[PULL 0/8] Net patches

[PULL 0/8] Net patches

[Jason Wang]

The following changes since commit 31669121a01a14732f57c49400bc239cf9fd505f:

  Merge tag 'pull-target-arm-20240801' of https://git.linaro.org/people/pmaydell/qemu-arm into staging (2024-08-02 08:18:37 +1000)

are available in the Git repository at:

  https://github.com/jasowang/qemu.git tags/net-pull-request

for you to fetch changes up to 64f75f57f9d2c8c12ac6d9355fa5d3a2af5879ca:

  net: Reinstate '-net nic, model=help' output as documented in man page (2024-08-02 11:09:52 +0800)

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----------------------------------------------------------------
Akihiko Odaki (1):
      virtio-net: Ensure queue index fits with RSS

David Woodhouse (1):
      net: Reinstate '-net nic, model=help' output as documented in man page

Hans (1):
      rtl8139: Fix behaviour for old kernels.

Laurent Vivier (4):
      net: update netdev stream/dgram man page
      net: update netdev stream man page with unix socket
      net: update netdev dgram man page with unix socket
      net: update netdev stream man page with the reconnect parameter

thomas (1):
      virtio-net: Fix network stall at the host side waiting for kick

 hw/net/rtl8139.c           |   6 +-
 hw/net/virtio-net.c        |  31 ++++----
 hw/virtio/virtio.c         |  64 ++++++++++++++-
 include/hw/virtio/virtio.h |  19 ++++-
 net/net.c                  |  25 +++++-
 qemu-options.hx            | 189 +++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 310 insertions(+), 24 deletions(-)

[PULL 1/8] rtl8139: Fix behaviour for old kernels.

[Jason Wang]

From: Hans <sungdgdhtryrt@gmail.com>

Old linux kernel rtl8139 drivers (ex. debian 2.1) uses outb to set the rx
mode for RxConfig. Unfortunatelly qemu does not support outb for RxConfig.

Signed-off-by: Hans <sungdgdhtryrt@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/rtl8139.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
index 897c86ec41..03a204ef8a 100644
--- a/hw/net/rtl8139.c
+++ b/hw/net/rtl8139.c
@@ -2738,7 +2738,11 @@ static void rtl8139_io_writeb(void *opaque, uint8_t addr, uint32_t val)
             }
 
             break;
-
+        case RxConfig:
+            DPRINTF("RxConfig write(b) val=0x%02x\n", val);
+            rtl8139_RxConfig_write(s,
+                (rtl8139_RxConfig_read(s) & 0xFFFFFF00) | val);
+            break;
         default:
             DPRINTF("not implemented write(b) addr=0x%x val=0x%02x\n", addr,
                 val);
-- 
2.42.0

[PULL 2/8] virtio-net: Ensure queue index fits with RSS

[Jason Wang]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

Ensure the queue index points to a valid queue when software RSS
enabled. The new calculation matches with the behavior of Linux's TAP
device with the RSS eBPF program.

Fixes: 4474e37a5b3a ("virtio-net: implement RX RSS processing")
Reported-by: Zhibin Hu <huzhibin5@huawei.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 8f30972708..5635620a31 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1905,7 +1905,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
     if (!no_rss && n->rss_data.enabled && n->rss_data.enabled_software_rss) {
         int index = virtio_net_process_rss(nc, buf, size, &extra_hdr);
         if (index >= 0) {
-            NetClientState *nc2 = qemu_get_subqueue(n->nic, index);
+            NetClientState *nc2 =
+                qemu_get_subqueue(n->nic, index % n->curr_queue_pairs);
             return virtio_net_receive_rcu(nc2, buf, size, true);
         }
     }
-- 
2.42.0

Re: [PULL 2/8] virtio-net: Ensure queue index fits with RSS

[Daniel P. Berrangé]

On Fri, Aug 02, 2024 at 11:19:23AM +0800, Jason Wang wrote:
> From: Akihiko Odaki <akihiko.odaki@daynix.com>
> 
> Ensure the queue index points to a valid queue when software RSS
> enabled. The new calculation matches with the behavior of Linux's TAP
> device with the RSS eBPF program.
> 
> Fixes: 4474e37a5b3a ("virtio-net: implement RX RSS processing")
> Reported-by: Zhibin Hu <huzhibin5@huawei.com>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  hw/net/virtio-net.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

FYI, this patch is the fix for CVE-2024-6505.

