Re: [Xen-devel] hvm crash on hypercall event channel

[Daniel Castro <evil.dani@xxxxxxxxx>]

On Wed, Apr 11, 2012 at 9:44 PM, Keir Fraser <keir@xxxxxxx> wrote:
> On 11/04/2012 13:24, "Daniel Castro" <evil.dani@xxxxxxxxx> wrote:
>
>>> It's looking likely that you'll have to go to 32 bit mode to do all of
>>> the actual I/O associated with the PV devices. That ought to simplify a
>>> bunch of stuff WRT handling the rings etc too.
>>
>> What are my choices?
>> 1. Add support for 16bit hypercalls on Xen.
>> 2. Jump to 32 bit
>
> I think this is best. Compile the 32-bit drivers as 32-bit code, then use
> stubs to transfer between 16-bit and 32-bit execution modes at run time. Our
> old rombios has code you could borrow for this, if seabios doesn't already
> have such functionality.

SeaBIOS allows me to call a function wrapped in 32 bit.
Also I found that I can not write the ring indexes in 16BIT mode
because the memory is marked read-only. So jumping to 32 bit is my
only option.

>
>  -- Keir
>
>> 3. make a 16bit "special" hypercall on SeaBIOS
>> 4. Any other choice?
>>
>> Thanks to all the comments.
>
>



-- 
+-=====---------------------------+
| +---------------------------------+ | This space intentionally blank
for notetaking.
| |   | Daniel Castro,                |
| |   | Consultant/Programmer.|
| |   | U Andes                         |
+-------------------------------------+

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel