[PATCH] mac80211_hwsim: add frame transmission support over virtio

[PATCH] mac80211_hwsim: add frame transmission support over virtio

[Johannes Berg]

From: Erel Geron <erelx.geron@intel.com>

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]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/mac80211_hwsim.c | 331 ++++++++++++++++++++++++--
 drivers/net/wireless/mac80211_hwsim.h |  21 ++
 2 files changed, 334 insertions(+), 18 deletions(-)

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index da0a6b6c4771..3fb003a7fbad 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -4,7 +4,7 @@
  * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
  * Copyright (c) 2011, Javier Lopez <jlopex@gmail.com>
  * Copyright (c) 2016 - 2017 Intel Deutschland GmbH
- * Copyright (C) 2018 Intel Corporation
+ * Copyright (C) 2018 - 2020 Intel Corporation
  */
 
 /*
@@ -33,6 +33,9 @@
 #include <net/netns/generic.h>
 #include <linux/rhashtable.h>
 #include <linux/nospec.h>
+#include <linux/virtio.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
 #include "mac80211_hwsim.h"
 
 #define WARN_QUEUE 100
@@ -613,14 +616,14 @@ static const struct genl_multicast_group hwsim_mcgrps[] = {
 /* MAC80211_HWSIM netlink policy */
 
 static const struct nla_policy hwsim_genl_policy[HWSIM_ATTR_MAX + 1] = {
-	[HWSIM_ATTR_ADDR_RECEIVER] = { .type = NLA_UNSPEC, .len = ETH_ALEN },
-	[HWSIM_ATTR_ADDR_TRANSMITTER] = { .type = NLA_UNSPEC, .len = ETH_ALEN },
+	[HWSIM_ATTR_ADDR_RECEIVER] = NLA_POLICY_ETH_ADDR_COMPAT,
+	[HWSIM_ATTR_ADDR_TRANSMITTER] = NLA_POLICY_ETH_ADDR_COMPAT,
 	[HWSIM_ATTR_FRAME] = { .type = NLA_BINARY,
 			       .len = IEEE80211_MAX_DATA_LEN },
 	[HWSIM_ATTR_FLAGS] = { .type = NLA_U32 },
 	[HWSIM_ATTR_RX_RATE] = { .type = NLA_U32 },
 	[HWSIM_ATTR_SIGNAL] = { .type = NLA_U32 },
-	[HWSIM_ATTR_TX_INFO] = { .type = NLA_UNSPEC,
+	[HWSIM_ATTR_TX_INFO] = { .type = NLA_BINARY,
 				 .len = IEEE80211_TX_MAX_RATES *
 					sizeof(struct hwsim_tx_rate)},
 	[HWSIM_ATTR_COOKIE] = { .type = NLA_U64 },
@@ -630,15 +633,65 @@ static const struct nla_policy hwsim_genl_policy[HWSIM_ATTR_MAX + 1] = {
 	[HWSIM_ATTR_REG_CUSTOM_REG] = { .type = NLA_U32 },
 	[HWSIM_ATTR_REG_STRICT_REG] = { .type = NLA_FLAG },
 	[HWSIM_ATTR_SUPPORT_P2P_DEVICE] = { .type = NLA_FLAG },
+	[HWSIM_ATTR_USE_CHANCTX] = { .type = NLA_FLAG },
 	[HWSIM_ATTR_DESTROY_RADIO_ON_CLOSE] = { .type = NLA_FLAG },
 	[HWSIM_ATTR_RADIO_NAME] = { .type = NLA_STRING },
 	[HWSIM_ATTR_NO_VIF] = { .type = NLA_FLAG },
 	[HWSIM_ATTR_FREQ] = { .type = NLA_U32 },
-	[HWSIM_ATTR_PERM_ADDR] = { .type = NLA_UNSPEC, .len = ETH_ALEN },
+	[HWSIM_ATTR_TX_INFO_FLAGS] = { .type = NLA_BINARY },
+	[HWSIM_ATTR_PERM_ADDR] = NLA_POLICY_ETH_ADDR_COMPAT,
 	[HWSIM_ATTR_IFTYPE_SUPPORT] = { .type = NLA_U32 },
 	[HWSIM_ATTR_CIPHER_SUPPORT] = { .type = NLA_BINARY },
 };
 
