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virtio_scsi(4) [freebsd man page]

VIRTIO_SCSI(4)						   BSD Kernel Interfaces Manual 					    VIRTIO_SCSI(4)

virtio_scsi -- VirtIO SCSI driver SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file: device virtio_scsi Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): virtio_scsi_load="YES" DESCRIPTION
The virtio_scsi device driver provides support for VirtIO SCSI devices. LOADER TUNABLES
Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5). hw.vtscsi.bus_reset_disable In the initial QEMU release with VirtIO SCSI support, in-flight operations were not aborted when stopping the device, rendering bus reset ineffective. This tunable disables attempts to issue reset bus commands. The default value is 1. DEBUGGING
To enable debugging prints from the virtio_scsi driver, set the hw.vtscsi.X.debug_level variable, where X is the adapter number, either in loader.conf(5) or via sysctl(8). The following bits have the described effects: 0x01 Enable informational prints. 0x02 Enable prints for driver errors. 0x04 Enable tracing prints. SEE ALSO
virtio(4) HISTORY
The virtio_scsi driver was written by Bryan Venteicher <>. It first appeared in FreeBSD 10.0. BSD
June 24, 2012 BSD

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VIRTIO(4)						   BSD Kernel Interfaces Manual 						 VIRTIO(4)

virtio -- VirtIO Device Support SYNOPSIS
To compile VirtIO device support into the kernel, place the following lines in your kernel configuration file: device virtio device virtio_pci Alternatively, to load VirtIO support as modules at boot time, place the following lines in loader.conf(5): virtio_load="YES" virtio_pci_load="YES" DESCRIPTION
VirtIO is a specification for para-virtualized I/O in a virtual machine (VM). Traditionally, the hypervisor emulated real devices such as an Ethernet interface or disk controller to provide the VM with I/O. This emulation is often inefficient. VirtIO defines an interface for efficient I/O between the hypervisor and VM. The virtio module provides a shared memory transport called a virtqueue. The virtio_pci device driver represents an emulated PCI device that the hypervisor makes available to the VM. This device pro- vides the probing, configuration, and interrupt notifications needed to interact with the hypervisor. FreeBSD supports the following VirtIO devices: Ethernet An emulated Ethernet device is provided by the vtnet(4) device driver. Block An emulated disk controller is provided by the virtio_blk(4) device driver. SCSI An emulated SCSI HBA is provided by the virtio_scsi(4) device driver. Balloon A pseudo-device to allow the VM to release memory back to the hypervisor is provided by the virtio_balloon(4) device driver. SEE ALSO
virtio_balloon(4), virtio_blk(4), virtio_console(4), virtio_scsi(4), vtnet(4) HISTORY
Support for VirtIO first appeared in FreeBSD 9.0. AUTHORS
FreeBSD support for VirtIO was first added by Bryan Venteicher <>. BSD
January 22, 2012 BSD
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