Re: [PATCH v2 3/5] lib/lpm: R-V V rte_lpm_lookupx4

["Stanisław Kardach" <stanislaw.kardach@gmail.com>]

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On Tue, 1 Jul 2025, 20:20 , <uk7b@foxmail.com> wrote:

> From: Sun Yuechi <sunyuechi@iscas.ac.cn>
>
> Implement LPM lookupx4 function for RISC-V architecture using RISC-V
> Vector Extension instruction set
>
> Signed-off-by: Sun Yuechi <sunyuechi@iscas.ac.cn>
>
Reviewed-by: Stanisław Kardach <stanislaw.kardach@gmail.com>

> ---
>  MAINTAINERS           |  2 ++
>  lib/lpm/meson.build   |  1 +
>  lib/lpm/rte_lpm.h     |  2 ++
>  lib/lpm/rte_lpm_rvv.h | 59 +++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 64 insertions(+)
>  create mode 100644 lib/lpm/rte_lpm_rvv.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0e9357f3a3..9bd97879b6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -341,6 +341,8 @@ M: Stanislaw Kardach <stanislaw.kardach@gmail.com>
>  F: config/riscv/
>  F: doc/guides/linux_gsg/cross_build_dpdk_for_riscv.rst
>  F: lib/eal/riscv/
> +M: sunyuechi <sunyuechi@iscas.ac.cn>
> +F: lib/**/*rvv*
>
>  Intel x86
>  M: Bruce Richardson <bruce.richardson@intel.com>
> diff --git a/lib/lpm/meson.build b/lib/lpm/meson.build
> index cff8fed473..c4522eaf0c 100644
> --- a/lib/lpm/meson.build
> +++ b/lib/lpm/meson.build
> @@ -11,6 +11,7 @@ indirect_headers += files(
>          'rte_lpm_scalar.h',
>          'rte_lpm_sse.h',
>          'rte_lpm_sve.h',
> +        'rte_lpm_rvv.h',
>  )
>  deps += ['hash']
>  deps += ['rcu']
> diff --git a/lib/lpm/rte_lpm.h b/lib/lpm/rte_lpm.h
> index 6bf8d9d883..edfe77b458 100644
> --- a/lib/lpm/rte_lpm.h
> +++ b/lib/lpm/rte_lpm.h
> @@ -420,6 +420,8 @@ rte_lpm_lookupx4(const struct rte_lpm *lpm, xmm_t ip,
> uint32_t hop[4],
>  #include "rte_lpm_altivec.h"
>  #elif defined(RTE_ARCH_X86)
>  #include "rte_lpm_sse.h"
> +#elif defined(RTE_ARCH_RISCV) && defined(RTE_RISCV_FEATURE_V)
> +#include "rte_lpm_rvv.h"
>  #else
>  #include "rte_lpm_scalar.h"
>  #endif
> diff --git a/lib/lpm/rte_lpm_rvv.h b/lib/lpm/rte_lpm_rvv.h
> new file mode 100644
> index 0000000000..0d3dc91055
> --- /dev/null
> +++ b/lib/lpm/rte_lpm_rvv.h
> @@ -0,0 +1,59 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright (c) 2025 Institute of Software Chinese Academy of Sciences
> (ISCAS).
> + */
> +
> +#ifndef _RTE_LPM_RVV_H_
> +#define _RTE_LPM_RVV_H_
> +
> +#include <rte_vect.h>
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +#define RTE_LPM_LOOKUP_SUCCESS 0x01000000
> +#define RTE_LPM_VALID_EXT_ENTRY_BITMASK 0x03000000
> +
> +static inline void rte_lpm_lookupx4(
> +       const struct rte_lpm *lpm, xmm_t ip, uint32_t hop[4], uint32_t
> defv)
> +{
> +       size_t vl = 4;
> +
> +       const uint32_t *tbl24_p = (const uint32_t *)lpm->tbl24;
> +       uint32_t tbl_entries[4] = {
> +               tbl24_p[((uint32_t)ip[0]) >> 8],
> +               tbl24_p[((uint32_t)ip[1]) >> 8],
> +               tbl24_p[((uint32_t)ip[2]) >> 8],
> +               tbl24_p[((uint32_t)ip[3]) >> 8],
> +       };
> +       vuint32m1_t vtbl_entry = __riscv_vle32_v_u32m1(tbl_entries, vl);
> +
> +       vbool32_t mask = __riscv_vmseq_vx_u32m1_b32(
> +           __riscv_vand_vx_u32m1(vtbl_entry,
> RTE_LPM_VALID_EXT_ENTRY_BITMASK, vl),
> +           RTE_LPM_VALID_EXT_ENTRY_BITMASK, vl);
> +
> +       vuint32m1_t vtbl8_index = __riscv_vsll_vx_u32m1(
> +           __riscv_vadd_vv_u32m1(
> +               __riscv_vsll_vx_u32m1(__riscv_vand_vx_u32m1(vtbl_entry,
> 0x00FFFFFF, vl), 8, vl),
> +               __riscv_vand_vx_u32m1(
> +                   __riscv_vle32_v_u32m1((const uint32_t *)&ip, vl),
> 0x000000FF, vl),
> +               vl),
> +           2, vl);
> +
> +       vtbl_entry = __riscv_vluxei32_v_u32m1_mu(
> +           mask, vtbl_entry, (const uint32_t *)(lpm->tbl8), vtbl8_index,
> vl);
> +
> +       vuint32m1_t vnext_hop = __riscv_vand_vx_u32m1(vtbl_entry,
> 0x00FFFFFF, vl);
> +       mask = __riscv_vmseq_vx_u32m1_b32(
> +           __riscv_vand_vx_u32m1(vtbl_entry, RTE_LPM_LOOKUP_SUCCESS, vl),
> 0, vl);
> +
> +       vnext_hop = __riscv_vmerge_vxm_u32m1(vnext_hop, defv, mask, vl);
> +
> +       __riscv_vse32_v_u32m1(hop, vnext_hop, vl);
> +}
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif /* _RTE_LPM_RVV_H_ */
> --
> 2.50.0
>
>

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