+#if IS_REACHABLE(CONFIG_VIRTIO)
+
+#ifndef VIRTIO_ID_MAC80211_HWSIM
+#define VIRTIO_ID_MAC80211_HWSIM 29
+#endif
+
+/* MAC80211_HWSIM virtio queues */
+static struct virtqueue *hwsim_vqs[HWSIM_NUM_VQS];
+static bool hwsim_virtio_enabled;
+static spinlock_t hwsim_virtio_lock;
+
+static void hwsim_virtio_rx_work(struct work_struct *work);
+static DECLARE_WORK(hwsim_virtio_rx, hwsim_virtio_rx_work);
+
+static int hwsim_tx_virtio(struct mac80211_hwsim_data *data,
+			   struct sk_buff *skb)
+{
+	struct scatterlist sg[1];
+	unsigned long flags;
+	int err;
+
+	spin_lock_irqsave(&hwsim_virtio_lock, flags);
+	if (!hwsim_virtio_enabled) {
+		err = -ENODEV;
+		goto out_free;
+	}
+
+	sg_init_one(sg, skb->head, skb_end_offset(skb));
+	err = virtqueue_add_outbuf(hwsim_vqs[HWSIM_VQ_TX], sg, 1, skb,
+				   GFP_ATOMIC);
+	if (err)
+		goto out_free;
+	virtqueue_kick(hwsim_vqs[HWSIM_VQ_TX]);
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+	return 0;
+
+out_free:
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+	nlmsg_free(skb);
+	return err;
+}
+#else
+/* cause a linker error if this ends up being needed */
+extern int hwsim_tx_virtio(struct mac80211_hwsim_data *data,
+			   struct sk_buff *skb);
+#define hwsim_virtio_enabled false
+#endif
+
 static void mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
 				    struct sk_buff *skb,
 				    struct ieee80211_channel *chan);
@@ -1138,8 +1191,14 @@ static void mac80211_hwsim_tx_frame_nl(struct ieee80211_hw *hw,
 		goto nla_put_failure;
 
 	genlmsg_end(skb, msg_head);
-	if (hwsim_unicast_netgroup(data, skb, dst_portid))
-		goto err_free_txskb;
+
+	if (hwsim_virtio_enabled) {
+		if (hwsim_tx_virtio(data, skb))
+			goto err_free_txskb;
+	} else {
+		if (hwsim_unicast_netgroup(data, skb, dst_portid))
+			goto err_free_txskb;
+	}
 
 	/* Enqueue the packet */
 	skb_queue_tail(&data->pending, my_skb);
@@ -1441,7 +1500,7 @@ static void mac80211_hwsim_tx(struct ieee80211_hw *hw,
 	/* wmediumd mode check */
 	_portid = READ_ONCE(data->wmediumd);
 
-	if (_portid)
+	if (_portid || hwsim_virtio_enabled)
 		return mac80211_hwsim_tx_frame_nl(hw, skb, _portid);
 
 	/* NO wmediumd detected, perfect medium simulation */
@@ -1547,7 +1606,7 @@ static void mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
 
 	mac80211_hwsim_monitor_rx(hw, skb, chan);
 
-	if (_pid)
+	if (_pid || hwsim_virtio_enabled)
 		return mac80211_hwsim_tx_frame_nl(hw, skb, _pid);
 
 	mac80211_hwsim_tx_frame_no_nl(hw, skb, chan);
@@ -3293,11 +3352,14 @@ static int hwsim_tx_info_frame_received_nl(struct sk_buff *skb_2,
 	if (!data2)
 		goto out;
 
-	if (hwsim_net_get_netgroup(genl_info_net(info)) != data2->netgroup)
-		goto out;
+	if (!hwsim_virtio_enabled) {
+		if (hwsim_net_get_netgroup(genl_info_net(info)) !=
+		    data2->netgroup)
+			goto out;
 
-	if (info->snd_portid != data2->wmediumd)
-		goto out;
+		if (info->snd_portid != data2->wmediumd)
+			goto out;
+	}
 
 	/* look for the skb matching the cookie passed back from user */
 	skb_queue_walk_safe(&data2->pending, skb, tmp) {
@@ -3387,11 +3449,14 @@ static int hwsim_cloned_frame_received_nl(struct sk_buff *skb_2,
 	if (!data2)
 		goto out;
 
-	if (hwsim_net_get_netgroup(genl_info_net(info)) != data2->netgroup)
-		goto out;
+	if (!hwsim_virtio_enabled) {
+		if (hwsim_net_get_netgroup(genl_info_net(info)) !=
+		    data2->netgroup)
+			goto out;
 
-	if (info->snd_portid != data2->wmediumd)
-		goto out;
+		if (info->snd_portid != data2->wmediumd)
+			goto out;
+	}
 
