[PATCH 2/2] iommu/vt-d: Only handle IOPF for SVA when PRI is supported

[Lu Baolu]

In intel_svm_set_dev_pasid(), the driver unconditionally manages the IOPF
handling during a domain transition. However, commit a86fb7717320
("iommu/vt-d: Allow SVA with device-specific IOPF") introduced support for
SVA on devices that handle page faults internally without utilizing the
PCI PRI. On such devices, the IOMMU-side IOPF infrastructure is not
required. Calling iopf_for_domain_replace() on these devices is incorrect
and can lead to unexpected failures during PASID attachment or unwinding.

Add a check for info->pri_supported to ensure that the IOPF queue logic
is only invoked for devices that actually rely on the IOMMU's PRI-based
fault handling.

Fixes: 17fce9d2336d ("iommu/vt-d: Put iopf enablement in domain attach path")
Cc: stable@xxxxxxxxxxxxxxx
Suggested-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20260310075520.295104-1-baolu.lu@xxxxxxxxxxxxxxx
---
 drivers/iommu/intel/svm.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index fea10acd4f02..57cd1db7207a 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -164,9 +164,12 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 	if (IS_ERR(dev_pasid))
 		return PTR_ERR(dev_pasid);
 
-	ret = iopf_for_domain_replace(domain, old, dev);
-	if (ret)
-		goto out_remove_dev_pasid;
+	/* SVA with non-IOMMU/PRI IOPF handling is allowed. */
+	if (info->pri_supported) {
+		ret = iopf_for_domain_replace(domain, old, dev);
+		if (ret)
+			goto out_remove_dev_pasid;
+	}
 
 	/* Setup the pasid table: */
 	sflags = cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
@@ -181,7 +184,8 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
 
 	return 0;
 out_unwind_iopf:
-	iopf_for_domain_replace(old, domain, dev);
+	if (info->pri_supported)
+		iopf_for_domain_replace(old, domain, dev);
 out_remove_dev_pasid:
 	domain_remove_dev_pasid(domain, dev, pasid);
 	return ret;
-- 
2.43.0