[Qemu-devel] [PULL 0/6] virtio, vhost, pc fixes for 2.4

[Qemu-devel] [PULL 0/6] virtio, vhost, pc fixes for 2.4

[Michael S. Tsirkin]

The following changes since commit b4329bf41c86bac8b56cadb097081960cc4839a0:

  Update version for v2.4.0-rc1 release (2015-07-16 20:32:20 +0100)

are available in the git repository at:

  git://git.kernel.org/pub/scm/virt/kvm/mst/qemu.git tags/for_upstream

for you to fetch changes up to f9d6dbf0bf6e91b8ed896369ab1b7e91e5a1a4df:

  virtio-net: remove virtio queues if the guest doesn't support multiqueue (2015-07-20 14:19:42 +0300)

----------------------------------------------------------------
virtio, vhost, pc fixes for 2.4

The only notable thing here is vhost-user multiqueue
revert. We'll work on making it stable in 2.5,
reverting now means we won't have to maintain
bug for bug compability forever.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

----------------------------------------------------------------
Chen Hanxiao (1):
      pci_add_capability: remove duplicate comments

Fam Zheng (1):
      virtio-net: Flush incoming queues when DRIVER_OK is being set

Jason Wang (1):
      virtio-net: unbreak any layout

Michael S. Tsirkin (1):
      Revert "vhost-user: add multi queue support"

Paulo Alcantara (1):
      ich9: fix skipped vmstate_memhp_state subsection

Wen Congyang (1):
      virtio-net: remove virtio queues if the guest doesn't support multiqueue

 qapi-schema.json                  |   6 +-
 include/hw/virtio/virtio-access.h |   9 +++
 hw/acpi/ich9.c                    |   3 -
 hw/net/vhost_net.c                |   3 +-
 hw/net/virtio-net.c               | 143 +++++++++++++++++++++++++++++---------
 hw/pci/pci.c                      |   6 +-
 hw/virtio/vhost-user.c            |  11 +--
 net/vhost-user.c                  |  37 ++++------
 docs/specs/vhost-user.txt         |   5 --
 qemu-options.hx                   |   5 +-
 10 files changed, 138 insertions(+), 90 deletions(-)

[Qemu-devel] [PULL 1/6] ich9: fix skipped vmstate_memhp_state subsection

[Michael S. Tsirkin]

From: Paulo Alcantara <pcacjr@gmail.com>

By declaring another .subsections array for vmstate_tco_io_state made
vmstate_memhp_state not registered anymore. There must be only one
.subsections array for all subsections.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Amit Shah <amit.shah@redhat.com>
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
---
 hw/acpi/ich9.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 5fb7a87..f04f6dc 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -206,9 +206,6 @@ const VMStateDescription vmstate_ich9_pm = {
     },
     .subsections = (const VMStateDescription*[]) {
         &vmstate_memhp_state,
-        NULL
-    },
-    .subsections = (const VMStateDescription*[]) {
         &vmstate_tco_io_state,
         NULL
     }
-- 
MST

[Qemu-devel] [PULL 2/6] Revert "vhost-user: add multi queue support"

[Michael S. Tsirkin]

This reverts commit 830d70db692e374b55555f4407f96a1ceefdcc97.

The interface isn't fully backwards-compatible, which is bad.
Let's redo this properly after 2.4.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 qapi-schema.json          |  6 +-----
 hw/net/vhost_net.c        |  3 +--
 hw/virtio/vhost-user.c    | 11 +----------
 net/vhost-user.c          | 37 +++++++++++++------------------------
 docs/specs/vhost-user.txt |  5 -----
 qemu-options.hx           |  5 ++---
 6 files changed, 18 insertions(+), 49 deletions(-)

diff --git a/qapi-schema.json b/qapi-schema.json
index 1285b8c..a0a45f7 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2466,16 +2466,12 @@
 #
 # @vhostforce: #optional vhost on for non-MSIX virtio guests (default: false).
 #
-# @queues: #optional number of queues to be created for multiqueue vhost-user
-#          (default: 1) (Since 2.4)
-#
 # Since 2.1
 ##
 { 'struct': 'NetdevVhostUserOptions',
   'data': {
     'chardev':        'str',
-    '*vhostforce':    'bool',
-    '*queues':        'uint32' } }
+    '*vhostforce':    'bool' } }
 
