[dpdk-dev] [RFC PATCH v2] eal: add mask and unmask interrupt apis

[Nithin Dabilpuram <ndabilpuram@marvell.com>]

Add new mask and unmask interrupt api's specifically for
VFIO_LEGACY type of interrupts. For legacy/intx vfio-pci masks the
interrupt before posting the event and application has to unmask it
as a part of its interrupt handling. Hence these new api's can be used
for the light-weight operation of masking and unmasking.

In all the other VFIO interrupts i.e MSI & MSIx, vfio-pci doesn't
do anything like that and there is also no implementation for
masking and unmasking.

For qede intx handling, we can call the new api for unmasking interrupt.
We have not tested it on qede.
---
 drivers/net/qede/qede_ethdev.c                 |   6 +-
 lib/librte_eal/common/include/rte_interrupts.h |  23 ++++
 lib/librte_eal/linux/eal/eal_interrupts.c      | 155 +++++++++++++++++++++++++
 3 files changed, 180 insertions(+), 4 deletions(-)

diff --git a/drivers/net/qede/qede_ethdev.c b/drivers/net/qede/qede_ethdev.c
index 82363e6..20b7587 100644
--- a/drivers/net/qede/qede_ethdev.c
+++ b/drivers/net/qede/qede_ethdev.c
@@ -248,8 +248,8 @@ qede_interrupt_handler_intx(void *param)
 	if (status & 0x1) {
 		qede_interrupt_action(ECORE_LEADING_HWFN(edev));
 
-		if (rte_intr_enable(eth_dev->intr_handle))
-			DP_ERR(edev, "rte_intr_enable failed\n");
+		if (rte_intr_unmask(eth_dev->intr_handle))
+			DP_ERR(edev, "rte_intr_unmask failed\n");
 	}
 }
 
@@ -261,8 +261,6 @@ qede_interrupt_handler(void *param)
 	struct ecore_dev *edev = &qdev->edev;
 
 	qede_interrupt_action(ECORE_LEADING_HWFN(edev));
-	if (rte_intr_enable(eth_dev->intr_handle))
-		DP_ERR(edev, "rte_intr_enable failed\n");
 }
 
 static void
diff --git a/lib/librte_eal/common/include/rte_interrupts.h b/lib/librte_eal/common/include/rte_interrupts.h
index c1e912c..b0675be 100644
--- a/lib/librte_eal/common/include/rte_interrupts.h
+++ b/lib/librte_eal/common/include/rte_interrupts.h
@@ -118,6 +118,29 @@ int rte_intr_enable(const struct rte_intr_handle *intr_handle);
  */
 int rte_intr_disable(const struct rte_intr_handle *intr_handle);
 
+/**
+ * It masks the interrupt for the specified handle.
+ *
+ * @param intr_handle
+ *  pointer to the interrupt handle.
+ *
+ * @return
+ *  - On success, zero.
+ *  - On failure, a negative value.
+ */
+int rte_intr_mask(const struct rte_intr_handle *intr_handle);
+
+/**
+ * It unmasks the interrupt for the specified handle.
+ *
+ * @param intr_handle
+ *  pointer to the interrupt handle.
+ *
+ * @return
+ *  - On success, zero.
+ *  - On failure, a negative value.
+ */
+int rte_intr_unmask(const struct rte_intr_handle *intr_handle);
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_eal/linux/eal/eal_interrupts.c b/lib/librte_eal/linux/eal/eal_interrupts.c
index 79ad5e8..d91022c 100644
--- a/lib/librte_eal/linux/eal/eal_interrupts.c
+++ b/lib/librte_eal/linux/eal/eal_interrupts.c
@@ -197,6 +197,63 @@ vfio_disable_intx(const struct rte_intr_handle *intr_handle) {
 	return 0;
 }
 
