Currently, virtual AHCI disk is not providing SMART capability, even using the raw disk. In some use case, users are lack of VT-d or unable to provide extra HBA for passthrough, but still want to let VM know the SMART.

This patch will let virtual AHCI hdd has the host's hdd SMART.

In order to get the SMART from Host's device. I am using code from camcontrol.c and create a new cam_if.c file.

Inside vm, using smartctl utility, check the output of SMART, and compare it to Host's output.