diff options
| author | Zeng Heng <zengheng4@huawei.com> | 2026-03-13 14:45:38 +0000 |
|---|---|---|
| committer | James Morse <james.morse@arm.com> | 2026-03-27 15:25:19 +0000 |
| commit | f91e913355f49c878fc77f995fd71b7800352bd2 (patch) | |
| tree | 20dfdb5d7a8b50c2852d075148d3edc88a9029dd /drivers/resctrl | |
| parent | 1f318b96cc84d7c2ab792fcc0bfd42a7ca890681 (diff) | |
arm_mpam: Ensure in_reset_state is false after applying configuration
The per-RIS flag, in_reset_state, indicates whether or not the MSC
registers are in reset state, and allows avoiding resetting when they are
already in reset state. However, when mpam_apply_config() updates the
configuration it doesn't update the in_reset_state flag and so even after
the configuration update in_reset_state can be true and mpam_reset_ris()
will skip the actual register restoration on subsequent resets.
Once resctrl has a MPAM backend it will use resctrl_arch_reset_all_ctrls()
to reset the MSC configuration on unmount and, if the in_reset_state flag
is bogusly true, fail to reset the MSC configuration. The resulting
non-reset MSC configuration can lead to persistent performance restrictions
even after resctrl is unmounted.
Fix by clearing in_reset_state to false immediately after successful
configuration application, ensuring that the next reset operation
properly restores MSC register defaults.
Fixes: 09b89d2a72f3 ("arm_mpam: Allow configuration to be applied and restored during cpu online")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Acked-by: Ben Horgan <ben.horgan@arm.com>
[Horgan: rewrite commit message to not be specific to resctrl unmount]
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Jesse Chick <jessechick@os.amperecomputing.com>
Signed-off-by: James Morse <james.morse@arm.com>
Diffstat (limited to 'drivers/resctrl')
| -rw-r--r-- | drivers/resctrl/mpam_devices.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 1eebc2602187..0fd6590a9b5c 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -2692,6 +2692,7 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid, srcu_read_lock_held(&mpam_srcu)) { arg.ris = ris; mpam_touch_msc(msc, __write_config, &arg); + ris->in_reset_state = false; } mutex_unlock(&msc->cfg_lock); } |