iommu/vt-d: Allow SVA with device-specific IOPF

Currently enabling SVA requires IOPF support from the IOMMU and device
PCI PRI. However, some devices can handle IOPF by itself without ever
sending PCI page requests nor advertising PRI capability.

Allow SVA support with IOPF handled either by IOMMU (PCI PRI) or device
driver (device-specific IOPF). As long as IOPF could be handled, SVA
should continue to work.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20230324120234.313643-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 7c2f4bd335823c7bc516c013f401443d552cc902..caf664448ee9511cb164d5ae51c10236480c24b7 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4650,7 +4650,21 @@ static int intel_iommu_enable_sva(struct device *dev)
        if (!(iommu->flags & VTD_FLAG_SVM_CAPABLE))
                return -ENODEV;
 
-       if (!info->pasid_enabled || !info->pri_enabled || !info->ats_enabled)
+       if (!info->pasid_enabled || !info->ats_enabled)
+               return -EINVAL;
+
+       /*
+        * Devices having device-specific I/O fault handling should not
+        * support PCI/PRI. The IOMMU side has no means to check the
+        * capability of device-specific IOPF.  Therefore, IOMMU can only
+        * default that if the device driver enables SVA on a non-PRI
+        * device, it will handle IOPF in its own way.
+        */
+       if (!info->pri_supported)
+               return 0;
+
+       /* Devices supporting PRI should have it enabled. */
+       if (!info->pri_enabled)
                return -EINVAL;
 
        ret = iopf_queue_add_device(iommu->iopf_queue, dev);