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iommu/vt-d: Only handle IOPF for SVA when PRI is supported

PATCH In review Lu Baolu 2 participants 3 messages Mar 10 – Mar 17

Subsystems (3)
Stable branch IOMMU Intel IOMMU (VT-d)
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Lu Baolu

author maintainer
#0 lore raw

PATCH 1/1 iommu/vt-d: Only handle IOPF for SVA when PRI is supported

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 [email protected]
Suggested-by Kevin Tian <[email protected]>
Signed-off-by Lu Baolu <[email protected]>
---
 drivers/iommu/intel/svm.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
drivers/iommu/intel/svm.c +8 -4
index fea10acd4f02..57cd1db7207a 100644
@@ -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;
Signature · 1 line
2.43.0
Reviewed-by on v1 1/1
#1 lore raw
Quoted 15 lines

From: Lu Baolu <[email protected]>
Sent: Tuesday, March 10, 2026 3:55 PM

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.

Quoted 5 lines
Fixes 17fce9d2336d ("iommu/vt-d: Put iopf enablement in domain attach

path")

Cc [email protected]
Suggested-by Kevin Tian <[email protected]>
Signed-off-by Lu Baolu <[email protected]>
Reviewed-by Kevin Tian <[email protected]>
author maintainer
#2 lore raw
In reply to Lu Baolu
Quoted 12 lines · 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.

Quoted 7 lines
Fixes 17fce9d2336d ("iommu/vt-d: Put iopf enablement in domain attach path")
Cc [email protected]
Suggested-by Kevin Tian<[email protected]>
Signed-off-by Lu Baolu<[email protected]>
---
  drivers/iommu/intel/svm.c | 12 ++++++++----
  1 file changed, 8 insertions(+), 4 deletions(-)

Queued for v7.0-rc.