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
>  	int len, ret;
> 
>  	len = sizeof(struct vfio_irq_set);
> @@ -824,3 +807,119 @@ rte_eal_intr_init(void)
>  	return -ret;
>  }
> 
> +static void
> +eal_intr_process_rx_interrupts(uint8_t port_id, struct epoll_event *events, int
> nfds)
> +{
> +	int n, bytes_read;
> +	union rte_intr_read_buffer buf;
> +	struct rte_intr_handle intr_handle = rte_eth_devices[port_id].pci_dev-
> >intr_handle;
[LCM] column number large than 80.
> +
> +	for (n = 0; n < nfds; n++) {
> +		/* set the length to be read for different handle type */
> +		switch (intr_handle.type) {
> +		case RTE_INTR_HANDLE_UIO:
> +			bytes_read = sizeof(buf.uio_intr_count);
> +			break;
> +		case RTE_INTR_HANDLE_ALARM:
> +			bytes_read = sizeof(buf.timerfd_num);
> +			break;
> +#ifdef VFIO_PRESENT
> +		case RTE_INTR_HANDLE_VFIO_MSIX:
> +		case RTE_INTR_HANDLE_VFIO_MSI:
> +		case RTE_INTR_HANDLE_VFIO_LEGACY:
> +			bytes_read = sizeof(buf.vfio_intr_count);
> +			break;
> +#endif
> +		default:
> +			bytes_read = 1;
> +			break;
> +		}
> +
> +		/**
> +		* read out to clear the ready-to-be-read flag
> +		* for epoll_wait.
> +		*/
> +		bytes_read = read(events[n].data.fd, &buf, bytes_read);
> +		if (bytes_read < 0)
> +			RTE_LOG(ERR, EAL, "Error reading from file "
> +				"descriptor %d: %s\n", events[n].data.fd,
> +							strerror(errno));
> +		else if (bytes_read == 0)
> +			RTE_LOG(ERR, EAL, "Read nothing from file "
> +				"descriptor %d\n", events[n].data.fd);
> +	}
> +}
> +
> +static void
> +eal_intr_handle_rx_interrupts(uint8_t port_id, int pfd, unsigned totalfds)
> +{
> +	struct epoll_event events[totalfds];
> +	int nfds = 0;
> +
> +	do {
> +		nfds = epoll_wait(pfd, events, totalfds,
> +				EAL_INTR_EPOLL_WAIT_FOREVER);
> +		/* epoll_wait fail */
> +		if (nfds < 0) {
> +			RTE_LOG(ERR, EAL,
> +				"epoll_wait returns with fail\n");
> +			return;
> +		}
> +	} while (nfds == 0);
> +
> +	/* epoll_wait has at least one fd ready to read */
> +	eal_intr_process_rx_interrupts(port_id, events, nfds);
> +}
> +
> +int
> +rte_eal_wait_rx_intr(uint8_t port_id, uint8_t queue_id)
> +{
> +	struct rte_intr_handle intr_handle = rte_eth_devices[port_id].pci_dev-
> >intr_handle;
[LCM] exceed margin.

> +	struct epoll_event ev;
> +	unsigned numfds = 0;
> +
> +	/* create epoll fd */
> +	int pfd = epoll_create(1);
> +	if (pfd < 0) {
> +		RTE_LOG(ERR, EAL, "Cannot create epoll instance\n");
> +		return -1;
> +	}
> +
> +	rte_spinlock_lock(&intr_lock);
> +
> +	ev.events = EPOLLIN | EPOLLPRI;
> +	switch (intr_handle.type) {
> +	case RTE_INTR_HANDLE_UIO:
> +		ev.data.fd = intr_handle.fd;
> +		break;
> +#ifdef VFIO_PRESENT
> +	case RTE_INTR_HANDLE_VFIO_MSIX:
> +	case RTE_INTR_HANDLE_VFIO_MSI:
> +	case RTE_INTR_HANDLE_VFIO_LEGACY:
> +		ev.data.fd = intr_handle.queue_fd[queue_id];
> +		break;
> +#endif
> +	default:
> +		rte_spinlock_unlock(&intr_lock);
> +		close(pfd);
> +		return -1;
> +	}
> +
> +	if (epoll_ctl(pfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0) {
> +		RTE_LOG(ERR, EAL, "Error adding fd %d epoll_ctl, %s\n",
> +				intr_handle.queue_fd[queue_id],
> strerror(errno));
> +	} else
> +		numfds++;
> +
> +	rte_spinlock_unlock(&intr_lock);
> +	/* serve the interrupt */
> +	eal_intr_handle_rx_interrupts(port_id, pfd, numfds);
> +
> +	/**
> +	* when we return, we need to rebuild the
> +	* list of fds to monitor.
> +	*/
> +	close(pfd);
> +
> +	return 0;
> +}
> diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> index 20e0977..63d0ae8 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
> @@ -283,7 +283,6 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev, int
> vfio_dev_fd)
> 
>  		dev->intr_handle.fd = fd;
>  		dev->intr_handle.vfio_dev_fd = vfio_dev_fd;
> -
>  		switch (i) {
>  		case VFIO_PCI_MSIX_IRQ_INDEX:
>  			internal_config.vfio_intr_mode = RTE_INTR_MODE_MSIX;
> @@ -302,6 +301,16 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev,
> int vfio_dev_fd)
>  			return -1;
>  		}
> 
> +		for (i = 0; i < VFIO_MAX_QUEUE_ID; i++) {
[LCM] I think before assigning queue_fd, it shall check VFIO_PCI_MSIX_IRQ_INDEX first.
Otherwise, no matter MSI or INTX, either one will set queue_fd as well.

> +			fd = eventfd(0, 0);
> +			if (fd < 0) {
> +				RTE_LOG(ERR, EAL, "  cannot set up eventfd, "
> +						"error %i (%s)\n", errno,
> strerror(errno));
[LCM] Cleanup the eventfd before return ?


-Steve