[dpdk-dev] [PATCH v4 2/4] net/virtio: skip device probe in vdpa mode

[Xiao Wang <xiao.w.wang@intel.com>]

If we want a virtio device to work in vDPA (vhost data path acceleration)
mode, we could add a "vdpa=1" devarg for this device to specify the mode.

This patch let virtio pmd skip device probe when detecting this parameter.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 drivers/net/virtio/virtio_ethdev.c | 43 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 2ef213d1a..afb096804 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -28,6 +28,7 @@
 #include <rte_eal.h>
 #include <rte_dev.h>
 #include <rte_cycles.h>
+#include <rte_kvargs.h>
 
 #include "virtio_ethdev.h"
 #include "virtio_pci.h"
@@ -1708,9 +1709,51 @@ eth_virtio_dev_uninit(struct rte_eth_dev *eth_dev)
 	return 0;
 }
 
+static int vdpa_check_handler(__rte_unused const char *key,
+		const char *value, __rte_unused void *opaque)
+{
+	if (strcmp(value, "1"))
+		return -1;
+
+	return 0;
+}
+
+static int
+vdpa_mode_selected(struct rte_devargs *devargs)
+{
+	struct rte_kvargs *kvlist;
+	const char *key = "vdpa";
+	int ret = 0;
+
+	if (devargs == NULL)
+		return 0;
+
+	kvlist = rte_kvargs_parse(devargs->args, NULL);
+	if (kvlist == NULL)
+		return 0;
+
+	if (!rte_kvargs_count(kvlist, key))
+		goto exit;
+
+	/* vdpa mode selected when there's a key-value pair: vdpa=1 */
+	if (rte_kvargs_process(kvlist, key,
+				vdpa_check_handler, NULL) < 0) {
+		goto exit;
+	}
+	ret = 1;
+
+exit:
+	rte_kvargs_free(kvlist);
+	return ret;
+}
+
 static int eth_virtio_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
 	struct rte_pci_device *pci_dev)
 {
+	/* virtio pmd skips probe if device needs to work in vdpa mode */
+	if (vdpa_mode_selected(pci_dev->device.devargs))
+		return 1;
+
 	return rte_eth_dev_pci_generic_probe(pci_dev, sizeof(struct virtio_hw),
 		eth_virtio_dev_init);
 }
-- 
2.15.1