Subject: Re: [PATCH v3 3/6] vbus: add a "vbus-proxy" bus model for vbus_driver objects

From: Avi Kivity <[email-masked]>
Date: Tue, 18 Aug 2009 13:13:57 +0300

On 08/18/2009 01:09 PM, Michael S. Tsirkin wrote:
>
>> mmio and pio don't have this problem since the host can use the address
>> to locate the destination.
>>      
> So userspace could map hypercall to address during setup and tell the
> host kernel?
>    

Suppose a nested guest has two devices.  One a virtual device backed by 
its host (our guest), and one a virtual device backed by us (the real 
host), and assigned by the guest to the nested guest.  If both devices 
use hypercalls, there is no way to distinguish between them.

-- 
error compiling committee.c: too many arguments to function