Re: [Qemu-devel] Supporting emulation of IOMMUs

[Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>]

On Tue, May 10, 2011 at 11:44:26AM +1000, David Gibson wrote:
> On Thu, Apr 21, 2011 at 09:47:31PM +0300, Eduard - Gabriel Munteanu wrote:
> > On Thu, Apr 21, 2011 at 05:03:47PM +1000, David Gibson wrote:
> > > A few months ago, Eduard - Gabriel Munteanu posted a series of patches
> > > implementing support for emulating the AMD PCI IOMMU
> > > (http://lists.nongnu.org/archive/html/qemu-devel/2011-01/msg03196.html).
> > > 
> > > In fact, this series implemented a general DMA/IOMMU layer which can
> > > be used by any device model, and one translation backend for this
> > > implementing the AMD specific PCI IOMMU.
> > > 
> > > These patches don't seem to have gone anywhere for the last few
> > > months, however, and so far I've been unable to contact the author
> > > (trying again with this mail).
> > > 
> > > I have an interest in this code, because the pSeries machine will also
> > > need IOMMU emulation support.  At present we only support virtual
> > > devices, through the PAPR interface, and we have support for the
> > > hypervisor-controller IOMMU translation in the PAPR VIO code.
> > > However, we want to add PCI device support and this will also need
> > > IOMMU translation.
> > > 
> > > The series seems to have the right basic approach, so if the author is
> > > indeed MIA, I was planning to pick up the patches and resubmit them
> > > (with support for the pSeries IOMMU added).
> > 
> > Hi,
> > 
> > Not really MIA, but I've been a bit busy lately, so I'm sorry if I
> > couldn't answer your mail in a timely fashion.
> > 
> > I'll try making another merge attempt tonight/tomorrow.
> 
> Ok.  Did this happen?  Sorry, I've been away the last couple of weeks
> - I had a google at the qemu-devel archives but couldn't spot a new
> merge, but did I just not look hard enough?

[snip]

No, I've made some progress but I've still got a few concerns to
address, mainly how to handle unaligned accesses and some things related
to the IOMMU behavior like target aborts.

I've added some macro magic to declare bus-specific interfaces and
converted PCI devices to use pci_memory_*().

I'll try not to hold this back too much, but I can't make promises wrt
timing.


	Eduard