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,
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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