[PATCH RFC 08/11] iommu: Handle IO page faults directly

Lu Baolu
2022-03-20T06:44:39Z

Directly call the IO page fault handler in iommu_report_device_fault()
unless the device driver registered its own page fault handler. There
is no need to explicitly register the fault handler in IOMMU drivers.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 13 +------------
drivers/iommu/intel/iommu.c | 14 ++------------
drivers/iommu/iommu.c | 11 ++++++++---
3 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 3537a2291d7c..8497425f3c13 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -426,7 +426,6 @@ bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)

static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
{
- int ret;
struct device *dev = master->dev;

/*
@@ -439,16 +438,7 @@ static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
if (!master->iopf_enabled)
return -EINVAL;

- ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
- if (ret)
- return ret;
-
- ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
- if (ret) {
- iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
- return ret;
- }
- return 0;
+ return iopf_queue_add_device(master->smmu->evtq.iopf, dev);
}

static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
@@ -458,7 +448,6 @@ static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
if (!master->iopf_enabled)
return;

- iommu_unregister_device_fault_handler(dev);
iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
}

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 8781305b9a02..8f9cc66787c3 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4760,7 +4760,6 @@ static int intel_iommu_enable_sva(struct device *dev)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
struct intel_iommu *iommu;
- int ret;

if (!info || dmar_disabled)
return -EINVAL;
@@ -4778,24 +4777,15 @@ static int intel_iommu_enable_sva(struct device *dev)
if (!info->pasid_enabled || !info->pri_enabled || !info->ats_enabled)
return -EINVAL;

- ret = iopf_queue_add_device(iommu->iopf_queue, dev);
- if (!ret)
- ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
-
- return ret;
+ return iopf_queue_add_device(iommu->iopf_queue, dev);
}

static int intel_iommu_disable_sva(struct device *dev)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
struct intel_iommu *iommu = info->iommu;
- int ret;
-
- ret = iommu_unregister_device_fault_handler(dev);
- if (!ret)
- ret = iopf_queue_remove_device(iommu->iopf_queue, dev);

- return ret;
+ return iopf_queue_remove_device(iommu->iopf_queue, dev);
}

static int intel_iommu_enable_iopf(struct device *dev)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c0966fc9b686..4f90b71c6f6e 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -27,6 +27,8 @@
#include <linux/cc_platform.h>
#include <trace/events/iommu.h>

+#include "iommu-sva-lib.h"
+
static struct kset *iommu_group_kset;
static DEFINE_IDA(iommu_group_ida);

@@ -1177,10 +1179,9 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
if (!param || !evt)
return -EINVAL;

- /* we only report device fault if there is a handler registered */
mutex_lock(&param->lock);
fparam = param->fault_param;
- if (!fparam || !fparam->handler) {
+ if (!fparam) {
ret = -EINVAL;
goto done_unlock;
}
@@ -1198,7 +1199,11 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
mutex_unlock(&fparam->lock);
}

- ret = fparam->handler(&evt->fault, fparam->data);
+ if (fparam->handler)
+ ret = fparam->handler(&evt->fault, fparam->data);
+ else
+ ret = iommu_queue_iopf(&evt->fault, fparam->data);
+
if (ret && evt_pending) {
mutex_lock(&fparam->lock);
list_del(&evt_pending->list);
--
2.25.1