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Subject: Re: [RFC PATCH 00/22] Enhance VHOST to enable SoC-to-SoC
 communication
To:     Kishon Vijay Abraham I <kishon@ti.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Jon Mason <jdmason@kudzu.us>,
        Dave Jiang <dave.jiang@intel.com>,
        Allen Hubbe <allenbh@gmail.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-remoteproc@vger.kernel.org, linux-ntb@googlegroups.com,
        linux-pci@vger.kernel.org, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org
References: <20200702082143.25259-1-kishon@ti.com>
 <20200702055026-mutt-send-email-mst@kernel.org>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <603970f5-3289-cd53-82a9-aa62b292c552@redhat.com>
Date:   Thu, 2 Jul 2020 18:10:22 +0800
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On 2020/7/2 下午5:51, Michael S. Tsirkin wrote:
> On Thu, Jul 02, 2020 at 01:51:21PM +0530, Kishon Vijay Abraham I wrote:
>> This series enhances Linux Vhost support to enable SoC-to-SoC
>> communication over MMIO. This series enables rpmsg communication between
>> two SoCs using both PCIe RC<->EP and HOST1-NTB-HOST2
>>
>> 1) Modify vhost to use standard Linux driver model
>> 2) Add support in vring to access virtqueue over MMIO
>> 3) Add vhost client driver for rpmsg
>> 4) Add PCIe RC driver (uses virtio) and PCIe EP driver (uses vhost) for
>>     rpmsg communication between two SoCs connected to each other
>> 5) Add NTB Virtio driver and NTB Vhost driver for rpmsg communication
>>     between two SoCs connected via NTB
>> 6) Add configfs to configure the components
>>
>> UseCase1 :
>>
>>   VHOST RPMSG                     VIRTIO RPMSG
>>        +                               +
>>        |                               |
>>        |                               |
>>        |                               |
>>        |                               |
>> +-----v------+                 +------v-------+
>> |   Linux    |                 |     Linux    |
>> |  Endpoint  |                 | Root Complex |
>> |            <----------------->              |
>> |            |                 |              |
>> |    SOC1    |                 |     SOC2     |
>> +------------+                 +--------------+
>>
>> UseCase 2:
>>
>>       VHOST RPMSG                                      VIRTIO RPMSG
>>            +                                                 +
>>            |                                                 |
>>            |                                                 |
>>            |                                                 |
>>            |                                                 |
>>     +------v------+                                   +------v------+
>>     |             |                                   |             |
>>     |    HOST1    |                                   |    HOST2    |
>>     |             |                                   |             |
>>     +------^------+                                   +------^------+
>>            |                                                 |
>>            |                                                 |
>> +---------------------------------------------------------------------+
>> |  +------v------+                                   +------v------+  |
>> |  |             |                                   |             |  |
>> |  |     EP      |                                   |     EP      |  |
>> |  | CONTROLLER1 |                                   | CONTROLLER2 |  |
>> |  |             <----------------------------------->             |  |
>> |  |             |                                   |             |  |
>> |  |             |                                   |             |  |
>> |  |             |  SoC With Multiple EP Instances   |             |  |
>> |  |             |  (Configured using NTB Function)  |             |  |
>> |  +-------------+                                   +-------------+  |
>> +---------------------------------------------------------------------+
>>
>> Software Layering:
>>
>> The high-level SW layering should look something like below. This series
>> adds support only for RPMSG VHOST, however something similar should be
>> done for net and scsi. With that any vhost device (PCI, NTB, Platform
>> device, user) can use any of the vhost client driver.
>>
>>
>>      +----------------+  +-----------+  +------------+  +----------+
>>      |  RPMSG VHOST   |  | NET VHOST |  | SCSI VHOST |  |    X     |
>>      +-------^--------+  +-----^-----+  +-----^------+  +----^-----+
>>              |                 |              |              |
>>              |                 |              |              |
>>              |                 |              |              |
>> +-----------v-----------------v--------------v--------------v----------+
>> |                            VHOST CORE                                |
>> +--------^---------------^--------------------^------------------^-----+
>>           |               |                    |                  |
>>           |               |                    |                  |
>>           |               |                    |                  |
>> +--------v-------+  +----v------+  +----------v----------+  +----v-----+
>> |  PCI EPF VHOST |  | NTB VHOST |  |PLATFORM DEVICE VHOST|  |    X     |
>> +----------------+  +-----------+  +---------------------+  +----------+
>>
>> This was initially proposed here [1]
>>
>> [1] -> https://lore.kernel.org/r/2cf00ec4-1ed6-f66e-6897-006d1a5b6390@ti.com
>
> I find this very interesting. A huge patchset so will take a bit
> to review, but I certainly plan to do that. Thanks!


Yes, it would be better if there's a git branch for us to have a look.

Btw, I'm not sure I get the big picture, but I vaguely feel some of the 
work is duplicated with vDPA (e.g the epf transport or vhost bus).

Have you considered to implement these through vDPA?

