Hi Christophe,Thanks for doing this work. I saw that you intend to submit a v3 due to failure in Ubuntu. Please, see my comment regarding emit_b below.
Followed by emit_b() above there is an emit_call(). It invokes emit_mov_imm() which could possibly generate different number of movk instructions depending on the address of the __rte_pktmbuf_read. So, emit_b(ctx, 4), may not necessarily land at the intended location because there could be more than 4 instructions emitted by emit_call.+ /* A64_R(0) = mbuf->buf_addr */ + emit_mov_imm(ctx, 1, tmp1, offsetof(struct rte_mbuf, buf_addr)); + emit_ldr(ctx, EBPF_DW, A64_R(0), r6, tmp1); + /* tmp2 = * mbuf->data_off */ + emit_mov_imm(ctx, 1, tmp2, offsetof(struct rte_mbuf, data_off)); + emit_ldr(ctx, BPF_H, tmp2, r6, tmp2); + + /* A64_R(0) += data_off + off */ + emit_add(ctx, 1, A64_R(0), tmp2); + emit_add(ctx, 1, A64_R(0), A64_R(1)); + + /* End of Fast Path, skip slow path */ + emit_b(ctx, 4); +
+ /* slow path, call __rte_pktmbuf_read */ + emit_call(ctx, tmp1, __rte_pktmbuf_read); + /* check return value of __rte_pktmbuf_read */ + emit_return_zero_if_src_zero(ctx, 1, A64_R(0)); + + /* A64_R(0) points to the data, load 1/2/4 bytes into r0*/ + emit_ldr(ctx, opsz, r0, A64_R(0), A64_ZR); + if (sz != sizeof(uint8_t)) + emit_be(ctx, r0, sz * CHAR_BIT); +} +
--wathsala
