Re: [dpdk-dev] [PATCH v6 00/10] vhost: support inflight share memory protocol feature

["Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>]

Hi Jin,

I see in this patch set there are several callings rte_compiler_barrier() which is sufficient for x86 but not for aarch64/ppc and other weaker memory model architectures.
EAL has defined coherent memory io barriers(I think this should be the right barrier) for mutli-arch support. Could you change these barriers to rte_cio_r/wmb barriers?
http://git.dpdk.org/dpdk/tree/lib/librte_eal/common/include/generic/rte_atomic.h#n110

Best Regards,
Gavin

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of JinYu
> Sent: Thursday, August 29, 2019 10:12 PM
> To: dev@dpdk.org
> Cc: changpeng.liu@intel.com; maxime.coquelin@redhat.com;
> tiwei.bie@intel.com; zhihong.wang@intel.com; JinYu <jin.yu@intel.com>
> Subject: [dpdk-dev] [PATCH v6 00/10] vhost: support inflight share memory
> protocol feature
>
> This patches introduces two new messages
> VHOST_USER_GET_INFLIGHT_FD
> and VHOST_USER_SET_INFLIGHT_FD to support transferring a shared
> buffer between qemu and backend for backend reconnection.
> Now It can both support split and packed ring. The example code show
> how these APIs work. The test has passed.
>
> How to test the example:
> 1, Qemu need a patch.
> https://patchwork.kernel.org/patch/10861411/
> it also needs some manual modifications:
> we should confirm that before we send get inflight we have already
> sent the set features but it seems Qemu didn't do like this. So we
> manually revise this, we can add below code in vhost_dev_get_inflight
>     int r;
>
>     r = vhost_dev_set_features(dev, dev->log_enabled);
>     if (r < 0) {
>         return -errno;
>     }
> before get_inflight_fd.
> 2, Guest OS version >= 5.0
> 3, run the example
> 4, run the qemu with vhost-user-blk-pci.
>  eg:
>         -chardev socket,id=spdk_vhost_blk0,reconnect=1,path=xxxx\
>         -device vhost-user-blk-
> pci,ring_packed=on,chardev=spdk_vhost_blk0,num-queues=1\
> 5, run fio in the guest
> 6, kill the example and run again.
> 7, the fio in the guest should continue run without errors.
>
> JinYu (10):
>   vhost: add the inflight description
>   vhost: add packed ring
>   vhost: add the inflight structure
>   vhost: add two new messages to support a shared buffer
>   vhost: checkout and cleanup the resubmit inflight information
>   vhost: add the APIs to operate inflight ring
>   vhost: add APIs for user getting inflight ring
>   vhost: fix vring functions to support packed ring
>   vhost: add an API for judging vq format
>   vhost: add vhost-user-blk example which support inflight
>
>  examples/vhost_blk/Makefile           |   67 ++
>  examples/vhost_blk/blk.c              |  125 +++
>  examples/vhost_blk/blk_spec.h         |   95 ++
>  examples/vhost_blk/meson.build        |   20 +
>  examples/vhost_blk/vhost_blk.c        | 1313 +++++++++++++++++++++++++
>  examples/vhost_blk/vhost_blk.h        |  116 +++
>  examples/vhost_blk/vhost_blk_compat.c |  195 ++++
>  lib/librte_vhost/rte_vhost.h          |  250 ++++-
>  lib/librte_vhost/vhost.c              |  396 +++++++-
>  lib/librte_vhost/vhost.h              |   16 +
>  lib/librte_vhost/vhost_user.c         |  439 +++++++++
>  lib/librte_vhost/vhost_user.h         |   12 +-
>  12 files changed, 3032 insertions(+), 12 deletions(-)
>  create mode 100644 examples/vhost_blk/Makefile
>  create mode 100644 examples/vhost_blk/blk.c
>  create mode 100644 examples/vhost_blk/blk_spec.h
>  create mode 100644 examples/vhost_blk/meson.build
>  create mode 100644 examples/vhost_blk/vhost_blk.c
>  create mode 100644 examples/vhost_blk/vhost_blk.h
>  create mode 100644 examples/vhost_blk/vhost_blk_compat.c
>
> --
> 2.17.2

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