The vfio No-IOMMU mode was supported by this
'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")',
but it only support vfio-pci.
Using vfio_iommu_group_get/put, but not iommu_group_get/put,
the platform devices can be exposed to userspace with
CONFIG_VFIO_NOIOMMU and the "enable_unsafe_noiommu_mode"
option enabled.
>From 'commit 03a76b60f8ba2797 ("vfio: Include No-IOMMU mode")',
"This should make it very clear that this mode is not safe.
Additionally, CAP_SYS_RAWIO privileges are necessary to work
with groups and containers using this mode. Groups making
use of this support are named /dev/vfio/noiommu-$GROUP and
can only make use of the special VFIO_NOIOMMU_IOMMU for the
container. Use of this mode, specifically binding a device
without a native IOMMU group to a VFIO bus driver will taint
the kernel and should therefore not be considered supported.",
Actually, for vfio-platform No-IOMMU mode, the userspace can
not do DMA, because the ioctl API of noiommu container only
supports VFIO_CHECK_EXTENSION and VFIO_IOMMU_MAP_DMA is not
supported.
Signed-off-by: Peng Fan <van.freenix@xxxxxxxxx>
Cc: Eric Auger <eric.auger@xxxxxxxxxx>
Cc: Baptiste Reynal <b.reynal@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
V2:
Rename subject to support No-IOMMU
Add more commit log.
I wrote a simple program following this
https://github.com/virtualopensystems/vfio-host-test/blob/master/src_test/vfio_device_test.c
,no dma support. The device's register can be
accessed in userspace using command './vfio_dev_test 30b60000.usdhc 0 1 platform'
drivers/vfio/platform/vfio_platform_common.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index e65b142..993b2f9 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -561,7 +561,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
vdev->device = dev;
- group = iommu_group_get(dev);
+ group = vfio_iommu_group_get(dev);
if (!group) {
pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);
return -EINVAL;
@@ -569,7 +569,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
if (ret) {
- iommu_group_put(group);
+ vfio_iommu_group_put(group, dev);
return ret;
}
@@ -589,7 +589,7 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
if (vdev) {
vfio_platform_put_reset(vdev);
- iommu_group_put(dev->iommu_group);
+ vfio_iommu_group_put(dev->iommu_group, dev);
}
return vdev;
--
2.6.2
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