Please make sure to mention CVE assignments in the commit message
when one is available.

> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 8f30972708..5635620a31 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1905,7 +1905,8 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
>      if (!no_rss && n->rss_data.enabled && n->rss_data.enabled_software_rss) {
>          int index = virtio_net_process_rss(nc, buf, size, &extra_hdr);
>          if (index >= 0) {
> -            NetClientState *nc2 = qemu_get_subqueue(n->nic, index);
> +            NetClientState *nc2 =
> +                qemu_get_subqueue(n->nic, index % n->curr_queue_pairs);
>              return virtio_net_receive_rcu(nc2, buf, size, true);
>          }
>      }

With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|

[PULL 3/8] virtio-net: Fix network stall at the host side waiting for kick

[Jason Wang]

From: thomas <east.moutain.yang@gmail.com>

Patch 06b12970174 ("virtio-net: fix network stall under load")
added double-check to test whether the available buffer size
can satisfy the request or not, in case the guest has added
some buffers to the avail ring simultaneously after the first
check. It will be lucky if the available buffer size becomes
okay after the double-check, then the host can send the packet
to the guest. If the buffer size still can't satisfy the request,
even if the guest has added some buffers, viritio-net would
stall at the host side forever.

The patch enables notification and checks whether the guest has
added some buffers since last check of available buffers when
the available buffers are insufficient. If no buffer is added,
return false, else recheck the available buffers in the loop.
If the available buffers are sufficient, disable notification
and return true.

Changes:
1. Change the return type of virtqueue_get_avail_bytes() from void
   to int, it returns an opaque that represents the shadow_avail_idx
   of the virtqueue on success, else -1 on error.
2. Add a new API: virtio_queue_enable_notification_and_check(),
   it takes an opaque as input arg which is returned from
   virtqueue_get_avail_bytes(). It enables notification firstly,
   then checks whether the guest has added some buffers since
   last check of available buffers or not by virtio_queue_poll(),
   return ture if yes.

The patch also reverts patch "06b12970174".

The case below can reproduce the stall.

                                       Guest 0
                                     +--------+
                                     | iperf  |
                    ---------------> | server |
         Host       |                +--------+
       +--------+   |                    ...
       | iperf  |----
       | client |----                  Guest n
       +--------+   |                +--------+
                    |                | iperf  |
                    ---------------> | server |
                                     +--------+

Boot many guests from qemu with virtio network:
 qemu ... -netdev tap,id=net_x \
    -device virtio-net-pci-non-transitional,\
    iommu_platform=on,mac=xx:xx:xx:xx:xx:xx,netdev=net_x

Each guest acts as iperf server with commands below:
 iperf3 -s -D -i 10 -p 8001
 iperf3 -s -D -i 10 -p 8002

The host as iperf client:
 iperf3 -c guest_IP -p 8001 -i 30 -w 256k -P 20 -t 40000
 iperf3 -c guest_IP -p 8002 -i 30 -w 256k -P 20 -t 40000

After some time, the host loses connection to the guest,
the guest can send packet to the host, but can't receive
packet from the host.

