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From: Maxim Mikityanskiy <maximmi@mellanox.com>
To: Kevin Laatz <kevin.laatz@intel.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"ast@kernel.org" <ast@kernel.org>,
	"daniel@iogearbox.net" <daniel@iogearbox.net>,
	"bjorn.topel@intel.com" <bjorn.topel@intel.com>,
	"magnus.karlsson@intel.com" <magnus.karlsson@intel.com>,
	"jakub.kicinski@netronome.com" <jakub.kicinski@netronome.com>,
	"jonathan.lemon@gmail.com" <jonathan.lemon@gmail.com>,
	Saeed Mahameed <saeedm@mellanox.com>,
	"stephen@networkplumber.org" <stephen@networkplumber.org>,
	"bruce.richardson@intel.com" <bruce.richardson@intel.com>,
	"ciara.loftus@intel.com" <ciara.loftus@intel.com>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"intel-wired-lan@lists.osuosl.org"
	<intel-wired-lan@lists.osuosl.org>
Subject: Re: [PATCH bpf-next v3 03/11] xsk: add support to allow unaligned chunk placement
Date: Thu, 25 Jul 2019 09:27:04 +0000	[thread overview]
Message-ID: <3af74e26-8899-cf1e-6fd4-5ea0bd349fc3@mellanox.com> (raw)
In-Reply-To: <20190724051043.14348-4-kevin.laatz@intel.com>

On 2019-07-24 08:10, Kevin Laatz wrote:
> Currently, addresses are chunk size aligned. This means, we are very
> restricted in terms of where we can place chunk within the umem. For
> example, if we have a chunk size of 2k, then our chunks can only be placed
> at 0,2k,4k,6k,8k... and so on (ie. every 2k starting from 0).
> 
> This patch introduces the ability to use unaligned chunks. With these
> changes, we are no longer bound to having to place chunks at a 2k (or
> whatever your chunk size is) interval. Since we are no longer dealing with
> aligned chunks, they can now cross page boundaries. Checks for page
> contiguity have been added in order to keep track of which pages are
> followed by a physically contiguous page.
> 
> Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> 
> ---
> v2:
>    - Add checks for the flags coming from userspace
>    - Fix how we get chunk_size in xsk_diag.c
>    - Add defines for masking the new descriptor format
>    - Modified the rx functions to use new descriptor format
>    - Modified the tx functions to use new descriptor format
> 
> v3:
>    - Add helper function to do address/offset masking/addition
> ---
>   include/net/xdp_sock.h      | 17 ++++++++
>   include/uapi/linux/if_xdp.h |  9 ++++
>   net/xdp/xdp_umem.c          | 18 +++++---
>   net/xdp/xsk.c               | 86 ++++++++++++++++++++++++++++++-------
>   net/xdp/xsk_diag.c          |  2 +-
>   net/xdp/xsk_queue.h         | 68 +++++++++++++++++++++++++----
>   6 files changed, 170 insertions(+), 30 deletions(-)
> 

<...>

> +/* If a buffer crosses a page boundary, we need to do 2 memcpy's, one for
> + * each page. This is only required in copy mode.
> + */
> +static void __xsk_rcv_memcpy(struct xdp_umem *umem, u64 addr, void *from_buf,
> +			     u32 len, u32 metalen)
> +{
> +	void *to_buf = xdp_umem_get_data(umem, addr);
> +
> +	if (xskq_crosses_non_contig_pg(umem, addr, len + metalen)) {
> +		void *next_pg_addr = umem->pages[(addr >> PAGE_SHIFT) + 1].addr;
> +		u64 page_start = addr & (PAGE_SIZE - 1);
> +		u64 first_len = PAGE_SIZE - (addr - page_start);

Let addr = 0x12345, PAGE_SIZE = 0x1000, len = 0x1000. Your calculations 
lead to page_start = 0x345, first_len = 0x1000 - 0x12000, which is 
negative. I think page_start is calculated incorrectly (is ~ missing?).

