[PATCH 3/3] iommu: Allow drivers to say if they use report_iommu_fault()

Jason Gunthorpe
2025-10-22T17:13:02Z

report_iommu_fault() is an older API that has been superseded by
iommu_report_device_fault() which is capable to support PRI.

Only two external drivers consume this, drivers/remoteproc and
drivers/gpu/drm/msm. Ideally they would move over to the new APIs, but for
now protect against accidentally mix and matching the wrong components.

The iommu drivers support either the old iommu_set_fault_handler() via the
driver calling report_iommu_fault(), or they are newer server focused
drivers that call iommu_report_device_fault().

Include a flag in the domain_ops if it calls report_iommu_fault() and
block iommu_set_fault_handler() on iommu's that can't support it.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 1 +
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 1 +
drivers/iommu/iommu.c | 6 +++++-
drivers/iommu/ipmmu-vmsa.c | 1 +
drivers/iommu/mtk_iommu.c | 1 +
drivers/iommu/mtk_iommu_v1.c | 1 +
drivers/iommu/omap-iommu.c | 1 +
drivers/iommu/rockchip-iommu.c | 1 +
drivers/iommu/sun50i-iommu.c | 1 +
include/linux/iommu.h | 3 +++
10 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 4ced4b5bee4df3..5ce8f82ddb534b 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1644,6 +1644,7 @@ static const struct iommu_ops arm_smmu_ops = {
.def_domain_type = arm_smmu_def_domain_type,
.owner = THIS_MODULE,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = arm_smmu_attach_dev,
.map_pages = arm_smmu_map_pages,
.unmap_pages = arm_smmu_unmap_pages,
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index c5be95e560317e..3163a23fcbaa4f 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -598,6 +598,7 @@ static const struct iommu_ops qcom_iommu_ops = {
.device_group = generic_device_group,
.of_xlate = qcom_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = qcom_iommu_attach_dev,
.map_pages = qcom_iommu_map,
.unmap_pages = qcom_iommu_unmap,
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 59244c744eabd2..34546a70fb5279 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2005,6 +2005,9 @@ EXPORT_SYMBOL_GPL(iommu_group_has_isolated_msi);
* This function should be used by IOMMU users which want to be notified
* whenever an IOMMU fault happens.
*
+ * This is a legacy API not supported by all drivers. New users should look
+ * to using domain->iopf_handler for the modern API.
+ *
* The fault handler itself should return 0 on success, and an appropriate
* error code otherwise.
*/
@@ -2012,7 +2015,8 @@ void iommu_set_fault_handler(struct iommu_domain *domain,
iommu_fault_handler_t handler,
void *token)
{
- if (WARN_ON(!domain || domain->cookie_type != IOMMU_COOKIE_NONE))
+ if (WARN_ON(!domain || domain->cookie_type != IOMMU_COOKIE_NONE ||
+ !domain->ops->report_iommu_fault_supported))
return;

domain->cookie_type = IOMMU_COOKIE_FAULT_HANDLER;
diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index ffa892f6571406..770fa248e30477 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -885,6 +885,7 @@ static const struct iommu_ops ipmmu_ops = {
? generic_device_group : generic_single_device_group,
.of_xlate = ipmmu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = ipmmu_attach_device,
.map_pages = ipmmu_map,
.unmap_pages = ipmmu_unmap,
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0e0285348d2b8e..0f44993eaadce3 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1019,6 +1019,7 @@ static const struct iommu_ops mtk_iommu_ops = {
.get_resv_regions = mtk_iommu_get_resv_regions,
.owner = THIS_MODULE,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = mtk_iommu_attach_device,
.map_pages = mtk_iommu_map,
.unmap_pages = mtk_iommu_unmap,
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 10cc0b1197e801..279e7acfd5c6d3 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -582,6 +582,7 @@ static const struct iommu_ops mtk_iommu_v1_ops = {
.device_group = generic_device_group,
.owner = THIS_MODULE,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = mtk_iommu_v1_attach_device,
.map_pages = mtk_iommu_v1_map,
.unmap_pages = mtk_iommu_v1_unmap,
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 5c6f5943f44b1f..3f3193de3ecd86 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1724,6 +1724,7 @@ static const struct iommu_ops omap_iommu_ops = {
.device_group = generic_single_device_group,
.of_xlate = omap_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = omap_iommu_attach_dev,
.map_pages = omap_iommu_map,
.unmap_pages = omap_iommu_unmap,
diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 0861dd469bd866..0053f5aa2cb781 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1174,6 +1174,7 @@ static const struct iommu_ops rk_iommu_ops = {
.device_group = generic_single_device_group,
.of_xlate = rk_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = rk_iommu_attach_device,
.map_pages = rk_iommu_map,
.unmap_pages = rk_iommu_unmap,
diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index de10b569d9a940..29b230050906a2 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -849,6 +849,7 @@ static const struct iommu_ops sun50i_iommu_ops = {
.of_xlate = sun50i_iommu_of_xlate,
.probe_device = sun50i_iommu_probe_device,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .report_iommu_fault_supported = true,
.attach_dev = sun50i_iommu_attach_device,
.flush_iotlb_all = sun50i_iommu_flush_iotlb_all,
.iotlb_sync_map = sun50i_iommu_iotlb_sync_map,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index c30d12e16473df..e2bf7885287fac 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -714,6 +714,8 @@ struct iommu_ops {

/**
* struct iommu_domain_ops - domain specific operations
+ * @report_iommu_fault_supported: True if the domain supports
+ * iommu_set_fault_handler()
* @attach_dev: attach an iommu domain to a device
* Return:
* * 0 - success
@@ -751,6 +753,7 @@ struct iommu_ops {
* @free: Release the domain after use.
*/
struct iommu_domain_ops {
+ bool report_iommu_fault_supported : 1;
int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
int (*set_dev_pasid)(struct iommu_domain *domain, struct device *dev,
ioasid_t pasid, struct iommu_domain *old);
--
2.43.0