 ##
 # @NetClientOptions
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 9bd360b..5c1d11f 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -160,7 +160,6 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
 
     net->dev.nvqs = 2;
     net->dev.vqs = net->vqs;
-    net->dev.vq_index = net->nc->queue_index;
 
     r = vhost_dev_init(&net->dev, options->opaque,
                        options->backend_type);
@@ -287,7 +286,7 @@ static void vhost_net_stop_one(struct vhost_net *net,
         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
             const VhostOps *vhost_ops = net->dev.vhost_ops;
             int r = vhost_ops->vhost_call(&net->dev, VHOST_RESET_OWNER,
-                                          &file);
+                                          NULL);
             assert(r >= 0);
         }
     }
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index d6f2163..e7ab829 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -210,12 +210,7 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
         break;
 
     case VHOST_SET_OWNER:
-        break;
-
     case VHOST_RESET_OWNER:
-        memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
-        msg.state.index += dev->vq_index;
-        msg.size = sizeof(m.state);
         break;
 
     case VHOST_SET_MEM_TABLE:
@@ -258,20 +253,17 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
     case VHOST_SET_VRING_NUM:
     case VHOST_SET_VRING_BASE:
         memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
-        msg.state.index += dev->vq_index;
         msg.size = sizeof(m.state);
         break;
 
     case VHOST_GET_VRING_BASE:
         memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
-        msg.state.index += dev->vq_index;
         msg.size = sizeof(m.state);
         need_reply = 1;
         break;
 
     case VHOST_SET_VRING_ADDR:
         memcpy(&msg.addr, arg, sizeof(struct vhost_vring_addr));
-        msg.addr.index += dev->vq_index;
         msg.size = sizeof(m.addr);
         break;
 
@@ -279,7 +271,7 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
     case VHOST_SET_VRING_CALL:
     case VHOST_SET_VRING_ERR:
         file = arg;
-        msg.u64 = (file->index + dev->vq_index) & VHOST_USER_VRING_IDX_MASK;
+        msg.u64 = file->index & VHOST_USER_VRING_IDX_MASK;
         msg.size = sizeof(m.u64);
         if (ioeventfd_enabled() && file->fd > 0) {
             fds[fd_num++] = file->fd;
@@ -321,7 +313,6 @@ static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
                 error_report("Received bad msg size.");
                 return -1;
             }
-            msg.state.index -= dev->vq_index;
             memcpy(arg, &msg.state, sizeof(struct vhost_vring_state));
             break;
         default:
diff --git a/net/vhost-user.c b/net/vhost-user.c
index b51bc04..93dcecd 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -120,39 +120,35 @@ static void net_vhost_user_event(void *opaque, int event)
     case CHR_EVENT_OPENED:
         vhost_user_start(s);
         net_vhost_link_down(s, false);
-        error_report("chardev \"%s\" went up", s->nc.info_str);
+        error_report("chardev \"%s\" went up", s->chr->label);
         break;
     case CHR_EVENT_CLOSED:
         net_vhost_link_down(s, true);
         vhost_user_stop(s);
-        error_report("chardev \"%s\" went down", s->nc.info_str);
+        error_report("chardev \"%s\" went down", s->chr->label);
         break;
     }
 }
 
 static int net_vhost_user_init(NetClientState *peer, const char *device,
-                               const char *name, CharDriverState *chr,
-                               uint32_t queues)
+                               const char *name, CharDriverState *chr)
 {
     NetClientState *nc;
     VhostUserState *s;
-    int i;
 
-    for (i = 0; i < queues; i++) {
-        nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
+    nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
 
-        snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
-                 i, chr->label);
+    snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s",
+             chr->label);
 
-        s = DO_UPCAST(VhostUserState, nc, nc);
+    s = DO_UPCAST(VhostUserState, nc, nc);
 
