From: Jianfeng Tan Date: Fri, 13 Jan 2017 12:18:39 +0000 (+0000) Subject: net/virtio-user: enable offloading X-Git-Tag: spdx-start~5158 X-Git-Url: http://git.droids-corp.org/?p=dpdk.git;a=commitdiff_plain;h=5e97e42025635e03ff5c256275d7d7650fff4dbc net/virtio-user: enable offloading When used with vhost kernel backend, we can offload at both directions. - From vhost kernel to virtio_user, the offload is enabled so that DPDK app can trust the flow is checksum-correct; and if DPDK app sends it through another port, the checksum needs to be recalculated or offloaded. It also applies to TSO. - From virtio_user to vhost_kernel, the offload is enabled so that kernel can trust the flow is L4-checksum-correct, no need to verify it; if kernel will consume it, DPDK app should make sure the l3-checksum is correctly set. Signed-off-by: Jianfeng Tan Acked-by: Yuanhan Liu --- diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c index d3cbdbd19f..aeb5075b82 100644 --- a/drivers/net/virtio/virtio_user/vhost_kernel.c +++ b/drivers/net/virtio/virtio_user/vhost_kernel.c @@ -165,6 +165,28 @@ prepare_vhost_memory_kernel(void) return vm; } +/* with below features, vhost kernel does not need to do the checksum and TSO, + * these info will be passed to virtio_user through virtio net header. + */ +#define VHOST_KERNEL_GUEST_OFFLOADS_MASK \ + ((1ULL << VIRTIO_NET_F_GUEST_CSUM) | \ + (1ULL << VIRTIO_NET_F_GUEST_TSO4) | \ + (1ULL << VIRTIO_NET_F_GUEST_TSO6) | \ + (1ULL << VIRTIO_NET_F_GUEST_ECN) | \ + (1ULL << VIRTIO_NET_F_GUEST_UFO)) + +/* with below features, when flows from virtio_user to vhost kernel + * (1) if flows goes up through the kernel networking stack, it does not need + * to verify checksum, which can save CPU cycles; + * (2) if flows goes through a Linux bridge and outside from an interface + * (kernel driver), checksum and TSO will be done by GSO in kernel or even + * offloaded into real physical device. + */ +#define VHOST_KERNEL_HOST_OFFLOADS_MASK \ + ((1ULL << VIRTIO_NET_F_HOST_TSO4) | \ + (1ULL << VIRTIO_NET_F_HOST_TSO6) | \ + (1ULL << VIRTIO_NET_F_CSUM)) + static int vhost_kernel_ioctl(struct virtio_user_dev *dev, enum vhost_user_request req, @@ -186,10 +208,15 @@ vhost_kernel_ioctl(struct virtio_user_dev *dev, arg = (void *)vm; } - /* We don't need memory protection here */ - if (req_kernel == VHOST_SET_FEATURES) + if (req_kernel == VHOST_SET_FEATURES) { + /* We don't need memory protection here */ *(uint64_t *)arg &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM); + /* VHOST kernel does not know about below flags */ + *(uint64_t *)arg &= ~VHOST_KERNEL_GUEST_OFFLOADS_MASK; + *(uint64_t *)arg &= ~VHOST_KERNEL_HOST_OFFLOADS_MASK; + } + for (i = 0; i < dev->max_queue_pairs; ++i) { if (dev->vhostfds[i] < 0) continue; @@ -199,6 +226,15 @@ vhost_kernel_ioctl(struct virtio_user_dev *dev, break; } + if (!ret && req_kernel == VHOST_GET_FEATURES) { + /* with tap as the backend, all these features are supported + * but not claimed by vhost-net, so we add them back when + * reporting to upper layer. + */ + *((uint64_t *)arg) |= VHOST_KERNEL_GUEST_OFFLOADS_MASK; + *((uint64_t *)arg) |= VHOST_KERNEL_HOST_OFFLOADS_MASK; + } + if (vm) free(vm); diff --git a/drivers/net/virtio/virtio_user/vhost_kernel_tap.c b/drivers/net/virtio/virtio_user/vhost_kernel_tap.c index 797713b7e1..cdb5c3c180 100644 --- a/drivers/net/virtio/virtio_user/vhost_kernel_tap.c +++ b/drivers/net/virtio/virtio_user/vhost_kernel_tap.c @@ -50,6 +50,12 @@ vhost_kernel_open_tap(char **p_ifname, int hdr_size) int sndbuf = INT_MAX; struct ifreq ifr; int tapfd; + unsigned int offload = + TUN_F_CSUM | + TUN_F_TSO4 | + TUN_F_TSO6 | + TUN_F_TSO_ECN | + TUN_F_UFO; /* TODO: * 1. verify we can get/set vnet_hdr_len, tap_probe_vnet_hdr_len @@ -106,6 +112,14 @@ vhost_kernel_open_tap(char **p_ifname, int hdr_size) goto error; } + /* TODO: before set the offload capabilities, we'd better (1) check + * negotiated features to see if necessary to offload; (2) query tap + * to see if it supports the offload capabilities. + */ + if (ioctl(tapfd, TUNSETOFFLOAD, offload) != 0) + PMD_DRV_LOG(ERR, "TUNSETOFFLOAD ioctl() failed: %s", + strerror(errno)); + if (!(*p_ifname)) *p_ifname = strdup(ifr.ifr_name); diff --git a/drivers/net/virtio/virtio_user/vhost_kernel_tap.h b/drivers/net/virtio/virtio_user/vhost_kernel_tap.h index 1fc58ff1fa..8535116c96 100644 --- a/drivers/net/virtio/virtio_user/vhost_kernel_tap.h +++ b/drivers/net/virtio/virtio_user/vhost_kernel_tap.h @@ -54,6 +54,13 @@ #define IFF_ATTACH_QUEUE 0x0200 #define IFF_DETACH_QUEUE 0x0400 +/* Features for GSO (TUNSETOFFLOAD). */ +#define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */ +#define TUN_F_TSO4 0x02 /* I can handle TSO for IPv4 packets */ +#define TUN_F_TSO6 0x04 /* I can handle TSO for IPv6 packets */ +#define TUN_F_TSO_ECN 0x08 /* I can handle TSO with ECN bits. */ +#define TUN_F_UFO 0x10 /* I can handle UFO packets */ + /* Constants */ #define PATH_NET_TUN "/dev/net/tun"