[PATCH v4 4/4] vdpa: Support reading device features

[Eli Cohen <elic@nvidia.com>]

When showing the available management devices, check if
VDPA_ATTR_DEV_SUPPORTED_FEATURES feature is available and print the
supported features for a management device.

Examples:
$ vdpa mgmtdev show
auxiliary/mlx5_core.sf.1:
  supported_classes net
  max_supported_vqs 257
  dev_features CSUM GUEST_CSUM MTU HOST_TSO4 HOST_TSO6 STATUS CTRL_VQ MQ \
               CTRL_MAC_ADDR VERSION_1 ACCESS_PLATFORM

$ vdpa -jp mgmtdev show
{
    "mgmtdev": {
        "auxiliary/mlx5_core.sf.1": {
            "supported_classes": [ "net" ],
            "max_supported_vqs": 257,
            "dev_features": [
"CSUM","GUEST_CSUM","MTU","HOST_TSO4","HOST_TSO6","STATUS","CTRL_VQ","MQ",\
"CTRL_MAC_ADDR","VERSION_1","ACCESS_PLATFORM" ]
        }
    }
}

Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 vdpa/include/uapi/linux/vdpa.h |  1 +
 vdpa/vdpa.c                    | 15 +++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/vdpa/include/uapi/linux/vdpa.h b/vdpa/include/uapi/linux/vdpa.h
index a3ebf4d4d9b8..96ccbf305d14 100644
--- a/vdpa/include/uapi/linux/vdpa.h
+++ b/vdpa/include/uapi/linux/vdpa.h
@@ -42,6 +42,7 @@ enum vdpa_attr {
 
 	VDPA_ATTR_DEV_NEGOTIATED_FEATURES,	/* u64 */
 	VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,          /* u32 */
+	VDPA_ATTR_DEV_SUPPORTED_FEATURES,	/* u64 */
 
 	/* new attributes must be added above here */
 	VDPA_ATTR_MAX,
diff --git a/vdpa/vdpa.c b/vdpa/vdpa.c
index 22064c755baa..bdc366880ab9 100644
--- a/vdpa/vdpa.c
+++ b/vdpa/vdpa.c
@@ -84,6 +84,7 @@ static const enum mnl_attr_data_type vdpa_policy[VDPA_ATTR_MAX + 1] = {
 	[VDPA_ATTR_DEV_MAX_VQ_SIZE] = MNL_TYPE_U16,
 	[VDPA_ATTR_DEV_NEGOTIATED_FEATURES] = MNL_TYPE_U64,
 	[VDPA_ATTR_DEV_MGMTDEV_MAX_VQS] = MNL_TYPE_U32,
+	[VDPA_ATTR_DEV_SUPPORTED_FEATURES] = MNL_TYPE_U64,
 };
 
 static int attr_cb(const struct nlattr *attr, void *data)
@@ -494,14 +495,14 @@ static void print_features(struct vdpa *vdpa, uint64_t features, bool mgmtdevf,
 static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
 				struct nlattr **tb)
 {
+	uint64_t classes = 0;
 	const char *class;
 	unsigned int i;
 
 	pr_out_handle_start(vdpa, tb);
 
 	if (tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]) {
-		uint64_t classes = mnl_attr_get_u64(tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]);
-
+		classes = mnl_attr_get_u64(tb[VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES]);
 		pr_out_array_start(vdpa, "supported_classes");
 
 		for (i = 1; i < 64; i++) {
@@ -523,6 +524,16 @@ static void pr_out_mgmtdev_show(struct vdpa *vdpa, const struct nlmsghdr *nlh,
 		print_uint(PRINT_ANY, "max_supported_vqs", "  max_supported_vqs %d", num_vqs);
 	}
 
+	if (tb[VDPA_ATTR_DEV_SUPPORTED_FEATURES]) {
+		uint64_t features;
+
+		features  = mnl_attr_get_u64(tb[VDPA_ATTR_DEV_SUPPORTED_FEATURES]);
+		if (classes & BIT(VIRTIO_ID_NET))
+			print_features(vdpa, features, true, VIRTIO_ID_NET);
+		else
+			print_features(vdpa, features, true, 0);
+	}
+
 	pr_out_handle_end(vdpa);
 }
 
-- 
2.35.1