From 9b02e1618cf26aa52cf786f215d757506dda14f8 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Wed, 28 Jun 2017 10:37:59 +0800 Subject: virtio-net: enable configurable tx queue size 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 crosses a MemoryRegion thereby generating more than 1024 iovs after translation from guest-physical address in the backend. Signed-off-by: Wei Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/net/virtio-net.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) (limited to 'hw/net') diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 91eddaf93b..a1fc0dbb6d 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 +#define VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE 256 + /* for now, only allow larger queues; with virtio-1, guest can downsize */ #define VIRTIO_NET_RX_QUEUE_MIN_SIZE VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE +#define VIRTIO_NET_TX_QUEUE_MIN_SIZE VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE /* * Calculate the number of bytes up to and including the given 'field' of @@ -1508,15 +1511,18 @@ static void virtio_net_add_queue(VirtIONet *n, int index) n->vqs[index].rx_vq = virtio_add_queue(vdev, n->net_conf.rx_queue_size, 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); + virtio_add_queue(vdev, n->net_conf.tx_queue_size, + 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); + virtio_add_queue(vdev, n->net_conf.tx_queue_size, + virtio_net_handle_tx_bh); n->vqs[index].tx_bh = qemu_bh_new(virtio_net_tx_bh, &n->vqs[index]); } @@ -1927,6 +1933,17 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp) return; } + if (n->net_conf.tx_queue_size < VIRTIO_NET_TX_QUEUE_MIN_SIZE || + n->net_conf.tx_queue_size > VIRTQUEUE_MAX_SIZE || + !is_power_of_2(n->net_conf.tx_queue_size)) { + error_setg(errp, "Invalid tx_queue_size (= %" PRIu16 "), " + "must be a power of 2 between %d and %d", + n->net_conf.tx_queue_size, VIRTIO_NET_TX_QUEUE_MIN_SIZE, + VIRTQUEUE_MAX_SIZE); + virtio_cleanup(vdev); + return; + } + n->max_queues = MAX(n->nic_conf.peers.queues, 1); if (n->max_queues * 2 + 1 > VIRTIO_QUEUE_MAX) { error_setg(errp, "Invalid number of queues (= %" PRIu32 "), " @@ -1947,6 +1964,15 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp) error_report("Defaulting to \"bh\""); } + /* + * Currently, backends other than vhost-user don't support 1024 queue + * size. + */ + if (n->net_conf.tx_queue_size == VIRTQUEUE_MAX_SIZE && + n->nic_conf.peers.ncs[0]->info->type != NET_CLIENT_DRIVER_VHOST_USER) { + n->net_conf.tx_queue_size = VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE; + } + for (i = 0; i < n->max_queues; i++) { virtio_net_add_queue(n, i); } @@ -2106,6 +2132,8 @@ static Property virtio_net_properties[] = { DEFINE_PROP_STRING("tx", VirtIONet, net_conf.tx), DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size, VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE), + DEFINE_PROP_UINT16("tx_queue_size", VirtIONet, net_conf.tx_queue_size, + VIRTIO_NET_TX_QUEUE_DEFAULT_SIZE), DEFINE_PROP_UINT16("host_mtu", VirtIONet, net_conf.mtu, 0), DEFINE_PROP_BOOL("x-mtu-bypass-backend", VirtIONet, mtu_bypass_backend, true), -- cgit v1.2.3