"attach_handle" was added exclusively for the iommufd_fault_iopf_handler()
used by IOPF/PRI use cases. Now, both the MSI and PASID series require to
reuse the attach_handle for non-fault cases.

Add a set of new attach/detach/replace helpers that does the attach_handle
allocation/releasing/replacement in the common path and also handles those
fault specific routines such as iopf enabling/disabling and auto response.

This covers both non-fault and fault cases in a clean way, replacing those
inline helpers in the header. The following patch will clean up those old
helpers in the fault.c file.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |  33 +-------
 drivers/iommu/iommufd/device.c          | 101 ++++++++++++++++++++++++
 drivers/iommu/iommufd/fault.c           |   8 +-
 3 files changed, 109 insertions(+), 33 deletions(-)

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 0b1bafc7fd99..02fe1ada97cc 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -504,35 +504,10 @@ int iommufd_fault_domain_replace_dev(struct iommufd_device *idev,
 				     struct iommufd_hw_pagetable *hwpt,
 				     struct iommufd_hw_pagetable *old);
 
-static inline int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
-					     struct iommufd_device *idev)
-{
-	if (hwpt->fault)
-		return iommufd_fault_domain_attach_dev(hwpt, idev);
-
-	return iommu_attach_group(hwpt->domain, idev->igroup->group);
-}
-
-static inline void iommufd_hwpt_detach_device(struct iommufd_hw_pagetable *hwpt,
-					      struct iommufd_device *idev)
-{
-	if (hwpt->fault) {
-		iommufd_fault_domain_detach_dev(hwpt, idev);
-		return;
-	}
-
-	iommu_detach_group(hwpt->domain, idev->igroup->group);
-}
-
-static inline int iommufd_hwpt_replace_device(struct iommufd_device *idev,
-					      struct iommufd_hw_pagetable *hwpt,
-					      struct iommufd_hw_pagetable *old)
-{
-	if (old->fault || hwpt->fault)
-		return iommufd_fault_domain_replace_dev(idev, hwpt, old);
-
-	return iommu_group_replace_domain(idev->igroup->group, hwpt->domain);
-}
+int iommufd_fault_iopf_enable(struct iommufd_device *idev);
+void iommufd_fault_iopf_disable(struct iommufd_device *idev);
+void iommufd_auto_response_faults(struct iommufd_hw_pagetable *hwpt,
+				  struct iommufd_attach_handle *handle);
 
 static inline struct iommufd_viommu *
 iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index dfd0898fb6c1..360ba3ed8545 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -352,6 +352,107 @@ iommufd_device_attach_reserved_iova(struct iommufd_device *idev,
 	return 0;
 }
 
+/* The device attach/detach/replace helpers for attach_handle */
+
+static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
+				      struct iommufd_device *idev)
+{
+	struct iommufd_attach_handle *handle;
+	int rc;
+
+	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
+	if (!handle)
+		return -ENOMEM;
+
+	if (hwpt->fault) {
+		rc = iommufd_fault_iopf_enable(idev);
+		if (rc)
+			goto out_free_handle;
+	}
+
+	handle->idev = idev;
+	rc = iommu_attach_group_handle(hwpt->domain, idev->igroup->group,
+				       &handle->handle);
+	if (rc)
+		goto out_disable_iopf;
+
+	return 0;
+
+out_disable_iopf:
+	if (hwpt->fault)
+		iommufd_fault_iopf_disable(idev);
+out_free_handle:
+	kfree(handle);
+	return rc;
+}
+
+static struct iommufd_attach_handle *
+iommufd_device_get_attach_handle(struct iommufd_device *idev)
+{
+	struct iommu_attach_handle *handle;
+
+	handle =
+		iommu_attach_handle_get(idev->igroup->group, IOMMU_NO_PASID, 0);
+	if (IS_ERR(handle))
+		return NULL;
+	return to_iommufd_handle(handle);
+}
+
+static void iommufd_hwpt_detach_device(struct iommufd_hw_pagetable *hwpt,
+				       struct iommufd_device *idev)
+{
+	struct iommufd_attach_handle *handle;
+
+	handle = iommufd_device_get_attach_handle(idev);
+	iommu_detach_group_handle(hwpt->domain, idev->igroup->group);
+	if (hwpt->fault) {
+		iommufd_auto_response_faults(hwpt, handle);
+		iommufd_fault_iopf_disable(idev);
+	}
+	kfree(handle);
+}
+
+static int iommufd_hwpt_replace_device(struct iommufd_device *idev,
+				       struct iommufd_hw_pagetable *hwpt,
+				       struct iommufd_hw_pagetable *old)
+{
+	struct iommufd_attach_handle *handle, *old_handle =
+		iommufd_device_get_attach_handle(idev);
+	int rc;
+
+	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
+	if (!handle)
+		return -ENOMEM;
+
+	if (hwpt->fault && !old->fault) {
+		rc = iommufd_fault_iopf_enable(idev);
+		if (rc)
+			goto out_free_handle;
+	}
+
+	handle->idev = idev;
+	rc = iommu_replace_group_handle(idev->igroup->group, hwpt->domain,
+					&handle->handle);
+	if (rc)
+		goto out_disable_iopf;
+
+	if (old->fault) {
+		iommufd_auto_response_faults(hwpt, old_handle);
+		if (!hwpt->fault)
+			iommufd_fault_iopf_disable(idev);
+	}
+	kfree(old_handle);
+
+	return 0;
+
+out_disable_iopf:
+	if (hwpt->fault && !old->fault)
+		iommufd_fault_iopf_disable(idev);
+out_free_handle:
+	kfree(handle);
+	return rc;
+}
+
 int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
 				struct iommufd_device *idev)
 {
diff --git a/drivers/iommu/iommufd/fault.c b/drivers/iommu/iommufd/fault.c
index d9a937450e55..cb844e6799d4 100644
--- a/drivers/iommu/iommufd/fault.c
+++ b/drivers/iommu/iommufd/fault.c
@@ -17,7 +17,7 @@
 #include "../iommu-priv.h"
 #include "iommufd_private.h"
 
