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virtio_net: add page_pool support for buffer allocation

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Use page_pool for RX buffer allocation in mergeable and small buffer
modes to enable page recycling and avoid repeated page allocator calls.
skb_mark_for_recycle() enables page reuse in the network stack.

Big packets mode is unchanged because it uses page->private for linked
list chaining of multiple pages per buffer, which conflicts with
page_pool's internal use of page->private.

Implement conditional DMA premapping using virtqueue_dma_dev():
- When non-NULL (vhost, virtio-pci): use PP_FLAG_DMA_MAP with page_pool
  handling DMA mapping, submit via virtqueue_add_inbuf_premapped()
- When NULL (VDUSE, direct physical): page_pool handles allocation only,
  submit via virtqueue_add_inbuf_ctx()

This preserves the DMA premapping optimization from commit 31f3cd4e57
("virtio-net: rq submits premapped per-buffer") while adding page_pool
support as a prerequisite for future zero-copy features (devmem TCP,
io_uring ZCRX).

Page pools are created in probe and destroyed in remove (not open/close),
following existing driver behavior where RX buffers remain in virtqueues
across interface state changes.

Signed-off-by: Vishwanath Seshagiri <vishs@meta.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20260310183107.2822016-1-vishs@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Vishwanath Seshagiri 2026-03-10 11:31:04 -07:00 committed by Jakub Kicinski
parent 5446b8691e
commit 24fbd3967f
2 changed files with 251 additions and 247 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/net/Kconfig
View File

@ -452,6 +452,7 @@ config VIRTIO_NET
depends on VIRTIO
select NET_FAILOVER
select DIMLIB
select PAGE_POOL
help
This is the virtual network driver for virtio. It can be used with
QEMU based VMMs (like KVM or Xen). Say Y or M.

497
drivers/net/virtio_net.c
View File

@ -26,6 +26,7 @@
#include <net/netdev_rx_queue.h>
#include <net/netdev_queues.h>
#include <net/xdp_sock_drv.h>
#include <net/page_pool/helpers.h>
static int napi_weight = NAPI_POLL_WEIGHT;
module_param(napi_weight, int, 0444);
@ -290,14 +291,6 @@ struct virtnet_interrupt_coalesce {
u32 max_usecs;
};
/* The dma information of pages allocated at a time. */
struct virtnet_rq_dma {
dma_addr_t addr;
u32 ref;
u16 len;
u16 need_sync;
};
/* Internal representation of a send virtqueue */
struct send_queue {
/* Virtqueue associated with this send _queue */
@ -356,8 +349,10 @@ struct receive_queue {
/* Average packet length for mergeable receive buffers. */
struct ewma_pkt_len mrg_avg_pkt_len;
/* Page frag for packet buffer allocation. */
struct page_frag alloc_frag;
struct page_pool *page_pool;
/* True if page_pool handles DMA mapping via PP_FLAG_DMA_MAP */
bool use_page_pool_dma;
/* RX: fragments + linear part + virtio header */
struct scatterlist sg[MAX_SKB_FRAGS + 2];
@ -370,9 +365,6 @@ struct receive_queue {
struct xdp_rxq_info xdp_rxq;
/* Record the last dma info to free after new pages is allocated. */
struct virtnet_rq_dma *last_dma;
struct xsk_buff_pool *xsk_pool;
/* xdp rxq used by xsk */
@ -521,11 +513,14 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
struct virtnet_rq_stats *stats);
static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,
struct sk_buff *skb, u8 flags);
static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
static struct sk_buff *virtnet_skb_append_frag(struct receive_queue *rq,
struct sk_buff *head_skb,
struct sk_buff *curr_skb,
struct page *page, void *buf,
int len, int truesize);
static void virtnet_xsk_completed(struct send_queue *sq, int num);
static void free_unused_bufs(struct virtnet_info *vi);
static void virtnet_del_vqs(struct virtnet_info *vi);
enum virtnet_xmit_type {
VIRTNET_XMIT_TYPE_SKB,
@ -709,12 +704,10 @@ static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
static void virtnet_rq_free_buf(struct virtnet_info *vi,
struct receive_queue *rq, void *buf)
{
if (vi->mergeable_rx_bufs)
put_page(virt_to_head_page(buf));
else if (vi->big_packets)
if (!rq->page_pool)
give_pages(rq, buf);
else
put_page(virt_to_head_page(buf));
page_pool_put_page(rq->page_pool, virt_to_head_page(buf), -1, false);
}
static void enable_rx_mode_work(struct virtnet_info *vi)
@ -876,10 +869,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
skb = virtnet_build_skb(buf, truesize, p - buf, len);
if (unlikely(!skb))
return NULL;
/* Big packets mode chains pages via page->private, which is
* incompatible with the way page_pool uses page->private.