 	/* check if radio is configured properly */
 
@@ -3932,6 +3997,229 @@ static void hwsim_exit_netlink(void)
 	genl_unregister_family(&hwsim_genl_family);
 }
 
+#if IS_REACHABLE(CONFIG_VIRTIO)
+static void hwsim_virtio_tx_done(struct virtqueue *vq)
+{
+	unsigned int len;
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	spin_lock_irqsave(&hwsim_virtio_lock, flags);
+	while ((skb = virtqueue_get_buf(vq, &len)))
+		nlmsg_free(skb);
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+}
+
+static int hwsim_virtio_handle_cmd(struct sk_buff *skb)
+{
+	struct nlmsghdr *nlh;
+	struct genlmsghdr *gnlh;
+	struct nlattr *tb[HWSIM_ATTR_MAX + 1];
+	struct genl_info info = {};
+	int err;
+
+	nlh = nlmsg_hdr(skb);
+	gnlh = nlmsg_data(nlh);
+	err = genlmsg_parse(nlh, &hwsim_genl_family, tb, HWSIM_ATTR_MAX,
+			    hwsim_genl_policy, NULL);
+	if (err) {
+		pr_err_ratelimited("hwsim: genlmsg_parse returned %d\n", err);
+		return err;
+	}
+
+	info.attrs = tb;
+
+	switch (gnlh->cmd) {
+	case HWSIM_CMD_FRAME:
+		hwsim_cloned_frame_received_nl(skb, &info);
+		break;
+	case HWSIM_CMD_TX_INFO_FRAME:
+		hwsim_tx_info_frame_received_nl(skb, &info);
+		break;
+	default:
+		pr_err_ratelimited("hwsim: invalid cmd: %d\n", gnlh->cmd);
+		return -EPROTO;
+	}
+	return 0;
+}
+
+static void hwsim_virtio_rx_work(struct work_struct *work)
+{
+	struct virtqueue *vq;
+	unsigned int len;
+	struct sk_buff *skb;
+	struct scatterlist sg[1];
+	int err;
+	unsigned long flags;
+
+	spin_lock_irqsave(&hwsim_virtio_lock, flags);
+	if (!hwsim_virtio_enabled)
+		goto out_unlock;
+
+	skb = virtqueue_get_buf(hwsim_vqs[HWSIM_VQ_RX], &len);
+	if (!skb)
+		goto out_unlock;
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+
+	skb->data = skb->head;
+	skb_set_tail_pointer(skb, len);
+	hwsim_virtio_handle_cmd(skb);
+
+	spin_lock_irqsave(&hwsim_virtio_lock, flags);
+	if (!hwsim_virtio_enabled) {
+		nlmsg_free(skb);
+		goto out_unlock;
+	}
+	vq = hwsim_vqs[HWSIM_VQ_RX];
+	sg_init_one(sg, skb->head, skb_end_offset(skb));
+	err = virtqueue_add_inbuf(vq, sg, 1, skb, GFP_KERNEL);
+	if (WARN(err, "virtqueue_add_inbuf returned %d\n", err))
+		nlmsg_free(skb);
+	else
+		virtqueue_kick(vq);
+	schedule_work(&hwsim_virtio_rx);
+
+out_unlock:
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+}
+
+static void hwsim_virtio_rx_done(struct virtqueue *vq)
+{
+	schedule_work(&hwsim_virtio_rx);
+}
+
+static int init_vqs(struct virtio_device *vdev)
+{
+	vq_callback_t *callbacks[HWSIM_NUM_VQS] = {
+		[HWSIM_VQ_TX] = hwsim_virtio_tx_done,
+		[HWSIM_VQ_RX] = hwsim_virtio_rx_done,
+	};
+	const char *names[HWSIM_NUM_VQS] = {
+		[HWSIM_VQ_TX] = "tx",
+		[HWSIM_VQ_RX] = "rx",
+	};
+
+	return virtio_find_vqs(vdev, HWSIM_NUM_VQS,
+			       hwsim_vqs, callbacks, names, NULL);
+}
+
+static int fill_vq(struct virtqueue *vq)
+{
+	int i, err;
+	struct sk_buff *skb;
+	struct scatterlist sg[1];
+
+	for (i = 0; i < virtqueue_get_vring_size(vq); i++) {
+		skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+		if (!skb)
+			return -ENOMEM;
+
+		sg_init_one(sg, skb->head, skb_end_offset(skb));
+		err = virtqueue_add_inbuf(vq, sg, 1, skb, GFP_KERNEL);
+		if (err) {
+			nlmsg_free(skb);
+			return err;
+		}
+	}
+	virtqueue_kick(vq);
+	return 0;
+}
+
+static void remove_vqs(struct virtio_device *vdev)
+{
+	int i;
+
+	vdev->config->reset(vdev);
+
+	for (i = 0; i < ARRAY_SIZE(hwsim_vqs); i++) {
+		struct virtqueue *vq = hwsim_vqs[i];
+		struct sk_buff *skb;
+
+		while ((skb = virtqueue_detach_unused_buf(vq)))
+			nlmsg_free(skb);
+	}
+
+	vdev->config->del_vqs(vdev);
+}
+
+static int hwsim_virtio_probe(struct virtio_device *vdev)
+{
+	int err;
+	unsigned long flags;
+
+	spin_lock_irqsave(&hwsim_virtio_lock, flags);
+	if (hwsim_virtio_enabled) {
+		spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+		return -EEXIST;
+	}
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+
+	err = init_vqs(vdev);
+	if (err)
+		return err;
+
+	err = fill_vq(hwsim_vqs[HWSIM_VQ_RX]);
+	if (err)
+		goto out_remove;
+
+	spin_lock_irqsave(&hwsim_virtio_lock, flags);
+	hwsim_virtio_enabled = true;
+	spin_unlock_irqrestore(&hwsim_virtio_lock, flags);
+
+	schedule_work(&hwsim_virtio_rx);
+	return 0;
+
+out_remove:
+	remove_vqs(vdev);
+	return err;
+}
+
+static void hwsim_virtio_remove(struct virtio_device *vdev)
+{
+	hwsim_virtio_enabled = false;
+
+	cancel_work_sync(&hwsim_virtio_rx);
+
+	remove_vqs(vdev);
+}
+
+/* MAC80211_HWSIM virtio device id table */
+static const struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_MAC80211_HWSIM, VIRTIO_DEV_ANY_ID },
+	{ 0 }
+};
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+static struct virtio_driver virtio_hwsim = {
+	.driver.name = KBUILD_MODNAME,
+	.driver.owner = THIS_MODULE,
+	.id_table = id_table,
+	.probe = hwsim_virtio_probe,
+	.remove = hwsim_virtio_remove,
+};
+
+static int hwsim_register_virtio_driver(void)
+{
+	spin_lock_init(&hwsim_virtio_lock);
+
+	return register_virtio_driver(&virtio_hwsim);
+}
+
+static void hwsim_unregister_virtio_driver(void)
+{
+	unregister_virtio_driver(&virtio_hwsim);
+}
+#else
+static inline int hwsim_register_virtio_driver(void)
+{
+	return 0;
+}
+
+static inline void hwsim_unregister_virtio_driver(void)
+{
+}
+#endif
+
 static int __init init_mac80211_hwsim(void)
 {
 	int i, err;
@@ -3960,10 +4248,14 @@ static int __init init_mac80211_hwsim(void)
 	if (err)
 		goto out_unregister_driver;
 
