[Qemu-devel] Re: [PATCH v3 1/1] Shared memory uio_pci driver

[Avi Kivity]

On 03/25/2010 06:24 PM, Cam Macdonell wrote:
> > There is now a generic PCI 2.3 driver that can handle all PCI devices.  It
> > doesn't support MSI, but if we add MSI support then it can be used without
> > the need for a specialized driver.
> >      
> Agreed, I'd be happy to use the generic driver if MSI is there.  What
> would MSI support for UIO look like?  An array of "struct uio_irq" for
> the different vectors?
>    

I'm not familiar with the uio internals, but for the interface, an 
ioctl() on the fd to assign an eventfd to an MSI vector.  Similar to 
ioeventfd, but instead of mapping a doorbell to an eventfd, it maps a 
real MSI to an eventfd.

That would be very useful for device assignment: we can pick up a uio 
device, map its vectors, and give them to a guest.


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