* Currently, big packets mode doesn't use page pools.
*/
if (!rq->page_pool) {
page = (struct page *)page->private;
if (page)
give_pages(rq, page);
}
page = (struct page *)page->private;
if (page)
give_pages(rq, page);
goto ok;
}
@ -925,133 +924,16 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
hdr = skb_vnet_common_hdr(skb);
memcpy(hdr, hdr_p, hdr_len);
if (page_to_free)
put_page(page_to_free);
page_pool_put_page(rq->page_pool, page_to_free, -1, true);
return skb;
}
static void virtnet_rq_unmap(struct receive_queue *rq, void *buf, u32 len)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
struct page *page = virt_to_head_page(buf);
struct virtnet_rq_dma *dma;
void *head;
int offset;
BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
head = page_address(page);
dma = head;
--dma->ref;
if (dma->need_sync && len) {
offset = buf - (head + sizeof(*dma));
virtqueue_map_sync_single_range_for_cpu(rq->vq, dma->addr,
offset, len,
DMA_FROM_DEVICE);
}
if (dma->ref)
return;
virtqueue_unmap_single_attrs(rq->vq, dma->addr, dma->len,
DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
put_page(page);
}
static void *virtnet_rq_get_buf(struct receive_queue *rq, u32 *len, void **ctx)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
void *buf;
BUG_ON(!rq->page_pool);
BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
if (buf)
virtnet_rq_unmap(rq, buf, *len);
return buf;
}
static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
struct virtnet_rq_dma *dma;
dma_addr_t addr;
u32 offset;
void *head;
BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
head = page_address(rq->alloc_frag.page);
offset = buf - head;
dma = head;
addr = dma->addr - sizeof(*dma) + offset;
sg_init_table(rq->sg, 1);
sg_fill_dma(rq->sg, addr, len);
}
static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
{
struct page_frag *alloc_frag = &rq->alloc_frag;
struct virtnet_info *vi = rq->vq->vdev->priv;
struct virtnet_rq_dma *dma;
void *buf, *head;
dma_addr_t addr;
BUG_ON(vi->big_packets && !vi->mergeable_rx_bufs);
head = page_address(alloc_frag->page);
dma = head;
/* new pages */
if (!alloc_frag->offset) {
if (rq->last_dma) {
/* Now, the new page is allocated, the last dma
* will not be used. So the dma can be unmapped
* if the ref is 0.
*/
virtnet_rq_unmap(rq, rq->last_dma, 0);
rq->last_dma = NULL;
}
dma->len = alloc_frag->size - sizeof(*dma);
addr = virtqueue_map_single_attrs(rq->vq, dma + 1,
dma->len, DMA_FROM_DEVICE, 0);
if (virtqueue_map_mapping_error(rq->vq, addr))
return NULL;
dma->addr = addr;
dma->need_sync = virtqueue_map_need_sync(rq->vq, addr);
/* Add a reference to dma to prevent the entire dma from
* being released during error handling. This reference
* will be freed after the pages are no longer used.
