vdev ser8250

Synopsis:

vdev ser8250 options

Options:

batch timeout

Instead of writing one character at a time, batch the output until the number of microseconds specifed by timeout has passed with no new characters coming in.

delayed seconds|forever

Delay opening the host device until it is first referenced by the guest.

If the device isn't found in the host, keep trying to find the device for the number of seconds given by seconds before timing out (e.g., delayed 5). If seconds is set to 0 (i.e., delayed 0), try only once to find the device. If it is set to forever (i.e., delayed forever), never time out and just keep trying to find the device.

hostdev [<|>]host_device_name

hostdev >"|command_string"

The first form means use the host_device_name as the source and/or destination of characters for the vdev.

For a given hostdev option, you can use one of < (input) or > (output) so the host device specified by host_device_name provides input or receives output.

To specify separate input and output devices, you can use multiple hostdev options:

hostdev <myhostinputdevice
hostdev >myhostoutputdevice

Or, you can use neither < nor > to indicate the same device is used for both input and output:

hostdev myhostdevice

The second form means redirect the vdev's output to a process created by executing command_string. The command string must be immediately preceded by the pipe character (|) and then surrounded by double quotes, as shown here:

hostdev >"|/guests/tee /guests/pipe_test.log"

Here the vdev's output is sent as input to the /guests/tee program which takes the pathname of a log file, /guests/pipe_test.log, as an argument. The command you name can do whatever you want; for example, it could perform logging with file size limits. For further explanation, refer to Logging output in the vdev virtio-console reference.

intr intr

Signal intr for device interrupts.

loc addr

Set the base address of the device registers to addr. Default space is io:.

name device_path

Specify a device path that you can write commands to in order to control the size and number of log files created for storing the vdev's output. For example, you can issue a command to reopen a log file (i.e., truncate it to zero bytes) after you noticed it was getting too big. For information about performing this log rotation, refer to Logging output in the vdev virtio-console reference.

sched priority

Set the priority specified by priority for pulses indicating that input is available.

For a list of options available to all vdevs, see Common vdev options earlier in this chapter.

Description:

The ser8250 vdev emulates the Intel 8250 UART.