Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers

[Avi Kivity]

On 05/30/2010 04:03 PM, Michael S. Tsirkin wrote:
>    
> > > > > IMO this was because this driver does two things: programming iommu and
> > > > > handling interrupts. uio does interrupt handling.
> > > > > We could have moved iommu / DMA programming to
> > > > > a separate driver, and have uio work with it.
> > > > > This would solve limitation of the current driver
> > > > > that is needs an iommu domain per device.
> > > > >
> > > > >
> > > > >            
> > > > How do we enforce security then?  We need to ensure that unprivileged
> > > > users can only use the device with an iommu.
> > > >
> > > >          
> > > Force assigning to iommu before we allow any other operation?
> > >
> > >        
> > That means the driver must be aware of the iommu.
> >      
> The userspace driver? Yes. And It is a good thing to be explicit
> there anyway, since this lets userspace map a non-contigious
> virtual address list into a contiguous bus address range.
>    

No, the kernel driver.  It cannot allow userspace to enable bus 
mastering unless it knows the iommu is enabled for the device and remaps 
dma to user pages.


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

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