On 2017年06月26日 12:55, Wei Wang wrote:
On 06/26/2017 11:18 AM, Jason Wang wrote:
On 2017年06月23日 10:32, Wei Wang wrote:
This patch enables the virtio-net tx queue size to be configurable
between 256 (the default queue size) and 1024 by the user when the
vhost-user backend is used.
Currently, the maximum tx queue size for other backends is 512 due
to the following limitations:
- QEMU backend: the QEMU backend implementation in some cases may
send 1024+1 iovs to writev.
- Vhost_net backend: there are possibilities that the guest sends
a vring_desc of memory which corsses a MemoryRegion thereby
generating more than 1024 iovs after translattion from guest-physical
address in the backend.
Signed-off-by: Wei Wang <wei.w.w...@intel.com>
---
hw/net/virtio-net.c | 45
+++++++++++++++++++++++++++++++++---------
include/hw/virtio/virtio-net.h | 1 +
2 files changed, 37 insertions(+), 9 deletions(-)
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 91eddaf..d13ca60 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -34,8 +34,11 @@
/* previously fixed value */
#define VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE 256
+
+ /*
+ * Currently, backends other than vhost-user don't support 1024
queue
+ * size.
+ */
+ if (n->net_conf.tx_queue_size == VIRTQUEUE_MAX_SIZE &&
+ nc->peer->info->type != NET_CLIENT_DRIVER_VHOST_USER) {
+ n->net_conf.tx_queue_size = VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE;
Do we really want assume all vhost-user backend support 1024 queue size?
Do you know any vhost-user backend implementation that doesn't support
1024 tx queue size?
I don't but the issue is vhost-user uditis an open protocol, there could
be even closed source implementation on this. So we can't audit all
kinds of backends.
+ }
+
+ for (i = 0; i < n->max_queues; i++) {
+ virtio_net_add_queue(n, i);
+ }
Any reason to move virtio_net_add_queue() here?
Please check the whole init steps. It was moved here (after
qemu_new_nic())
to make sure nc->peer is not NULL.
I don't get here, can't you get peer just from nic_conf.peers?
Thanks
Best,
Wei
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