net/virtio-user: enable offloading

[dpdk.git] / drivers / net / virtio / virtio_user / vhost_kernel.c

diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c
index d3cbdbd..aeb5075 100644 (file)
--- 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);