*/
get_page(alloc_frag->page);
dma->ref = 1;
alloc_frag->offset = sizeof(*dma);
rq->last_dma = dma;
}
++dma->ref;
buf = head + alloc_frag->offset;
get_page(alloc_frag->page);
alloc_frag->offset += size;
return buf;
return virtqueue_get_buf_ctx(rq->vq, len, ctx);
}
static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
@ -1067,9 +949,6 @@ static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
return;
}
if (!vi->big_packets || vi->mergeable_rx_bufs)
virtnet_rq_unmap(rq, buf, 0);
virtnet_rq_free_buf(vi, rq, buf);
}
@ -1335,7 +1214,7 @@ static int xsk_append_merge_buffer(struct virtnet_info *vi,
truesize = len;
curr_skb = virtnet_skb_append_frag(head_skb, curr_skb, page,
curr_skb = virtnet_skb_append_frag(rq, head_skb, curr_skb, page,
buf, len, truesize);
if (!curr_skb) {
put_page(page);
@ -1790,7 +1669,7 @@ static int virtnet_xdp_xmit(struct net_device *dev,
return ret;
}
static void put_xdp_frags(struct xdp_buff *xdp)
static void put_xdp_frags(struct receive_queue *rq, struct xdp_buff *xdp)
{
struct skb_shared_info *shinfo;
struct page *xdp_page;
@ -1800,7 +1679,7 @@ static void put_xdp_frags(struct xdp_buff *xdp)
shinfo = xdp_get_shared_info_from_buff(xdp);
for (i = 0; i < shinfo->nr_frags; i++) {
xdp_page = skb_frag_page(&shinfo->frags[i]);
put_page(xdp_page);
page_pool_put_page(rq->page_pool, xdp_page, -1, true);
}
}
}
@ -1892,7 +1771,7 @@ static struct page *xdp_linearize_page(struct net_device *dev,
if (page_off + *len + tailroom > PAGE_SIZE)
return NULL;
page = alloc_page(GFP_ATOMIC);
page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
if (!page)
return NULL;
@ -1915,8 +1794,12 @@ static struct page *xdp_linearize_page(struct net_device *dev,
p = virt_to_head_page(buf);
off = buf - page_address(p);
if (rq->use_page_pool_dma)
page_pool_dma_sync_for_cpu(rq->page_pool, p,
off, buflen);
if (check_mergeable_len(dev, ctx, buflen)) {
put_page(p);
page_pool_put_page(rq->page_pool, p, -1, true);
goto err_buf;
}
@ -1924,38 +1807,36 @@ static struct page *xdp_linearize_page(struct net_device *dev,
* is sending packet larger than the MTU.
*/
if ((page_off + buflen + tailroom) > PAGE_SIZE) {
put_page(p);
page_pool_put_page(rq->page_pool, p, -1, true);
goto err_buf;
}
memcpy(page_address(page) + page_off,
page_address(p) + off, buflen);
page_off += buflen;
put_page(p);
page_pool_put_page(rq->page_pool, p, -1, true);
}
/* Headroom does not contribute to packet length */
*len = page_off - XDP_PACKET_HEADROOM;
return page;
err_buf:
__free_pages(page, 0);
page_pool_put_page(rq->page_pool, page, -1, true);
return NULL;
}
static struct sk_buff *receive_small_build_skb(struct virtnet_info *vi,
unsigned int xdp_headroom,
void *buf,
unsigned int len)
unsigned int len,
unsigned int buflen)
{
unsigned int header_offset;
unsigned int headroom;
unsigned int buflen;
struct sk_buff *skb;
header_offset = VIRTNET_RX_PAD + xdp_headroom;
headroom = vi->hdr_len + header_offset;
buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
skb = virtnet_build_skb(buf, buflen, headroom, len);
if (unlikely(!skb))
@ -1974,6 +1855,7 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
void *buf,
unsigned int xdp_headroom,
unsigned int len,
unsigned int buflen,
unsigned int *xdp_xmit,
struct virtnet_rq_stats *stats)
{
@ -1982,7 +1864,6 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset;
struct page *page = virt_to_head_page(buf);
struct page *xdp_page;
unsigned int buflen;
struct xdp_buff xdp;
struct sk_buff *skb;
unsigned int metasize = 0;
@ -1995,9 +1876,6 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
if (unlikely(hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
goto err_xdp;
buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
if (unlikely(xdp_headroom < virtnet_get_headroom(vi))) {
int offset = buf - page_address(page) + header_offset;
unsigned int tlen = len + vi->hdr_len;
@ -2015,7 +1893,7 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
goto err_xdp;
buf = page_address(xdp_page);
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
page = xdp_page;
}
@ -2047,13 +1925,15 @@ static struct sk_buff *receive_small_xdp(struct net_device *dev,
if (metasize)
skb_metadata_set(skb, metasize);
skb_mark_for_recycle(skb);
return skb;
err_xdp:
u64_stats_inc(&stats->xdp_drops);
err:
u64_stats_inc(&stats->drops);
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
xdp_xmit:
