[dpdk-stable] [PATCH] net/virtio: fix read isr as MSI is enabled
Jianfeng Tan
jianfeng.tan at intel.com
Tue Mar 28 08:46:51 CEST 2017
We should not always check isr to know if link status is changed.
Here is how driver should handle interrupt quoted from virtio spec,
If MSI-X capability is disabled:
– Read the ISR Status field, which will reset it to zero.
– If the lower bit is set: look through the used rings of all
virtqueues for the device, to see if any progress has been made
by the device which requires servicing.
– If the second lower bit is set: re-examine the configuration
space to see what changed.
If MSI-X capability is enabled:
– Look through the used rings of all virtqueues mapped to that
MSI-X vector for the device, to see if any progress has been
made by the device which requires servicing.
– If the MSI-X vector is equal to config_msix_vector, re-examine
the configuration space to see what changed
Fixes: 8d6d7e5cb3b1 ("virtio: support link state interrupt")
CC: stable at dpdk.org
CC: Stephen Hemminger <stephen at networkplumber.org>
Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
---
drivers/net/virtio/virtio_ethdev.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 3cf4102..cb30d11 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -36,6 +36,7 @@
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
+#include <stdbool.h>
#include <rte_ethdev.h>
#include <rte_memcpy.h>
@@ -1197,20 +1198,23 @@ virtio_interrupt_handler(struct rte_intr_handle *handle,
struct rte_eth_dev *dev = param;
struct virtio_hw *hw = dev->data->dev_private;
uint8_t isr;
+ bool check_config;
- /* Read interrupt status which clears interrupt */
- isr = vtpci_isr(hw);
- PMD_DRV_LOG(INFO, "interrupt status = %#x", isr);
+ /* isr is used only when msix is not enabled */
+ if (!hw->modern && !hw->use_msix) {
+ isr = vtpci_isr(hw); /* Read to clears interrupt */
+ PMD_DRV_LOG(INFO, "interrupt status = %#x", isr);
+ check_config = (isr & VIRTIO_PCI_ISR_CONFIG) ? true : false;
+ } else {
+ check_config = true;
+ }
if (rte_intr_enable(handle) < 0)
PMD_DRV_LOG(ERR, "interrupt enable failed");
- if (isr & VIRTIO_PCI_ISR_CONFIG) {
- if (virtio_dev_link_update(dev, 0) == 0)
- _rte_eth_dev_callback_process(dev,
- RTE_ETH_EVENT_INTR_LSC, NULL);
- }
-
+ if (check_config && virtio_dev_link_update(dev, 0) == 0)
+ _rte_eth_dev_callback_process(dev,
+ RTE_ETH_EVENT_INTR_LSC, NULL);
}
static void
--
2.7.4
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