[v5,2/3] eal: add ack interrupt API
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Commit Message
From: Nithin Dabilpuram <ndabilpuram@marvell.com>
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>
Tested-by: Shahed Shaikh <shshaikh@marvell.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
---
Changelog since v4:
- added EXPERIMENTAL banner + little rewording in header
- simplified vfio ioctl code by shrinking the passed buffer
- fixed comments
- sorted new symbol in map file
Changelog since v3:
- Move note to implementation and change the expectation to must call for
new api.
Changelog since v2:
- Update note on new api
---
lib/librte_eal/common/include/rte_interrupts.h | 20 +++++++
lib/librte_eal/freebsd/eal/eal_interrupts.c | 9 +++
lib/librte_eal/linux/eal/eal_interrupts.c | 82 ++++++++++++++++++++++++++
lib/librte_eal/rte_eal_version.map | 1 +
4 files changed, 112 insertions(+)
@@ -118,6 +118,26 @@ int rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
*/
int rte_intr_disable(const struct rte_intr_handle *intr_handle);
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * It acknowledges 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
@@ -387,6 +387,15 @@ struct rte_intr_source {
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 +197,28 @@ struct rte_intr_source {
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;
+
+ /* unmask INTx */
+ memset(&irq_set, 0, sizeof(irq_set));
+ irq_set.argsz = sizeof(irq_set);
+ 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;
+
+ if (ioctl(intr_handle->vfio_dev_fd, VFIO_DEVICE_SET_IRQS, &irq_set)) {
+ 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 +715,66 @@ struct rte_intr_source {
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 enabling 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
+ /* VFIO MSI* is implicitly acked unlike INTx, nothing to do */
+ 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)
{
@@ -403,6 +403,7 @@ EXPERIMENTAL {
rte_realloc_socket;
# added in 19.08
+ rte_intr_ack;
rte_lcore_cpuset;
rte_lcore_to_cpu_id;
rte_mcfg_timer_lock;