Introduce the module param "experiment_premapped" to enable the function
that the virtio-net do dma mapping.
If that is true, the vq of virtio-net is under the premapped mode.
It just handle the sg with dma_address. And the driver must get the dma
address of the buffer to unmap after get the buffer from virtio core.
That will be useful when AF_XDP is enable, AF_XDP tx and the kernel packet
xmit will share the tx queue, so the skb xmit must support the premapped
mode.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 163 +++++++++++++++++++++++++++++++++------
1 file changed, 141 insertions(+), 22 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 2396c28c0122..5898212fcb3c 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -26,10 +26,11 @@
static int napi_weight = NAPI_POLL_WEIGHT;
module_param(napi_weight, int, 0444);
-static bool csum = true, gso = true, napi_tx = true;
+static bool csum = true, gso = true, napi_tx = true, experiment_premapped;
module_param(csum, bool, 0444);
module_param(gso, bool, 0444);
module_param(napi_tx, bool, 0644);
+module_param(experiment_premapped, bool, 0644);
/* FIXME: MTU in config. */
#define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
@@ -142,6 +143,9 @@ struct send_queue {
/* Record whether sq is in reset state. */
bool reset;
+
+ /* The vq is premapped mode. */
+ bool premapped;
};
/* Internal representation of a receive virtqueue */
@@ -174,6 +178,9 @@ struct receive_queue {
char name[16];
struct xdp_rxq_info xdp_rxq;
+
+ /* The vq is premapped mode. */
+ bool premapped;
};
/* This structure can contain rss message with maximum settings for indirection table and keysize
@@ -546,6 +553,105 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
return skb;
}
+static int virtnet_generic_unmap(struct virtqueue *vq, struct virtqueue_detach_cursor *cursor)
+{
+ enum dma_data_direction dir;
+ dma_addr_t addr;
+ u32 len;
+ int err;
+
+ do {
+ err = virtqueue_detach(vq, cursor, &addr, &len, &dir);
+ if (!err || err == -EAGAIN)
+ dma_unmap_page_attrs(virtqueue_dma_dev(vq), addr, len, dir, 0);
+
+ } while (err == -EAGAIN);
+
+ return err;
+}
+
+static void *virtnet_detach_unused_buf(struct virtqueue *vq, bool premapped)
+{
+ struct virtqueue_detach_cursor cursor;
+ void *buf;
+
+ if (!premapped)
+ return virtqueue_detach_unused_buf(vq);
+
+ buf = virtqueue_detach_unused_buf_premapped(vq, &cursor);
+ if (buf)
+ virtnet_generic_unmap(vq, &cursor);
+
+ return buf;
+}
+
+static void *virtnet_get_buf_ctx(struct virtqueue *vq, bool premapped, u32 *len, void **ctx)
+{
+ struct virtqueue_detach_cursor cursor;
+ void *buf;
+
+ if (!premapped)
+ return virtqueue_get_buf_ctx(vq, len, ctx);
+
+ buf = virtqueue_get_buf_premapped(vq, len, ctx, &cursor);
+ if (buf)
+ virtnet_generic_unmap(vq, &cursor);
+
+ return buf;
+}
+
+#define virtnet_rq_get_buf(rq, plen, pctx) \
+({ \
+ typeof(rq) _rq = (rq); \
+ virtnet_get_buf_ctx(_rq->vq, _rq->premapped, plen, pctx); \
+})
+
+#define virtnet_sq_get_buf(sq, plen, pctx) \
+({ \
+ typeof(sq) _sq = (sq); \
+ virtnet_get_buf_ctx(_sq->vq, _sq->premapped, plen, pctx); \
+})
+
+static int virtnet_add_sg(struct virtqueue *vq, bool premapped,
+ struct scatterlist *sg, unsigned int num, bool out,
+ void *data, void *ctx, gfp_t gfp)
+{
+ enum dma_data_direction dir;
+ struct device *dev;
+ int err, ret;
+
+ if (!premapped)
+ return virtqueue_add_sg(vq, sg, num, out, data, ctx, gfp);
+
+ dir = out ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+ dev = virtqueue_dma_dev(vq);
+
+ ret = dma_map_sg_attrs(dev, sg, num, dir, 0);
+ if (ret != num)
+ goto err;
+
+ err = virtqueue_add_sg(vq, sg, num, out, data, ctx, gfp);
+ if (err < 0)
+ goto err;
+
+ return 0;
+
+err:
+ dma_unmap_sg_attrs(dev, sg, num, dir, 0);
+ return -ENOMEM;
+}
+
+static int virtnet_add_outbuf(struct send_queue *sq, unsigned int num, void *data)
+{
+ return virtnet_add_sg(sq->vq, sq->premapped, sq->sg, num, true, data, NULL, GFP_ATOMIC);
+}
+
+static int virtnet_add_inbuf(struct receive_queue *rq, unsigned int num, void *data,
+ void *ctx, gfp_t gfp)
+{
+ return virtnet_add_sg(rq->vq, rq->premapped, rq->sg, num, false, data, ctx, gfp);
+}
+
static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi)
{
unsigned int len;
@@ -553,7 +659,7 @@ static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi)
unsigned int bytes = 0;
void *ptr;
- while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
+ while ((ptr = virtnet_sq_get_buf(sq, &len, NULL)) != NULL) {
if (likely(!is_xdp_frame(ptr))) {
struct sk_buff *skb = ptr;
@@ -667,8 +773,7 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
skb_frag_size(frag), skb_frag_off(frag));
}
- err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1,
- xdp_to_ptr(xdpf), GFP_ATOMIC);
+ err = virtnet_add_outbuf(sq, nr_frags + 1, xdp_to_ptr(xdpf));
