[PATCH 06/10] iommu/ioasid: Convert to set aware allocations

From: Jacob Pan
Date: Wed Mar 25 2020 - 13:49:53 EST

The current ioasid_alloc function takes a token/ioasid_set then record it
on the IOASID being allocated. There is no alloc/free on the ioasid_set.

With the IOASID set APIs, callers must allocate an ioasid_set before
allocate IOASIDs within the set. Quota and other ioasid_set level
activities can then be enforced.

This patch converts existing API to the new ioasid_set model.

Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 10 +++---
drivers/iommu/intel-svm.c | 10 +++---
drivers/iommu/ioasid.c | 78 +++++++++++++++++++++++++++++++++------------
include/linux/ioasid.h | 11 +++----
4 files changed, 72 insertions(+), 37 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index af7a1ef7b31e..c571cc8d9e57 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3323,11 +3323,11 @@ static void intel_ioasid_free(ioasid_t ioasid, void *data)
if (!iommu)
return;
/*
- * Sanity check the ioasid owner is done at upper layer, e.g. VFIO
- * We can only free the PASID when all the devices are unbound.
+ * In the guest, all IOASIDs belong to the system_ioasid set.
+ * Sanity check against the system set.
*/
- if (ioasid_find(NULL, ioasid, NULL)) {
- pr_alert("Cannot free active IOASID %d\n", ioasid);
+ if (IS_ERR(ioasid_find(system_ioasid_sid, ioasid, NULL))) {
+ pr_err("Cannot free IOASID %d, not in system set\n", ioasid);
return;
}
vcmd_free_pasid(iommu, ioasid);
@@ -5541,7 +5541,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
int pasid;

/* No private data needed for the default pasid */
- pasid = ioasid_alloc(NULL, PASID_MIN,
+ pasid = ioasid_alloc(system_ioasid_sid, PASID_MIN,
pci_max_pasids(to_pci_dev(dev)) - 1,
NULL);
if (pasid == INVALID_IOASID) {
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 1991587fd3fd..f511855d187b 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -268,7 +268,7 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain,
}

mutex_lock(&pasid_mutex);
- svm = ioasid_find(NULL, data->hpasid, NULL);
+ svm = ioasid_find(INVALID_IOASID_SET, data->hpasid, NULL);
if (IS_ERR(svm)) {
ret = PTR_ERR(svm);
goto out;
@@ -401,7 +401,7 @@ int intel_svm_unbind_gpasid(struct device *dev, int pasid)
return -EINVAL;

mutex_lock(&pasid_mutex);
- svm = ioasid_find(NULL, pasid, NULL);
+ svm = ioasid_find(INVALID_IOASID_SET, pasid, NULL);
if (!svm) {
ret = -EINVAL;
goto out;
@@ -559,7 +559,7 @@ static int intel_svm_bind_mm(struct device *dev, int flags, struct svm_dev_ops *
pasid_max = intel_pasid_max_id;

/* Do not use PASID 0, reserved for RID to PASID */
- svm->pasid = ioasid_alloc(NULL, PASID_MIN,
+ svm->pasid = ioasid_alloc(system_ioasid_sid, PASID_MIN,
pasid_max - 1, svm);
if (svm->pasid == INVALID_IOASID) {
kfree(svm);
@@ -642,7 +642,7 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
if (!iommu)
goto out;

- svm = ioasid_find(NULL, pasid, NULL);
+ svm = ioasid_find(system_ioasid_sid, pasid, NULL);
if (!svm)
goto out;

@@ -778,7 +778,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)

if (!svm || svm->pasid != req->pasid) {
rcu_read_lock();
- svm = ioasid_find(NULL, req->pasid, NULL);
+ svm = ioasid_find(INVALID_IOASID_SET, req->pasid, NULL);
/* It *can't* go away, because the driver is not permitted
* to unbind the mm while any page faults are outstanding.
* So we only need RCU to protect the internal idr code. */
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
index 9135af171a7c..f89a595f6978 100644
--- a/drivers/iommu/ioasid.c
+++ b/drivers/iommu/ioasid.c
@@ -31,7 +31,7 @@ struct ioasid_set_data {

struct ioasid_data {
ioasid_t id;
- struct ioasid_set *set;
+ struct ioasid_set_data *sdata;
void *private;
struct rcu_head rcu;
};
@@ -334,7 +334,7 @@ EXPORT_SYMBOL_GPL(ioasid_attach_data);

