Interface ac_device.h

The ARM access control device interface facilitates the creation of generic virtual devices in a VM instance with access control permissions over the devices addressable memory. An access controlled device is often used to abstract the memory of a specific platform hardware device e.g a clock device. This allows the user to present hardware devices to a VM instance but limit their permissions with regards to modifying its register state.

Brief content:

Functions:

vm_install_generic_ac_device(vm, d, mask, size, action)

Functions

The interface ac_device.h defines the following functions.

Function vm_install_generic_ac_device(vm, d, mask, size, action)

Installs a generic access controlled device are modifiable by the guest. ‘1’ represents bits that the guest can read and write ‘0’ represents bits that can only be read by the guest Underlying memory for the mask should remain accessible for the life of this device. The mask may be updated at run time on demand. cases where the underlying device does not occupy a full page. If an access lies outside of the range of the mask, guest access.

Parameters:

• vm {vm_t *}: The VM to install the device into
• d {const struct device *}: A description of the device to install
• mask {void *}: An access mask. The mask provides a map of device bits that
• size {size_t}: The size of the mask. This is useful for conserving memory in
• action {enum vacdev_action}: Action to take when access is violated.

Returns:

• 0 on success, -1 on error

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