On Thu, 2009-10-08 at 11:07 +0100, Mark McLoughlin wrote: > On Wed, 2009-10-07 at 14:50 -0700, Sridhar Samudrala wrote: > > linux 2.6.32 includes UDP fragmentation offload support in software. > > So we can enable UFO on the host tap device if supported and allow setting > > UFO on virtio-net in the guest. > > Hmm, we really need to detect whether the host has tuntap UFO support > before advertising it to the guest. Maybe in net_tap_fd_init() we should > toggle TUN_F_UFO back and forth and check for EINVAL? Sure. Here is an updated patch that checks for UFO support in host. Thanks Sridhar Signed-off-by: Sridhar Samudrala <sri@xxxxxxxxxx> diff --git a/hw/virtio-net.c b/hw/virtio-net.c index ce8e6cb..9561f34 100644 --- a/hw/virtio-net.c +++ b/hw/virtio-net.c @@ -150,7 +150,10 @@ static uint32_t virtio_net_get_features(VirtIODevice *vdev) features |= (1 << VIRTIO_NET_F_HOST_TSO6); features |= (1 << VIRTIO_NET_F_HOST_ECN); features |= (1 << VIRTIO_NET_F_MRG_RXBUF); - /* Kernel can't actually handle UFO in software currently. */ + if (tap_has_ufo(host)) { + features |= (1 << VIRTIO_NET_F_GUEST_UFO); + features |= (1 << VIRTIO_NET_F_HOST_UFO); + } } #endif @@ -189,7 +192,8 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint32_t features) (features >> VIRTIO_NET_F_GUEST_CSUM) & 1, (features >> VIRTIO_NET_F_GUEST_TSO4) & 1, (features >> VIRTIO_NET_F_GUEST_TSO6) & 1, - (features >> VIRTIO_NET_F_GUEST_ECN) & 1); + (features >> VIRTIO_NET_F_GUEST_ECN) & 1, + (features >> VIRTIO_NET_F_GUEST_UFO) & 1); #endif } diff --git a/net.c b/net.c index 8032ff8..838e42c 100644 --- a/net.c +++ b/net.c @@ -1271,6 +1271,11 @@ void tap_using_vnet_hdr(void *opaque, int using_vnet_hdr) { } +int tap_has_ufo(void *opaque) +{ + return 0; +} + #else /* !defined(_WIN32) */ /* Maximum GSO packet size (64k) plus plenty of room for @@ -1292,6 +1297,7 @@ typedef struct TAPState { unsigned int write_poll : 1; unsigned int has_vnet_hdr : 1; unsigned int using_vnet_hdr : 1; + unsigned int has_ufo: 1; } TAPState; static int launch_script(const char *setup_script, const char *ifname, int fd); @@ -1527,9 +1533,22 @@ static int tap_probe_vnet_hdr(int fd) #endif } +int tap_has_ufo(void *opaque) +{ + VLANClientState *vc = opaque; + TAPState *s = vc->opaque; + + return s ? s->has_ufo : 0; +} + #ifdef TUNSETOFFLOAD + +#ifndef TUN_F_UFO +#define TUN_F_UFO 0x10 +#endif + static void tap_set_offload(VLANClientState *vc, int csum, int tso4, int tso6, - int ecn) + int ecn, int ufo) { TAPState *s = vc->opaque; unsigned int offload = 0; @@ -1542,11 +1561,18 @@ static void tap_set_offload(VLANClientState *vc, int csum, int tso4, int tso6, offload |= TUN_F_TSO6; if ((tso4 || tso6) && ecn) offload |= TUN_F_TSO_ECN; + if (ufo) + offload |= TUN_F_UFO; } - if (ioctl(s->fd, TUNSETOFFLOAD, offload) != 0) - fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n", - strerror(errno)); + if (ioctl(s->fd, TUNSETOFFLOAD, offload) != 0) { + /* Try without UFO */ + offload &= ~TUN_F_UFO; + if (ioctl(s->fd, TUNSETOFFLOAD, offload) != 0) { + fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n", + strerror(errno)); + } + } } #endif /* TUNSETOFFLOAD */ @@ -1574,6 +1600,7 @@ static TAPState *net_tap_fd_init(VLANState *vlan, int vnet_hdr) { TAPState *s; + unsigned int offload; s = qemu_mallocz(sizeof(TAPState)); s->fd = fd; @@ -1583,7 +1610,14 @@ static TAPState *net_tap_fd_init(VLANState *vlan, s->vc->receive_raw = tap_receive_raw; #ifdef TUNSETOFFLOAD s->vc->set_offload = tap_set_offload; - tap_set_offload(s->vc, 0, 0, 0, 0); + + s->has_ufo = 0; + /* Check if tap supports UFO */ + offload = TUN_F_CSUM | TUN_F_UFO; + if (ioctl(s->fd, TUNSETOFFLOAD, offload) == 0) + s->has_ufo = 1; + + tap_set_offload(s->vc, 0, 0, 0, 0, 0); #endif tap_read_poll(s, 1); snprintf(s->vc->info_str, sizeof(s->vc->info_str), "fd=%d", fd); diff --git a/net.h b/net.h index 925c67c..6bb6434 100644 --- a/net.h +++ b/net.h @@ -14,7 +14,7 @@ typedef ssize_t (NetReceive)(VLANClientState *, const uint8_t *, size_t); typedef ssize_t (NetReceiveIOV)(VLANClientState *, const struct iovec *, int); typedef void (NetCleanup) (VLANClientState *); typedef void (LinkStatusChanged)(VLANClientState *); -typedef void (SetOffload)(VLANClientState *, int, int, int, int); +typedef void (SetOffload)(VLANClientState *, int, int, int, int, int); struct VLANClientState { NetReceive *receive; @@ -92,6 +92,7 @@ void do_info_usernet(Monitor *mon); int tap_has_vnet_hdr(void *opaque); void tap_using_vnet_hdr(void *opaque, int using_vnet_hdr); +int tap_has_ufo(void *opaque); /* NIC info */ -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html