+	err = hwsim_register_virtio_driver();
+	if (err)
+		goto out_exit_netlink;
+
 	hwsim_class = class_create(THIS_MODULE, "mac80211_hwsim");
 	if (IS_ERR(hwsim_class)) {
 		err = PTR_ERR(hwsim_class);
-		goto out_exit_netlink;
+		goto out_exit_virtio;
 	}
 
 	for (i = 0; i < radios; i++) {
@@ -4075,6 +4367,8 @@ static int __init init_mac80211_hwsim(void)
 	free_netdev(hwsim_mon);
 out_free_radios:
 	mac80211_hwsim_free();
+out_exit_virtio:
+	hwsim_unregister_virtio_driver();
 out_exit_netlink:
 	hwsim_exit_netlink();
 out_unregister_driver:
@@ -4091,6 +4385,7 @@ static void __exit exit_mac80211_hwsim(void)
 {
 	pr_debug("mac80211_hwsim: unregister radios\n");
 
+	hwsim_unregister_virtio_driver();
 	hwsim_exit_netlink();
 
 	mac80211_hwsim_free();
diff --git a/drivers/net/wireless/mac80211_hwsim.h b/drivers/net/wireless/mac80211_hwsim.h
index a85bc7c5c030..28ade92adcb4 100644
--- a/drivers/net/wireless/mac80211_hwsim.h
+++ b/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 */
-- 
2.24.1

Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Marcel Holtmann]

Hi Johannes,

> 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]
> Signed-off-by: Johannes Berg <johannes.berg@intel.com>

since the module now can auto-load, don’t you want to change radios = 2 to radio = 0?

