[dpdk-dev] [PATCH v3 2/4] net/virtio: skip device probe in vdpa mode

[Xiao Wang]

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.w...@intel.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 884f74ad0..6551a367f 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -29,6 +29,7 @@
 #include <rte_eal.h>
 #include <rte_dev.h>
 #include <rte_cycles.h>
+#include <rte_kvargs.h>
 
 #include "virtio_ethdev.h"
 #include "virtio_pci.h"
@@ -1744,9 +1745,51 @@ 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