On Thu, May 13, 2010 at 02:00:24PM +0300, Gleb Natapov wrote:
On Wed, May 12, 2010 at 07:25:55PM -0400, Kevin O'Connor wrote:
The blksize needs to be 512, because the BIOS interface that virtio binds to requires 512 byte sectors. Shouldn't this look something like:
[...]
Hmm, I guess you are right. Boot indeed fails if I configure logical block size bigger then 512 bytes. But shouldn't BIOS emulate 512 byte access on top of bigger block size? Future disks will use much large logical block sizes.
SeaBIOS only supports 512 byte sectors for floppies/harddrives and only supports 2048 byte sectors for cdroms. I suppose one could implement an emulation layer (similar to the way the "El Torito" spec can make a cdrom look like a harddrive), but so far nothing has required that.
I suspect future drives will boot in a legacy mode that uses a 512 byte block interface - exactly because of these types of issues.
-Kevin