How to understand vvfat

[沈梦姣]

Hello,
Recently I’m learning QEMU storage. I think the two structures are very 
important, BlockBackend and BlockDriver. Usually BlockBackend resides in the 
block device structure like disk, flash etc and the block device is storage 
device seen by guest OS and driver. BlockDriver will handle the stuff with 
host. Hope my understanding isn’t wrong.

And vvfat is BlockDriver, can I understand it as: it is constructing a raw disk 
image (based on the host directory) which can be read by guest? If my bare meta 
guest setup a fat filesystem, the raw disk image can be read and write 
correctly?

Thanks a lot