iommu/amd: Implement notifiers for IOMMUv2
Since pages are not pinned anymore we need notifications
when the VMM changes the page-tables. Use mmu_notifiers for
that.
Also use the task_exit notifier from the profiling subsystem
to shutdown all contexts related to this task.
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 8804b22..abdb839 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -16,8 +16,10 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+#include <linux/mmu_notifier.h>
#include <linux/amd-iommu.h>
#include <linux/mm_types.h>
+#include <linux/profile.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/iommu.h>
@@ -45,6 +47,7 @@
atomic_t count; /* Reference count */
struct task_struct *task; /* Task bound to this PASID */
struct mm_struct *mm; /* mm_struct for the faults */
+ struct mmu_notifier mn; /* mmu_otifier handle */
struct pri_queue pri[PRI_QUEUE_SIZE]; /* PRI tag states */
struct device_state *device_state; /* Link to our device_state */
int pasid; /* PASID index */
@@ -85,8 +88,16 @@
static struct workqueue_struct *iommu_wq;
+/*
+ * Empty page table - Used between
+ * mmu_notifier_invalidate_range_start and
+ * mmu_notifier_invalidate_range_end
+ */
+static u64 *empty_page_table;
+
static void free_pasid_states(struct device_state *dev_state);
static void unbind_pasid(struct device_state *dev_state, int pasid);
+static int task_exit(struct notifier_block *nb, unsigned long e, void *data);
static u16 device_id(struct pci_dev *pdev)
{
@@ -144,6 +155,11 @@
free_device_state(dev_state);
}
+
+static struct notifier_block profile_nb = {
+ .notifier_call = task_exit,
+};
+
static void link_pasid_state(struct pasid_state *pasid_state)
{
spin_lock(&ps_lock);
@@ -294,6 +310,23 @@
free_pasid_state(pasid_state);
}
+static void __unbind_pasid(struct pasid_state *pasid_state)
+{
+ struct iommu_domain *domain;
+
+ domain = pasid_state->device_state->domain;
+
+ amd_iommu_domain_clear_gcr3(domain, pasid_state->pasid);
+ clear_pasid_state(pasid_state->device_state, pasid_state->pasid);
+
+ /* Make sure no more pending faults are in the queue */
+ flush_workqueue(iommu_wq);
+
+ mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);
+
+ put_pasid_state(pasid_state); /* Reference taken in bind() function */
+}
+
static void unbind_pasid(struct device_state *dev_state, int pasid)
{
struct pasid_state *pasid_state;
@@ -303,12 +336,8 @@
return;
unlink_pasid_state(pasid_state);
-
- amd_iommu_domain_clear_gcr3(dev_state->domain, pasid);
- clear_pasid_state(dev_state, pasid);
-
- put_pasid_state(pasid_state); /* Reference taken in this function */
- put_pasid_state_wait(pasid_state); /* Reference from bind() function */
+ __unbind_pasid(pasid_state);
+ put_pasid_state_wait(pasid_state); /* Reference taken in this function */
}
static void free_pasid_states_level1(struct pasid_state **tbl)
@@ -361,6 +390,83 @@
free_page((unsigned long)dev_state->states);
}
+static struct pasid_state *mn_to_state(struct mmu_notifier *mn)
+{
+ return container_of(mn, struct pasid_state, mn);
+}
+
+static void __mn_flush_page(struct mmu_notifier *mn,
+ unsigned long address)
+{
+ struct pasid_state *pasid_state;
+ struct device_state *dev_state;
+
+ pasid_state = mn_to_state(mn);
+ dev_state = pasid_state->device_state;
+
+ amd_iommu_flush_page(dev_state->domain, pasid_state->pasid, address);
+}
+
+static int mn_clear_flush_young(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long address)
+{
+ __mn_flush_page(mn, address);
+
+ return 0;
+}
+
+static void mn_change_pte(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long address,
+ pte_t pte)
+{
+ __mn_flush_page(mn, address);
+}
+
+static void mn_invalidate_page(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long address)
+{
+ __mn_flush_page(mn, address);
+}
+
+static void mn_invalidate_range_start(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct pasid_state *pasid_state;
