Yes, I think it would good to have facilities like this available
in FreeMWare. I was thinking of having these available to our
own debugger environment. Never thought about offering them
to a driver running inside the VM if that's what you're saying.
Though, if it helps, sound like a good plan to me.
-Kevin
> Well, I mean this:
>
> - I/O-based drivers allocate I/O ports
> - Memory-based drivers (i.e., VGA card) allocate physical memory
> I guess you could even make physical memory itself a driver, dynamically
> allocating host memory at need (just a wild idea).
> - A real x86 has an INTR pin. In stead of simulating this, it would be easier
> just to be able to generate an interrupt by ioctl()ing the driver, that's
> logical.
> However, there may be drivers that want to *catch* generated interrupts
> (software or hardware). This is especially useful for simulating an ICE,
> for me that would be one of the most useful aspects of such a system (vICE).
> Another idea would be that you could potentially speed up emulation of an OS
> by implementing parts of it outside the VM; an idea would be having WINE
> collaborate with the VM (solves the VxD problem ?) You could do this
> by giving drivers the ability to "hook" interrupts.
>
> In general, I think every resource that might trigger some driver action should
> be hookable. However, if such a resource is not hooked you should notice no
> performance decrease from if hooking were not implemented in the first place.
> (for instance, memory-based hooking may be done at page level; I/O hooking
> has fine-grained control through I/O permission bitmaps; interrupts are
> also simple
> to implement).
>
> Right now, I can think of these kinds of devices:
>
> - I/O based. Traditional.
> - DMA based. Need a DMA driver, and some way to access memory
> (but not hook it).
> - Memory based I/O. VGA cards, APIC, etc. Need memory hooking.
> - Bus snooping. Intel Paragon NIC, etc. Memory hooking would be okay I guess.
> However, it doesn't sound very *efficient*.
>
> Have I missed any ?
>
> I think memory hooking should have an "urgent" flag.
