[PATCH v12 15/16] iommu: Make iopf_group_response() return void

Lu Baolu
2024-02-07T01:40:21Z

The iopf_group_response() should return void, as nothing can do anything
with the failure. This implies that ops->page_response() must also return
void; this is consistent with what the drivers do. The failure paths,
which are all integrity validations of the fault, should be WARN_ON'd,
not return codes.

If the iommu core fails to enqueue the fault, it should respond the fault
directly by calling ops->page_response() instead of returning an error
number and relying on the iommu drivers to do so. Consolidate the error
fault handling code in the core.

Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
include/linux/iommu.h | 14 +-
drivers/iommu/intel/iommu.h | 4 +-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 50 +++-----
drivers/iommu/intel/svm.c | 18 +--
drivers/iommu/io-pgfault.c | 134 +++++++++++---------
5 files changed, 99 insertions(+), 121 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f8ed1cc7212e..f632775414a5 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -574,9 +574,8 @@ struct iommu_ops {
int (*dev_enable_feat)(struct device *dev, enum iommu_dev_features f);
int (*dev_disable_feat)(struct device *dev, enum iommu_dev_features f);

- int (*page_response)(struct device *dev,
- struct iopf_fault *evt,
- struct iommu_page_response *msg);
+ void (*page_response)(struct device *dev, struct iopf_fault *evt,
+ struct iommu_page_response *msg);

int (*def_domain_type)(struct device *dev);
void (*remove_dev_pasid)(struct device *dev, ioasid_t pasid);
@@ -1547,8 +1546,8 @@ void iopf_queue_free(struct iopf_queue *queue);
int iopf_queue_discard_partial(struct iopf_queue *queue);
void iopf_free_group(struct iopf_group *group);
int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt);
-int iopf_group_response(struct iopf_group *group,
- enum iommu_page_response_code status);
+void iopf_group_response(struct iopf_group *group,
+ enum iommu_page_response_code status);
#else
static inline int
iopf_queue_add_device(struct iopf_queue *queue, struct device *dev)
@@ -1590,10 +1589,9 @@ iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
return -ENODEV;
}

-static inline int iopf_group_response(struct iopf_group *group,
- enum iommu_page_response_code status)
+static inline void iopf_group_response(struct iopf_group *group,
+ enum iommu_page_response_code status)
{
- return -ENODEV;
}
#endif /* CONFIG_IOMMU_IOPF */
#endif /* __LINUX_IOMMU_H */
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 696d95293a69..cf9a28c7fab8 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -1079,8 +1079,8 @@ struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain *parent,
void intel_svm_check(struct intel_iommu *iommu);
int intel_svm_enable_prq(struct intel_iommu *iommu);
int intel_svm_finish_prq(struct intel_iommu *iommu);
-int intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
- struct iommu_page_response *msg);
+void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
+ struct iommu_page_response *msg);
struct iommu_domain *intel_svm_domain_alloc(void);
void intel_svm_remove_dev_pasid(struct device *dev, ioasid_t pasid);
void intel_drain_pasid_prq(struct device *dev, u32 pasid);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 4e93e845458c..42eb59cb99f4 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -920,31 +920,29 @@ static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
return arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmds, cmds->num, true);
}

-static int arm_smmu_page_response(struct device *dev,
- struct iopf_fault *unused,
- struct iommu_page_response *resp)
+static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused,
+ struct iommu_page_response *resp)
{
struct arm_smmu_cmdq_ent cmd = {0};
struct arm_smmu_master *master = dev_iommu_priv_get(dev);
int sid = master->streams[0].id;

- if (master->stall_enabled) {
- cmd.opcode = CMDQ_OP_RESUME;
- cmd.resume.sid = sid;
- cmd.resume.stag = resp->grpid;
- switch (resp->code) {
- case IOMMU_PAGE_RESP_INVALID:
- case IOMMU_PAGE_RESP_FAILURE:
- cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT;
- break;
- case IOMMU_PAGE_RESP_SUCCESS:
- cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY;
- break;
- default:
- return -EINVAL;
- }
- } else {
- return -ENODEV;
+ if (WARN_ON(!master->stall_enabled))
+ return;
+
+ cmd.opcode = CMDQ_OP_RESUME;
+ cmd.resume.sid = sid;
+ cmd.resume.stag = resp->grpid;
+ switch (resp->code) {
+ case IOMMU_PAGE_RESP_INVALID:
+ case IOMMU_PAGE_RESP_FAILURE:
+ cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT;
+ break;
+ case IOMMU_PAGE_RESP_SUCCESS:
+ cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY;
+ break;
+ default:
+ break;
}

arm_smmu_cmdq_issue_cmd(master->smmu, &cmd);
@@ -954,8 +952,6 @@ static int arm_smmu_page_response(struct device *dev,
* terminated... at some point in the future. PRI_RESP is fire and
* forget.
*/
-
- return 0;
}