-static int iommufd_fault_iopf_enable(struct iommufd_device *idev)
+int iommufd_fault_iopf_enable(struct iommufd_device *idev)
 {
 	struct device *dev = idev->dev;
 	int ret;
@@ -50,7 +50,7 @@ static int iommufd_fault_iopf_enable(struct iommufd_device *idev)
 	return ret;
 }
 
-static void iommufd_fault_iopf_disable(struct iommufd_device *idev)
+void iommufd_fault_iopf_disable(struct iommufd_device *idev)
 {
 	mutex_lock(&idev->iopf_lock);
 	if (!WARN_ON(idev->iopf_enabled == 0)) {
@@ -98,8 +98,8 @@ int iommufd_fault_domain_attach_dev(struct iommufd_hw_pagetable *hwpt,
 	return ret;
 }
 
-static void iommufd_auto_response_faults(struct iommufd_hw_pagetable *hwpt,
-					 struct iommufd_attach_handle *handle)
+void iommufd_auto_response_faults(struct iommufd_hw_pagetable *hwpt,
+				  struct iommufd_attach_handle *handle)
 {
 	struct iommufd_fault *fault = hwpt->fault;
 	struct iopf_group *group, *next;
-- 
2.43.0

On Mon, Feb 03, 2025 at 09:00:54PM -0800, Nicolin Chen wrote:
> "attach_handle" was added exclusively for the iommufd_fault_iopf_handler()
> used by IOPF/PRI use cases. Now, both the MSI and PASID series require to
> reuse the attach_handle for non-fault cases.
> 
> Add a set of new attach/detach/replace helpers that does the attach_handle
> allocation/releasing/replacement in the common path and also handles those
> fault specific routines such as iopf enabling/disabling and auto response.
> 
> This covers both non-fault and fault cases in a clean way, replacing those
> inline helpers in the header. The following patch will clean up those old
> helpers in the fault.c file.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  drivers/iommu/iommufd/iommufd_private.h |  33 +-------
>  drivers/iommu/iommufd/device.c          | 101 ++++++++++++++++++++++++
>  drivers/iommu/iommufd/fault.c           |   8 +-
>  3 files changed, 109 insertions(+), 33 deletions(-)

I am going to add some lockdeps to this:

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 360ba3ed85455e..0786290b4056df 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -360,6 +360,8 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt,
 	struct iommufd_attach_handle *handle;
 	int rc;
 
+	lockdep_assert_held(&idev->igroup->lock);
+
 	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
 	if (!handle)
 		return -ENOMEM;
@@ -391,6 +393,8 @@ iommufd_device_get_attach_handle(struct iommufd_device *idev)
 {
 	struct iommu_attach_handle *handle;
 
+	lockdep_assert_held(&idev->igroup->lock);
+
 	handle =
 		iommu_attach_handle_get(idev->igroup->group, IOMMU_NO_PASID, 0);
 	if (IS_ERR(handle))


I think the one in get_attach_handle is important to discourage misuse
of that ..

Thanks,
Jason

On 2025/2/4 13:00, Nicolin Chen wrote:
> "attach_handle" was added exclusively for the iommufd_fault_iopf_handler()
> used by IOPF/PRI use cases. Now, both the MSI and PASID series require to
> reuse the attach_handle for non-fault cases.
> 
> Add a set of new attach/detach/replace helpers that does the attach_handle
> allocation/releasing/replacement in the common path and also handles those
> fault specific routines such as iopf enabling/disabling and auto response.
> 
> This covers both non-fault and fault cases in a clean way, replacing those
> inline helpers in the header. The following patch will clean up those old
> helpers in the fault.c file.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>   drivers/iommu/iommufd/iommufd_private.h |  33 +-------
>   drivers/iommu/iommufd/device.c          | 101 ++++++++++++++++++++++++
>   drivers/iommu/iommufd/fault.c           |   8 +-
>   3 files changed, 109 insertions(+), 33 deletions(-)

Reviewed-by: Yi Liu <yi.l.liu@intel.com>


-- 
Regards,
Yi Liu