vdpa: Define vdpa mgmt device, ops and a netlink interface

To add one or more VDPA devices, define a management device which
allows adding or removing vdpa device. A management device defines
set of callbacks to manage vdpa devices.

To begin with, it defines add and remove callbacks through which a user
defined vdpa device can be added or removed.

A unique management device is identified by its unique handle identified
by management device name and optionally the bus name.

Hence, introduce routine through which driver can register a
management device and its callback operations for adding and remove
a vdpa device.

Introduce vdpa netlink socket family so that user can query management
device and its attributes.

Example of show vdpa management device which allows creating vdpa device of
networking class (device id = 0x1) of virtio specification 1.1
section 5.1.1.

$ vdpa mgmtdev show
vdpasim_net:
  supported_classes:
    net

Example of showing vdpa management device in JSON format.

$ vdpa mgmtdev show -jp
{
    "show": {
        "vdpasim_net": {
            "supported_classes": [ "net" ]
        }
    }
}

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210105103203.82508-4-parav@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Including a bugfix:

vpda: correctly size vdpa_nl_policy

We need to ensure last entry of vdpa_nl_policy[]
is zero, otherwise out-of-bounds access is hurting us.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Parav Pandit <parav@nvidia.com>
Cc: Eli Cohen <elic@nvidia.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20210210134911.4119555-1-eric.dumazet@gmail.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
new file mode 100644
index 000000000000..d44d82e567b1
--- /dev/null
+++ b/include/uapi/linux/vdpa.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * vdpa device management interface
+ * Copyright (c) 2020 Mellanox Technologies Ltd. All rights reserved.
+ */
+
+#ifndef _UAPI_LINUX_VDPA_H_
+#define _UAPI_LINUX_VDPA_H_
+
+#define VDPA_GENL_NAME "vdpa"
+#define VDPA_GENL_VERSION 0x1
+
+enum vdpa_command {
+	VDPA_CMD_UNSPEC,
+	VDPA_CMD_MGMTDEV_NEW,
+	VDPA_CMD_MGMTDEV_GET,		/* can dump */
+};
+
+enum vdpa_attr {
+	VDPA_ATTR_UNSPEC,
+
+	/* bus name (optional) + dev name together make the parent device handle */
+	VDPA_ATTR_MGMTDEV_BUS_NAME,		/* string */
+	VDPA_ATTR_MGMTDEV_DEV_NAME,		/* string */
+	VDPA_ATTR_MGMTDEV_SUPPORTED_CLASSES,	/* u64 */
+
+	/* new attributes must be added above here */
+	VDPA_ATTR_MAX,
+};
+
+#endif