[2/3] eal: add ack interrupt API
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Commit Message
Add new ack interrupt API to avoid using
VFIO_IRQ_SET_ACTION_TRIGGER(rte_intr_enable()) for
acking interrupt purpose for VFIO based interrupt handlers.
This implementation is specific to Linux.
Using rte_intr_enable() for acking interrupt has below issues
* Time consuming to do for every interrupt received as it will
free_irq() followed by request_irq() and all other initializations
* A race condition because of a window between free_irq() and
request_irq() with packet reception still on and device still
enabled and would throw warning messages like below.
[158764.159833] do_IRQ: 9.34 No irq handler for vector
In this patch, rte_intr_ack() is a no-op for VFIO_MSIX/VFIO_MSI interrupts
as they are edge triggered and kernel would not mask the interrupt before
delivering the event to userspace and we don't need to ack.
Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
---
lib/librte_eal/common/include/rte_interrupts.h | 22 +++++++
lib/librte_eal/freebsd/eal/eal_interrupts.c | 9 +++
lib/librte_eal/linux/eal/eal_interrupts.c | 81 ++++++++++++++++++++++++++
lib/librte_eal/rte_eal_version.map | 1 +
4 files changed, 113 insertions(+)
@@ -118,6 +118,28 @@ int rte_intr_enable(const struct rte_intr_handle *intr_handle);
*/
int rte_intr_disable(const struct rte_intr_handle *intr_handle);
+/**
+ * It acks an interrupt raised for the specified handle.
+ *
+ * Call this function to ack an interrupt from interrupt
+ * handler either from application or driver, so that
+ * new interrupts are raised.
+ *
+ * @note For interrupt handle types VFIO_MSIX and VFIO_MSI,
+ * this function is a no-op and returns success without
+ * changing anything as kernel doesn't expect
+ * them to be acked.
+ *
+ * @param intr_handle
+ * pointer to the interrupt handle.
+ *
+ * @return
+ * - On success, zero.
+ * - On failure, a negative value.
+ */
+__rte_experimental
+int rte_intr_ack(const struct rte_intr_handle *intr_handle);
+
#ifdef __cplusplus
}
#endif
@@ -387,6 +387,15 @@ rte_intr_disable(const struct rte_intr_handle *intr_handle)
return 0;
}
+int
+rte_intr_ack(const struct rte_intr_handle *intr_handle)
+{
+ if (intr_handle && intr_handle->type == RTE_INTR_HANDLE_VDEV)
+ return 0;
+
+ return -1;
+}
+
static void
eal_intr_process_interrupts(struct kevent *events, int nfds)
{
@@ -197,6 +197,35 @@ vfio_disable_intx(const struct rte_intr_handle *intr_handle) {
return 0;
}
+/* unmask/ack legacy (INTx) interrupts */
+static int
+vfio_ack_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;
+}
+
/* enable MSI interrupts */
static int
vfio_enable_msi(const struct rte_intr_handle *intr_handle) {
@@ -694,6 +723,58 @@ rte_intr_enable(const struct rte_intr_handle *intr_handle)
}
int
+rte_intr_ack(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 acking 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
+ /* Since VFIO_MSIX is implicitly acked
+ * unlike INTx, we report success
+ */
+ case RTE_INTR_HANDLE_VFIO_MSIX:
+ case RTE_INTR_HANDLE_VFIO_MSI:
+ return 0;
+ case RTE_INTR_HANDLE_VFIO_LEGACY:
+ if (vfio_ack_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)
@@ -407,4 +407,5 @@ EXPERIMENTAL {
rte_lcore_to_cpu_id;
rte_mcfg_timer_lock;
rte_mcfg_timer_unlock;
+ rte_intr_ack;
};