-        /* We don't provide a receive callback */
-        s->nc.receive_disabled = 1;
-        s->chr = chr;
-        s->nc.queue_index = i;
+    /* We don't provide a receive callback */
+    s->nc.receive_disabled = 1;
+    s->chr = chr;
+
+    qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
 
-        qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
-    }
     return 0;
 }
 
@@ -230,7 +226,6 @@ static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
                         NetClientState *peer, Error **errp)
 {
-    uint32_t queues;
     const NetdevVhostUserOptions *vhost_user_opts;
     CharDriverState *chr;
 
@@ -248,12 +243,6 @@ int net_init_vhost_user(const NetClientOptions *opts, const char *name,
         return -1;
     }
 
-    /* number of queues for multiqueue */
-    if (vhost_user_opts->has_queues) {
-        queues = vhost_user_opts->queues;
-    } else {
-        queues = 1;
-    }
 
-    return net_vhost_user_init(peer, "vhost_user", name, chr, queues);
+    return net_vhost_user_init(peer, "vhost_user", name, chr);
 }
diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 2c8e934..650bb18 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -127,11 +127,6 @@ in the ancillary data:
 If Master is unable to send the full message or receives a wrong reply it will
 close the connection. An optional reconnection mechanism can be implemented.
 
-Multi queue support
--------------------
-The protocol supports multiple queues by setting all index fields in the sent
-messages to a properly calculated value.
-
 Message types
 -------------
 
diff --git a/qemu-options.hx b/qemu-options.hx
index 7b8efbf..8c9add9 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1963,14 +1963,13 @@ The hubport netdev lets you connect a NIC to a QEMU "vlan" instead of a single
 netdev.  @code{-net} and @code{-device} with parameter @option{vlan} create the
 required hub automatically.
 
-@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off][,queues=n]
+@item -netdev vhost-user,chardev=@var{id}[,vhostforce=on|off]
 
 Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
 be a unix domain socket backed one. The vhost-user uses a specifically defined
 protocol to pass vhost ioctl replacement messages to an application on the other
 end of the socket. On non-MSIX guests, the feature can be forced with
-@var{vhostforce}. Use 'queues=@var{n}' to specify the number of queues to
-be created for multiqueue vhost-user.
+@var{vhostforce}.
 
 Example:
 @example
-- 
MST

[Qemu-devel] [PULL 3/6] virtio-net: unbreak any layout

[Michael S. Tsirkin]

From: Jason Wang <jasowang@redhat.com>

Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611
("virtio-net: byteswap virtio-net header") breaks any layout by
requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by
copying header to temporary buffer if swap is needed, and then use
this buffer as part of out_sg.

Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611
("virtio-net: byteswap virtio-net header")
Cc: qemu-stable@nongnu.org
Cc: clg@fr.ibm.com
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/hw/virtio/virtio-access.h |  9 +++++++++
 hw/net/virtio-net.c               | 23 ++++++++++++++++++-----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/include/hw/virtio/virtio-access.h b/include/hw/virtio/virtio-access.h
index cee5dd7..1ec1dfd 100644
--- a/include/hw/virtio/virtio-access.h
+++ b/include/hw/virtio/virtio-access.h
@@ -143,6 +143,15 @@ static inline uint64_t virtio_ldq_p(VirtIODevice *vdev, const void *ptr)
     }
 }
 
+static inline bool virtio_needs_swap(VirtIODevice *vdev)
+{
+#ifdef HOST_WORDS_BIGENDIAN
+    return virtio_access_is_big_endian(vdev) ? false : true;
+#else
+    return virtio_access_is_big_endian(vdev) ? true : false;
+#endif
+}
+
 static inline uint16_t virtio_tswap16(VirtIODevice *vdev, uint16_t s)
 {
 #ifdef HOST_WORDS_BIGENDIAN
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index e3c2db3..9f7e91d 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1142,7 +1142,8 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
         ssize_t ret, len;
         unsigned int out_num = elem.out_num;
         struct iovec *out_sg = &elem.out_sg[0];
-        struct iovec sg[VIRTQUEUE_MAX_SIZE];
+        struct iovec sg[VIRTQUEUE_MAX_SIZE], sg2[VIRTQUEUE_MAX_SIZE + 1];
+        struct virtio_net_hdr_mrg_rxbuf mhdr;
 
