r256926
Fix AHCI ATAPI emulation when backed with /dev/cd0
- remove assumption that the backing file/device had
512-byte sectors
- fix incorrect iovec size variable that would result
in a buffer overrun when an o/s issued an i/o request
with more s/g elements than the blockif api
r257005
Export the block size capability to guests.
- Use #defines for capability bits
- Export the VTBLK_F_BLK_SIZE capability
- Fix bug in calculating capacity: it is in
512-byte units, not the underlying sector size
This allows virtio-blk to have backing devices
with non 512-byte sector sizes e.g. /dev/cd0, and
4K-block harddrives.