return NULL;
}
@ -2066,7 +1946,8 @@ static struct sk_buff *receive_small(struct net_device *dev,
unsigned int *xdp_xmit,
struct virtnet_rq_stats *stats)
{
unsigned int xdp_headroom = (unsigned long)ctx;
unsigned int xdp_headroom = mergeable_ctx_to_headroom(ctx);
unsigned int buflen = mergeable_ctx_to_truesize(ctx);
struct page *page = virt_to_head_page(buf);
struct sk_buff *skb;
@ -2075,6 +1956,13 @@ static struct sk_buff *receive_small(struct net_device *dev,
*/
buf -= VIRTNET_RX_PAD + xdp_headroom;
if (rq->use_page_pool_dma) {
int offset = buf - page_address(page) +
VIRTNET_RX_PAD + xdp_headroom;
page_pool_dma_sync_for_cpu(rq->page_pool, page, offset, len);
}
len -= vi->hdr_len;
u64_stats_add(&stats->bytes, len);
@ -2092,21 +1980,23 @@ static struct sk_buff *receive_small(struct net_device *dev,
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
skb = receive_small_xdp(dev, vi, rq, xdp_prog, buf,
xdp_headroom, len, xdp_xmit,
stats);
xdp_headroom, len, buflen,
xdp_xmit, stats);
rcu_read_unlock();
return skb;
}
rcu_read_unlock();
}
skb = receive_small_build_skb(vi, xdp_headroom, buf, len);
if (likely(skb))
skb = receive_small_build_skb(vi, xdp_headroom, buf, len, buflen);
if (likely(skb)) {
skb_mark_for_recycle(skb);
return skb;
}
err:
u64_stats_inc(&stats->drops);
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
return NULL;
}
@ -2161,7 +2051,7 @@ static void mergeable_buf_free(struct receive_queue *rq, int num_buf,
}
u64_stats_add(&stats->bytes, len);
page = virt_to_head_page(buf);
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
}
}
@ -2271,8 +2161,12 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
page = virt_to_head_page(buf);
offset = buf - page_address(page);
if (rq->use_page_pool_dma)
page_pool_dma_sync_for_cpu(rq->page_pool, page,
offset, len);
if (check_mergeable_len(dev, ctx, len)) {
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
goto err;
}
@ -2291,7 +2185,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
return 0;
err:
put_xdp_frags(xdp);
put_xdp_frags(rq, xdp);
return -EINVAL;
}
@ -2356,7 +2250,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
if (*len + xdp_room > PAGE_SIZE)
return NULL;
xdp_page = alloc_page(GFP_ATOMIC);
xdp_page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
if (!xdp_page)
return NULL;
@ -2366,7 +2260,7 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
*frame_sz = PAGE_SIZE;
put_page(*page);
page_pool_put_page(rq->page_pool, *page, -1, true);
*page = xdp_page;
@ -2412,6 +2306,8 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
if (unlikely(!head_skb))
break;
skb_mark_for_recycle(head_skb);
return head_skb;
case XDP_TX:
@ -2422,10 +2318,10 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
break;
}
put_xdp_frags(&xdp);
put_xdp_frags(rq, &xdp);
err_xdp:
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
mergeable_buf_free(rq, num_buf, dev, stats);
u64_stats_inc(&stats->xdp_drops);
@ -2433,7 +2329,8 @@ static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
return NULL;
}
static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
static struct sk_buff *virtnet_skb_append_frag(struct receive_queue *rq,
struct sk_buff *head_skb,
struct sk_buff *curr_skb,
struct page *page, void *buf,
int len, int truesize)
@ -2448,6 +2345,9 @@ static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
if (unlikely(!nskb))
return NULL;
if (head_skb->pp_recycle)
skb_mark_for_recycle(nskb);
if (curr_skb == head_skb)
skb_shinfo(curr_skb)->frag_list = nskb;
else
@ -2465,7 +2365,10 @@ static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
offset = buf - page_address(page);
if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
put_page(page);
if (head_skb->pp_recycle)
page_pool_put_page(rq->page_pool, page, -1, true);
else
put_page(page);
skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
len, truesize);
} else {
@ -2494,6 +2397,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
unsigned int headroom = mergeable_ctx_to_headroom(ctx);
head_skb = NULL;
if (rq->use_page_pool_dma)
page_pool_dma_sync_for_cpu(rq->page_pool, page, offset, len);
u64_stats_add(&stats->bytes, len - vi->hdr_len);
if (check_mergeable_len(dev, ctx, len))
@ -2518,6 +2425,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
if (unlikely(!curr_skb))
goto err_skb;
skb_mark_for_recycle(head_skb);
while (--num_buf) {