         if (out_num < 1) {
             error_report("virtio-net header not in first element");
@@ -1150,13 +1151,25 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
         }
 
         if (n->has_vnet_hdr) {
-            if (out_sg[0].iov_len < n->guest_hdr_len) {
+            if (iov_to_buf(out_sg, out_num, 0, &mhdr, n->guest_hdr_len) <
+                n->guest_hdr_len) {
                 error_report("virtio-net header incorrect");
                 exit(1);
             }
-            virtio_net_hdr_swap(vdev, (void *) out_sg[0].iov_base);
+            if (virtio_needs_swap(vdev)) {
+                virtio_net_hdr_swap(vdev, (void *) &mhdr);
+                sg2[0].iov_base = &mhdr;
+                sg2[0].iov_len = n->guest_hdr_len;
+                out_num = iov_copy(&sg2[1], ARRAY_SIZE(sg2) - 1,
+                                   out_sg, out_num,
+                                   n->guest_hdr_len, -1);
+                if (out_num == VIRTQUEUE_MAX_SIZE) {
+                    goto drop;
+		}
+                out_num += 1;
+                out_sg = sg2;
+	    }
         }
-
         /*
          * If host wants to see the guest header as is, we can
          * pass it on unchanged. Otherwise, copy just the parts
@@ -1186,7 +1199,7 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
         }
 
         len += ret;
-
+drop:
         virtqueue_push(q->tx_vq, &elem, 0);
         virtio_notify(vdev, q->tx_vq);
 
-- 
MST

Re: [Qemu-devel] [PULL 3/6] virtio-net: unbreak any layout

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 970 bytes --]

On 07/20/2015 06:12 AM, Michael S. Tsirkin wrote:
> From: Jason Wang <jasowang@redhat.com>
> 
> Commit 032a74a1c0fcdd5fd1c69e56126b4c857ee36611
> ("virtio-net: byteswap virtio-net header") breaks any layout by
> requiring out_sg[0].iov_len >= n->guest_hdr_len. Fixing this by
> copying header to temporary buffer if swap is needed, and then use
> this buffer as part of out_sg.
> 
> Fixes 032a74a1c0fcdd5fd1c69e56126b4c857ee36611
> ("virtio-net: byteswap virtio-net header")
> Cc: qemu-stable@nongnu.org
> Cc: clg@fr.ibm.com
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>

I think my R-b was intended for 2/6, not this one. But if this has
already been pulled, it's not a show-stopper.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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[Qemu-devel] [PULL 4/6] pci_add_capability: remove duplicate comments

[Michael S. Tsirkin]

From: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/pci/pci.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 442f822..a017614 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2101,12 +2101,10 @@ static void pci_del_option_rom(PCIDevice *pdev)
 }
 
 /*
- * if !offset
- * Reserve space and add capability to the linked list in pci config space
- *
  * if offset = 0,
  * Find and reserve space and add capability to the linked list
- * in pci config space */
+ * in pci config space
+ */
 int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
                        uint8_t offset, uint8_t size)
 {
-- 
MST

[Qemu-devel] [PULL 5/6] virtio-net: Flush incoming queues when DRIVER_OK is being set

[Michael S. Tsirkin]

From: Fam Zheng <famz@redhat.com>

This patch fixes network hang after "stop" then "cont", while network
packets keep arriving.

Tested both manually (tap, host pinging guest) and with Jason's qtest
series (plus his "[PATCH 2.4] socket: pass correct size in
net_socket_send()" fix).

As virtio_net_set_status is called when guest driver is setting status
byte and when vm state is changing, it is a good opportunity to flush
queued packets.

This is necessary because during vm stop the backend (e.g. tap) would
stop rx processing after .can_receive returns false, until the queue is
explicitly flushed or purged.