It's more likely to happen if SWIOTLB is enabled in the guest,
allocating and freeing bounce buffer takes some CPU ticks,
copying from/to bounce buffer takes more CPU ticks, compared
with that there is no bounce buffer in the guest.
Once the rate of producing packets from the host approximates
the rate of receiveing packets in the guest, the guest would
loop in NAPI.

         receive packets    ---
               |             |
               v             |
           free buf      virtnet_poll
               |             |
               v             |
     add buf to avail ring  ---
               |
               |  need kick the host?
               |  NAPI continues
               v
         receive packets    ---
               |             |
               v             |
           free buf      virtnet_poll
               |             |
               v             |
     add buf to avail ring  ---
               |
               v
              ...           ...

On the other hand, the host fetches free buf from avail
ring, if the buf in the avail ring is not enough, the
host notifies the guest the event by writing the avail
idx read from avail ring to the event idx of used ring,
then the host goes to sleep, waiting for the kick signal
from the guest.

Once the guest finds the host is waiting for kick singal
(in virtqueue_kick_prepare_split()), it kicks the host.

The host may stall forever at the sequences below:

         Host                        Guest
     ------------                 -----------
 fetch buf, send packet           receive packet ---
         ...                          ...         |
 fetch buf, send packet             add buf       |
         ...                        add buf   virtnet_poll
    buf not enough      avail idx-> add buf       |
    read avail idx                  add buf       |
                                    add buf      ---
                                  receive packet ---
    write event idx                   ...         |
    wait for kick                   add buf   virtnet_poll
                                      ...         |
                                                 ---
                                 no more packet, exit NAPI

In the first loop of NAPI above, indicated in the range of
virtnet_poll above, the host is sending packets while the
guest is receiving packets and adding buffers.
 step 1: The buf is not enough, for example, a big packet
         needs 5 buf, but the available buf count is 3.
         The host read current avail idx.
 step 2: The guest adds some buf, then checks whether the
         host is waiting for kick signal, not at this time.
         The used ring is not empty, the guest continues
         the second loop of NAPI.
 step 3: The host writes the avail idx read from avail
         ring to used ring as event idx via
         virtio_queue_set_notification(q->rx_vq, 1).
 step 4: At the end of the second loop of NAPI, recheck
         whether kick is needed, as the event idx in the
         used ring written by the host is beyound the
         range of kick condition, the guest will not
         send kick signal to the host.

Fixes: 06b12970174 ("virtio-net: fix network stall under load")
Cc: qemu-stable@nongnu.org
Signed-off-by: Wencheng Yang <east.moutain.yang@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c        | 28 ++++++++++-------
 hw/virtio/virtio.c         | 64 +++++++++++++++++++++++++++++++++++---
 include/hw/virtio/virtio.h | 19 +++++++++--
 3 files changed, 92 insertions(+), 19 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 5635620a31..08aa0b65e3 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1641,24 +1641,28 @@ static bool virtio_net_can_receive(NetClientState *nc)
 
 static int virtio_net_has_buffers(VirtIONetQueue *q, int bufsize)
 {
+    int opaque;
+    unsigned int in_bytes;
     VirtIONet *n = q->n;
-    if (virtio_queue_empty(q->rx_vq) ||
-        (n->mergeable_rx_bufs &&
-         !virtqueue_avail_bytes(q->rx_vq, bufsize, 0))) {
-        virtio_queue_set_notification(q->rx_vq, 1);
-
-        /* To avoid a race condition where the guest has made some buffers
-         * available after the above check but before notification was
-         * enabled, check for available buffers again.
-         */
-        if (virtio_queue_empty(q->rx_vq) ||
-            (n->mergeable_rx_bufs &&
-             !virtqueue_avail_bytes(q->rx_vq, bufsize, 0))) {
+
+    while (virtio_queue_empty(q->rx_vq) || n->mergeable_rx_bufs) {
+        opaque = virtqueue_get_avail_bytes(q->rx_vq, &in_bytes, NULL,
+                                           bufsize, 0);
+        /* Buffer is enough, disable notifiaction */
+        if (bufsize <= in_bytes) {
+            break;
+        }
+
+        if (virtio_queue_enable_notification_and_check(q->rx_vq, opaque)) {
+            /* Guest has added some buffers, try again */
+            continue;
+        } else {
             return 0;
         }
     }
 
     virtio_queue_set_notification(q->rx_vq, 0);
+
     return 1;
 }
 
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 397c261c3c..9e10cbc058 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -744,6 +744,60 @@ int virtio_queue_empty(VirtQueue *vq)
     }
 }
 