buf = virtnet_rq_get_buf(rq, &len, &ctx);
if (unlikely(!buf)) {
@ -2532,11 +2441,17 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
u64_stats_add(&stats->bytes, len);
page = virt_to_head_page(buf);
if (rq->use_page_pool_dma) {
offset = buf - page_address(page);
page_pool_dma_sync_for_cpu(rq->page_pool, page,
offset, len);
}
if (check_mergeable_len(dev, ctx, len))
goto err_skb;
truesize = mergeable_ctx_to_truesize(ctx);
curr_skb = virtnet_skb_append_frag(head_skb, curr_skb, page,
curr_skb = virtnet_skb_append_frag(rq, head_skb, curr_skb, page,
buf, len, truesize);
if (!curr_skb)
goto err_skb;
@ -2546,7 +2461,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
return head_skb;
err_skb:
put_page(page);
page_pool_put_page(rq->page_pool, page, -1, true);
mergeable_buf_free(rq, num_buf, dev, stats);
err_buf:
@ -2677,40 +2592,54 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
virtnet_receive_done(vi, rq, skb, flags);
}
/* Unlike mergeable buffers, all buffers are allocated to the
* same size, except for the headroom. For this reason we do
* not need to use mergeable_len_to_ctx here - it is enough
* to store the headroom as the context ignoring the truesize.
static int virtnet_rq_submit(struct receive_queue *rq, char *buf,
int len, void *ctx, gfp_t gfp)
{
if (rq->use_page_pool_dma) {
struct page *page = virt_to_head_page(buf);
dma_addr_t addr = page_pool_get_dma_addr(page) +
(buf - (char *)page_address(page));
sg_init_table(rq->sg, 1);
sg_fill_dma(rq->sg, addr, len);
return virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1,
buf, ctx, gfp);
}
sg_init_one(rq->sg, buf, len);
return virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
}
/* With page_pool, the actual allocation may exceed the requested size
* when the remaining page fragment can't fit another buffer. Encode
* the actual allocation size in ctx so build_skb() gets the correct
* buflen for truesize accounting.
*/
static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
gfp_t gfp)
{
char *buf;
unsigned int xdp_headroom = virtnet_get_headroom(vi);
void *ctx = (void *)(unsigned long)xdp_headroom;
int len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom;
unsigned int len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom;
unsigned int alloc_len;
char *buf;
void *ctx;
int err;
len = SKB_DATA_ALIGN(len) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
if (unlikely(!skb_page_frag_refill(len, &rq->alloc_frag, gfp)))
return -ENOMEM;
buf = virtnet_rq_alloc(rq, len, gfp);
alloc_len = len;
buf = page_pool_alloc_va(rq->page_pool, &alloc_len, gfp);
if (unlikely(!buf))
return -ENOMEM;
buf += VIRTNET_RX_PAD + xdp_headroom;
virtnet_rq_init_one_sg(rq, buf, vi->hdr_len + GOOD_PACKET_LEN);
err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
if (err < 0) {
virtnet_rq_unmap(rq, buf, 0);
put_page(virt_to_head_page(buf));
}
ctx = mergeable_len_to_ctx(alloc_len, xdp_headroom);
err = virtnet_rq_submit(rq, buf, vi->hdr_len + GOOD_PACKET_LEN, ctx, gfp);
if (err < 0)
page_pool_put_page(rq->page_pool, virt_to_head_page(buf), -1, false);
return err;
}
@ -2783,13 +2712,12 @@ static unsigned int get_mergeable_buf_len(struct receive_queue *rq,
static int add_recvbuf_mergeable(struct virtnet_info *vi,
struct receive_queue *rq, gfp_t gfp)
{
struct page_frag *alloc_frag = &rq->alloc_frag;
unsigned int headroom = virtnet_get_headroom(vi);
unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
unsigned int len, hole;
void *ctx;
unsigned int len, alloc_len;
char *buf;
void *ctx;
int err;
/* Extra tailroom is needed to satisfy XDP's assumption. This
@ -2798,39 +2726,22 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
*/
len = get_mergeable_buf_len(rq, &rq->mrg_avg_pkt_len, room);
if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp)))
return -ENOMEM;
if (!alloc_frag->offset && len + room + sizeof(struct virtnet_rq_dma) > alloc_frag->size)
len -= sizeof(struct virtnet_rq_dma);
buf = virtnet_rq_alloc(rq, len + room, gfp);
alloc_len = len + room;
buf = page_pool_alloc_va(rq->page_pool, &alloc_len, gfp);
if (unlikely(!buf))
return -ENOMEM;
buf += headroom; /* advance address leaving hole at front of pkt */
hole = alloc_frag->size - alloc_frag->offset;
if (hole < len + room) {
/* To avoid internal fragmentation, if there is very likely not
* enough space for another buffer, add the remaining space to
* the current buffer.
