From 7365504f77e36fe487c4ef54af2457fbf5018ca4 Mon Sep 17 00:00:00 2001 From: Xiao Wang Date: Thu, 18 Jan 2018 10:20:38 +0800 Subject: [PATCH] net/virtio: support guest announce When live migration is done, for the backup VM, either the virtio frontend or the vhost backend needs to send out gratuitous RARP packet to announce its new network location. This patch enables VIRTIO_NET_F_GUEST_ANNOUNCE feature to support live migration scenario where the vhost backend doesn't have the ability to generate RARP packet. Brief introduction of the work flow: 1. QEMU finishes live migration, pokes the backup VM with an interrupt. 2. Virtio interrupt handler reads out the interrupt status value, and realizes it needs to send out RARP packet to announce its location. 3. Pause device to stop worker thread touching the queues. 4. Inject a RARP packet into a Tx Queue. 5. Ack the interrupt via control queue. 6. Resume device to continue packet processing. Signed-off-by: Xiao Wang Reviewed-by: Maxime Coquelin Acked-by: Yuanhan Liu --- drivers/net/virtio/virtio_ethdev.c | 50 ++++++++++++++++++++++++++++-- drivers/net/virtio/virtio_ethdev.h | 1 + drivers/net/virtio/virtqueue.h | 11 +++++++ 3 files changed, 60 insertions(+), 2 deletions(-) diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c index 1f0e239f3d..17ac04931e 100644 --- a/drivers/net/virtio/virtio_ethdev.c +++ b/drivers/net/virtio/virtio_ethdev.c @@ -19,6 +19,8 @@ #include #include #include +#include +#include #include #include #include @@ -81,6 +83,9 @@ static int virtio_dev_queue_stats_mapping_set( int virtio_logtype_init; int virtio_logtype_driver; +static void virtio_notify_peers(struct rte_eth_dev *dev); +static void virtio_ack_link_announce(struct rte_eth_dev *dev); + /* * The set of PCI devices this driver supports */ @@ -1275,9 +1280,46 @@ virtio_inject_pkts(struct rte_eth_dev *dev, struct rte_mbuf **tx_pkts, return ret; } +static void +virtio_notify_peers(struct rte_eth_dev *dev) +{ + struct virtio_hw *hw = dev->data->dev_private; + struct virtnet_rx *rxvq = dev->data->rx_queues[0]; + struct rte_mbuf *rarp_mbuf; + + rarp_mbuf = rte_net_make_rarp_packet(rxvq->mpool, + (struct ether_addr *)hw->mac_addr); + if (rarp_mbuf == NULL) { + PMD_DRV_LOG(ERR, "failed to make RARP packet."); + return; + } + + /* If virtio port just stopped, no need to send RARP */ + if (virtio_dev_pause(dev) < 0) { + rte_pktmbuf_free(rarp_mbuf); + return; + } + + virtio_inject_pkts(dev, &rarp_mbuf, 1); + virtio_dev_resume(dev); +} + +static void +virtio_ack_link_announce(struct rte_eth_dev *dev) +{ + struct virtio_hw *hw = dev->data->dev_private; + struct virtio_pmd_ctrl ctrl; + + ctrl.hdr.class = VIRTIO_NET_CTRL_ANNOUNCE; + ctrl.hdr.cmd = VIRTIO_NET_CTRL_ANNOUNCE_ACK; + + virtio_send_command(hw->cvq, &ctrl, NULL, 0); +} + /* - * Process Virtio Config changed interrupt and call the callback - * if link state changed. + * Process virtio config changed interrupt. Call the callback + * if link state changed, generate gratuitous RARP packet if + * the status indicates an ANNOUNCE. */ void virtio_interrupt_handler(void *param) @@ -1300,6 +1342,10 @@ virtio_interrupt_handler(void *param) NULL); } + if (isr & VIRTIO_NET_S_ANNOUNCE) { + virtio_notify_peers(dev); + virtio_ack_link_announce(dev); + } } /* set rx and tx handlers according to what is supported */ diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h index d98f7cdc95..4539d2e44b 100644 --- a/drivers/net/virtio/virtio_ethdev.h +++ b/drivers/net/virtio/virtio_ethdev.h @@ -33,6 +33,7 @@ 1u << VIRTIO_NET_F_HOST_TSO6 | \ 1u << VIRTIO_NET_F_MRG_RXBUF | \ 1u << VIRTIO_NET_F_MTU | \ + 1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE | \ 1u << VIRTIO_RING_F_INDIRECT_DESC | \ 1ULL << VIRTIO_F_VERSION_1 | \ 1ULL << VIRTIO_F_IOMMU_PLATFORM) diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h index fedbaa39c5..2d95992180 100644 --- a/drivers/net/virtio/virtqueue.h +++ b/drivers/net/virtio/virtqueue.h @@ -129,6 +129,17 @@ struct virtio_net_ctrl_mac { #define VIRTIO_NET_CTRL_VLAN_ADD 0 #define VIRTIO_NET_CTRL_VLAN_DEL 1 +/* + * Control link announce acknowledgement + * + * The command VIRTIO_NET_CTRL_ANNOUNCE_ACK is used to indicate that + * driver has recevied the notification; device would clear the + * VIRTIO_NET_S_ANNOUNCE bit in the status field after it receives + * this command. + */ +#define VIRTIO_NET_CTRL_ANNOUNCE 3 +#define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0 + struct virtio_net_ctrl_hdr { uint8_t class; uint8_t cmd; -- 2.20.1