+static bool virtio_queue_split_poll(VirtQueue *vq, unsigned shadow_idx)
+{
+    if (unlikely(!vq->vring.avail)) {
+        return false;
+    }
+
+    return (uint16_t)shadow_idx != vring_avail_idx(vq);
+}
+
+static bool virtio_queue_packed_poll(VirtQueue *vq, unsigned shadow_idx)
+{
+    VRingPackedDesc desc;
+    VRingMemoryRegionCaches *caches;
+
+    if (unlikely(!vq->vring.desc)) {
+        return false;
+    }
+
+    caches = vring_get_region_caches(vq);
+    if (!caches) {
+        return false;
+    }
+
+    vring_packed_desc_read(vq->vdev, &desc, &caches->desc,
+                           shadow_idx, true);
+
+    return is_desc_avail(desc.flags, vq->shadow_avail_wrap_counter);
+}
+
+static bool virtio_queue_poll(VirtQueue *vq, unsigned shadow_idx)
+{
+    if (virtio_device_disabled(vq->vdev)) {
+        return false;
+    }
+
+    if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+        return virtio_queue_packed_poll(vq, shadow_idx);
+    } else {
+        return virtio_queue_split_poll(vq, shadow_idx);
+    }
+}
+
+bool virtio_queue_enable_notification_and_check(VirtQueue *vq,
+                                                int opaque)
+{
+    virtio_queue_set_notification(vq, 1);
+
+    if (opaque >= 0) {
+        return virtio_queue_poll(vq, (unsigned)opaque);
+    } else {
+        return false;
+    }
+}
+
 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
                                unsigned int len)
 {
@@ -1442,9 +1496,9 @@ err:
     goto done;
 }
 
-void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
-                               unsigned int *out_bytes,
-                               unsigned max_in_bytes, unsigned max_out_bytes)
+int virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
+                              unsigned int *out_bytes, unsigned max_in_bytes,
+                              unsigned max_out_bytes)
 {
     uint16_t desc_size;
     VRingMemoryRegionCaches *caches;
@@ -1477,7 +1531,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
                                         caches);
     }
 
-    return;
+    return (int)vq->shadow_avail_idx;
 err:
     if (in_bytes) {
         *in_bytes = 0;
@@ -1485,6 +1539,8 @@ err:
     if (out_bytes) {
         *out_bytes = 0;
     }
+
+    return -1;
 }
 
 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index d2a1938757..0fcbc5c0c6 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -273,9 +273,13 @@ void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f,
                                 VirtQueueElement *elem);
 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
                           unsigned int out_bytes);
-void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
-                               unsigned int *out_bytes,
-                               unsigned max_in_bytes, unsigned max_out_bytes);
+/**
+ * Return <0 on error or an opaque >=0 to pass to
+ * virtio_queue_enable_notification_and_check on success.
+ */
+int virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
+                              unsigned int *out_bytes, unsigned max_in_bytes,
+                              unsigned max_out_bytes);
 
 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq);
 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq);
@@ -309,6 +313,15 @@ int virtio_queue_ready(VirtQueue *vq);
 
 int virtio_queue_empty(VirtQueue *vq);
 
+/**
+ * Enable notification and check whether guest has added some
+ * buffers since last call to virtqueue_get_avail_bytes.
+ *
+ * @opaque: value returned from virtqueue_get_avail_bytes
+ */
+bool virtio_queue_enable_notification_and_check(VirtQueue *vq,
+                                                int opaque);
+
 void virtio_queue_set_shadow_avail_idx(VirtQueue *vq, uint16_t idx);
 
 /* Host binding interface.  */
-- 
2.42.0

[PULL 4/8] net: update netdev stream/dgram man page

[Jason Wang]

From: Laurent Vivier <lvivier@redhat.com>

Add the description of "-netdev stream" and "-netdev dgram" in the QEMU
manpage.