* XDP core assumes that frame_size of xdp_buff and the length
* of the frag are PAGE_SIZE, so we disable the hole mechanism.
*/
if (!headroom)
len += hole;
alloc_frag->offset += hole;
}
virtnet_rq_init_one_sg(rq, buf, len);
if (!headroom)
len = alloc_len - room;
ctx = mergeable_len_to_ctx(len + room, headroom);
err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx, gfp);
if (err < 0) {
virtnet_rq_unmap(rq, buf, 0);
put_page(virt_to_head_page(buf));
}
err = virtnet_rq_submit(rq, buf, len, ctx, gfp);
if (err < 0)
page_pool_put_page(rq->page_pool, virt_to_head_page(buf), -1, false);
return err;
}
@ -2984,7 +2895,7 @@ static int virtnet_receive_packets(struct virtnet_info *vi,
int packets = 0;
void *buf;
if (!vi->big_packets || vi->mergeable_rx_bufs) {
if (rq->page_pool) {
void *ctx;
while (packets < budget &&
(buf = virtnet_rq_get_buf(rq, &len, &ctx))) {
@ -3149,7 +3060,10 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
return err;
err = xdp_rxq_info_reg_mem_model(&vi->rq[qp_index].xdp_rxq,
MEM_TYPE_PAGE_SHARED, NULL);
vi->rq[qp_index].page_pool ?
MEM_TYPE_PAGE_POOL :
MEM_TYPE_PAGE_SHARED,
vi->rq[qp_index].page_pool);
if (err < 0)
goto err_xdp_reg_mem_model;
@ -3189,6 +3103,82 @@ static void virtnet_update_settings(struct virtnet_info *vi)
vi->duplex = duplex;
}
static int virtnet_create_page_pools(struct virtnet_info *vi)
{
int i, err;
if (vi->big_packets && !vi->mergeable_rx_bufs)
return 0;
for (i = 0; i < vi->max_queue_pairs; i++) {
struct receive_queue *rq = &vi->rq[i];
struct page_pool_params pp_params = { 0 };
struct device *dma_dev;
if (rq->page_pool)
continue;
if (rq->xsk_pool)
continue;
pp_params.order = 0;
pp_params.pool_size = virtqueue_get_vring_size(rq->vq);
pp_params.nid = dev_to_node(vi->vdev->dev.parent);
pp_params.netdev = vi->dev;
pp_params.napi = &rq->napi;
/* Use page_pool DMA mapping if backend supports DMA API.
* DMA_SYNC_DEV is needed for non-coherent archs on recycle.
