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Re: [Qemu-devel] [PATCH 01/13] driver core: Add iommu_group tracking to
From: |
Greg KH |
Subject: |
Re: [Qemu-devel] [PATCH 01/13] driver core: Add iommu_group tracking to struct device |
Date: |
Fri, 11 May 2012 17:00:40 -0700 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, May 11, 2012 at 05:58:01PM -0600, Alex Williamson wrote:
> On Fri, 2012-05-11 at 16:38 -0700, Greg KH wrote:
> > On Fri, May 11, 2012 at 04:55:35PM -0600, Alex Williamson wrote:
> > > IOMMU groups allow IOMMU drivers to represent DMA visibility
> > > and isolation of devices. Multiple devices may be grouped
> > > together for the purposes of DMA. Placing a pointer on
> > > struct device enable easy access for things like streaming
> > > DMA programming and drivers like VFIO.
> > >
> > > Signed-off-by: Alex Williamson <address@hidden>
> >
> > Can't you get this today from the iommu_ops pointer that is on the bus
> > that the device is associated with? Or can devices on a bus have
> > different iommu_group pointers?
>
> The latter, each device on a bus might be it's own group. This is often
> the case on x86 unless PCIe-to-PCI bridges obscure the device
> visibility. Thanks,
Ah, ok, then I have no objection to add this to struct device:
Acked-by: Greg Kroah-Hartman <address@hidden>
[Qemu-devel] [PATCH 03/13] iommu: IOMMU groups for VT-d and AMD-Vi, Alex Williamson, 2012/05/11