Re: [Qemu-devel] PCI access virtualization

[Jim C. Brown]

On Thu, Jan 05, 2006 at 06:10:54PM +0000, Paul Brook wrote:
> On Thursday 05 January 2006 17:40, Mark Williamson wrote:
> > > - IRQ sharing. Sharing host IRQs between native and virtualized devices
> > > is hard because the host needs to ack the interrupt in the IRQ handler,
> > > but doesn't really know how to do that until after it's run the guest to
> > > see what that does.
> >
> > Could maybe have the (inevitable) kernel portion of the code grab the
> > interrupt, and not ack it until userspace does an ioctl on a special file
> > (or something like that?).  There are patches floating around for userspace
> > IRQ handling, so I guess that could work.
> 
> This still requires cooperation from both sides (ie. both the host and guest 
> drivers).
> 

This would be a lot easier if linux supported user-space device drivers..
and I believe work is being done in that area.

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.