The other interesting condition in .can_receive, virtio_queue_ready(),
is handled by virtio_net_handle_rx() when guest kicks; the 3rd condition
is invalid queue index which doesn't need flushing.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/net/virtio-net.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 9f7e91d..e1d9cbf 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -162,6 +162,8 @@ static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
     virtio_net_vhost_status(n, status);
 
     for (i = 0; i < n->max_queues; i++) {
+        NetClientState *ncs = qemu_get_subqueue(n->nic, i);
+        bool queue_started;
         q = &n->vqs[i];
 
         if ((!n->multiqueue && i != 0) || i >= n->curr_queues) {
@@ -169,12 +171,18 @@ static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)
         } else {
             queue_status = status;
         }
+        queue_started =
+            virtio_net_started(n, queue_status) && !n->vhost_started;
+
+        if (queue_started) {
+            qemu_flush_queued_packets(ncs);
+        }
 
         if (!q->tx_waiting) {
             continue;
         }
 
-        if (virtio_net_started(n, queue_status) && !n->vhost_started) {
+        if (queue_started) {
             if (q->tx_timer) {
                 timer_mod(q->tx_timer,
                                qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + n->tx_timeout);
-- 
MST

[Qemu-devel] [PULL 6/6] virtio-net: remove virtio queues if the guest doesn't support multiqueue

[Michael S. Tsirkin]

From: Wen Congyang <wency@cn.fujitsu.com>

commit da51a335 adds all queues in .realize(). But if the
guest doesn't support multiqueue, we forget to remove them. And
we cannot handle the ctrl vq corretly. The guest will hang.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 hw/net/virtio-net.c | 110 +++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 82 insertions(+), 28 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index e1d9cbf..304d3dd 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1327,9 +1327,86 @@ static void virtio_net_tx_bh(void *opaque)
     }
 }
 
+static void virtio_net_add_queue(VirtIONet *n, int index)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(n);
+
+    n->vqs[index].rx_vq = virtio_add_queue(vdev, 256, virtio_net_handle_rx);
+    if (n->net_conf.tx && !strcmp(n->net_conf.tx, "timer")) {
+        n->vqs[index].tx_vq =
+            virtio_add_queue(vdev, 256, virtio_net_handle_tx_timer);
+        n->vqs[index].tx_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                              virtio_net_tx_timer,
+                                              &n->vqs[index]);
+    } else {
+        n->vqs[index].tx_vq =
+            virtio_add_queue(vdev, 256, virtio_net_handle_tx_bh);
+        n->vqs[index].tx_bh = qemu_bh_new(virtio_net_tx_bh, &n->vqs[index]);
+    }
+
+    n->vqs[index].tx_waiting = 0;
+    n->vqs[index].n = n;
+}
+
+static void virtio_net_del_queue(VirtIONet *n, int index)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(n);
+    VirtIONetQueue *q = &n->vqs[index];
+    NetClientState *nc = qemu_get_subqueue(n->nic, index);
+
+    qemu_purge_queued_packets(nc);
+
+    virtio_del_queue(vdev, index * 2);
+    if (q->tx_timer) {
+        timer_del(q->tx_timer);
+        timer_free(q->tx_timer);
+    } else {
+        qemu_bh_delete(q->tx_bh);
+    }
+    virtio_del_queue(vdev, index * 2 + 1);
+}
+
+static void virtio_net_change_num_queues(VirtIONet *n, int new_max_queues)
+{
+    VirtIODevice *vdev = VIRTIO_DEVICE(n);
+    int old_num_queues = virtio_get_num_queues(vdev);
+    int new_num_queues = new_max_queues * 2 + 1;
+    int i;
+
+    assert(old_num_queues >= 3);
+    assert(old_num_queues % 2 == 1);
+
+    if (old_num_queues == new_num_queues) {
+        return;
+    }
+
+    /*
+     * We always need to remove and add ctrl vq if
+     * old_num_queues != new_num_queues. Remove ctrl_vq first,
+     * and then we only enter one of the following too loops.
+     */
+    virtio_del_queue(vdev, old_num_queues - 1);
+
+    for (i = new_num_queues - 1; i < old_num_queues - 1; i += 2) {
+        /* new_num_queues < old_num_queues */
+        virtio_net_del_queue(n, i / 2);
+    }
+
+    for (i = old_num_queues - 1; i < new_num_queues - 1; i += 2) {
+        /* new_num_queues > old_num_queues */
+        virtio_net_add_queue(n, i / 2);
+    }
+
+    /* add ctrl_vq last */
+    n->ctrl_vq = virtio_add_queue(vdev, 64, virtio_net_handle_ctrl);
+}
+
 static void virtio_net_set_multiqueue(VirtIONet *n, int multiqueue)
 {
+    int max = multiqueue ? n->max_queues : 1;
+
     n->multiqueue = multiqueue;
+    virtio_net_change_num_queues(n, max);
 
