Hi, > -----Original Message----- > From: Maxime Coquelin [mailto:maxime.coque...@redhat.com] > Sent: Tuesday, January 9, 2018 4:50 PM > To: Wang, Xiao W <xiao.w.w...@intel.com>; y...@fridaylinux.org > Cc: Bie, Tiwei <tiwei....@intel.com>; dev@dpdk.org; > step...@networkplumber.org > Subject: Re: [dpdk-dev] [PATCH v7 3/3] net/virtio: support GUEST ANNOUNCE > > > > On 01/09/2018 03:26 PM, Xiao Wang wrote: > > 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 <xiao.w.w...@intel.com> > > --- > > drivers/net/virtio/virtio_ethdev.c | 95 > +++++++++++++++++++++++++++++++++++++- > > drivers/net/virtio/virtio_ethdev.h | 1 + > > drivers/net/virtio/virtqueue.h | 11 +++++ > > 3 files changed, 105 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/virtio/virtio_ethdev.c > b/drivers/net/virtio/virtio_ethdev.c > > index e8ff1e449..9606df514 100644 > > --- a/drivers/net/virtio/virtio_ethdev.c > > +++ b/drivers/net/virtio/virtio_ethdev.c > > @@ -19,6 +19,8 @@ > > #include <rte_pci.h> > > #include <rte_bus_pci.h> > > #include <rte_ether.h> > > +#include <rte_ip.h> > > +#include <rte_arp.h> > > #include <rte_common.h> > > #include <rte_errno.h> > > #include <rte_cpuflags.h> > > @@ -78,6 +80,11 @@ static int virtio_dev_queue_stats_mapping_set( > > uint8_t stat_idx, > > uint8_t is_rx); > > > > +static int make_rarp_packet(struct rte_mbuf *rarp_mbuf, > > + const struct ether_addr *mac); > > +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 > > */ > > @@ -1272,9 +1279,89 @@ virtio_inject_pkts(struct rte_eth_dev *dev, struct > rte_mbuf **tx_pkts, > > return ret; > > } > > > > +#define RARP_PKT_SIZE 64 > > +static int > > +make_rarp_packet(struct rte_mbuf *rarp_mbuf, const struct ether_addr > *mac) > > +{ > > + struct ether_hdr *eth_hdr; > > + struct arp_hdr *rarp; > > + > > + if (rarp_mbuf->buf_len < RARP_PKT_SIZE) { > > + PMD_DRV_LOG(ERR, "mbuf size too small %u (< %d)", > > + rarp_mbuf->buf_len, RARP_PKT_SIZE); > > + return -1; > > + } > > + > > + /* Ethernet header. */ > > + eth_hdr = rte_pktmbuf_mtod(rarp_mbuf, struct ether_hdr *); > > + memset(eth_hdr->d_addr.addr_bytes, 0xff, ETHER_ADDR_LEN); > > + ether_addr_copy(mac, ð_hdr->s_addr); > > + eth_hdr->ether_type = htons(ETHER_TYPE_RARP); > > + > > + /* RARP header. */ > > + rarp = (struct arp_hdr *)(eth_hdr + 1); > > + rarp->arp_hrd = htons(ARP_HRD_ETHER); > > + rarp->arp_pro = htons(ETHER_TYPE_IPv4); > > + rarp->arp_hln = ETHER_ADDR_LEN; > > + rarp->arp_pln = 4; > > + rarp->arp_op = htons(ARP_OP_REVREQUEST); > > + > > + ether_addr_copy(mac, &rarp->arp_data.arp_sha); > > + ether_addr_copy(mac, &rarp->arp_data.arp_tha); > > + memset(&rarp->arp_data.arp_sip, 0x00, 4); > > + memset(&rarp->arp_data.arp_tip, 0x00, 4); > > + > > + rarp_mbuf->data_len = RARP_PKT_SIZE; > > + rarp_mbuf->pkt_len = RARP_PKT_SIZE; > > + > > + return 0; > > +} > > Do you think it could make sense to have this function in a lib, as > vhost user lib does exactly the same? > > I don't know if it could be useful to others than vhost/virtio though. > > Thanks, > Maxime
Hi Thomas, Do you think it's worth adding a new helper for ARP in lib/librte_net/? Currently we just need a helper to build RARP packet (the above make_rarp_packet) BRs, Xiao
