mac80211_hwsim: add frame transmission support over virtio

This allows communication with external entities.

It also required fixing up the netlink policy, since NLA_UNSPEC
attributes are no longer accepted.
Signed-off-by: Erel Geron <erelx.geron@intel.com>
[port to backports, inline the ID, use 29 as the ID as requested,
 drop != NULL checks, reduce ifdefs]
Link: https://lore.kernel.org/r/20200305143212.c6e4c87d225b.I7ce60bf143e863dcdf0fb8040aab7168ba549b99@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/mac80211_hwsim.h

@@ -3,6 +3,7 @@
  * mac80211_hwsim - software simulator of 802.11 radio(s) for mac80211
  * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
  * Copyright (c) 2011, Javier Lopez <jlopex@gmail.com>
+ * Copyright (C) 2020 Intel Corporation
  */
 
 #ifndef __MAC80211_HWSIM_H
@@ -245,4 +246,24 @@ struct hwsim_tx_rate_flag {
 	s8 idx;
 	u16 flags;
 } __packed;
+
+/**
+ * DOC: Frame transmission support over virtio
+ *
+ * Frame transmission is also supported over virtio to allow communication
+ * with external entities.
+ */
+
+/**
+ * enum hwsim_vqs - queues for virtio frame transmission
+ *
+ * @HWSIM_VQ_TX: send frames to external entity
+ * @HWSIM_VQ_RX: receive frames and transmission info reports
+ * @HWSIM_NUM_VQS: enum limit
+ */
+enum {
+	HWSIM_VQ_TX,
+	HWSIM_VQ_RX,
+	HWSIM_NUM_VQS,
+};
 #endif /* __MAC80211_HWSIM_H */

include/uapi/linux/virtio_ids.h

@@ -46,5 +46,6 @@
 #define VIRTIO_ID_IOMMU        23 /* virtio IOMMU */
 #define VIRTIO_ID_FS           26 /* virtio filesystem */
 #define VIRTIO_ID_PMEM         27 /* virtio pmem */
+#define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */
 
 #endif /* _LINUX_VIRTIO_IDS_H */