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 <ndabilpu...@marvell.com>
Signed-off-by: Jerin Jacob <jer...@marvell.com>
Tested-by: Shahed Shaikh <shsha...@marvell.com>
---
v4:
* Move note to implementation and change
the expectation to must call for new api.
v3:
* Update note on new api
v2:
* No change
lib/librte_eal/common/include/rte_interrupts.h | 18 ++++++
lib/librte_eal/freebsd/eal/eal_interrupts.c | 9 +++
lib/librte_eal/linux/eal/eal_interrupts.c | 90 ++++++++++++++++++++++++++
lib/librte_eal/rte_eal_version.map | 1 +
4 files changed, 118 insertions(+)
diff --git a/lib/librte_eal/common/include/rte_interrupts.h
b/lib/librte_eal/common/include/rte_interrupts.h
index c1e912c..c463265 100644
--- a/lib/librte_eal/common/include/rte_interrupts.h
+++ b/lib/librte_eal/common/include/rte_interrupts.h
@@ -118,6 +118,24 @@ 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.
+ *
+ * This function should be called at the end of each interrupt
+ * handler either from application or driver, so that
+ * currently raised interrupt is acked and further
+ * new interrupts are raised.
+ *
+ * @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
diff --git a/lib/librte_eal/freebsd/eal/eal_interrupts.c
b/lib/librte_eal/freebsd/eal/eal_interrupts.c
index 10375bd..f6831b7 100644
--- a/lib/librte_eal/freebsd/eal/eal_interrupts.c
+++ b/lib/librte_eal/freebsd/eal/eal_interrupts.c
@@ -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)
{
diff --git a/lib/librte_eal/linux/eal/eal_interrupts.c
b/lib/librte_eal/linux/eal/eal_interrupts.c
index 79ad5e8..794374e 100644
--- a/lib/librte_eal/linux/eal/eal_interrupts.c
+++ b/lib/librte_eal/linux/eal/eal_interrupts.c
@@ -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) {
@@ -693,6 +722,67 @@ rte_intr_enable(const struct rte_intr_handle *intr_handle)
return 0;
}
+
+/**
+ * PMD generally calls this function at the end of its IRQ callback.
+ * Internally, it unmasks the interrupt if possible. For INTx, unmasking
+ * is required as the interrupt is auto-masked prior to invoking
+ * callback. For MSI/MSI-X, unmasking is typically not needed as the
+ * interrupt is not auto-masked. In fact, for interrupt handle types
+ * VFIO_MSIX and VFIO_MSI, this function is no-op.
+ */
+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)
{
diff --git a/lib/librte_eal/rte_eal_version.map
b/lib/librte_eal/rte_eal_version.map
index 1892d9e..0537a6d 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -407,4 +407,5 @@ EXPERIMENTAL {
rte_lcore_to_cpu_id;
rte_mcfg_timer_lock;
rte_mcfg_timer_unlock;
+ rte_intr_ack;
};
--
2.8.4
