Re: [PATCH v3 0/6] ATS capability support for Intel IOMMU

[Greg KH <greg@kroah.com>]

On Thu, Feb 26, 2009 at 10:50:35AM +0800, Yu Zhao wrote:
> On Sun, Feb 15, 2009 at 06:59:10AM +0800, Grant Grundler wrote:
> > On Thu, Feb 12, 2009 at 08:50:32PM +0800, Yu Zhao wrote:
> > > This patch series implements Address Translation Service support for
> > > the Intel IOMMU. ATS makes the PCI Endpoint be able to request the
> > > DMA address translation from the IOMMU and cache the translation in
> > > the Endpoint, thus alleviate IOMMU pressure and improve the hardware
> > > performance in the I/O virtualization environment.
> > > 
> > > 
> > > Changelog: v2 -> v3
> > >   1, throw error message if VT-d hardware detects invalid descriptor
> > >      on Queued Invalidation interface (David Woodhouse)
> > >   2, avoid using pci_find_ext_capability every time when reading ATS
> > >      Invalidate Queue Depth (Matthew Wilcox)
> > > Changelog: v1 -> v2
> > >   added 'static' prefix to a local LIST_HEAD (Andrew Morton)
> > > 
> > > 
> > > Yu Zhao (6):
> > >   PCI: support the ATS capability
> > >   VT-d: parse ATSR in DMA Remapping Reporting Structure
> > >   VT-d: add queue invalidation fault status support
> > >   VT-d: add device IOTLB invalidation support
> > >   VT-d: cleanup iommu_flush_iotlb_psi and flush_unmaps
> > >   VT-d: support the device IOTLB
> > > 
> > >  drivers/pci/dmar.c           |  230 ++++++++++++++++++++++++++++++++++++++----
> > 
> > Yu,
> > Can you please add something to Documentation/PCI/pci.txt?
> > New API I'm seeing are:
> > +extern int pci_enable_ats(struct pci_dev *dev, int ps);
> > +extern void pci_disable_ats(struct pci_dev *dev);
> > +extern int pci_ats_queue_depth(struct pci_dev *dev);
> 
> Yes, I'll document these new API.
> 
> > Do these also need to be EXPORT_SYMBOL_GPL() as well?
> > Or are drivers never expected to call the above?
> 
> PCI device driver shouldn't use these API, only IOMMU driver (can't be module)
> would use them. Anyway it's a good idea to export them :-)

Don't export them if no one is using them, that's just a waste of space.

thanks,

greg k-h