On Friday, October 20, 2023 1:50 AM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
>For zerocopy mode, tx_desc->addr can point to the arbitrary offset
>and carry some TX metadata in the headroom. For copy mode, there
>is no way currently to populate skb metadata.
>
>Introduce new tx_metadata_len umem config option that indicates how many
>bytes to treat as metadata. Metadata bytes come prior to tx_desc address
>(same as in RX case).
>
>The size of the metadata has the same constraints as XDP:
>- less than 256 bytes
>- 4-byte aligned
>- non-zero
>
>This data is not interpreted in any way right now.
>
>Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
LGTM.
Reviewed-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>
>---
> include/net/xdp_sock.h | 1 +
> include/net/xsk_buff_pool.h | 1 +
> include/uapi/linux/if_xdp.h | 1 +
> net/xdp/xdp_umem.c | 4 ++++
> net/xdp/xsk.c | 12 +++++++++++-
> net/xdp/xsk_buff_pool.c | 1 +
> net/xdp/xsk_queue.h | 17 ++++++++++-------
> tools/include/uapi/linux/if_xdp.h | 1 +
> 8 files changed, 30 insertions(+), 8 deletions(-)
>
>diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
>index 7dd0df2f6f8e..5ae88a00f34a 100644
>--- a/include/net/xdp_sock.h
>+++ b/include/net/xdp_sock.h
>@@ -30,6 +30,7 @@ struct xdp_umem {
> struct user_struct *user;
> refcount_t users;
> u8 flags;
>+ u8 tx_metadata_len;
> bool zc;
> struct page **pgs;
> int id;
>diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
>index b0bdff26fc88..1985ffaf9b0c 100644
>--- a/include/net/xsk_buff_pool.h
>+++ b/include/net/xsk_buff_pool.h
>@@ -77,6 +77,7 @@ struct xsk_buff_pool {
> u32 chunk_size;
> u32 chunk_shift;
> u32 frame_len;
>+ u8 tx_metadata_len; /* inherited from umem */
> u8 cached_need_wakeup;
> bool uses_need_wakeup;
> bool dma_need_sync;
>diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
>index 8d48863472b9..2ecf79282c26 100644
>--- a/include/uapi/linux/if_xdp.h
>+++ b/include/uapi/linux/if_xdp.h
>@@ -76,6 +76,7 @@ struct xdp_umem_reg {
> __u32 chunk_size;
> __u32 headroom;
> __u32 flags;
>+ __u32 tx_metadata_len;
> };
>
> struct xdp_statistics {
>diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
>index 06cead2b8e34..333f3d53aad4 100644
>--- a/net/xdp/xdp_umem.c
>+++ b/net/xdp/xdp_umem.c
>@@ -199,6 +199,9 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct
>xdp_umem_reg *mr)
> if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
> return -EINVAL;
>
>+ if (mr->tx_metadata_len > 256 || mr->tx_metadata_len % 4)
>+ return -EINVAL;
>+
> umem->size = size;
> umem->headroom = headroom;
> umem->chunk_size = chunk_size;
>@@ -207,6 +210,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct
>xdp_umem_reg *mr)
> umem->pgs = NULL;
> umem->user = NULL;
> umem->flags = mr->flags;
>+ umem->tx_metadata_len = mr->tx_metadata_len;
>
> INIT_LIST_HEAD(&umem->xsk_dma_list);
> refcount_set(&umem->users, 1);
>diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
>index ba070fd37d24..ba4c77a24a83 100644
>--- a/net/xdp/xsk.c
>+++ b/net/xdp/xsk.c
>@@ -1265,6 +1265,14 @@ struct xdp_umem_reg_v1 {
> __u32 headroom;
> };
>
>+struct xdp_umem_reg_v2 {
>+ __u64 addr; /* Start of packet data area */
