iommu/amd: Implement IO page-fault handler
Register the notifier for PPR faults and handle them as
necessary.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index b5ee09e..8804b22 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -21,9 +21,11 @@
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/iommu.h>
+#include <linux/wait.h>
#include <linux/pci.h>
#include <linux/gfp.h>
+#include "amd_iommu_types.h"
#include "amd_iommu_proto.h"
MODULE_LICENSE("GPL v2");
@@ -35,6 +37,7 @@
struct pri_queue {
atomic_t inflight;
bool finish;
+ int status;
};
struct pasid_state {
@@ -45,6 +48,8 @@
struct pri_queue pri[PRI_QUEUE_SIZE]; /* PRI tag states */
struct device_state *device_state; /* Link to our device_state */
int pasid; /* PASID index */
+ spinlock_t lock; /* Protect pri_queues */
+ wait_queue_head_t wq; /* To wait for count == 0 */
};
struct device_state {
@@ -55,6 +60,20 @@
int pasid_levels;
int max_pasids;
spinlock_t lock;
+ wait_queue_head_t wq;
+};
+
+struct fault {
+ struct work_struct work;
+ struct device_state *dev_state;
+ struct pasid_state *state;
+ struct mm_struct *mm;
+ u64 address;
+ u16 devid;
+ u16 pasid;
+ u16 tag;
+ u16 finish;
+ u16 flags;
};
struct device_state **state_table;
@@ -64,6 +83,8 @@
static LIST_HEAD(pasid_state_list);
static DEFINE_SPINLOCK(ps_lock);
+static struct workqueue_struct *iommu_wq;
+
static void free_pasid_states(struct device_state *dev_state);
static void unbind_pasid(struct device_state *dev_state, int pasid);
@@ -109,9 +130,20 @@
static void put_device_state(struct device_state *dev_state)
{
if (atomic_dec_and_test(&dev_state->count))
- free_device_state(dev_state);
+ wake_up(&dev_state->wq);
}
+static void put_device_state_wait(struct device_state *dev_state)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&dev_state->wq, &wait, TASK_UNINTERRUPTIBLE);
+ if (!atomic_dec_and_test(&dev_state->count))
+ schedule();
+ finish_wait(&dev_state->wq, &wait);
+
+ free_device_state(dev_state);
+}
static void link_pasid_state(struct pasid_state *pasid_state)
{
spin_lock(&ps_lock);
@@ -242,11 +274,26 @@
{
if (atomic_dec_and_test(&pasid_state->count)) {
put_device_state(pasid_state->device_state);
- mmput(pasid_state->mm);
- free_pasid_state(pasid_state);
+ wake_up(&pasid_state->wq);
}
}
+static void put_pasid_state_wait(struct pasid_state *pasid_state)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&pasid_state->wq, &wait, TASK_UNINTERRUPTIBLE);
+
+ if (atomic_dec_and_test(&pasid_state->count))
+ put_device_state(pasid_state->device_state);
+ else
+ schedule();
+
+ finish_wait(&pasid_state->wq, &wait);
+ mmput(pasid_state->mm);
+ free_pasid_state(pasid_state);
+}
+
static void unbind_pasid(struct device_state *dev_state, int pasid)
{
struct pasid_state *pasid_state;
@@ -261,7 +308,7 @@
clear_pasid_state(dev_state, pasid);
put_pasid_state(pasid_state); /* Reference taken in this function */
- put_pasid_state(pasid_state); /* Reference taken in bind() function */
+ put_pasid_state_wait(pasid_state); /* Reference from bind() function */
}
static void free_pasid_states_level1(struct pasid_state **tbl)
@@ -300,8 +347,8 @@
if (pasid_state == NULL)
continue;
- unbind_pasid(dev_state, i);
put_pasid_state(pasid_state);
+ unbind_pasid(dev_state, i);
}
if (dev_state->pasid_levels == 2)
@@ -314,6 +361,120 @@
free_page((unsigned long)dev_state->states);
}
+static void set_pri_tag_status(struct pasid_state *pasid_state,
+ u16 tag, int status)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&pasid_state->lock, flags);
+ pasid_state->pri[tag].status = status;
+ spin_unlock_irqrestore(&pasid_state->lock, flags);
+}
+
+static void finish_pri_tag(struct device_state *dev_state,
+ struct pasid_state *pasid_state,
+ u16 tag)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&pasid_state->lock, flags);
+ if (atomic_dec_and_test(&pasid_state->pri[tag].inflight) &&
+ pasid_state->pri[tag].finish) {
+ amd_iommu_complete_ppr(dev_state->pdev, pasid_state->pasid,
+ pasid_state->pri[tag].status, tag);
+ pasid_state->pri[tag].finish = false;
+ pasid_state->pri[tag].status = PPR_SUCCESS;
+ }
+ spin_unlock_irqrestore(&pasid_state->lock, flags);