> +
> +		memcpy(to_buf, from_buf, first_len + metalen);
> +		memcpy(next_pg_addr, from_buf + first_len, len - first_len);
> +
> +		return;
> +	}
> +
> +	memcpy(to_buf, from_buf, len + metalen);
> +}
> +

<...>

> +static inline bool xskq_is_valid_addr_unaligned(struct xsk_queue *q, u64 addr,
> +						u64 length,
> +						struct xdp_umem *umem)
> +{
> +	addr += addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
> +	addr &= XSK_UNALIGNED_BUF_ADDR_MASK;
> +	if (addr >= q->size ||

Addresses like 0x00aaffffffffffff will pass the validation (0xaa + 
0xffffffffffff will overflow mod 2^48 and become a small number), 
whereas such addresses don't look valid for me.

> +	    xskq_crosses_non_contig_pg(umem, addr, length)) {

If the region is not contiguous, we cant RX into it - that's clear. 
However, how can the userspace determine whether these two pages of UMEM 
are mapped contiguously in the DMA space? Are we going to silently drop 
descriptors to non-contiguous frames and leak them? Please explain how 
to use it correctly from the application side.

> +		q->invalid_descs++;
> +		return false;
> +	}
> +
> +	return true;
> +}

<...>


  parent reply	other threads:[~2019-07-25  9:27 UTC|newest]

