When vhost support VIRTIO_VSOCK_F_MRG_RXBUF feature,
it will merge big packet into rx vq.
Signed-off-by: Yiwen Jiang <jiangyiwen@xxxxxxxxxx>
---
drivers/vhost/vsock.c | 117 +++++++++++++++++++++++++++++++-------
include/linux/virtio_vsock.h | 1 +
include/uapi/linux/virtio_vsock.h | 5 ++
3 files changed, 102 insertions(+), 21 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 34bc3ab..648be39 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -22,7 +22,8 @@
#define VHOST_VSOCK_DEFAULT_HOST_CID 2
enum {
- VHOST_VSOCK_FEATURES = VHOST_FEATURES,
+ VHOST_VSOCK_FEATURES = VHOST_FEATURES |
+ (1ULL << VIRTIO_VSOCK_F_MRG_RXBUF),
};
/* Used to track all the vhost_vsock instances on the system. */
@@ -80,6 +81,68 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
return vsock;
}
+static int get_rx_bufs(struct vhost_virtqueue *vq,
+ struct vring_used_elem *heads, int datalen,
+ unsigned *iovcount, unsigned int quota)
+{
+ unsigned int out, in;
+ int seg = 0;
+ int headcount = 0;
+ unsigned d;
+ int ret;
+ /*
+ * len is always initialized before use since we are always called with
+ * datalen > 0.
+ */
+ u32 uninitialized_var(len);
+
+ while (datalen > 0 && headcount < quota) {
+ if (unlikely(seg >= UIO_MAXIOV)) {
+ ret = -ENOBUFS;
+ goto err;
+ }
+
+ ret = vhost_get_vq_desc(vq, vq->iov + seg,
+ ARRAY_SIZE(vq->iov) - seg, &out,
+ &in, NULL, NULL);
+ if (unlikely(ret < 0))
+ goto err;
+
+ d = ret;
+ if (d == vq->num) {
+ ret = 0;
+ goto err;
+ }
+
+ if (unlikely(out || in <= 0)) {
+ vq_err(vq, "unexpected descriptor format for RX: "
+ "out %d, in %d\n", out, in);
+ ret = -EINVAL;
+ goto err;
+ }
+
+ heads[headcount].id = cpu_to_vhost32(vq, d);
+ len = iov_length(vq->iov + seg, in);
+ heads[headcount].len = cpu_to_vhost32(vq, len);
+ datalen -= len;
+ ++headcount;
+ seg += in;
+ }
+
+ heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
+ *iovcount = seg;
+
+ /* Detect overrun */
+ if (unlikely(datalen > 0)) {
+ ret = UIO_MAXIOV + 1;
+ goto err;
+ }
+ return headcount;
+err:
+ vhost_discard_vq_desc(vq, headcount);
+ return ret;
+}
+
static void
vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
struct vhost_virtqueue *vq)
@@ -87,22 +150,34 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
bool added = false;
bool restart_tx = false;
+ int mergeable;
+ size_t vsock_hlen;
mutex_lock(&vq->mutex);
if (!vq->private_data)
goto out;
+ mergeable = vhost_has_feature(vq, VIRTIO_VSOCK_F_MRG_RXBUF);
+ /*
+ * Guest fill page for rx vq in mergeable case, so it will not
+ * allocate pkt structure, we should reserve size of pkt in advance.
