cpuhp callbacks aren't the only time the MSC configuration may need to
be reset. Resctrl has an API call to reset a class.
If an MPAM error interrupt arrives it indicates the driver has
misprogrammed an MSC. The safest thing to do is reset all the MSCs
and disable MPAM.
Add a helper to reset RIS via their class. Call this from mpam_disable(),
which can be scheduled from the error interrupt handler.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Ben Horgan <ben.horgan@arm.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
---
Changes since v2:
* Reduced the scop of arguments in mpam_reset_component_locked().
Changes since v1:
* more complete use of _srcu helpers.
* Use guard macro for srcu.
* Dropped a might_sleep() - something else will bark.
---
drivers/resctrl/mpam_devices.c | 58 ++++++++++++++++++++++++++++++++--
1 file changed, 55 insertions(+), 3 deletions(-)
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index ec089593acad..545482e112b7 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -802,15 +802,13 @@ static void mpam_reset_ris_partid(struct mpam_msc_ris *ris, u16 partid)
/*
* Called via smp_call_on_cpu() to prevent migration, while still being
- * pre-emptible.
+ * pre-emptible. Caller must hold mpam_srcu.
*/
static int mpam_reset_ris(void *arg)
{
u16 partid, partid_max;
struct mpam_msc_ris *ris = arg;
- WARN_ON_ONCE(!srcu_read_lock_held((&mpam_srcu)));
-
if (ris->in_reset_state)
return 0;
@@ -1328,8 +1326,56 @@ static void mpam_enable_once(void)
mpam_partid_max + 1, mpam_pmg_max + 1);
}
+static void mpam_reset_component_locked(struct mpam_component *comp)
+{
+
+ struct mpam_vmsc *vmsc;
+
+ lockdep_assert_cpus_held();
+
+ guard(srcu)(&mpam_srcu);
+ list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list,
+ srcu_read_lock_held(&mpam_srcu)) {
+ struct mpam_msc *msc = vmsc->msc;
+ struct mpam_msc_ris *ris;
+
+ list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list,
+ srcu_read_lock_held(&mpam_srcu)) {
+ if (!ris->in_reset_state)
+ mpam_touch_msc(msc, mpam_reset_ris, ris);
+ ris->in_reset_state = true;
+ }
+ }
+}
+
+static void mpam_reset_class_locked(struct mpam_class *class)
+{
+ struct mpam_component *comp;
+
+ lockdep_assert_cpus_held();
+
+ guard(srcu)(&mpam_srcu);
+ list_for_each_entry_srcu(comp, &class->components, class_list,
+ srcu_read_lock_held(&mpam_srcu))
+ mpam_reset_component_locked(comp);
+}
+
+static void mpam_reset_class(struct mpam_class *class)
+{
+ cpus_read_lock();
+ mpam_reset_class_locked(class);
+ cpus_read_unlock();
+}
+
+/*
+ * Called in response to an error IRQ.
+ * All of MPAMs errors indicate a software bug, restore any modified
+ * controls to their reset values.
+ */
void mpam_disable(struct work_struct *ignored)
{
+ int idx;
+ struct mpam_class *class;
struct mpam_msc *msc, *tmp;
mutex_lock(&mpam_cpuhp_state_lock);
@@ -1339,6 +1385,12 @@ void mpam_disable(struct work_struct *ignored)
}
mutex_unlock(&mpam_cpuhp_state_lock);
+ idx = srcu_read_lock(&mpam_srcu);
+ list_for_each_entry_srcu(class, &mpam_classes, classes_list,
+ srcu_read_lock_held(&mpam_srcu))
+ mpam_reset_class(class);
+ srcu_read_unlock(&mpam_srcu, idx);
+
mutex_lock(&mpam_list_lock);
list_for_each_entry_safe(msc, tmp, &mpam_all_msc, all_msc_list)
mpam_msc_destroy(msc);
--
2.39.5