/* Context descriptor manipulation functions */
@@ -1516,16 +1512,6 @@ static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
}

ret = iommu_report_device_fault(master->dev, &fault_evt);
- if (ret && flt->type == IOMMU_FAULT_PAGE_REQ) {
- /* Nobody cared, abort the access */
- struct iommu_page_response resp = {
- .pasid = flt->prm.pasid,
- .grpid = flt->prm.grpid,
- .code = IOMMU_PAGE_RESP_FAILURE,
- };
- arm_smmu_page_response(master->dev, &fault_evt, &resp);
- }
-
out_unlock:
mutex_unlock(&smmu->streams_mutex);
return ret;
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index e1cbcb9515f0..2f8716636dbb 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -740,9 +740,8 @@ static irqreturn_t prq_event_thread(int irq, void *d)
return IRQ_RETVAL(handled);
}

-int intel_svm_page_response(struct device *dev,
- struct iopf_fault *evt,
- struct iommu_page_response *msg)
+void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
+ struct iommu_page_response *msg)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
struct intel_iommu *iommu = info->iommu;
@@ -751,7 +750,6 @@ int intel_svm_page_response(struct device *dev,
bool private_present;
bool pasid_present;
bool last_page;
- int ret = 0;
u16 sid;

prm = &evt->fault.prm;
@@ -760,16 +758,6 @@ int intel_svm_page_response(struct device *dev,
private_present = prm->flags & IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
last_page = prm->flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;

- if (!pasid_present) {
- ret = -EINVAL;
- goto out;
- }
-
- if (prm->pasid == 0 || prm->pasid >= PASID_MAX) {
- ret = -EINVAL;
- goto out;
- }
-
/*
* Per VT-d spec. v3.0 ch7.7, system software must respond
* with page group response if private data is present (PDP)
@@ -798,8 +786,6 @@ int intel_svm_page_response(struct device *dev,

qi_submit_sync(iommu, &desc, 1, 0);
}
-out:
- return ret;
}

static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index c001b9d3e6dd..89d290e8de5d 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -39,7 +39,7 @@ static void iopf_put_dev_fault_param(struct iommu_fault_param *fault_param)
kfree_rcu(fault_param, rcu);
}

-void iopf_free_group(struct iopf_group *group)
+static void __iopf_free_group(struct iopf_group *group)
{
struct iopf_fault *iopf, *next;

@@ -50,6 +50,11 @@ void iopf_free_group(struct iopf_group *group)

/* Pair with iommu_report_device_fault(). */
iopf_put_dev_fault_param(group->fault_param);
+}
+
+void iopf_free_group(struct iopf_group *group)
+{
+ __iopf_free_group(group);
kfree(group);
}
EXPORT_SYMBOL_GPL(iopf_free_group);
@@ -97,14 +102,49 @@ static int report_partial_fault(struct iommu_fault_param *fault_param,
return 0;
}

+static struct iopf_group *iopf_group_alloc(struct iommu_fault_param *iopf_param,
+ struct iopf_fault *evt,
+ struct iopf_group *abort_group)
+{
+ struct iopf_fault *iopf, *next;
+ struct iopf_group *group;
+
+ group = kzalloc(sizeof(*group), GFP_KERNEL);
+ if (!group) {
+ /*
+ * We always need to construct the group as we need it to abort
+ * the request at the driver if it can't be handled.
+ */
+ group = abort_group;
+ }
+
+ group->fault_param = iopf_param;
+ group->last_fault.fault = evt->fault;
+ INIT_LIST_HEAD(&group->faults);
+ INIT_LIST_HEAD(&group->pending_node);
+ list_add(&group->last_fault.list, &group->faults);
+
+ /* See if we have partial faults for this group */
+ mutex_lock(&iopf_param->lock);
+ list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) {
+ if (iopf->fault.prm.grpid == evt->fault.prm.grpid)
+ /* Insert *before* the last fault */
+ list_move(&iopf->list, &group->faults);
+ }
+ list_add(&group->pending_node, &iopf_param->faults);
+ mutex_unlock(&iopf_param->lock);
+
+ return group;
+}
+
/**
* iommu_report_device_fault() - Report fault event to device driver
* @dev: the device
* @evt: fault event data
*
* Called by IOMMU drivers when a fault is detected, typically in a threaded IRQ
- * handler. When this function fails and the fault is recoverable, it is the
- * caller's responsibility to complete the fault.
+ * handler. If this function fails then ops->page_response() was called to
+ * complete evt if required.
*
* This module doesn't handle PCI PASID Stop Marker; IOMMU drivers must discard
* them before reporting faults. A PASID Stop Marker (LRW = 0b100) doesn't
@@ -143,22 +183,18 @@ int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
{
struct iommu_fault *fault = &evt->fault;
struct iommu_fault_param *iopf_param;
- struct iopf_fault *iopf, *next;
- struct iommu_domain *domain;
+ struct iopf_group abort_group = {};
struct iopf_group *group;
int ret;