>+ __u64 len; /* Length of packet data area */
>+ __u32 chunk_size;
>+ __u32 headroom;
>+ __u32 flags;
>+};
>+
> static int xsk_setsockopt(struct socket *sock, int level, int optname,
> sockptr_t optval, unsigned int optlen)
> {
>@@ -1308,8 +1316,10 @@ static int xsk_setsockopt(struct socket *sock, int level, int
>optname,
>
> if (optlen < sizeof(struct xdp_umem_reg_v1))
> return -EINVAL;
>- else if (optlen < sizeof(mr))
>+ else if (optlen < sizeof(struct xdp_umem_reg_v2))
> mr_size = sizeof(struct xdp_umem_reg_v1);
>+ else if (optlen < sizeof(mr))
>+ mr_size = sizeof(struct xdp_umem_reg_v2);
>
> if (copy_from_sockptr(&mr, optval, mr_size))
> return -EFAULT;
>diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
>index 49cb9f9a09be..386eddcdf837 100644
>--- a/net/xdp/xsk_buff_pool.c
>+++ b/net/xdp/xsk_buff_pool.c
>@@ -85,6 +85,7 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct
>xdp_sock *xs,
> XDP_PACKET_HEADROOM;
> pool->umem = umem;
> pool->addrs = umem->addrs;
>+ pool->tx_metadata_len = umem->tx_metadata_len;
> INIT_LIST_HEAD(&pool->free_list);
> INIT_LIST_HEAD(&pool->xskb_list);
> INIT_LIST_HEAD(&pool->xsk_tx_list);
>diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
>index 13354a1e4280..c74a1372bcb9 100644
>--- a/net/xdp/xsk_queue.h
>+++ b/net/xdp/xsk_queue.h
>@@ -143,15 +143,17 @@ static inline bool xp_unused_options_set(u32 options)
> static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
> struct xdp_desc *desc)
> {
>- u64 offset = desc->addr & (pool->chunk_size - 1);
>+ u64 addr = desc->addr - pool->tx_metadata_len;
>+ u64 len = desc->len + pool->tx_metadata_len;
>+ u64 offset = addr & (pool->chunk_size - 1);
>
> if (!desc->len)
> return false;
>
>- if (offset + desc->len > pool->chunk_size)
>+ if (offset + len > pool->chunk_size)
> return false;
>
>- if (desc->addr >= pool->addrs_cnt)
>+ if (addr >= pool->addrs_cnt)
> return false;
>
> if (xp_unused_options_set(desc->options))
>@@ -162,16 +164,17 @@ static inline bool xp_aligned_validate_desc(struct
>xsk_buff_pool *pool,
> static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool,
> struct xdp_desc *desc)
> {
>- u64 addr = xp_unaligned_add_offset_to_addr(desc->addr);
>+ u64 addr = xp_unaligned_add_offset_to_addr(desc->addr) - pool-
>>tx_metadata_len;
>+ u64 len = desc->len + pool->tx_metadata_len;
>
> if (!desc->len)
> return false;
>
>- if (desc->len > pool->chunk_size)
>+ if (len > pool->chunk_size)
> return false;
>
>- if (addr >= pool->addrs_cnt || addr + desc->len > pool->addrs_cnt ||
>- xp_desc_crosses_non_contig_pg(pool, addr, desc->len))
>+ if (addr >= pool->addrs_cnt || addr + len > pool->addrs_cnt ||
>+ xp_desc_crosses_non_contig_pg(pool, addr, len))
> return false;
>
> if (xp_unused_options_set(desc->options))
>diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
>index 73a47da885dc..34411a2e5b6c 100644
>--- a/tools/include/uapi/linux/if_xdp.h
>+++ b/tools/include/uapi/linux/if_xdp.h
>@@ -76,6 +76,7 @@ struct xdp_umem_reg {
> __u32 chunk_size;
> __u32 headroom;
> __u32 flags;
>+ __u32 tx_metadata_len;
> };
>
> struct xdp_statistics {
>--
>2.42.0.655.g421f12c284-goog
