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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>
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| Original file line number | Diff line number | Diff line change |
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| Using the mtty vfio-mdev sample code | ||
| ==================================== | ||
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| mtty is a sample vfio-mdev driver that demonstrates how to use the mediated | ||
| device framework. | ||
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| The sample driver creates an mdev device that simulates a serial port over a PCI | ||
| card. | ||
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| 1. Build and load the mtty.ko module. | ||
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| This step creates a dummy device, /sys/devices/virtual/mtty/mtty/ | ||
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| Files in this device directory in sysfs are similar to the following:: | ||
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| # 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 | ||
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| 2. Create a mediated device by using the dummy device that you created in the | ||
| previous step:: | ||
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| # echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" > \ | ||
| /sys/devices/virtual/mtty/mtty/mdev_supported_types/mtty-2/create | ||
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| 3. Add parameters to qemu-kvm:: | ||
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| -device vfio-pci,\ | ||
| sysfsdev=/sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001 | ||
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| 4. Boot the VM. | ||
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| In the Linux guest VM, with no hardware on the host, the device appears | ||
| as follows:: | ||
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| # 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 | ||
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| In the Linux guest VM, dmesg output for the device is as follows: | ||
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| 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 | ||
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| 5. In the Linux guest VM, check the serial ports:: | ||
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| # 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 | ||
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| 6. Using minicom or any terminal emulation program, open port /dev/ttyS1 or | ||
| /dev/ttyS2 with hardware flow control disabled. | ||
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| 7. Type data on the minicom terminal or send data to the terminal emulation | ||
| program and read the data. | ||
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| Data is loop backed from hosts mtty driver. | ||
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| 8. Destroy the mediated device that you created:: | ||
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| # echo 1 > /sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa1001/remove | ||
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