Add some examples on how to use them.

Fixes: 5166fe0ae46d ("qapi: net: add stream and dgram netdevs")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 qemu-options.hx | 114 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index 369ae81d7c..52143cfb8f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3353,6 +3353,120 @@ SRST
                          -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
                          -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
 
+``-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off]``
+    Configure a network backend to connect to another QEMU virtual machine or a proxy using a TCP/IP socket.
+
+    ``server=on|off``
+        if ``on`` create a server socket
+
+    ``addr.host=host,addr.port=port``
+        socket address to listen on (server=on) or connect to (server=off)
+
+    ``to=maxport``
+        if present, this is range of possible addresses, with port between ``port`` and ``maxport``.
+
+    ``numeric=on|off``
+        if ``on`` ``host`` and ``port`` are guaranteed to be numeric, otherwise a name resolution should be attempted (default: ``off``)
+
+    ``keep-alive=on|off``
+        enable keep-alive when connecting to this socket.  Not supported for passive sockets.
+
+    ``mptcp=on|off``
+        enable multipath TCP
+
+    ``ipv4=on|off``
+        whether to accept IPv4 addresses, default to try both IPv4 and IPv6
+
+    ``ipv6=on|off``
+        whether to accept IPv6 addresses, default to try both IPv4 and IPv6
+
+    Example (two guests connected using a TCP/IP socket):
+
+    .. parsed-literal::
+
+        # first VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
+                      -netdev stream,id=net0,server=on,addr.type=inet,addr.host=localhost,addr.port=1234
+        # second VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
+                      -netdev stream,id=net0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234
+
+``-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor``
+    Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented socket file descriptor.
+
+    ``server=on|off``
+        if ``on`` create a server socket
+
+    ``addr.str=file-descriptor``
+        file descriptor number to use as a socket
+
+``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]``
+    Configure a network backend to connect to a multicast address.
+
+    ``remote.host=maddr,remote.port=port``
+        multicast address
+
+    ``local.host=addr``
+        specify the host address to send packets from
+
+    Example:
+
+    .. parsed-literal::
+
+        # launch one QEMU instance
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
+                      -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234
+        # launch another QEMU instance on same "bus"
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
+                      -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234
+        # launch yet another QEMU instance on same "bus"
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:58 \\
+                      -netdev dgram,id=net0,remote.type=inet,remote.host=224.0.0.1,remote.port=1234
+
+``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]``
+    Configure a network backend to connect to a multicast address using a UDP socket file descriptor.
+
+    ``remote.host=maddr,remote.port=port``
+        multicast address
+
+    ``local.str=file-descriptor``
+        File descriptor to use to send packets
+
+``-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]``
+    Configure a network backend to connect to another QEMU virtual
+    machine or a proxy using a datagram oriented unix domain socket.
+
+    ``local.host=addr,local.port=port``
+        IP address to use to send the packets from
+
+    ``remote.host=addr,remote.port=port``
+        Destination IP address
+
+    Example (two guests connected using an UDP/IP socket):
+
+    .. parsed-literal::
+
+        # first VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
+                      -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1234,remote.type=inet,remote.host=localhost,remote.port=1235
+        # second VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
+                      -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1235,remote.type=inet,remote.host=localhost,remote.port=1234
+
+``-netdev dgram,id=str,local.type=fd,local.str=file-descriptor``
+    Configure a network backend to connect to another QEMU virtual
+    machine or a proxy using a datagram oriented socket file descriptor.
+
+    ``local.str=file-descriptor``
+        File descriptor to use to send packets
+
 ``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64=on|off][,counter=on|off][,pincounter=on|off][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]``
     Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931)
     is a popular protocol to transport Ethernet (and other Layer 2) data
-- 
2.42.0

[PULL 5/8] net: update netdev stream man page with unix socket

[Jason Wang]

From: Laurent Vivier <lvivier@redhat.com>

Add the description of "-netdev stream" with a unix domain socket.
The code has been added but the man page has not been updated.

