2018-05-18 12:00:21 +00:00
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/* SPDX-License-Identifier: GPL-2.0 */
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/* XDP user-space packet buffer
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2018-05-02 11:01:23 +00:00
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* Copyright(c) 2018 Intel Corporation.
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*/
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#ifndef XDP_UMEM_H_
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#define XDP_UMEM_H_
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2018-06-04 12:05:51 +00:00
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#include <net/xdp_sock.h>
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2018-05-02 11:01:23 +00:00
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xsk: new descriptor addressing scheme
Currently, AF_XDP only supports a fixed frame-size memory scheme where
each frame is referenced via an index (idx). A user passes the frame
index to the kernel, and the kernel acts upon the data. Some NICs,
however, do not have a fixed frame-size model, instead they have a
model where a memory window is passed to the hardware and multiple
frames are filled into that window (referred to as the "type-writer"
model).
By changing the descriptor format from the current frame index
addressing scheme, AF_XDP can in the future be extended to support
these kinds of NICs.
In the index-based model, an idx refers to a frame of size
frame_size. Addressing a frame in the UMEM is done by offseting the
UMEM starting address by a global offset, idx * frame_size + offset.
Communicating via the fill- and completion-rings are done by means of
idx.
In this commit, the idx is removed in favor of an address (addr),
which is a relative address ranging over the UMEM. To convert an
idx-based address to the new addr is simply: addr = idx * frame_size +
offset.
We also stop referring to the UMEM "frame" as a frame. Instead it is
simply called a chunk.
To transfer ownership of a chunk to the kernel, the addr of the chunk
is passed in the fill-ring. Note, that the kernel will mask addr to
make it chunk aligned, so there is no need for userspace to do
that. E.g., for a chunk size of 2k, passing an addr of 2048, 2050 or
3000 to the fill-ring will refer to the same chunk.
On the completion-ring, the addr will match that of the Tx descriptor,
passed to the kernel.
Changing the descriptor format to use chunks/addr will allow for
future changes to move to a type-writer based model, where multiple
frames can reside in one chunk. In this model passing one single chunk
into the fill-ring, would potentially result in multiple Rx
descriptors.
This commit changes the uapi of AF_XDP sockets, and updates the
documentation.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-04 11:57:13 +00:00
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static inline char *xdp_umem_get_data(struct xdp_umem *umem, u64 addr)
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2018-05-02 11:01:27 +00:00
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{
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2018-06-04 12:05:52 +00:00
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return umem->pages[addr >> PAGE_SHIFT].addr + (addr & (PAGE_SIZE - 1));
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2018-05-02 11:01:27 +00:00
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}
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2018-06-04 12:05:55 +00:00
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int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
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u32 queue_id, u16 flags);
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void xdp_umem_clear_dev(struct xdp_umem *umem);
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2018-05-02 11:01:26 +00:00
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bool xdp_umem_validate_queues(struct xdp_umem *umem);
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2018-05-02 11:01:23 +00:00
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void xdp_get_umem(struct xdp_umem *umem);
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void xdp_put_umem(struct xdp_umem *umem);
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2018-05-22 07:35:02 +00:00
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struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr);
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2018-05-02 11:01:23 +00:00
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#endif /* XDP_UMEM_H_ */
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