     virtio_net_set_queues(n);
 }
@@ -1604,21 +1681,7 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     }
 
     for (i = 0; i < n->max_queues; i++) {
-        n->vqs[i].rx_vq = virtio_add_queue(vdev, 256, virtio_net_handle_rx);
-        if (n->net_conf.tx && !strcmp(n->net_conf.tx, "timer")) {
-            n->vqs[i].tx_vq =
-                virtio_add_queue(vdev, 256, virtio_net_handle_tx_timer);
-            n->vqs[i].tx_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
-                                              virtio_net_tx_timer,
-                                              &n->vqs[i]);
-        } else {
-            n->vqs[i].tx_vq =
-                virtio_add_queue(vdev, 256, virtio_net_handle_tx_bh);
-            n->vqs[i].tx_bh = qemu_bh_new(virtio_net_tx_bh, &n->vqs[i]);
-        }
-
-        n->vqs[i].tx_waiting = 0;
-        n->vqs[i].n = n;
+        virtio_net_add_queue(n, i);
     }
 
     n->ctrl_vq = virtio_add_queue(vdev, 64, virtio_net_handle_ctrl);
@@ -1672,7 +1735,7 @@ static void virtio_net_device_unrealize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VirtIONet *n = VIRTIO_NET(dev);
-    int i;
+    int i, max_queues;
 
     /* This will stop vhost backend if appropriate. */
     virtio_net_set_status(vdev, 0);
@@ -1687,18 +1750,9 @@ static void virtio_net_device_unrealize(DeviceState *dev, Error **errp)
     g_free(n->mac_table.macs);
     g_free(n->vlans);
 
-    for (i = 0; i < n->max_queues; i++) {
-        VirtIONetQueue *q = &n->vqs[i];
-        NetClientState *nc = qemu_get_subqueue(n->nic, i);
-
-        qemu_purge_queued_packets(nc);
-
-        if (q->tx_timer) {
-            timer_del(q->tx_timer);
-            timer_free(q->tx_timer);
-        } else if (q->tx_bh) {
-            qemu_bh_delete(q->tx_bh);
-        }
+    max_queues = n->multiqueue ? n->max_queues : 1;
+    for (i = 0; i < max_queues; i++) {
+        virtio_net_del_queue(n, i);
     }
 
     timer_del(n->announce_timer);
-- 
MST

Re: [Qemu-devel] [PULL 0/6] virtio, vhost, pc fixes for 2.4

[Peter Maydell]

On 20 July 2015 at 13:12, Michael S. Tsirkin <mst@redhat.com> wrote:
> The following changes since commit b4329bf41c86bac8b56cadb097081960cc4839a0:
>
>   Update version for v2.4.0-rc1 release (2015-07-16 20:32:20 +0100)
>
> are available in the git repository at:
>
>   git://git.kernel.org/pub/scm/virt/kvm/mst/qemu.git tags/for_upstream
>
> for you to fetch changes up to f9d6dbf0bf6e91b8ed896369ab1b7e91e5a1a4df:
>
>   virtio-net: remove virtio queues if the guest doesn't support multiqueue (2015-07-20 14:19:42 +0300)
>
> ----------------------------------------------------------------
> virtio, vhost, pc fixes for 2.4
>
> The only notable thing here is vhost-user multiqueue
> revert. We'll work on making it stable in 2.5,
> reverting now means we won't have to maintain
> bug for bug compability forever.
>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Applied, thanks.

-- PMM