[dpdk-dev] [RFC PATCH] 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.
---
 lib/librte_eal/common/include/rte_interrupts.h |  23 ++++
 lib/librte_eal/linux/eal/eal_interrupts.c      | 155 +++++++++++++++++++++++++
 2 files changed, 178 insertions(+)

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