[SeaBIOS] ohci bulk?

Kevin O'Connor kevin at koconnor.net
Mon Nov 22 14:47:23 CET 2010

On Mon, Nov 22, 2010 at 11:52:56AM +0100, Gerd Hoffmann wrote:
> >I suppose one could implement a simple SMM gateway - write a magic IO
> >bit to invoke the SMM handler, have the SMM handler backup the cpu
> >state somewhere in BIOS owned memory, and then leave SMM mode with
> >execution at a BIOS handler running in 32bit flat mode.
> Hmm, how about having a virtual "I/O bounce" device?  Allocate two
> dwords in I/O space.  One dword for the address, one for the data.
> reads and writes to the data register will be bounced to the address
> written into the address register.

It could work.  However, having the ability to go into full 32bit mode
would be more flexible.

> On real hardware seabios could emulate this using SMM.
> On virtual hardware qemu could emulate this so we don't need SMM
> support in kvm.

How hard would it be to add SMM support into kvm?

> From a security point of view it might not be the best idea though.

If a program has access to iospace, it's basically fully privileged
anyway, so I don't think this is a problem.  (For example, the old
16bit DMA registers are fully programmed from iospace.)


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