Re: [libvirt] [PATCH v3 01/15] util: introduce virbpf helpers

In order to implement devices controller with cgroup v2 we need to add support for BPF programs, cgroup v2 doesn't have devices controller. This introduces required helpers wrapping linux syscalls. Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com&gt; --- configure.ac | 5 + include/libvirt/virterror.h | 2 + src/libvirt_private.syms | 16 ++ src/util/Makefile.inc.am | 2 + src/util/virbpf.c | 438 ++++++++++++++++++++++++++++++++++++ src/util/virbpf.h | 259 +++++++++++++++++++++ src/util/virerror.c | 2 + 7 files changed, 724 insertions(+) create mode 100644 src/util/virbpf.c create mode 100644 src/util/virbpf.h diff --git a/src/util/virbpf.h b/src/util/virbpf.h new file mode 100644 index 0000000000..b5874e1e8d --- /dev/null +++ b/src/util/virbpf.h @@ -0,0 +1,259 @@ +/* + * virbpf.h: methods for eBPF + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see + * <http://www.gnu.org/licenses/>;. + */ +

+#ifndef LIBVIRT_VIRBPF_H +# define LIBVIRT_VIRBPF_H

+ +# if HAVE_DECL_BPF_PROG_QUERY + +# include <linux/bpf.h> + +/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */ + +# define VIR_BPF_ALU64_REG(op, dst, src) \ + ((struct bpf_insn) { \ + .code = BPF_ALU64 | BPF_OP(op) | BPF_X, \ + .dst_reg = dst, \ + .src_reg = src, \ + .off = 0, \ + .imm = 0, \ + }) + +/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */ + +# define VIR_BPF_ALU64_IMM(op, dst, immval) \ + ((struct bpf_insn) { \ + .code = BPF_ALU64 | BPF_OP(op) | BPF_K, \ + .dst_reg = dst, \ + .src_reg = 0, \ + .off = 0, \ + .imm = immval, \ + }) + +/* mov of registers, dst_reg = src_reg */ + +# define VIR_BPF_MOV64_REG(dst, src) \ + ((struct bpf_insn) { \ + .code = BPF_ALU64 | BPF_MOV | BPF_X, \ + .dst_reg = dst, \ + .src_reg = src, \ + .off = 0, \ + .imm = 0, \ + }) + +/* mov of immediates, dst_reg = imm32 */ + +# define VIR_BPF_MOV64_IMM(dst, immval) \ + ((struct bpf_insn) { \ + .code = BPF_ALU64 | BPF_MOV | BPF_K, \ + .dst_reg = dst, \ + .src_reg = 0, \ + .off = 0, \ + .imm = immval, \ + }) + +/* helper to encode 16 byte instruction */ + +# define _VIR_BPF_LD_IMM64_RAW(dst, src, immval) \ + ((struct bpf_insn) { \ + .code = BPF_LD | BPF_DW | BPF_IMM, \ + .dst_reg = dst, \ + .src_reg = src, \ + .off = 0, \ + .imm = (uint32_t)immval, \ + }), \ + ((struct bpf_insn) { \ + .code = 0, \ + .dst_reg = 0, \ + .src_reg = 0, \ + .off = 0, \ + .imm = ((uint64_t)immval) >> 32, \ + }) +