[SeaBIOS] [PATCH] fix two issues with virtio-blk

[Kevin O'Connor]

On Sun, May 16, 2010 at 02:59:19PM +0200, Sebastian Herbszt wrote:
> Kevin O'Connor wrote:
> >On Sat, May 15, 2010 at 10:08:54PM +0200, Sebastian Herbszt wrote:
> >>with CDROM support. Sure you can grab another 4 KB for a RMW buffer,
> >It's only 2KB more - the buffer could be shared.
> Even if you want to be able to copy from CDROM emulation to a disk with 4 KB
> physical sectors? I assume you need 2 KB for CDROM emulation and 4 KB for RMW.

There is no "copy" BIOS command.  To copy data, the caller must read a
sector into memory and then write the sector from its memory to the
new disk.  Both read and write BIOS operations can use the same 4KB
buffer.

> >>Why is a 4 KB physical sector size needed in a VM anyway?
> >It isn't - I was just describing where one could get the memory.  I'm
> >not planning on implementing this.
[...]
> Even if drives use a bigger physical sector size they can still use
> a logical sector size of 512 bytes. This is what those drives with
> the Advanced Format Technology

I think we are both in agreement.

-Kevin