/**
* ioasid_alloc - Allocate an IOASID
- * @set: the IOASID set
+ * @sid: the IOASID set ID
* @min: the minimum ID (inclusive)
* @max: the maximum ID (inclusive)
* @private: data private to the caller
@@ -344,18 +344,30 @@ EXPORT_SYMBOL_GPL(ioasid_attach_data);
*
* Return: the allocated ID on success, or %INVALID_IOASID on failure.
*/
-ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
- void *private)
+ioasid_t ioasid_alloc(int sid, ioasid_t min, ioasid_t max, void *private)
{
+ struct ioasid_set_data *sdata;
struct ioasid_data *data;
void *adata;
ioasid_t id;

- data = kzalloc(sizeof(*data), GFP_ATOMIC);
+ /* Check if the IOASID set has been allocated and initialized */
+ sdata = xa_load(&ioasid_sets, sid);
+ if (!sdata) {
+ pr_err("Invalid IOASID set %d to allocate from\n", sid);
+ return INVALID_IOASID;
+ }
+
+ if (sdata->size <= sdata->nr_ioasids) {
+ pr_err("IOASID set %d out of quota\n", sid);
+ return INVALID_IOASID;
+ }
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return INVALID_IOASID;

- data->set = set;
+ data->sdata = sdata;
data->private = private;

/*
@@ -379,6 +391,9 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
}
data->id = id;

+ /* Store IOASID in the per set data */
+ xa_store(&sdata->xa, id, data, GFP_KERNEL);
+ sdata->nr_ioasids++;
spin_unlock(&ioasid_allocator_lock);
return id;
exit_free:
@@ -388,19 +403,15 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
}
EXPORT_SYMBOL_GPL(ioasid_alloc);

-/**
- * ioasid_free - Free an IOASID
- * @ioasid: the ID to remove
- */
-void ioasid_free(ioasid_t ioasid)
+static void ioasid_free_locked(ioasid_t ioasid)
{
struct ioasid_data *ioasid_data;
+ struct ioasid_set_data *sdata;

- spin_lock(&ioasid_allocator_lock);
ioasid_data = xa_load(&active_allocator->xa, ioasid);
if (!ioasid_data) {
pr_err("Trying to free unknown IOASID %u\n", ioasid);
- goto exit_unlock;
+ return;
}

active_allocator->ops->free(ioasid, active_allocator->ops->pdata);
@@ -410,7 +421,27 @@ void ioasid_free(ioasid_t ioasid)
kfree_rcu(ioasid_data, rcu);
}

-exit_unlock:
+ sdata = xa_load(&ioasid_sets, ioasid_data->sdata->sid);
+ if (!sdata) {
+ pr_err("No set %d for IOASID %d\n", ioasid_data->sdata->sid,
+ ioasid);
+ return;
+ }
+ xa_erase(&sdata->xa, ioasid);
+ sdata->nr_ioasids--;
+}
+
+/**
+ * ioasid_free - Free an IOASID and notify users who registered a notifier
+ * on the IOASID set.
+ * IOASID can be re-allocated upon return
+ *
+ * @ioasid: the ID to remove
+ */
+void ioasid_free(ioasid_t ioasid)
+{
+ spin_lock(&ioasid_allocator_lock);
+ ioasid_free_locked(ioasid);
spin_unlock(&ioasid_allocator_lock);
}
EXPORT_SYMBOL_GPL(ioasid_free);
@@ -499,8 +530,12 @@ void ioasid_free_set(int sid, bool destroy_set)
goto done_destroy;
}

