On Fri, 2015-10-16 at 16:03 +0200, Eric Auger wrote:
> Hi Alex,
> On 10/15/2015 10:52 PM, Alex Williamson wrote:
> > We can only provide isolation if DMA is forced through the IOMMU
> > aperture. Don't allow type1 to be used if this is not the case.
> >
> > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > ---
> >
> > Eric, I see a number of IOMMU drivers enable this, do the ones you
> > care about for ARM set geometry.force_aperture? Thanks,
> I am currently using arm-smmu.c. I don't see force_aperture being set.
Hi Will,
Would it be possible to add iommu_domain_geometry support to arm-smmu.c?
In addition to this test to verify that DMA cannot bypass the IOMMU, I'd
eventually like to pass the aperture information out through the VFIO
API. Thanks,
Alex
> > drivers/vfio/vfio_iommu_type1.c | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> > index 57d8c37..6afa9d4 100644
> > --- a/drivers/vfio/vfio_iommu_type1.c
> > +++ b/drivers/vfio/vfio_iommu_type1.c
> > @@ -728,6 +728,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> > struct vfio_group *group, *g;
> > struct vfio_domain *domain, *d;
> > struct bus_type *bus = NULL;
> > + struct iommu_domain_geometry geometry;
> > int ret;
> >
> > mutex_lock(&iommu->lock);
> > @@ -762,6 +763,17 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> > goto out_free;
> > }
> >
> > + /*
> > + * If a domain does not force DMA within the aperture, devices are not
> > + * isolated and type1 is not an appropriate IOMMU model.
> > + */
> > + ret = iommu_domain_get_attr(domain->domain,
> > + DOMAIN_ATTR_GEOMETRY, &geometry);
> > + if (ret || !geometry.force_aperture) {
> > + ret = -EPERM;
> > + goto out_domain;
> > + }
> > +
> > if (iommu->nesting) {
> > int attr = 1;
> >
> >
>
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