linux/samples/vfio-mdev
Linus Torvalds ec0e2dc810 VFIO updates for v6.6-rc1
- VFIO direct character device (cdev) interface support.  This extracts
    the vfio device fd from the container and group model, and is intended
    to be the native uAPI for use with IOMMUFD. (Yi Liu)
 
  - Enhancements to the PCI hot reset interface in support of cdev usage.
    (Yi Liu)
 
  - Fix a potential race between registering and unregistering vfio files
    in the kvm-vfio interface and extend use of a lock to avoid extra
    drop and acquires. (Dmitry Torokhov)
 
  - A new vfio-pci variant driver for the AMD/Pensando Distributed Services
    Card (PDS) Ethernet device, supporting live migration. (Brett Creeley)
 
  - Cleanups to remove redundant owner setup in cdx and fsl bus drivers,
    and simplify driver init/exit in fsl code. (Li Zetao)
 
  - Fix uninitialized hole in data structure and pad capability structures
    for alignment. (Stefan Hajnoczi)
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Merge tag 'vfio-v6.6-rc1' of https://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - VFIO direct character device (cdev) interface support. This extracts
   the vfio device fd from the container and group model, and is
   intended to be the native uAPI for use with IOMMUFD (Yi Liu)

 - Enhancements to the PCI hot reset interface in support of cdev usage
   (Yi Liu)

 - Fix a potential race between registering and unregistering vfio files
   in the kvm-vfio interface and extend use of a lock to avoid extra
   drop and acquires (Dmitry Torokhov)

 - A new vfio-pci variant driver for the AMD/Pensando Distributed
   Services Card (PDS) Ethernet device, supporting live migration (Brett
   Creeley)

 - Cleanups to remove redundant owner setup in cdx and fsl bus drivers,
   and simplify driver init/exit in fsl code (Li Zetao)

 - Fix uninitialized hole in data structure and pad capability
   structures for alignment (Stefan Hajnoczi)

* tag 'vfio-v6.6-rc1' of https://github.com/awilliam/linux-vfio: (53 commits)
  vfio/pds: Send type for SUSPEND_STATUS command
  vfio/pds: fix return value in pds_vfio_get_lm_file()
  pds_core: Fix function header descriptions
  vfio: align capability structures
  vfio/type1: fix cap_migration information leak
  vfio/fsl-mc: Use module_fsl_mc_driver macro to simplify the code
  vfio/cdx: Remove redundant initialization owner in vfio_cdx_driver
  vfio/pds: Add Kconfig and documentation
  vfio/pds: Add support for firmware recovery
  vfio/pds: Add support for dirty page tracking
  vfio/pds: Add VFIO live migration support
  vfio/pds: register with the pds_core PF
  pds_core: Require callers of register/unregister to pass PF drvdata
  vfio/pds: Initial support for pds VFIO driver
  vfio: Commonize combine_ranges for use in other VFIO drivers
  kvm/vfio: avoid bouncing the mutex when adding and deleting groups
  kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add()
  docs: vfio: Add vfio device cdev description
  vfio: Compile vfio_group infrastructure optionally
  vfio: Move the IOMMU_CAP_CACHE_COHERENCY check in __vfio_register_dev()
  ...
2023-08-30 20:36:01 -07:00
..
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
mbochs.c vfio-iommufd: Add detach_ioas support for emulated VFIO devices 2023-07-25 10:19:18 -06:00
mdpy-defs.h PCI: Move PCI_VENDOR_ID_REDHAT definition to pci_ids.h 2020-07-09 17:00:47 -05:00
mdpy-fb.c vfio-dev/mdpy-fb: Use fbdev I/O helpers 2023-08-04 15:54:39 +02:00
mdpy.c vfio-iommufd: Add detach_ioas support for emulated VFIO devices 2023-07-25 10:19:18 -06:00
mtty.c vfio-iommufd: Add detach_ioas support for emulated VFIO devices 2023-07-25 10:19:18 -06:00
README.rst vfio-mdev: move the mtty usage documentation 2023-01-23 11:26:29 -07:00

Using the mtty vfio-mdev sample code
====================================

mtty is a sample vfio-mdev driver that demonstrates how to use the mediated
device framework.

The sample driver creates an mdev device that simulates a serial port over a PCI
card.

1. Build and load the mtty.ko module.

   This step creates a dummy device, /sys/devices/virtual/mtty/mtty/

   Files in this device directory in sysfs are similar to the following::

     # tree /sys/devices/virtual/mtty/mtty/
        /sys/devices/virtual/mtty/mtty/
        |-- mdev_supported_types
        |   |-- mtty-1
        |   |   |-- available_instances
        |   |   |-- create
        |   |   |-- device_api
        |   |   |-- devices
        |   |   `-- name
        |   `-- mtty-2
        |       |-- available_instances
        |       |-- create
        |       |-- device_api
        |       |-- devices
        |       `-- name
        |-- mtty_dev
        |   `-- sample_mtty_dev
        |-- power
        |   |-- autosuspend_delay_ms
        |   |-- control
        |   |-- runtime_active_time
        |   |-- runtime_status
        |   `-- runtime_suspended_time
        |-- subsystem -> ../../../../class/mtty
        `-- uevent

2. Create a mediated device by using the dummy device that you created in the
   previous step::

     # echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" >	\
              /sys/devices/virtual/mtty/mtty/mdev_supported_types/mtty-2/create

3. Add parameters to qemu-kvm::

     -device vfio-pci,\
      sysfsdev=/sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001

4. Boot the VM.

   In the Linux guest VM, with no hardware on the host, the device appears
   as  follows::

     # lspci -s 00:05.0 -xxvv
     00:05.0 Serial controller: Device 4348:3253 (rev 10) (prog-if 02 [16550])
             Subsystem: Device 4348:3253
             Physical Slot: 5
             Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
     Stepping- SERR- FastB2B- DisINTx-
             Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
     <TAbort- <MAbort- >SERR- <PERR- INTx-
             Interrupt: pin A routed to IRQ 10
             Region 0: I/O ports at c150 [size=8]
             Region 1: I/O ports at c158 [size=8]
             Kernel driver in use: serial
     00: 48 43 53 32 01 00 00 02 10 02 00 07 00 00 00 00
     10: 51 c1 00 00 59 c1 00 00 00 00 00 00 00 00 00 00
     20: 00 00 00 00 00 00 00 00 00 00 00 00 48 43 53 32
     30: 00 00 00 00 00 00 00 00 00 00 00 00 0a 01 00 00

     In the Linux guest VM, dmesg output for the device is as follows:

     serial 0000:00:05.0: PCI INT A -> Link[LNKA] -> GSI 10 (level, high) -> IRQ 10
     0000:00:05.0: ttyS1 at I/O 0xc150 (irq = 10) is a 16550A
     0000:00:05.0: ttyS2 at I/O 0xc158 (irq = 10) is a 16550A


5. In the Linux guest VM, check the serial ports::

     # setserial -g /dev/ttyS*
     /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
     /dev/ttyS1, UART: 16550A, Port: 0xc150, IRQ: 10
     /dev/ttyS2, UART: 16550A, Port: 0xc158, IRQ: 10

6. Using minicom or any terminal emulation program, open port /dev/ttyS1 or
   /dev/ttyS2 with hardware flow control disabled.

7. Type data on the minicom terminal or send data to the terminal emulation
   program and read the data.

   Data is loop backed from hosts mtty driver.

8. Destroy the mediated device that you created::

     # echo 1 > /sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001/remove