Regards

Marcel

Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Johannes Berg]

Hi Marcel,
> 
> > 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]
> > Signed-off-by: Johannes Berg <johannes.berg@intel.com>
> 
> since the module now can auto-load, don’t you want to change radios = 2 to radio = 0?

Hmm. I didn't really want to change the behaviour there, and the auto-
loading is *highly* unlikely, you need to specifically set up a vhost-
user wmediumd (which I'm in the process of publishing).

And even then, you still need to have the radios, they just don't
communicate directly with each other but will go into wmediumd over the
virtio when you actually have virtio.

I'm not principally opposed to changing the default, but I'm not
convinced it'd be related to this patch in any way.

johannes

Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Marcel Holtmann]

Hi Johannes,

>>> 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]
>>> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
>> 
>> since the module now can auto-load, don’t you want to change radios = 2 to radio = 0?
> 
> Hmm. I didn't really want to change the behaviour there, and the auto-
> loading is *highly* unlikely, you need to specifically set up a vhost-
> user wmediumd (which I'm in the process of publishing).
> 
> And even then, you still need to have the radios, they just don't
> communicate directly with each other but will go into wmediumd over the
> virtio when you actually have virtio.
> 
> I'm not principally opposed to changing the default, but I'm not
> convinced it'd be related to this patch in any way.

can we just make it a Kconfig option that defaults to 2, but gets set to 0 when virtio support is included.

Regards

Marcel

Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Johannes Berg]

On Thu, 2020-03-05 at 15:09 +0100, Marcel Holtmann wrote:
> 
> can we just make it a Kconfig option that defaults to 2, but gets set
> to 0 when virtio support is included.

We could, I guess, but I don't understand why?

I don't understand why you think there should be any relation between
virtio and the number of fake radios?

Basically, hwsim works like this:

There are a number of virtual radios (defaulting to two), which can
communicate with each other. This communication can be

1) handled inside the hwsim driver itself, "perfect" medium simulation
   without any latency etc.
2) handled over netlink with wmediumd (running inside the same kernel),
   i.e. calling out to userspace for all frame transmissions etc.

With this patch, in addition, the communication can be

3) handled over virtio to wmediumd running *outside* the qemu (untested)
   or user-mode-linux virtual machine.


So you still need virtual radios inside, and virtio doesn't *create* any
new virtual radios, it just provides the wmediumd communication
mechanism. Regardless of virtio, you can have any number of virtual
radios inside the kernel.

johannes

Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Marcel Holtmann]

Hi Johannes,

>> can we just make it a Kconfig option that defaults to 2, but gets set
>> to 0 when virtio support is included.
> 
> We could, I guess, but I don't understand why?
> 
> I don't understand why you think there should be any relation between
> virtio and the number of fake radios?
> 
> Basically, hwsim works like this:
> 
> There are a number of virtual radios (defaulting to two), which can
> communicate with each other. This communication can be
> 
> 1) handled inside the hwsim driver itself, "perfect" medium simulation
>   without any latency etc.
> 2) handled over netlink with wmediumd (running inside the same kernel),
>   i.e. calling out to userspace for all frame transmissions etc.
> 
> With this patch, in addition, the communication can be
> 
> 3) handled over virtio to wmediumd running *outside* the qemu (untested)
>   or user-mode-linux virtual machine.
> 
> 
> So you still need virtual radios inside, and virtio doesn't *create* any
> new virtual radios, it just provides the wmediumd communication
> mechanism. Regardless of virtio, you can have any number of virtual
> radios inside the kernel.

of course and I would prefer they are created by using genl or when you set the kernel module option to the number you want.

The default of 2 radios is just bugging me. I refrained from adding genl autoloading to mac80211_hwsim because of this 2 radios default. I would like to get that added as well.

Regards

Marcel

Re: [PATCH] mac80211_hwsim: add frame transmission support over virtio

[Johannes Berg]

On Thu, 2020-03-05 at 15:18 +0100, Marcel Holtmann wrote:
> 
> of course and I would prefer they are created by using genl or when
> you set the kernel module option to the number you want.
> 
> The default of 2 radios is just bugging me. I refrained from adding
> genl autoloading to mac80211_hwsim because of this 2 radios default. I
> would like to get that added as well.

Sure, I don't really have any objection to either of those. I just don't
really see the connection to this particular patch?

johannes