Include an example how to use "-netdev stream" and "passt" in place
of "-netdev user".
("passt" is a non privileged translation proxy between layer-2, like
"-netdev stream", and layer-4 on host, like TCP, UDP, ICMP/ICMPv6 echo)

Fixes: 13c6be96618c ("net: stream: add unix socket")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 qemu-options.hx | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index 52143cfb8f..2614eea4d7 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3393,6 +3393,46 @@ SRST
                       -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
                       -netdev stream,id=net0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234
 
+``-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off]``
+    Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented unix domain socket.
+
+    ``server=on|off``
+        if ``on`` create a server socket
+
+    ``addr.path=path``
+        filesystem path to use
+
+    ``abstract=on|off``
+        if ``on``, this is a Linux abstract socket address.
+
+    ``tight=on|off``
+        if false, pad an abstract socket address with enough null bytes to make it fill struct sockaddr_un member sun_path.
+
+    Example (using passt as a replacement of -netdev user):
+
+    .. parsed-literal::
+
+        # start passt server as a non privileged user
+        passt
+        UNIX domain socket bound at /tmp/passt_1.socket
+        # start QEMU to connect to passt
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0 \\
+                      -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/passt_1.socket
+
+    Example (two guests connected using a stream oriented unix domain socket):
+
+    .. parsed-literal::
+
+        # first VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
+                      netdev stream,id=net0,server=on,addr.type=unix,addr.path=/tmp/qemu0
+        # second VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
+                      -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/qemu0
+
 ``-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor``
     Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented socket file descriptor.
 
-- 
2.42.0

[PULL 6/8] net: update netdev dgram man page with unix socket

[Jason Wang]

From: Laurent Vivier <lvivier@redhat.com>

Add the description of "-netdev dgram" with a unix domain socket.
The code has been added but the man page has not been updated.

Fixes: 784e7a253104 ("net: dgram: add unix socket")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 qemu-options.hx | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/qemu-options.hx b/qemu-options.hx
index 2614eea4d7..23a53a7190 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3500,6 +3500,29 @@ SRST
                       -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
                       -netdev dgram,id=net0,local.type=inet,local.host=localhost,local.port=1235,remote.type=inet,remote.host=localhost,remote.port=1234
 
+``-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]``
+    Configure a network backend to connect to another QEMU virtual
+    machine or a proxy using a datagram oriented unix socket.
+
+    ``local.path=path``
+        filesystem path to use to bind the socket
+
+    ``remote.path=path``
+        filesystem path to use as a destination (see sendto(2))
+
+    Example (two guests connected using an UDP/UNIX socket):
+
+    .. parsed-literal::
+
+        # first VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:56 \\
+                      -netdev dgram,id=net0,local.type=unix,local.path=/tmp/qemu0,remote.type=unix,remote.path=/tmp/qemu1
+        # second VM
+        |qemu_system| linux.img \\
+                      -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
+                      -netdev dgram,id=net0,local.type=unix,local.path=/tmp/qemu1,remote.type=unix,remote.path=/tmp/qemu0
+
 ``-netdev dgram,id=str,local.type=fd,local.str=file-descriptor``
     Configure a network backend to connect to another QEMU virtual
     machine or a proxy using a datagram oriented socket file descriptor.
-- 
2.42.0

[PULL 7/8] net: update netdev stream man page with the reconnect parameter

[Jason Wang]

From: Laurent Vivier <lvivier@redhat.com>

"-netdev stream" supports a reconnect parameter that attempts to
reconnect automatically the socket if it is disconnected. The code
has been added but the man page has not been updated.

