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authorChristoph Hellwig <hch@lst.de>2023-01-10 10:10:08 +0100
committerAlex Williamson <alex.williamson@redhat.com>2023-01-23 11:26:29 -0700
commit0030d7d6ce319c32551395ebc00c533f50a0b0fe (patch)
treedfad9fd1461ec2853f133bc5292b557fa2a1e944 /Documentation/driver-api/vfio-mediated-device.rst
parentvfio-mdev: turn VFIO_MDEV into a selectable symbol (diff)
downloadwireguard-linux-0030d7d6ce319c32551395ebc00c533f50a0b0fe.tar.xz
wireguard-linux-0030d7d6ce319c32551395ebc00c533f50a0b0fe.zip
vfio-mdev: move the mtty usage documentation
Move the documentation on how to use mtty to samples/vfio-mdev/README.rst as it is in no way related to the vfio API. This matches how the bpf and pktgen samples are documented. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/20230110091009.474427-4-hch@lst.de Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'Documentation/driver-api/vfio-mediated-device.rst')
-rw-r--r--Documentation/driver-api/vfio-mediated-device.rst100
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diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index fdf7d69378ec..d4267243b4f5 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -270,106 +270,6 @@ these callbacks are supported in the TYPE1 IOMMU module. To enable them for
other IOMMU backend modules, such as PPC64 sPAPR module, they need to provide
these two callback functions.
-Using the Sample Code
-=====================
-
-mtty.c in samples/vfio-mdev/ directory is a sample driver program to
-demonstrate 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
-
References
==========