*/
dma_dev = virtqueue_dma_dev(rq->vq);
if (dma_dev) {
pp_params.dev = dma_dev;
pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;
pp_params.dma_dir = DMA_FROM_DEVICE;
pp_params.max_len = PAGE_SIZE;
pp_params.offset = 0;
rq->use_page_pool_dma = true;
} else {
/* No DMA API (e.g., VDUSE): page_pool for allocation only. */
pp_params.flags = 0;
rq->use_page_pool_dma = false;
}
rq->page_pool = page_pool_create(&pp_params);
if (IS_ERR(rq->page_pool)) {
err = PTR_ERR(rq->page_pool);
rq->page_pool = NULL;
goto err_cleanup;
}
}
return 0;
err_cleanup:
while (--i >= 0) {
struct receive_queue *rq = &vi->rq[i];
if (rq->page_pool) {
page_pool_destroy(rq->page_pool);
rq->page_pool = NULL;
}
}
return err;
}
static void virtnet_destroy_page_pools(struct virtnet_info *vi)
{
int i;
for (i = 0; i < vi->max_queue_pairs; i++) {
struct receive_queue *rq = &vi->rq[i];
if (rq->page_pool) {
page_pool_destroy(rq->page_pool);
rq->page_pool = NULL;
}
}
}
static int virtnet_open(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
@ -5736,6 +5726,10 @@ static int virtnet_restore_up(struct virtio_device *vdev)
if (err)
return err;
err = virtnet_create_page_pools(vi);
if (err)
goto err_del_vqs;
virtio_device_ready(vdev);
enable_rx_mode_work(vi);
@ -5745,12 +5739,24 @@ static int virtnet_restore_up(struct virtio_device *vdev)
err = virtnet_open(vi->dev);
rtnl_unlock();
if (err)
return err;
goto err_destroy_pools;
}
netif_tx_lock_bh(vi->dev);
netif_device_attach(vi->dev);
netif_tx_unlock_bh(vi->dev);
return 0;
err_destroy_pools:
virtio_reset_device(vdev);
free_unused_bufs(vi);
virtnet_destroy_page_pools(vi);
virtnet_del_vqs(vi);
return err;
err_del_vqs:
virtio_reset_device(vdev);
virtnet_del_vqs(vi);
return err;
}
@ -5878,7 +5884,7 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
/* In big_packets mode, xdp cannot work, so there is no need to
* initialize xsk of rq.
*/
if (vi->big_packets && !vi->mergeable_rx_bufs)
if (!vi->rq[qid].page_pool)
return -ENOENT;
if (qid >= vi->curr_queue_pairs)
@ -6308,17 +6314,6 @@ static void free_receive_bufs(struct virtnet_info *vi)
rtnl_unlock();
}
static void free_receive_page_frags(struct virtnet_info *vi)
{
int i;
for (i = 0; i < vi->max_queue_pairs; i++)
if (vi->rq[i].alloc_frag.page) {
if (vi->rq[i].last_dma)
virtnet_rq_unmap(&vi->rq[i], vi->rq[i].last_dma, 0);
put_page(vi->rq[i].alloc_frag.page);
}
}
static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
{
struct virtnet_info *vi = vq->vdev->priv;
@ -6422,7 +6417,7 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
vqs_info = kzalloc_objs(*vqs_info, total_vqs);
if (!vqs_info)
goto err_vqs_info;
if (!vi->big_packets || vi->mergeable_rx_bufs) {
if (vi->mergeable_rx_bufs || !vi->big_packets) {
ctx = kzalloc_objs(*ctx, total_vqs);
if (!ctx)
goto err_ctx;
@ -6462,10 +6457,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
vi->rq[i].min_buf_len = mergeable_min_buf_len(vi, vi->rq[i].vq);
vi->sq[i].vq = vqs[txq2vq(i)];
}
/* run here: ret == 0. */
err_find:
kfree(ctx);
err_ctx:
@ -6966,6 +6959,14 @@ static int virtnet_probe(struct virtio_device *vdev)
goto free;
}
/* Create page pools for receive queues.
* Page pools are created at probe time so they can be used
* with premapped DMA addresses throughout the device lifetime.
*/
err = virtnet_create_page_pools(vi);
if (err)
goto free_irq_moder;
#ifdef CONFIG_SYSFS
if (vi->mergeable_rx_bufs)
dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
@ -6979,7 +6980,7 @@ static int virtnet_probe(struct virtio_device *vdev)
vi->failover = net_failover_create(vi->dev);
if (IS_ERR(vi->failover)) {
err = PTR_ERR(vi->failover);
goto free_vqs;
goto free_page_pools;
}
}
@ -7096,9 +7097,11 @@ static int virtnet_probe(struct virtio_device *vdev)
unregister_netdev(dev);
free_failover:
net_failover_destroy(vi->failover);
free_vqs:
free_page_pools:
virtnet_destroy_page_pools(vi);
free_irq_moder:
virtnet_free_irq_moder(vi);
virtio_reset_device(vdev);
free_receive_page_frags(vi);
virtnet_del_vqs(vi);
free:
free_netdev(dev);
@ -7123,7 +7126,7 @@ static void remove_vq_common(struct virtnet_info *vi)
free_receive_bufs(vi);
free_receive_page_frags(vi);
virtnet_destroy_page_pools(vi);
virtnet_del_vqs(vi);
}