Fixes: 148fbf0d58a6 ("net: stream: add a new option to automatically reconnect"
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 qemu-options.hx | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 23a53a7190..cee0da2014 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3353,7 +3353,7 @@ SRST
                          -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\
                          -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4
 
-``-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off]``
+``-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]``
     Configure a network backend to connect to another QEMU virtual machine or a proxy using a TCP/IP socket.
 
     ``server=on|off``
@@ -3380,6 +3380,10 @@ SRST
     ``ipv6=on|off``
         whether to accept IPv6 addresses, default to try both IPv4 and IPv6
 
+    ``reconnect=seconds``
+        for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds.
+        Setting this to zero disables this function.  (default: 0)
+
     Example (two guests connected using a TCP/IP socket):
 
     .. parsed-literal::
@@ -3391,9 +3395,9 @@ SRST
         # second VM
         |qemu_system| linux.img \\
                       -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
-                      -netdev stream,id=net0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234
+                      -netdev stream,id=net0,server=off,addr.type=inet,addr.host=localhost,addr.port=1234,reconnect=5
 
-``-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off]``
+``-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]``
     Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented unix domain socket.
 
     ``server=on|off``
@@ -3408,6 +3412,10 @@ SRST
     ``tight=on|off``
         if false, pad an abstract socket address with enough null bytes to make it fill struct sockaddr_un member sun_path.
 
+    ``reconnect=seconds``
+        for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds.
+        Setting this to zero disables this function.  (default: 0)
+
     Example (using passt as a replacement of -netdev user):
 
     .. parsed-literal::
@@ -3431,9 +3439,9 @@ SRST
         # second VM
         |qemu_system| linux.img \\
                       -device virtio-net,netdev=net0,mac=52:54:00:12:34:57 \\
-                      -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/qemu0
+                      -netdev stream,id=net0,server=off,addr.type=unix,addr.path=/tmp/qemu0,reconnect=5
 
-``-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor``
+``-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]``
     Configure a network backend to connect to another QEMU virtual machine or a proxy using a stream oriented socket file descriptor.
 
     ``server=on|off``
@@ -3442,6 +3450,10 @@ SRST
     ``addr.str=file-descriptor``
         file descriptor number to use as a socket
 
+    ``reconnect=seconds``
+        for a client socket, if a socket is disconnected, then attempt a reconnect after the given number of seconds.
+        Setting this to zero disables this function.  (default: 0)
+
 ``-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]``
     Configure a network backend to connect to a multicast address.
 
-- 
2.42.0

[PULL 8/8] net: Reinstate '-net nic, model=help' output as documented in man page

[Jason Wang]

From: David Woodhouse <dwmw@amazon.co.uk>

While refactoring the NIC initialization code, I broke '-net nic,model=help'
which no longer outputs a list of available NIC models.

Fixes: 2cdeca04adab ("net: report list of available models according to platform")
Cc: qemu-stable@nongnu.org
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 net/net.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/net/net.c b/net/net.c
index 6938da05e0..2eb8bc9c0b 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1139,6 +1139,21 @@ NICInfo *qemu_find_nic_info(const char *typename, bool match_default,
     return NULL;
 }
 
+static bool is_nic_model_help_option(const char *model)
+{
+    if (model && is_help_option(model)) {
+        /*
+         * Trigger the help output by instantiating the hash table which
+         * will gather tha available models as they get registered.
+         */
+        if (!nic_model_help) {
+            nic_model_help = g_hash_table_new_full(g_str_hash, g_str_equal,
+                                                   g_free, NULL);
+        }
+        return true;
+    }
+    return false;
+}
 