if (unlikely(err))
return -ENOSPC; /* Caller handle free/refcnt */
@@ -744,7 +849,7 @@ static int virtnet_xdp_xmit(struct net_device *dev,
}
/* Free up any pending old buffers before queueing new ones. */
- while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
+ while ((ptr = virtnet_sq_get_buf(sq, &len, NULL)) != NULL) {
if (likely(is_xdp_frame(ptr))) {
struct xdp_frame *frame = ptr_to_xdp(ptr);
@@ -828,7 +933,7 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,
void *buf;
int off;
- buf = virtqueue_get_buf(rq->vq, &buflen);
+ buf = virtnet_rq_get_buf(rq, &buflen, NULL);
if (unlikely(!buf))
goto err_buf;
@@ -1119,7 +1224,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
return -EINVAL;
while (--*num_buf > 0) {
- buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx);
+ buf = virtnet_rq_get_buf(rq, &len, &ctx);
if (unlikely(!buf)) {
pr_debug("%s: rx error: %d buffers out of %d missing\n",
dev->name, *num_buf,
@@ -1344,7 +1449,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
while (--num_buf) {
int num_skb_frags;
- buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx);
+ buf = virtnet_rq_get_buf(rq, &len, &ctx);
if (unlikely(!buf)) {
pr_debug("%s: rx error: %d buffers out of %d missing\n",
dev->name, num_buf,
@@ -1407,7 +1512,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
err_skb:
put_page(page);
while (num_buf-- > 1) {
- buf = virtqueue_get_buf(rq->vq, &len);
+ buf = virtnet_rq_get_buf(rq, &len, NULL);
if (unlikely(!buf)) {
pr_debug("%s: rx error: %d buffers missing\n",
dev->name, num_buf);
@@ -1534,7 +1639,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
alloc_frag->offset += len;
sg_init_one(rq->sg, buf + VIRTNET_RX_PAD + xdp_headroom,
vi->hdr_len + GOOD_PACKET_LEN);
- err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
+ err = virtnet_add_inbuf(rq, 1, buf, ctx, gfp);
if (err < 0)
put_page(virt_to_head_page(buf));
return err;
@@ -1581,8 +1686,8 @@ static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
/* chain first in list head */
first->private = (unsigned long)list;
- err = virtqueue_add_inbuf(rq->vq, rq->sg, vi->big_packets_num_skbfrags + 2,
- first, gfp);
+ err = virtnet_add_inbuf(rq, vi->big_packets_num_skbfrags + 2,
+ first, NULL, gfp);
if (err < 0)
give_pages(rq, first);
@@ -1645,7 +1750,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
sg_init_one(rq->sg, buf, len);
ctx = mergeable_len_to_ctx(len + room, headroom);
- err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
+ err = virtnet_add_inbuf(rq, 1, buf, ctx, gfp);
if (err < 0)
put_page(virt_to_head_page(buf));
@@ -1768,13 +1873,13 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
void *ctx;
while (stats.packets < budget &&
- (buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx))) {
+ (buf = virtnet_rq_get_buf(rq, &len, &ctx))) {
receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &stats);
stats.packets++;
}
} else {
while (stats.packets < budget &&
- (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
+ (buf = virtnet_rq_get_buf(rq, &len, NULL)) != NULL) {
receive_buf(vi, rq, buf, len, NULL, xdp_xmit, &stats);
stats.packets++;
}
@@ -1984,7 +2089,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
return num_sg;
num_sg++;
}
- return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
+ return virtnet_add_outbuf(sq, num_sg, skb);
}
static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -3552,15 +3657,17 @@ static void free_unused_bufs(struct virtnet_info *vi)
int i;
for (i = 0; i < vi->max_queue_pairs; i++) {
- struct virtqueue *vq = vi->sq[i].vq;
- while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
- virtnet_sq_free_unused_buf(vq, buf);
+ struct send_queue *sq = &vi->sq[i];
+
+ while ((buf = virtnet_detach_unused_buf(sq->vq, sq->premapped)) != NULL)
+ virtnet_sq_free_unused_buf(sq->vq, buf);
}
for (i = 0; i < vi->max_queue_pairs; i++) {
- struct virtqueue *vq = vi->rq[i].vq;
- while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
- virtnet_rq_free_unused_buf(vq, buf);
+ struct receive_queue *rq = &vi->rq[i];
+
+ while ((buf = virtnet_detach_unused_buf(rq->vq, rq->premapped)) != NULL)
+ virtnet_rq_free_unused_buf(rq->vq, buf);
}
}
@@ -3658,6 +3765,18 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
vi->rq[i].vq = vqs[rxq2vq(i)];
vi->rq[i].min_buf_len = mergeable_min_buf_len(vi, vi->rq[i].vq);
vi->sq[i].vq = vqs[txq2vq(i)];
+
+ if (experiment_premapped) {
+ if (!virtqueue_set_premapped(vi->rq[i].vq))
+ vi->rq[i].premapped = true;
+ else
+ netdev_warn(vi->dev, "RXQ (%d) enable premapped failure.\n", i);
+
+ if (!virtqueue_set_premapped(vi->sq[i].vq))
+ vi->sq[i].premapped = true;
+ else
+ netdev_warn(vi->dev, "TXQ (%d) enable premapped failure.\n", i);
+ }
}
/* run here: ret == 0. */
--
2.32.0.3.g01195cf9f
