Manual Pages  — NTB_HW_AMD

Or, to load the driver as a module at boot, place the following line in loader.conf(5):

ntb_hw_amd_load="YES"

The following sysctls are supported in this driver

dev.ntb_hw.X.info	Reading this sysctl will give the basic details like the number of memory windows, scratchpads and doorbells exposed by the NTB on the local host to access the devices beyond the bridge. It also provides details about the masked doorbells, translation address and size limit of each exposed memory window and link status information.

The hardware provides 2 (both 64-bit) or 3 (one 32-bit and two 64-bit) memory windows to the other system's memory, up to 16 scratchpad registers and 16 doorbells to communicate with and interrupt the other system respectively.