+}
+
+static void do_fault(struct work_struct *work)
+{
+ struct fault *fault = container_of(work, struct fault, work);
+ int npages, write;
+ struct page *page;
+
+ write = !!(fault->flags & PPR_FAULT_WRITE);
+
+ npages = get_user_pages(fault->state->task, fault->state->mm,
+ fault->address, 1, write, 0, &page, NULL);
+
+ if (npages == 1)
+ put_page(page);
+ else
+ set_pri_tag_status(fault->state, fault->tag, PPR_INVALID);
+
+ finish_pri_tag(fault->dev_state, fault->state, fault->tag);
+
+ put_pasid_state(fault->state);
+
+ kfree(fault);
+}
+
+static int ppr_notifier(struct notifier_block *nb, unsigned long e, void *data)
+{
+ struct amd_iommu_fault *iommu_fault;
+ struct pasid_state *pasid_state;
+ struct device_state *dev_state;
+ unsigned long flags;
+ struct fault *fault;
+ bool finish;
+ u16 tag;
+ int ret;
+
+ iommu_fault = data;
+ tag = iommu_fault->tag & 0x1ff;
+ finish = (iommu_fault->tag >> 9) & 1;
+
+ ret = NOTIFY_DONE;
+ dev_state = get_device_state(iommu_fault->device_id);
+ if (dev_state == NULL)
+ goto out;
+
+ pasid_state = get_pasid_state(dev_state, iommu_fault->pasid);
+ if (pasid_state == NULL) {
+ /* We know the device but not the PASID -> send INVALID */
+ amd_iommu_complete_ppr(dev_state->pdev, iommu_fault->pasid,
+ PPR_INVALID, tag);
+ goto out_drop_state;
+ }
+
+ spin_lock_irqsave(&pasid_state->lock, flags);
+ atomic_inc(&pasid_state->pri[tag].inflight);
+ if (finish)
+ pasid_state->pri[tag].finish = true;
+ spin_unlock_irqrestore(&pasid_state->lock, flags);
+
+ fault = kzalloc(sizeof(*fault), GFP_ATOMIC);
+ if (fault == NULL) {
+ /* We are OOM - send success and let the device re-fault */
+ finish_pri_tag(dev_state, pasid_state, tag);
+ goto out_drop_state;
+ }
+
+ fault->dev_state = dev_state;
+ fault->address = iommu_fault->address;
+ fault->state = pasid_state;
+ fault->tag = tag;
+ fault->finish = finish;
+ fault->flags = iommu_fault->flags;
+ INIT_WORK(&fault->work, do_fault);
+
+ queue_work(iommu_wq, &fault->work);
+
+ ret = NOTIFY_OK;
+
+out_drop_state:
+ put_device_state(dev_state);
+
+out:
+ return ret;
+}
+
+static struct notifier_block ppr_nb = {
+ .notifier_call = ppr_notifier,
+};
+
int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
struct task_struct *task)
{
@@ -343,6 +504,7 @@
goto out;
atomic_set(&pasid_state->count, 1);
+ init_waitqueue_head(&pasid_state->wq);
pasid_state->task = task;
pasid_state->mm = get_task_mm(task);
pasid_state->device_state = dev_state;
@@ -368,7 +530,7 @@
clear_pasid_state(dev_state, pasid);
out_free:
- put_pasid_state(pasid_state);
+ free_pasid_state(pasid_state);
out:
put_device_state(dev_state);
@@ -424,6 +586,7 @@
return -ENOMEM;
spin_lock_init(&dev_state->lock);
+ init_waitqueue_head(&dev_state->wq);
dev_state->pdev = pdev;
tmp = pasids;
@@ -505,13 +668,14 @@
/* Get rid of any remaining pasid states */
free_pasid_states(dev_state);
- put_device_state(dev_state);
+ put_device_state_wait(dev_state);
}
EXPORT_SYMBOL(amd_iommu_free_device);
static int __init amd_iommu_v2_init(void)
{
size_t state_table_size;
+ int ret;
pr_info("AMD IOMMUv2 driver by Joerg Roedel <joerg.roedel@amd.com>");
@@ -523,7 +687,21 @@
if (state_table == NULL)
return -ENOMEM;
+ ret = -ENOMEM;
+ iommu_wq = create_workqueue("amd_iommu_v2");
+ if (iommu_wq == NULL) {
+ ret = -ENOMEM;
+ goto out_free;
+ }
+
+ amd_iommu_register_ppr_notifier(&ppr_nb);
+
return 0;
+
+out_free:
+ free_pages((unsigned long)state_table, get_order(state_table_size));
+
+ return ret;
}
static void __exit amd_iommu_v2_exit(void)
@@ -532,6 +710,14 @@
size_t state_table_size;
int i;
+ amd_iommu_unregister_ppr_notifier(&ppr_nb);
+
+ flush_workqueue(iommu_wq);
+
+ /*
+ * The loop below might call flush_workqueue(), so call
+ * destroy_workqueue() after it
+ */
for (i = 0; i < MAX_DEVICES; ++i) {
dev_state = get_device_state(i);
@@ -540,10 +726,12 @@
WARN_ON_ONCE(1);
- amd_iommu_free_device(dev_state->pdev);
put_device_state(dev_state);
+ amd_iommu_free_device(dev_state->pdev);
}
+ destroy_workqueue(iommu_wq);
+
state_table_size = MAX_DEVICES * sizeof(struct device_state *);
free_pages((unsigned long)state_table, get_order(state_table_size));
}