+/* unmask legacy (INTx) interrupts */
+static int
+vfio_unmask_intx(const struct rte_intr_handle *intr_handle)
+{
+	struct vfio_irq_set *irq_set;
+	char irq_set_buf[IRQ_SET_BUF_LEN];
+	int len, ret;
+
+	len = sizeof(struct vfio_irq_set);
+
+	/* unmask INTx */
+	irq_set = (struct vfio_irq_set *) irq_set_buf;
+	memset(irq_set, 0, len);
+	irq_set->argsz = len;
+	irq_set->count = 1;
+	irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_UNMASK;
+	irq_set->index = VFIO_PCI_INTX_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 unmasking INTx interrupts for fd %d\n",
+			intr_handle->fd);
+		return -1;
+	}
+	return 0;
+}
+
+/* mask legacy (INTx) interrupts */
+static int
+vfio_mask_intx(const struct rte_intr_handle *intr_handle)
+{
+	struct vfio_irq_set *irq_set;
+	char irq_set_buf[IRQ_SET_BUF_LEN];
+	int len, ret;
+
+	len = sizeof(struct vfio_irq_set);
+
+	/* mask interrupts */
+	irq_set = (struct vfio_irq_set *) irq_set_buf;
+	irq_set->argsz = len;
+	irq_set->count = 1;
+	irq_set->flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_MASK;
+	irq_set->index = VFIO_PCI_INTX_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 masking INTx interrupts for fd %d\n",
+			intr_handle->fd);
+		return -1;
+	}
+
+	return 0;
+}
 /* enable MSI interrupts */
 static int
 vfio_enable_msi(const struct rte_intr_handle *intr_handle) {
@@ -694,6 +751,104 @@ rte_intr_enable(const struct rte_intr_handle *intr_handle)
 }
 
 int
+rte_intr_mask(const struct rte_intr_handle *intr_handle)
+{
+	if (intr_handle && intr_handle->type == RTE_INTR_HANDLE_VDEV)
+		return 0;
+
+	if (!intr_handle || intr_handle->fd < 0 || intr_handle->uio_cfg_fd < 0)
+		return -1;
+
+	switch (intr_handle->type){
+	/* Both masking and disabling are same for UIO */
+	case RTE_INTR_HANDLE_UIO:
+		if (uio_intr_disable(intr_handle))
+			return -1;
+		break;
+	case RTE_INTR_HANDLE_UIO_INTX:
+		if (uio_intx_intr_disable(intr_handle))
+			return -1;
+		break;
+	/* not used at this moment */
+	case RTE_INTR_HANDLE_ALARM:
+		return -1;
+#ifdef VFIO_PRESENT
+	case RTE_INTR_HANDLE_VFIO_MSIX:
+	case RTE_INTR_HANDLE_VFIO_MSI:
+		return -1;
+	case RTE_INTR_HANDLE_VFIO_LEGACY:
+		if (vfio_mask_intx(intr_handle))
+			return -1;
+		break;
+#ifdef HAVE_VFIO_DEV_REQ_INTERFACE
+	case RTE_INTR_HANDLE_VFIO_REQ:
+		return -1;
+#endif
+#endif
+	/* not used at this moment */
+	case RTE_INTR_HANDLE_DEV_EVENT:
+		return -1;
+	/* unknown handle type */
+	default:
+		RTE_LOG(ERR, EAL,
+			"Unknown handle type of fd %d\n",
+					intr_handle->fd);
+		return -1;
+	}
+
+	return 0;
+}
+
+int
+rte_intr_unmask(const struct rte_intr_handle *intr_handle)
+{
+	if (intr_handle && intr_handle->type == RTE_INTR_HANDLE_VDEV)
+		return 0;
+
+	if (!intr_handle || intr_handle->fd < 0 || intr_handle->uio_cfg_fd < 0)
+		return -1;
+
+	switch (intr_handle->type){
+	/* Both unmasking and disabling are same for UIO */
+	case RTE_INTR_HANDLE_UIO:
+		if (uio_intr_enable(intr_handle))
+			return -1;
+		break;
+	case RTE_INTR_HANDLE_UIO_INTX:
+		if (uio_intx_intr_enable(intr_handle))
+			return -1;
+		break;
+	/* not used at this moment */
+	case RTE_INTR_HANDLE_ALARM:
+		return -1;
+#ifdef VFIO_PRESENT
+	case RTE_INTR_HANDLE_VFIO_MSIX:
+	case RTE_INTR_HANDLE_VFIO_MSI:
+		return -1;
+	case RTE_INTR_HANDLE_VFIO_LEGACY:
+		if (vfio_unmask_intx(intr_handle))
+			return -1;
+		break;
+#ifdef HAVE_VFIO_DEV_REQ_INTERFACE
+	case RTE_INTR_HANDLE_VFIO_REQ:
+		return -1;
+#endif
+#endif
+	/* not used at this moment */
+	case RTE_INTR_HANDLE_DEV_EVENT:
+		return -1;
+	/* unknown handle type */
+	default:
+		RTE_LOG(ERR, EAL,
+			"Unknown handle type of fd %d\n",
+					intr_handle->fd);
+		return -1;
+	}
+
+	return 0;
+}
+
+int
 rte_intr_disable(const struct rte_intr_handle *intr_handle)
 {
 	if (intr_handle && intr_handle->type == RTE_INTR_HANDLE_VDEV)
-- 
2.8.4