From 3a330134b3effa3494051763b38f12a24715d53a Mon Sep 17 00:00:00 2001 From: Mark McLoughlin Date: Thu, 22 Oct 2009 17:43:45 +0100 Subject: [PATCH] virtio-net: add vnet_hdr support With '-netdev tap,id=foo -nic model=virtio,netdev=foo' virtio-net can detect that its peer (i.e. the tap backend) supports vnet headers and advertise to the guest that it can send packets with partial checksums and/or TSO packets. One complication is that if we're migrating and the source host supports IFF_VNET_HDR but the destination host doesn't, we can't then stop the guest from using those features. In this scenario, we just fail the migration. [v2: - add has_vnet_hdr uint32_t field for ease of vmstate conversion - use qemu_error() ] Signed-off-by: Mark McLoughlin Signed-off-by: Anthony Liguori --- hw/virtio-net.c | 51 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 44 insertions(+), 7 deletions(-) diff --git a/hw/virtio-net.c b/hw/virtio-net.c index 0a8d2aa859..d10d183035 100644 --- a/hw/virtio-net.c +++ b/hw/virtio-net.c @@ -32,6 +32,7 @@ typedef struct VirtIONet VLANClientState *vc; QEMUTimer *tx_timer; int tx_timer_active; + uint32_t has_vnet_hdr; struct { VirtQueueElement elem; ssize_t len; @@ -120,8 +121,22 @@ static void virtio_net_reset(VirtIODevice *vdev) memset(n->vlans, 0, MAX_VLAN >> 3); } +static int peer_has_vnet_hdr(VirtIONet *n) +{ + if (!n->vc->peer) + return 0; + + if (n->vc->peer->type != NET_CLIENT_TYPE_TAP) + return 0; + + n->has_vnet_hdr = tap_has_vnet_hdr(n->vc->peer); + + return n->has_vnet_hdr; +} + static uint32_t virtio_net_get_features(VirtIODevice *vdev) { + VirtIONet *n = to_virtio_net(vdev); uint32_t features = (1 << VIRTIO_NET_F_MAC) | (1 << VIRTIO_NET_F_MRG_RXBUF) | (1 << VIRTIO_NET_F_STATUS) | @@ -130,6 +145,15 @@ static uint32_t virtio_net_get_features(VirtIODevice *vdev) (1 << VIRTIO_NET_F_CTRL_VLAN) | (1 << VIRTIO_NET_F_CTRL_RX_EXTRA); + if (peer_has_vnet_hdr(n)) { + tap_using_vnet_hdr(n->vc->peer, 1); + + features |= (1 << VIRTIO_NET_F_CSUM); + features |= (1 << VIRTIO_NET_F_HOST_TSO4); + features |= (1 << VIRTIO_NET_F_HOST_TSO6); + features |= (1 << VIRTIO_NET_F_HOST_ECN); + } + return features; } @@ -359,6 +383,11 @@ static int receive_header(VirtIONet *n, struct iovec *iov, int iovcnt, hdr->flags = 0; hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; + if (n->has_vnet_hdr) { + memcpy(hdr, buf, sizeof(*hdr)); + offset = sizeof(*hdr); + } + /* We only ever receive a struct virtio_net_hdr from the tapfd, * but we may be passing along a larger header to the guest. */ @@ -378,6 +407,10 @@ static int receive_filter(VirtIONet *n, const uint8_t *buf, int size) if (n->promisc) return 1; + if (n->has_vnet_hdr) { + ptr += sizeof(struct virtio_net_hdr); + } + if (!memcmp(&ptr[12], vlan, sizeof(vlan))) { int vid = be16_to_cpup((uint16_t *)(ptr + 14)) & 0xfff; if (!(n->vlans[vid >> 5] & (1U << (vid & 0x1f)))) @@ -510,7 +543,6 @@ static void virtio_net_tx_complete(VLANClientState *vc, ssize_t len) static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq) { VirtQueueElement elem; - int has_vnet_hdr = 0; if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) return; @@ -537,7 +569,7 @@ static void virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq) } /* ignore the header if GSO is not supported */ - if (!has_vnet_hdr) { + if (!n->has_vnet_hdr) { out_num--; out_sg++; len += hdr_len; @@ -610,7 +642,7 @@ static void virtio_net_save(QEMUFile *f, void *opaque) qemu_put_be32(f, n->mac_table.in_use); qemu_put_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN); qemu_put_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3); - qemu_put_be32(f, 0); /* vnet-hdr placeholder */ + qemu_put_be32(f, n->has_vnet_hdr); qemu_put_byte(f, n->mac_table.multi_overflow); qemu_put_byte(f, n->mac_table.uni_overflow); qemu_put_byte(f, n->alluni); @@ -662,10 +694,15 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id) if (version_id >= 6) qemu_get_buffer(f, (uint8_t *)n->vlans, MAX_VLAN >> 3); - if (version_id >= 7 && qemu_get_be32(f)) { - fprintf(stderr, - "virtio-net: saved image requires vnet header support\n"); - exit(1); + if (version_id >= 7) { + if (qemu_get_be32(f) && !peer_has_vnet_hdr(n)) { + qemu_error("virtio-net: saved image requires vnet_hdr=on\n"); + return -1; + } + + if (n->has_vnet_hdr) { + tap_using_vnet_hdr(n->vc->peer, 1); + } } if (version_id >= 9) { -- 2.11.0