+ */
+ if (likely(mergeable))
+ vsock_hlen = sizeof(struct virtio_vsock_pkt);
+ else
+ vsock_hlen = sizeof(struct virtio_vsock_hdr);
+
/* Avoid further vmexits, we're already processing the virtqueue */
vhost_disable_notify(&vsock->dev, vq);
for (;;) {
struct virtio_vsock_pkt *pkt;
struct iov_iter iov_iter;
- unsigned out, in;
+ unsigned out = 0, in = 0;
size_t nbytes;
size_t len;
- int head;
+ s16 headcount;
spin_lock_bh(&vsock->send_pkt_list_lock);
if (list_empty(&vsock->send_pkt_list)) {
@@ -116,16 +191,9 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
list_del_init(&pkt->list);
spin_unlock_bh(&vsock->send_pkt_list_lock);
- head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
- &out, &in, NULL, NULL);
- if (head < 0) {
- spin_lock_bh(&vsock->send_pkt_list_lock);
- list_add(&pkt->list, &vsock->send_pkt_list);
- spin_unlock_bh(&vsock->send_pkt_list_lock);
- break;
- }
-
- if (head == vq->num) {
+ headcount = get_rx_bufs(vq, vq->heads, vsock_hlen + pkt->len,
+ &in, likely(mergeable) ? UIO_MAXIOV : 1);
+ if (headcount <= 0) {
spin_lock_bh(&vsock->send_pkt_list_lock);
list_add(&pkt->list, &vsock->send_pkt_list);
spin_unlock_bh(&vsock->send_pkt_list_lock);
@@ -133,19 +201,13 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
/* We cannot finish yet if more buffers snuck in while
* re-enabling notify.
*/
- if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
+ if (!headcount && unlikely(vhost_enable_notify(&vsock->dev, vq))) {
vhost_disable_notify(&vsock->dev, vq);
continue;
}
break;
}
- if (out) {
- virtio_transport_free_pkt(pkt);
- vq_err(vq, "Expected 0 output buffers, got %u\n", out);
- break;
- }
-
len = iov_length(&vq->iov[out], in);
iov_iter_init(&iov_iter, READ, &vq->iov[out], in, len);
@@ -156,6 +218,19 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
break;
}
+ if (likely(mergeable)) {
+ pkt->mrg_rxbuf_hdr.num_buffers = cpu_to_le16(headcount);
+ nbytes = copy_to_iter(&pkt->mrg_rxbuf_hdr,
+ sizeof(pkt->mrg_rxbuf_hdr), &iov_iter);
+ if (nbytes != sizeof(pkt->mrg_rxbuf_hdr)) {
+ virtio_transport_free_pkt(pkt);
+ vq_err(vq, "Faulted on copying rxbuf hdr\n");
+ break;
+ }
+ iov_iter_advance(&iov_iter, (vsock_hlen -
+ sizeof(pkt->mrg_rxbuf_hdr) - sizeof(pkt->hdr)));
+ }
+
nbytes = copy_to_iter(pkt->buf, pkt->len, &iov_iter);
if (nbytes != pkt->len) {
virtio_transport_free_pkt(pkt);
@@ -163,7 +238,7 @@ static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
break;
}
- vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len);
+ vhost_add_used_n(vq, vq->heads, headcount);
added = true;
if (pkt->reply) {
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index bf84418..da9e1fe 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -50,6 +50,7 @@ struct virtio_vsock_sock {
struct virtio_vsock_pkt {
struct virtio_vsock_hdr hdr;
+ struct virtio_vsock_mrg_rxbuf_hdr mrg_rxbuf_hdr;
struct work_struct work;
struct list_head list;
/* socket refcnt not held, only use for cancellation */
diff --git a/include/uapi/linux/virtio_vsock.h b/include/uapi/linux/virtio_vsock.h
index 1d57ed3..2292f30 100644
--- a/include/uapi/linux/virtio_vsock.h
+++ b/include/uapi/linux/virtio_vsock.h
@@ -63,6 +63,11 @@ struct virtio_vsock_hdr {
__le32 fwd_cnt;
} __attribute__((packed));
+/* It add mergeable rx buffers feature */
+struct virtio_vsock_mrg_rxbuf_hdr {
+ __le16 num_buffers; /* number of mergeable rx buffers */
+} __attribute__((packed));
+
enum virtio_vsock_type {
VIRTIO_VSOCK_TYPE_STREAM = 1,
};
--
1.8.3.1
