PCIe endpoint framework provides APIs to implement PCIe endpoint function. This framework allows defining various PCIe endpoint function behaviors in software. This patch extend the framework for virtio pci device. The virtio is defined to communicate guest on virtual machine and host side. Advantage of the virtio is the efficiency of data transfer and the conciseness of implementation device using software. It also be applied to PCIe endpoint function. We designed and implemented a PCIe EP virtio console function driver using the extended PCIe endpoint framework for virtio. It can be communicate host and endpoint over virtio as console. An architecture of the function driver is following: ┌────────────┐ ┌──────────────────────┬────────────┐ │virtio │ │ │virtio │ │console drv │ ├───────────────┐ │console drv │ ├────────────┤ │(virtio console│ ├────────────┤ │ virtio bus │ │ device) │◄────►│ virtio bus │ ├────────────┤ ├---------------┤ └────────────┤ │ │ │ pci ep virtio │ │ │ pci bus │ │ console drv │ │ │ │ pcie ├───────────────┤ │ │ │ ◄─────► │ pci ep Bus │ │ └────────────┘ └───────────────┴───────────────────┘ PCIe Root PCIe Endpoint Introduced driver is `pci ep virtio console drv` in the figure. It works as ep function for PCIe root and virtual virtio console device for PCIe endpoint. Each side of virtio console driver has virtqueue, and introduced driver transfers data on the virtqueue to each other. A data on root tx queue is transfered to endpoint rx queue and vice versa. This patchset is depend follwing patches which are under discussion. - [RFC PATCH 0/3] Deal with alignment restriction on EP side link: https://lore.kernel.org/linux-pci/20230113090350.1103494-1-mie@xxxxxxxxxx/ - [RFC PATCH v2 0/7] Introduce a vringh accessor for IO memory link: https://lore.kernel.org/virtualization/20230202090934.549556-1-mie@xxxxxxxxxx/ First of this patchset is introduce a helper function to realize pci virtio function using PCIe endpoint framework. The second one is adding a missing definition for virtio pci header. The last one is for PCIe endpoint virtio console driver. This is tested on linux-20230406 and RCar S4 board as PCIe endpoint. Shunsuke Mie (3): PCI: endpoint: introduce a helper to implement pci ep virtio function virtio_pci: add a definition of queue flag in ISR PCI: endpoint: Add EP function driver to provide virtio-console functionality drivers/pci/endpoint/functions/Kconfig | 19 + drivers/pci/endpoint/functions/Makefile | 2 + drivers/pci/endpoint/functions/pci-epf-vcon.c | 554 ++++++++++++++++++ .../pci/endpoint/functions/pci-epf-virtio.c | 469 +++++++++++++++ .../pci/endpoint/functions/pci-epf-virtio.h | 123 ++++ include/uapi/linux/virtio_pci.h | 3 + 6 files changed, 1170 insertions(+) create mode 100644 drivers/pci/endpoint/functions/pci-epf-vcon.c create mode 100644 drivers/pci/endpoint/functions/pci-epf-virtio.c create mode 100644 drivers/pci/endpoint/functions/pci-epf-virtio.h -- 2.25.1
