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.Dd January 15, 2025 .Dt VIRTIO_MMIO 4 .Os .Sh NAME .Nm virtio_mmio .Nd VirtIO over memory mapped device .Sh SYNOPSIS .Cd "pv* at pvbus?" .Cd "virtio* at pv?"
p .Cd "acpi0 at mainbus0" .Cd "virtio* at acpi?" .Sh DESCRIPTION .Nm can be used in virtual environments without .Xr pci 4 support
q a common situation in embedded devices models might use simple memory mapped device
q Nm instead of the .Xr pci 4 device.
p The memory mapped .Xr virtio 4 device behavior is based on the .Xr pci 4 device specification. Therefore most operations including device initialization, queues configuration and buffer transfers are nearly identical.
p Unlike .Xr pci 4 , .Nm provides no generic device discovery mechanism. For each device, the guest OS will need to know the location of the registers and interrupt(s) used.
p Device location can be read from either .Xr acpi 4 or via kernel command line parameters, implemented as a .Xr pv 4 virtual device. .Sh SEE ALSO .Xr virtio 4
p .Rs .%T Virtual I/O Device (VIRTIO) Version 1.2 .%U https://docs.oasis-open.org/virtio/virtio/v1.2/virtio-v1.2.html .Re
Indexes created Sat Sep 20 22:09:52 GMT 2025