vfio: Move the IOMMU_CAP_CACHE_COHERENCY check in __vfio_register_dev()

The IOMMU_CAP_CACHE_COHERENCY check only applies to the physical devices
that are IOMMU-backed. But it is now in the group code. If want to compile
vfio_group infrastructure out, this check needs to be moved out of the group
code.

Another reason for this change is to fail the device registration for the
physical devices that do not have IOMMU if the group code is not compiled
as the cdev interface does not support such devices.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-25-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
index 5c17ad81231374eec268ddaf1642b5d0b10108f6..610a429c61912568e35dba0431923f393afe718f 100644 (file)
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -682,16 +682,6 @@ static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
        if (!iommu_group)
                return ERR_PTR(-EINVAL);
 
-       /*
-        * VFIO always sets IOMMU_CACHE because we offer no way for userspace to
-        * restore cache coherency. It has to be checked here because it is only
-        * valid for cases where we are using iommu groups.
-        */
-       if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY)) {
-               iommu_group_put(iommu_group);
-               return ERR_PTR(-EINVAL);
-       }
-
        mutex_lock(&vfio.group_lock);
        group = vfio_group_find_from_iommu(iommu_group);
        if (group) {

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index ba1d84afe0816f281ed976a851f3ec100220eb77..902f06e52c4832f6a63a4a2ecc7b6605fddd8f24 100644 (file)
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -292,6 +292,17 @@ static int __vfio_register_dev(struct vfio_device *device,
        if (ret)
                return ret;
 
+       /*
+        * VFIO always sets IOMMU_CACHE because we offer no way for userspace to
+        * restore cache coherency. It has to be checked here because it is only
+        * valid for cases where we are using iommu groups.
+        */
+       if (type == VFIO_IOMMU && !vfio_device_is_noiommu(device) &&
+           !device_iommu_capable(device->dev, IOMMU_CAP_CACHE_COHERENCY)) {
+               ret = -EINVAL;
+               goto err_out;
+       }
+
        ret = vfio_device_add(device);
        if (ret)
                goto err_out;