Thanks


>
>> Kishon Vijay Abraham I (22):
>>    vhost: Make _feature_ bits a property of vhost device
>>    vhost: Introduce standard Linux driver model in VHOST
>>    vhost: Add ops for the VHOST driver to configure VHOST device
>>    vringh: Add helpers to access vring in MMIO
>>    vhost: Add MMIO helpers for operations on vhost virtqueue
>>    vhost: Introduce configfs entry for configuring VHOST
>>    virtio_pci: Use request_threaded_irq() instead of request_irq()
>>    rpmsg: virtio_rpmsg_bus: Disable receive virtqueue callback when
>>      reading messages
>>    rpmsg: Introduce configfs entry for configuring rpmsg
>>    rpmsg: virtio_rpmsg_bus: Add Address Service Notification support
>>    rpmsg: virtio_rpmsg_bus: Move generic rpmsg structure to
>>      rpmsg_internal.h
>>    virtio: Add ops to allocate and free buffer
>>    rpmsg: virtio_rpmsg_bus: Use virtio_alloc_buffer() and
>>      virtio_free_buffer()
>>    rpmsg: Add VHOST based remote processor messaging bus
>>    samples/rpmsg: Setup delayed work to send message
>>    samples/rpmsg: Wait for address to be bound to rpdev for sending
>>      message
>>    rpmsg.txt: Add Documentation to configure rpmsg using configfs
>>    virtio_pci: Add VIRTIO driver for VHOST on Configurable PCIe Endpoint
>>      device
>>    PCI: endpoint: Add EP function driver to provide VHOST interface
>>    NTB: Add a new NTB client driver to implement VIRTIO functionality
>>    NTB: Add a new NTB client driver to implement VHOST functionality
>>    NTB: Describe the ntb_virtio and ntb_vhost client in the documentation
>>
>>   Documentation/driver-api/ntb.rst              |   11 +
>>   Documentation/rpmsg.txt                       |   56 +
>>   drivers/ntb/Kconfig                           |   18 +
>>   drivers/ntb/Makefile                          |    2 +
>>   drivers/ntb/ntb_vhost.c                       |  776 +++++++++++
>>   drivers/ntb/ntb_virtio.c                      |  853 ++++++++++++
>>   drivers/ntb/ntb_virtio.h                      |   56 +
>>   drivers/pci/endpoint/functions/Kconfig        |   11 +
>>   drivers/pci/endpoint/functions/Makefile       |    1 +
>>   .../pci/endpoint/functions/pci-epf-vhost.c    | 1144 ++++++++++++++++
>>   drivers/rpmsg/Kconfig                         |   10 +
>>   drivers/rpmsg/Makefile                        |    3 +-
>>   drivers/rpmsg/rpmsg_cfs.c                     |  394 ++++++
>>   drivers/rpmsg/rpmsg_core.c                    |    7 +
>>   drivers/rpmsg/rpmsg_internal.h                |  136 ++
>>   drivers/rpmsg/vhost_rpmsg_bus.c               | 1151 +++++++++++++++++
>>   drivers/rpmsg/virtio_rpmsg_bus.c              |  184 ++-
>>   drivers/vhost/Kconfig                         |    1 +
>>   drivers/vhost/Makefile                        |    2 +-
>>   drivers/vhost/net.c                           |   10 +-
>>   drivers/vhost/scsi.c                          |   24 +-
>>   drivers/vhost/test.c                          |   17 +-
>>   drivers/vhost/vdpa.c                          |    2 +-
>>   drivers/vhost/vhost.c                         |  730 ++++++++++-
>>   drivers/vhost/vhost_cfs.c                     |  341 +++++
>>   drivers/vhost/vringh.c                        |  332 +++++
>>   drivers/vhost/vsock.c                         |   20 +-
>>   drivers/virtio/Kconfig                        |    9 +
>>   drivers/virtio/Makefile                       |    1 +
>>   drivers/virtio/virtio_pci_common.c            |   25 +-
>>   drivers/virtio/virtio_pci_epf.c               |  670 ++++++++++
>>   include/linux/mod_devicetable.h               |    6 +
>>   include/linux/rpmsg.h                         |    6 +
>>   {drivers/vhost => include/linux}/vhost.h      |  132 +-
>>   include/linux/virtio.h                        |    3 +
>>   include/linux/virtio_config.h                 |   42 +
>>   include/linux/vringh.h                        |   46 +
>>   samples/rpmsg/rpmsg_client_sample.c           |   32 +-
>>   tools/virtio/virtio_test.c                    |    2 +-
>>   39 files changed, 7083 insertions(+), 183 deletions(-)
>>   create mode 100644 drivers/ntb/ntb_vhost.c
>>   create mode 100644 drivers/ntb/ntb_virtio.c
>>   create mode 100644 drivers/ntb/ntb_virtio.h
>>   create mode 100644 drivers/pci/endpoint/functions/pci-epf-vhost.c
>>   create mode 100644 drivers/rpmsg/rpmsg_cfs.c
>>   create mode 100644 drivers/rpmsg/vhost_rpmsg_bus.c
>>   create mode 100644 drivers/vhost/vhost_cfs.c
>>   create mode 100644 drivers/virtio/virtio_pci_epf.c
>>   rename {drivers/vhost => include/linux}/vhost.h (66%)
>>
>> -- 
>> 2.17.1
>>