+ struct device_state *dev_state;
+
+ pasid_state = mn_to_state(mn);
+ dev_state = pasid_state->device_state;
+
+ amd_iommu_domain_set_gcr3(dev_state->domain, pasid_state->pasid,
+ __pa(empty_page_table));
+}
+
+static void mn_invalidate_range_end(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct pasid_state *pasid_state;
+ struct device_state *dev_state;
+
+ pasid_state = mn_to_state(mn);
+ dev_state = pasid_state->device_state;
+
+ amd_iommu_domain_set_gcr3(dev_state->domain, pasid_state->pasid,
+ __pa(pasid_state->mm->pgd));
+}
+
+static struct mmu_notifier_ops iommu_mn = {
+ .clear_flush_young = mn_clear_flush_young,
+ .change_pte = mn_change_pte,
+ .invalidate_page = mn_invalidate_page,
+ .invalidate_range_start = mn_invalidate_range_start,
+ .invalidate_range_end = mn_invalidate_range_end,
+};
+
static void set_pri_tag_status(struct pasid_state *pasid_state,
u16 tag, int status)
{
@@ -475,6 +581,50 @@
.notifier_call = ppr_notifier,
};
+static int task_exit(struct notifier_block *nb, unsigned long e, void *data)
+{
+ struct pasid_state *pasid_state;
+ struct task_struct *task;
+
+ task = data;
+
+ /*
+ * Using this notifier is a hack - but there is no other choice
+ * at the moment. What I really want is a sleeping notifier that
+ * is called when an MM goes down. But such a notifier doesn't
+ * exist yet. The notifier needs to sleep because it has to make
+ * sure that the device does not use the PASID and the address
+ * space anymore before it is destroyed. This includes waiting
+ * for pending PRI requests to pass the workqueue. The
+ * MMU-Notifiers would be a good fit, but they use RCU and so
+ * they are not allowed to sleep. Lets see how we can solve this
+ * in a more intelligent way in the future.
+ */
+again:
+ spin_lock(&ps_lock);
+ list_for_each_entry(pasid_state, &pasid_state_list, list) {
+ struct device_state *dev_state;
+ int pasid;
+
+ if (pasid_state->task != task)
+ continue;
+
+ /* Drop Lock and unbind */
+ spin_unlock(&ps_lock);
+
+ dev_state = pasid_state->device_state;
+ pasid = pasid_state->pasid;
+
+ unbind_pasid(dev_state, pasid);
+
+ /* Task may be in the list multiple times */
+ goto again;
+ }
+ spin_unlock(&ps_lock);
+
+ return NOTIFY_OK;
+}
+
int amd_iommu_bind_pasid(struct pci_dev *pdev, int pasid,
struct task_struct *task)
{
@@ -509,13 +659,16 @@
pasid_state->mm = get_task_mm(task);
pasid_state->device_state = dev_state;
pasid_state->pasid = pasid;
+ pasid_state->mn.ops = &iommu_mn;
if (pasid_state->mm == NULL)
goto out_free;
+ mmu_notifier_register(&pasid_state->mn, pasid_state->mm);
+
ret = set_pasid_state(dev_state, pasid_state, pasid);
if (ret)
- goto out_free;
+ goto out_unregister;
ret = amd_iommu_domain_set_gcr3(dev_state->domain, pasid,
__pa(pasid_state->mm->pgd));
@@ -529,6 +682,9 @@
out_clear_state:
clear_pasid_state(dev_state, pasid);
+out_unregister:
+ mmu_notifier_unregister(&pasid_state->mn, pasid_state->mm);
+
out_free:
free_pasid_state(pasid_state);
@@ -689,15 +845,22 @@
ret = -ENOMEM;
iommu_wq = create_workqueue("amd_iommu_v2");
- if (iommu_wq == NULL) {
- ret = -ENOMEM;
+ if (iommu_wq == NULL)
goto out_free;
- }
+
+ ret = -ENOMEM;
+ empty_page_table = (u64 *)get_zeroed_page(GFP_KERNEL);
+ if (empty_page_table == NULL)
+ goto out_destroy_wq;
amd_iommu_register_ppr_notifier(&ppr_nb);
+ profile_event_register(PROFILE_TASK_EXIT, &profile_nb);
return 0;
+out_destroy_wq:
+ destroy_workqueue(iommu_wq);
+
out_free:
free_pages((unsigned long)state_table, get_order(state_table_size));
@@ -710,6 +873,7 @@
size_t state_table_size;
int i;
+ profile_event_unregister(PROFILE_TASK_EXIT, &profile_nb);
amd_iommu_unregister_ppr_notifier(&ppr_nb);
flush_workqueue(iommu_wq);
@@ -734,6 +898,8 @@
state_table_size = MAX_DEVICES * sizeof(struct device_state *);
free_pages((unsigned long)state_table, get_order(state_table_size));
+
+ free_page((unsigned long)empty_page_table);
}
module_init(amd_iommu_v2_init);