Thread overview: 136+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-20  9:09 [PATCH 00/11] XDP unaligned chunk placement support Kevin Laatz
2019-06-20  9:09 ` [PATCH 01/11] i40e: simplify Rx buffer recycle Kevin Laatz
2019-06-24 14:29   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 02/11] ixgbe: " Kevin Laatz
2019-06-24 14:30   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 03/11] xdp: add offset param to zero_copy_allocator Kevin Laatz
2019-06-24 14:31   ` Björn Töpel
2019-06-24 19:23   ` Jakub Kicinski
2019-06-25 13:14     ` Laatz, Kevin
2019-06-20  9:09 ` [PATCH 04/11] i40e: add offset to zca_free Kevin Laatz
2019-06-24 14:32   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 05/11] ixgbe: " Kevin Laatz
2019-06-24 14:32   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 06/11] xsk: add support to allow unaligned chunk placement Kevin Laatz
2019-06-24 15:29   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 07/11] libbpf: add flags to umem config Kevin Laatz
2019-06-24 15:30   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 08/11] samples/bpf: add unaligned chunks mode support to xdpsock Kevin Laatz
2019-06-24 15:31   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 09/11] samples/bpf: add buffer recycling for unaligned chunks " Kevin Laatz
2019-06-24 15:35   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 10/11] samples/bpf: use hugepages in xdpsock app Kevin Laatz
2019-06-24 15:36   ` Björn Töpel
2019-06-20  9:09 ` [PATCH 11/11] doc/af_xdp: include unaligned chunk case Kevin Laatz
2019-06-24 15:34   ` Björn Töpel
2019-07-16  3:06 ` [PATCH v2 00/10] XDP unaligned chunk placement support Kevin Laatz
2019-07-16  3:06   ` [PATCH v2 01/10] i40e: simplify Rx buffer recycle Kevin Laatz
2019-07-19 17:19     ` [Intel-wired-lan] " Bowers, AndrewX
2019-07-16  3:06   ` [PATCH v2 02/10] ixgbe: " Kevin Laatz
2019-07-19 17:20     ` [Intel-wired-lan] " Bowers, AndrewX
2019-07-16  3:06   ` [PATCH v2 03/10] xsk: add support to allow unaligned chunk placement Kevin Laatz
2019-07-19 17:21     ` [Intel-wired-lan] " Bowers, AndrewX
2019-07-16  3:06   ` [PATCH v2 04/10] i40e: modify driver for handling offsets Kevin Laatz
2019-07-19 17:22     ` [Intel-wired-lan] " Bowers, AndrewX
2019-07-16  3:06   ` [PATCH v2 05/10] ixgbe: " Kevin Laatz
2019-07-19 17:22     ` [Intel-wired-lan] " Bowers, AndrewX
2019-07-16  3:06   ` [PATCH v2 06/10] libbpf: add flags to umem config Kevin Laatz
2019-07-16  3:06   ` [PATCH v2 07/10] samples/bpf: add unaligned chunks mode support to xdpsock Kevin Laatz
2019-07-16  3:06   ` [PATCH v2 08/10] samples/bpf: add buffer recycling for unaligned chunks " Kevin Laatz
2019-07-16  3:06   ` [PATCH v2 09/10] samples/bpf: use hugepages in xdpsock app Kevin Laatz
2019-07-16  3:06   ` [PATCH v2 10/10] doc/af_xdp: include unaligned chunk case Kevin Laatz
2019-07-23 21:08   ` [PATCH v2 00/10] XDP unaligned chunk placement support Alexei Starovoitov
2019-07-24 13:25     ` [Intel-wired-lan] " Magnus Karlsson
2019-07-25 15:43       ` Jonathan Lemon
2019-07-24  5:10   ` [PATCH bpf-next v3 00/11] " Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 01/11] i40e: simplify Rx buffer recycle Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 02/11] ixgbe: " Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 03/11] xsk: add support to allow unaligned chunk placement Kevin Laatz
2019-07-25  2:22       ` Jakub Kicinski
2019-07-25 17:01         ` Laatz, Kevin
2019-07-25  9:27       ` Maxim Mikityanskiy [this message]
2019-07-25 17:00         ` Laatz, Kevin
2019-07-25 10:08       ` Maxim Mikityanskiy
2019-07-25 15:39       ` Jonathan Lemon
2019-07-24  5:10     ` [PATCH bpf-next v3 04/11] i40e: modify driver for handling offsets Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 05/11] ixgbe: " Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 06/11] mlx5e: " Kevin Laatz
2019-07-25 10:15       ` Maxim Mikityanskiy
2019-07-25 17:00         ` Laatz, Kevin
2019-07-24  5:10     ` [PATCH bpf-next v3 07/11] libbpf: add flags to umem config Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 08/11] samples/bpf: add unaligned chunks mode support to xdpsock Kevin Laatz
2019-07-25  9:43       ` Maxim Mikityanskiy
2019-07-25 17:00         ` Laatz, Kevin
2019-07-24  5:10     ` [PATCH bpf-next v3 09/11] samples/bpf: add buffer recycling for unaligned chunks " Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 10/11] samples/bpf: use hugepages in xdpsock app Kevin Laatz
2019-07-24  5:10     ` [PATCH bpf-next v3 11/11] doc/af_xdp: include unaligned chunk case Kevin Laatz
2019-07-25 15:39     ` [PATCH bpf-next v3 00/11] XDP unaligned chunk placement support Jonathan Lemon
2019-07-25 15:56       ` Richardson, Bruce
2019-07-25 17:30         ` Jonathan Lemon
2019-07-26  8:41           ` Bruce Richardson
2019-07-30  8:53     ` [PATCH bpf-next v4 " Kevin Laatz