- if (fault->type != IOMMU_FAULT_PAGE_REQ)
- return -EOPNOTSUPP;
-
iopf_param = iopf_get_dev_fault_param(dev);
- if (!iopf_param)
+ if (WARN_ON(!iopf_param))
return -ENODEV;

if (!(fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) {
ret = report_partial_fault(iopf_param, fault);
iopf_put_dev_fault_param(iopf_param);
-
+ /* A request that is not the last does not need to be ack'd */
return ret;
}

@@ -170,56 +206,33 @@ int iommu_report_device_fault(struct device *dev, struct iopf_fault *evt)
* will send a response to the hardware. We need to clean up before
* leaving, otherwise partial faults will be stuck.
*/
- domain = get_domain_for_iopf(dev, fault);
- if (!domain) {
+ group = iopf_group_alloc(iopf_param, evt, &abort_group);
+ if (group == &abort_group) {
+ ret = -ENOMEM;
+ goto err_abort;
+ }
+
+ group->domain = get_domain_for_iopf(dev, fault);
+ if (!group->domain) {
ret = -EINVAL;
- goto cleanup_partial;
+ goto err_abort;
}

- group = kzalloc(sizeof(*group), GFP_KERNEL);
- if (!group) {
- ret = -ENOMEM;
- goto cleanup_partial;
- }
-
- group->fault_param = iopf_param;
- group->last_fault.fault = *fault;
- INIT_LIST_HEAD(&group->faults);
- INIT_LIST_HEAD(&group->pending_node);
- group->domain = domain;
- list_add(&group->last_fault.list, &group->faults);
-
- /* See if we have partial faults for this group */
- mutex_lock(&iopf_param->lock);
- list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) {
- if (iopf->fault.prm.grpid == fault->prm.grpid)
- /* Insert *before* the last fault */
- list_move(&iopf->list, &group->faults);
- }
- list_add(&group->pending_node, &iopf_param->faults);
- mutex_unlock(&iopf_param->lock);
+ /*
+ * On success iopf_handler must call iopf_group_response() and
+ * iopf_free_group()
+ */
+ ret = group->domain->iopf_handler(group);
+ if (ret)
+ goto err_abort;
+ return 0;

- ret = domain->iopf_handler(group);
- if (ret) {
- mutex_lock(&iopf_param->lock);
- list_del_init(&group->pending_node);
- mutex_unlock(&iopf_param->lock);
+err_abort:
+ iopf_group_response(group, IOMMU_PAGE_RESP_FAILURE);
+ if (group == &abort_group)
+ __iopf_free_group(group);
+ else
iopf_free_group(group);
- }
-
- return ret;
-
-cleanup_partial:
- mutex_lock(&iopf_param->lock);
- list_for_each_entry_safe(iopf, next, &iopf_param->partial, list) {
- if (iopf->fault.prm.grpid == fault->prm.grpid) {
- list_del(&iopf->list);
- kfree(iopf);
- }
- }
- mutex_unlock(&iopf_param->lock);
- iopf_put_dev_fault_param(iopf_param);
-
return ret;
}
EXPORT_SYMBOL_GPL(iommu_report_device_fault);
@@ -259,11 +272,9 @@ EXPORT_SYMBOL_GPL(iopf_queue_flush_dev);
* iopf_group_response - Respond a group of page faults
* @group: the group of faults with the same group id
* @status: the response code
- *
- * Return 0 on success and <0 on error.
*/
-int iopf_group_response(struct iopf_group *group,
- enum iommu_page_response_code status)
+void iopf_group_response(struct iopf_group *group,
+ enum iommu_page_response_code status)
{
struct iommu_fault_param *fault_param = group->fault_param;
struct iopf_fault *iopf = &group->last_fault;
@@ -274,17 +285,14 @@ int iopf_group_response(struct iopf_group *group,
.grpid = iopf->fault.prm.grpid,
.code = status,
};
- int ret = -EINVAL;

/* Only send response if there is a fault report pending */
mutex_lock(&fault_param->lock);
if (!list_empty(&group->pending_node)) {
- ret = ops->page_response(dev, &group->last_fault, &resp);
+ ops->page_response(dev, &group->last_fault, &resp);
list_del_init(&group->pending_node);
}
mutex_unlock(&fault_param->lock);
-
- return ret;
}
EXPORT_SYMBOL_GPL(iopf_group_response);

--
2.34.1