[RFC PATCH 00/22] Enhance VHOST to enable SoC-to-SoC communication

Kishon Vijay Abraham I
2020-07-02T08:26:05Z

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

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%)

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2.17.1