On 4/3/2019 11:42 AM, Luca Boccassi wrote: > On Wed, 2019-04-03 at 11:36 +0100, Luca Boccassi wrote: >> On Wed, 2019-04-03 at 17:59 +0800, Ye Xiaolong wrote: >>> Hi, Luca >>> >>> On 04/02, Luca Boccassi wrote: >>>> On Tue, 2019-04-02 at 23:46 +0800, Xiaolong Ye wrote: >>>>> diff --git a/drivers/net/af_xdp/Makefile >>>>> b/drivers/net/af_xdp/Makefile >>>>> new file mode 100644 >>>>> index 000000000..8343e3016 >>>>> --- /dev/null >>>>> +++ b/drivers/net/af_xdp/Makefile >>>>> @@ -0,0 +1,32 @@ >>>>> +# SPDX-License-Identifier: BSD-3-Clause >>>>> +# Copyright(c) 2019 Intel Corporation >>>>> + >>>>> +include $(RTE_SDK)/mk/rte.vars.mk >>>>> + >>>>> +# >>>>> +# library name >>>>> +# >>>>> +LIB = librte_pmd_af_xdp.a >>>>> + >>>>> +EXPORT_MAP := rte_pmd_af_xdp_version.map >>>>> + >>>>> +LIBABIVER := 1 >>>>> + >>>>> +CFLAGS += -O3 >>>>> + >>>>> +# require kernel version >= v5.1-rc1 >>>>> +CFLAGS += -I$(RTE_KERNELDIR)/tools/include >>>>> +CFLAGS += -I$(RTE_KERNELDIR)/tools/lib/bpf >>>> >>>> Sorry for not noticing this before, but doesn't this require the >>>> full >>>> kernel tree rather than just the typical headers package? >>>> Requiring >>>> the >>>> full kernel tree to be available at build time will make this >>>> unbuildable on distros that still use makefiles, like RHEL and >>>> SUSE. At >>>> least on Debian and Ubuntu, the kernel headers packages >>>> distributed >>>> do >>>> not include the full kernel tree, only the headers, so there's no >>>> tools/lib or tools/include. >>> >>> Currently we do have dependencies on the kernel src tree, as xsk.h >>> and >>> asm/barrier wouldn't be installed by libbpf, so before libbpf >>> handles >>> these >>> properly, can we keep the current RTE_KERNELDIR in Makefile for >>> now, >>> and mention >>> the dependencies in document, also suggest users to config >>> RTE_KERNELDIR to correct >>> kernel src tree if they want to use af_xdp pmd? >>> >>> Something like: >>> >>> dependencies: >>> - kernel source code (>= v5.1-rc1) >>> - build libbfp and install >>> >>> Thanks, >>> Xiaolong >> >> asm/barrier.h is installed by the kernel headers packages so it would >> be fine (although not ideal) and not need the full source tree. >> xsk.h is a bit more worrying, as it looks like an internal header >> from >> here. >> >> Is it really necessary for external applications to use an internal- >> only header and a kernel header to be able to use libbpf? > > Actually, xsk.h is now installed by the library makefile: > > https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=379e2014c95b
Good to have this one. But again it is in BPF tree and it won't be in 5.1. I suggested changing code as following for now, it would help to keep changes small when above patch merged into kernel: CFLAGS += -I$(RTE_KERNELDIR)/tools/lib [in makefile] #include <bpf/xsk.h> [in .c file] > > So the full kernel source tree is no longer required. > > Is asm/barrier.h really required? Isn't there an userspace alternative? The 'asm/barrier.h' in the kernel headers and the 'tools/include/asm/barrier.h' looks different, the one in the kernel source has dependency to other kernel headers. I wonder same thing, what is used from 'tools/include/asm/barrier.h' and if it can be avoided. Anyway, as Xiaolong mentioned, following is working, can it work from a distro point of view: - get kernel source code (>= v5.1-rc1) - build libbfp and install - set 'RTE_KERNELDIR' to point kernel source path - build dpdk with af_xdp enabled > > Also, the license in asm/barrier.h is GPL-2.0 only. It is not a > userspace header so it is not covered by the userspace exception, which > means at the very least the af_xdp PMD shared object is also licensed > under GPL-2.0 only, isn't it? >