- /* Just a place holder for now */
xa_for_each(&sdata->xa, index, entry) {
+ /*
+ * Free from system-wide IOASID pool, all subscribers gets
+ * notified and do cleanup.
+ */
+ ioasid_free_locked(index);
/* Free from per sub-set pool */
xa_erase(&sdata->xa, index);
}
@@ -508,7 +543,6 @@ void ioasid_free_set(int sid, bool destroy_set)
done_destroy:
if (destroy_set) {
xa_erase(&ioasid_sets, sid);
-
/* Return the quota back to system pool */
ioasid_capacity_avail += sdata->size;
kfree_rcu(sdata, rcu);
@@ -522,7 +556,7 @@ EXPORT_SYMBOL_GPL(ioasid_free_set);

/**
* ioasid_find - Find IOASID data
- * @set: the IOASID set
+ * @sid: the IOASID set ID
* @ioasid: the IOASID to find
* @getter: function to call on the found object
*
@@ -532,10 +566,12 @@ EXPORT_SYMBOL_GPL(ioasid_free_set);
*
* If the IOASID exists, return the private pointer passed to ioasid_alloc.
* Private data can be NULL if not set. Return an error if the IOASID is not
- * found, or if @set is not NULL and the IOASID does not belong to the set.
+ * found.
+ *
+ * If sid is INVALID_IOASID_SET, it will skip set ownership checking. Otherwise,
+ * error is returned even if the IOASID is found but does not belong the set.
*/
-void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
- bool (*getter)(void *))
+void *ioasid_find(int sid, ioasid_t ioasid, bool (*getter)(void *))
{
void *priv;
struct ioasid_data *ioasid_data;
@@ -548,7 +584,7 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
priv = ERR_PTR(-ENOENT);
goto unlock;
}
- if (set && ioasid_data->set != set) {
+ if (sid != INVALID_IOASID_SET && ioasid_data->sdata->sid != sid) {
/* data found but does not belong to the set */
priv = ERR_PTR(-EACCES);
goto unlock;
diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
index 097b1cc043a3..e19c0ad93bd7 100644
--- a/include/linux/ioasid.h
+++ b/include/linux/ioasid.h
@@ -6,6 +6,7 @@
#include <linux/errno.h>

#define INVALID_IOASID ((ioasid_t)-1)
+#define INVALID_IOASID_SET (-1)
typedef unsigned int ioasid_t;
typedef ioasid_t (*ioasid_alloc_fn_t)(ioasid_t min, ioasid_t max, void *data);
typedef void (*ioasid_free_fn_t)(ioasid_t ioasid, void *data);
@@ -35,11 +36,10 @@ extern int system_ioasid_sid;
#define DECLARE_IOASID_SET(name) struct ioasid_set name = { 0 }

#if IS_ENABLED(CONFIG_IOASID)
-ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
+ioasid_t ioasid_alloc(int sid, ioasid_t min, ioasid_t max,
void *private);
void ioasid_free(ioasid_t ioasid);
-void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
- bool (*getter)(void *));
+void *ioasid_find(int sid, ioasid_t ioasid, bool (*getter)(void *));
int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
void ioasid_unregister_allocator(struct ioasid_allocator_ops *allocator);
int ioasid_attach_data(ioasid_t ioasid, void *data);
@@ -49,7 +49,7 @@ int ioasid_alloc_set(struct ioasid_set *token, ioasid_t quota, int *sid);
void ioasid_free_set(int sid, bool destroy_set);
int ioasid_find_sid(ioasid_t ioasid);
#else /* !CONFIG_IOASID */
-static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min,
+static inline ioasid_t ioasid_alloc(int sid, ioasid_t min,
ioasid_t max, void *private)
{
return INVALID_IOASID;
@@ -68,8 +68,7 @@ static inline void ioasid_free_set(int sid, bool destroy_set)
{
}

-static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
- bool (*getter)(void *))
+static inline void *ioasid_find(int sid, ioasid_t ioasid, bool (*getter)(void *))
{
return NULL;
}
--
2.7.4