2019-07-30  8:53       ` [PATCH bpf-next v4 01/11] i40e: simplify Rx buffer recycle Kevin Laatz
2019-07-30  8:53       ` [PATCH bpf-next v4 02/11] ixgbe: " Kevin Laatz
2019-07-30  8:53       ` [PATCH bpf-next v4 03/11] libbpf: add flags to umem config Kevin Laatz
2019-07-31 12:45         ` [Intel-wired-lan] " Björn Töpel
2019-07-31 14:25         ` Björn Töpel
2019-08-01  6:59           ` Andrii Nakryiko
2019-08-01  7:34             ` Björn Töpel
2019-08-02  7:19               ` Andrii Nakryiko
2019-08-02  7:26                 ` Björn Töpel
2019-07-30  8:53       ` [PATCH bpf-next v4 04/11] xsk: add support to allow unaligned chunk placement Kevin Laatz
2019-07-31 18:11         ` Jonathan Lemon
2019-07-30  8:53       ` [PATCH bpf-next v4 05/11] i40e: modify driver for handling offsets Kevin Laatz
2019-07-30  8:53       ` [PATCH bpf-next v4 06/11] ixgbe: " Kevin Laatz
2019-07-30  8:53       ` [PATCH bpf-next v4 07/11] mlx5e: " Kevin Laatz
2019-07-31 18:10         ` Jonathan Lemon
2019-08-01 10:05         ` Maxim Mikityanskiy
2019-08-19 14:36           ` Maxim Mikityanskiy
2019-08-19 14:47             ` Laatz, Kevin
2019-07-30  8:53       ` [PATCH bpf-next v4 08/11] samples/bpf: add unaligned chunks mode support to xdpsock Kevin Laatz
2019-07-30  8:53       ` [PATCH bpf-next v4 09/11] samples/bpf: add buffer recycling for unaligned chunks " Kevin Laatz
2019-07-31 18:26         ` Jonathan Lemon
2019-07-30  8:53       ` [PATCH bpf-next v4 10/11] samples/bpf: use hugepages in xdpsock app Kevin Laatz
2019-07-30  8:54       ` [PATCH bpf-next v4 11/11] doc/af_xdp: include unaligned chunk case Kevin Laatz
2019-08-22  1:44       ` [PATCH bpf-next v5 00/11] XDP unaligned chunk placement support Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 01/11] i40e: simplify Rx buffer recycle Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 02/11] ixgbe: " Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 03/11] xsk: add support to allow unaligned chunk placement Kevin Laatz
2019-08-22 18:43           ` Jonathan Lemon
2019-08-23 13:35             ` Laatz, Kevin
2019-08-27  7:36           ` Maxim Mikityanskiy
2019-08-22  1:44         ` [PATCH bpf-next v5 04/11] i40e: modify driver for handling offsets Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 05/11] ixgbe: " Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 06/11] mlx5e: " Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 07/11] libbpf: add flags to umem config Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 08/11] samples/bpf: add unaligned chunks mode support to xdpsock Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 09/11] samples/bpf: add buffer recycling for unaligned chunks " Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 10/11] samples/bpf: use hugepages in xdpsock app Kevin Laatz
2019-08-22  1:44         ` [PATCH bpf-next v5 11/11] doc/af_xdp: include unaligned chunk case Kevin Laatz
2019-08-27  2:25         ` [PATCH bpf-next v6 00/12] XDP unaligned chunk placement support Kevin Laatz
2019-08-27  2:25           ` [PATCH bpf-next v6 01/12] i40e: simplify Rx buffer recycle Kevin Laatz
2019-08-30 15:37             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 02/12] ixgbe: " Kevin Laatz
2019-08-30 15:39             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 03/12] xsk: add support to allow unaligned chunk placement Kevin Laatz
2019-08-30 15:41             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 04/12] i40e: modify driver for handling offsets Kevin Laatz
2019-08-30 15:42             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 05/12] ixgbe: " Kevin Laatz
2019-08-30 15:42             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 06/12] mlx5e: " Kevin Laatz
2019-08-30 15:43             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 07/12] net/mlx5e: Allow XSK frames smaller than a page Kevin Laatz
2019-08-30 15:45             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 08/12] libbpf: add flags to umem config Kevin Laatz
2019-08-30 15:46             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 09/12] samples/bpf: add unaligned chunks mode support to xdpsock Kevin Laatz
2019-08-30 15:47             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 10/12] samples/bpf: add buffer recycling for unaligned chunks " Kevin Laatz
2019-08-30 15:49             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 11/12] samples/bpf: use hugepages in xdpsock app Kevin Laatz
2019-08-30 15:51             ` Jonathan Lemon
2019-08-27  2:25           ` [PATCH bpf-next v6 12/12] doc/af_xdp: include unaligned chunk case Kevin Laatz
2019-08-30 15:51             ` Jonathan Lemon
2019-08-30 15:52           ` [PATCH bpf-next v6 00/12] XDP unaligned chunk placement support Jonathan Lemon
2019-08-30 23:29           ` Daniel Borkmann

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