Fast AHCI driver

Created by: tjhu

Implement an AHCI driver that's not significantly slower than Linux's. Especially when the block size is smaller than 4MB. The AHCI driver that we borrow from Redox is slow, hard to debug, and doesn't support AIO so we need to reimplement it.

• Design a safe AIO interface.
• Implement a basic AHCI driver that supports synchronized R/W
• Implement AIO
• Implement Native Command Queueing(NCQ).
• Benchmark both sequential and random R/W