[dpdk-dev] [RFC PATCH 3/5] eal: add per rx queue interrupt handling based on VFIO

[Danny Zhou <danny.zhou@intel.com>]

Signed-off-by: Danny Zhou <danny.zhou@intel.com>
---
 lib/librte_eal/common/include/rte_eal.h            |   9 ++
 lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 120 ++++++++++++++++++++-
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c         |  11 +-
 .../linuxapp/eal/include/exec-env/rte_interrupts.h |   3 +
 4 files changed, 137 insertions(+), 6 deletions(-)

diff --git a/lib/librte_eal/common/include/rte_eal.h b/lib/librte_eal/common/include/rte_eal.h
index f4ecd2e..5f31aa5 100644
--- a/lib/librte_eal/common/include/rte_eal.h
+++ b/lib/librte_eal/common/include/rte_eal.h
@@ -150,6 +150,15 @@ int rte_eal_iopl_init(void);
  *   - On failure, a negative error value.
  */
 int rte_eal_init(int argc, char **argv);
+
+/**
+ * @param port_id
+ *   the port id
+ * @return
+ *   - On success, return 0
+ */
+int rte_eal_wait_rx_intr(uint8_t port_id, uint8_t queue_id);
+
 /**
  * Usage function typedef used by the application usage function.
  *
diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
index dc2668a..1be4ba7 100644
--- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
+++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
@@ -64,6 +64,7 @@
 #include <rte_malloc.h>
 #include <rte_errno.h>
 #include <rte_spinlock.h>
+#include <rte_ethdev.h>
 
 #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))
 
 /* enable legacy (INTx) interrupts */
 static int
@@ -293,7 +295,7 @@ vfio_disable_msi(struct rte_intr_handle *intr_handle) {
 static int
 vfio_enable_msix(struct rte_intr_handle *intr_handle) {
 	int len, ret;
-	char irq_set_buf[IRQ_SET_BUF_LEN];
+	char irq_set_buf[MSIX_IRQ_SET_BUF_LEN];
 	struct vfio_irq_set *irq_set;
 	int *fd_ptr;
 
@@ -301,12 +303,13 @@ 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;
+	irq_set->count = VFIO_MAX_QUEUE_ID + 1;
 	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[VFIO_MAX_QUEUE_ID] = intr_handle->fd;
 
 	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
 
@@ -323,7 +326,7 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
 	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;
+	irq_set->start = VFIO_MAX_QUEUE_ID;
 
 	ret = ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set);
 
@@ -332,6 +335,7 @@ vfio_enable_msix(struct rte_intr_handle *intr_handle) {
 						intr_handle->fd);
 		return -1;
 	}
+
 	return 0;
 }
 
@@ -339,7 +343,7 @@ 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 +828,109 @@ rte_eal_intr_init(void)
 	return -ret;
 }
 
+static int
+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;
+
+	for (n = 0; n < nfds; n++) {
+		/* set the length to be read dor 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);
+	}
+
+	return 0;
+}
+
+static void
+eal_intr_handle_rx_interrupts(uint8_t port_id, int pfd, unsigned totalfds)
+{
+	struct epoll_event events[totalfds];
+	int nfds = 0;
+
+m_wait:
+	nfds = epoll_wait(pfd, events, totalfds,
+			EAL_INTR_EPOLL_WAIT_FOREVER);
+	/* epoll_wait fail */
+	if (nfds < 0) {
+		if (errno == EINTR)
+			goto m_wait;/*continue;*/
+		RTE_LOG(ERR, EAL,
+			"epoll_wait returns with fail\n");
+		return;
+	}
+	/* epoll_wait timeout, will never happens here */
+	else if (nfds == 0)
+		goto m_wait;/*continue;*/
+	/* epoll_wait has at least one fd ready to read */
+	if (eal_intr_process_rx_interrupts(port_id, events, nfds) < 0)
+		return;
+}
+
+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;
+	struct epoll_event ev;
+	unsigned numfds = 0;
+
+	/* create epoll fd */
+	int pfd = epoll_create(1);
+	if (pfd < 0)
+		rte_panic("Cannot create epoll instance\n");
+
+	rte_spinlock_lock(&intr_lock);
+
+	ev.events = EPOLLIN | EPOLLPRI;
+	ev.data.fd = intr_handle.queue_fd[queue_id];
+
+	if (epoll_ctl(pfd, EPOLL_CTL_ADD,
+				intr_handle.queue_fd[queue_id], &ev) < 0){
+		rte_panic("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++) {
+			fd = eventfd(0, 0);
+			if (fd < 0) {
+				RTE_LOG(ERR, EAL, "  cannot set up eventfd, "
+						"error %i (%s)\n", errno, strerror(errno));
+				return -1;
+			}
+			dev->intr_handle.queue_fd[i] = fd;
+		}
+
 		return 0;
 	}
 
diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
index 23eafd9..83b717c 100644
--- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
+++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
@@ -38,6 +38,8 @@
 #ifndef _RTE_LINUXAPP_INTERRUPTS_H_
 #define _RTE_LINUXAPP_INTERRUPTS_H_
 
+#define VFIO_MAX_QUEUE_ID 32
+
 enum rte_intr_handle_type {
 	RTE_INTR_HANDLE_UNKNOWN = 0,
 	RTE_INTR_HANDLE_UIO,      /**< uio device handle */
@@ -52,6 +54,7 @@ enum rte_intr_handle_type {
 struct rte_intr_handle {
 	int vfio_dev_fd;                 /**< VFIO device file descriptor */
 	int fd;                          /**< file descriptor */
+	int queue_fd[VFIO_MAX_QUEUE_ID]; /**< rx and tx queue interrupt file descriptor */
 	enum rte_intr_handle_type type;  /**< handle type */
 };
 
-- 
1.8.1.4