[dpdk-users] Cross compile for ARM64 fails due to librte_vhost and pmdinfogen issues

[Michael Wildt]

Dear DPDK,

I'm attempting to cross compile DPDK on an x86 for an ARM64 target. This
fails in the following areas, using latest dpdk as of 9/12. When compiling
natively there are no issues.

- librte_vhost, fails with:

/projects/dpdk_latest/lib/librte_vhost/vhost_user/virtio-net-user.c:250:23:
error: array subscript is above array bounds [-Werror=array-bounds]
   rvq = dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_RXQ];
                       ^
/projects/dpdk_latest/lib/librte_vhost/vhost_user/virtio-net-user.c:251:23:
error: array subscript is above array bounds [-Werror=array-bounds]
   tvq = dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_TXQ];
                       ^
/projects/dpdk_latest/lib/librte_vhost/vhost_user/virtio-net-user.c:250:23:
error: array subscript is above array bounds [-Werror=array-bounds]
   rvq = dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_RXQ];
                       ^
/projects/dpdk_latest/lib/librte_vhost/vhost_user/virtio-net-user.c:251:23:
error: array subscript is above array bounds [-Werror=array-bounds]
   tvq = dev->virtqueue[i * VIRTIO_QNUM + VIRTIO_TXQ];
                       ^
cc1: all warnings being treated as errors


  - This is only a warning on the downloadable release v16.07 tar ball, not
error as in this case. I'm guessing the compile flags must have been
changed.

- buildtools/pmdinfogen, fails with:

== Build buildtools/pmdinfogen
  HOSTCC pmdinfogen.o
/projects/dpdk_test_wget/dpdk-16.07/build/include/rte_byteorder.h:
Assembler messages:
/projects/dpdk_test_wget/dpdk-16.07/build/include/rte_byteorder.h:53:
Error: no such instruction: `rev16 %bx,%bx'
/projects/dpdk_test_wget/dpdk-16.07/mk/internal/rte.compile-pre.mk:138:
recipe for target 'pmdinfogen.o' failed
make[3]: *** [pmdinfogen.o] Error 1
/projects/dpdk_test_wget/dpdk-16.07/mk/rte.subdir.mk:61: recipe for target
'pmdinfogen' failed
make[2]: *** [pmdinfogen] Error 2
/projects/dpdk_test_wget/dpdk-16.07/mk/rte.sdkbuild.mk:78: recipe for
target 'buildtools' failed
make[1]: *** [buildtools] Error 2
/projects/dpdk_test_wget/dpdk-16.07/mk/rte.sdkroot.mk:123: recipe for
target 'all' failed
make: *** [all] Error 2


  - The issue is due to the rte_byteorder.h file which gets symlink'ed with
the ARM version at the beginning of the build. The pmdinfogen is always
compiled for x86 thus the asm is failing. I see two ways to address this.

- Have pmdinfogen always pickup the local OS rte_byteorder.h file, not the
ARCH symlinked one.
- Fix pmdinfogen such that it gets cross compiled correctly as the rest of
the code. Did a quick attempt by setting the HOST_OS to 0, , but then it
fails at the HOST_LD.

If the pmdinfogen commit is removed, by checking out v16.07-rc1 followed by
a fresh build, then it is possible to cross compile for ARM64 fine.

Used tool chain: gcc-linaro-aarch64-linux-gnu-4.9-2014.09

It would be great if the forum could help with patches on these two issues.

Regards,
Michael