Re: virtio & hypercall interface?

[Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>]

On Sat, 2007-09-15 at 01:31 +0300, Dor Laor wrote:
> Second, regardless of the channel signal notification, there are still 
> real necessities for userspace hypercall handling:
> 1. For virtio drivers there is also registration hypercall for passing 
> the shared memory pfns.
>     Sure there are other possibilities, but why limit ourselves?

I really prefer doing this the more "hardware-like" way and having the
device description say where the pages are.  Surely this is simpler from
the qemu side, too?

I'm working from the lguest side to try to get uniform virtio, and
lguest does it this way.

> 2. For other purposes such as a balloon driver, a deflate/inflate 
> hypercalls are needed.
>     Although for x86 mmio/pio can be used but this is not compatible 
> with other architectures.

We could encode the notification method in the config space  ("execute
this!").

OK, maybe not.  But it'd be generic!

Rusty.



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