 /* "I have created a device. Please configure it if you can" */
 bool qemu_configure_nic_device(DeviceState *dev, bool match_default,
@@ -1722,6 +1737,12 @@ void net_check_clients(void)
 
 static int net_init_client(void *dummy, QemuOpts *opts, Error **errp)
 {
+    const char *model = qemu_opt_get_del(opts, "model");
+
+    if (is_nic_model_help_option(model)) {
+        return 0;
+    }
+
     return net_client_init(opts, false, errp);
 }
 
@@ -1778,9 +1799,7 @@ static int net_param_nic(void *dummy, QemuOpts *opts, Error **errp)
     memset(ni, 0, sizeof(*ni));
     ni->model = qemu_opt_get_del(opts, "model");
 
-    if (!nic_model_help && !g_strcmp0(ni->model, "help")) {
-        nic_model_help = g_hash_table_new_full(g_str_hash, g_str_equal,
-                                               g_free, NULL);
+    if (is_nic_model_help_option(ni->model)) {
         return 0;
     }
 
-- 
2.42.0

Re: [PULL 0/8] Net patches

[Richard Henderson]

On 8/2/24 13:19, Jason Wang wrote:
> The following changes since commit 31669121a01a14732f57c49400bc239cf9fd505f:
> 
>    Merge tag 'pull-target-arm-20240801' ofhttps://git.linaro.org/people/pmaydell/qemu-arm into staging (2024-08-02 08:18:37 +1000)
> 
> are available in the Git repository at:
> 
>    https://github.com/jasowang/qemu.git tags/net-pull-request
> 
> for you to fetch changes up to 64f75f57f9d2c8c12ac6d9355fa5d3a2af5879ca:
> 
>    net: Reinstate '-net nic, model=help' output as documented in man page (2024-08-02 11:09:52 +0800)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~

Re: [PULL 0/8] Net patches

[Jason Wang]

Hi Richard:

On Fri, Aug 2, 2024 at 5:48 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 8/2/24 13:19, Jason Wang wrote:
> > The following changes since commit 31669121a01a14732f57c49400bc239cf9fd505f:
> >
> >    Merge tag 'pull-target-arm-20240801' ofhttps://git.linaro.org/people/pmaydell/qemu-arm into staging (2024-08-02 08:18:37 +1000)
> >
> > are available in the Git repository at:
> >
> >    https://github.com/jasowang/qemu.git tags/net-pull-request
> >
> > for you to fetch changes up to 64f75f57f9d2c8c12ac6d9355fa5d3a2af5879ca:
> >
> >    net: Reinstate '-net nic, model=help' output as documented in man page (2024-08-02 11:09:52 +0800)
>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>
>

I guess it means it has been merged :) ?

Thanks

> r~
>

Re: [PULL 0/8] Net patches

[Richard Henderson]

On 8/5/24 12:38, Jason Wang wrote:
> Hi Richard:
> 
> On Fri, Aug 2, 2024 at 5:48 PM Richard Henderson
> <richard.henderson@linaro.org> wrote:
>>
>> On 8/2/24 13:19, Jason Wang wrote:
>>> The following changes since commit 31669121a01a14732f57c49400bc239cf9fd505f:
>>>
>>>     Merge tag 'pull-target-arm-20240801' ofhttps://git.linaro.org/people/pmaydell/qemu-arm into staging (2024-08-02 08:18:37 +1000)
>>>
>>> are available in the Git repository at:
>>>
>>>     https://github.com/jasowang/qemu.git tags/net-pull-request
>>>
>>> for you to fetch changes up to 64f75f57f9d2c8c12ac6d9355fa5d3a2af5879ca:
>>>
>>>     net: Reinstate '-net nic, model=help' output as documented in man page (2024-08-02 11:09:52 +0800)
>>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>>
>>
> 
> I guess it means it has been merged :) ?

Whoops, yes, wrong macro button pushed.  :-)


r~