From 0045b87f65bbdd3b433747cce0d723ae94f77d38 Mon Sep 17 00:00:00 2001 From: Ben Horgan Date: Thu, 17 Sep 2026 15:56:09 +0100 Subject: [PATCH] arm_mpam: Add missing mon_sel locking in MBWU save and restore The mon_sel_lock is used to protect the mbwu_state, as well as h/w accesses that use MPAMCFG_MON_SEL. However, in mpam_restore/save_mbwu_state(), mbwu_state is accessed without holding the mon_sel_lock. Add the missing locking. Fixes: 41e8a14950e1 ("arm_mpam: Track bandwidth counter state for power management") Signed-off-by: Ben Horgan Tested-by: Gavin Shan Reviewed-by: Gavin Shan Reviewed-by: James Morse Signed-off-by: James Morse --- drivers/resctrl/mpam_devices.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index e349db525882..d39d210574a6 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -1652,17 +1652,26 @@ static int mpam_restore_mbwu_state(void *_ris) u64 val; struct mon_read mwbu_arg; struct mpam_msc_ris *ris = _ris; + struct mpam_msc *msc = ris->vmsc->msc; struct mpam_class *class = ris->vmsc->comp->class; for (i = 0; i < ris->props.num_mbwu_mon; i++) { - if (ris->mbwu_state[i].enabled) { - mwbu_arg.ris = ris; - mwbu_arg.ctx = &ris->mbwu_state[i].cfg; - mwbu_arg.type = mpam_msmon_choose_counter(class); - mwbu_arg.val = &val; + if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc))) + return -EIO; - __ris_msmon_read(&mwbu_arg); + if (!ris->mbwu_state[i].enabled) { + mpam_mon_sel_unlock(msc); + continue; } + + mwbu_arg.ris = ris; + mwbu_arg.ctx = &ris->mbwu_state[i].cfg; + mwbu_arg.type = mpam_msmon_choose_counter(class); + mwbu_arg.val = &val; + + mpam_mon_sel_unlock(msc); + + __ris_msmon_read(&mwbu_arg); } return 0; @@ -1680,12 +1689,12 @@ static int mpam_save_mbwu_state(void *arg) struct mpam_msc *msc = ris->vmsc->msc; for (i = 0; i < ris->props.num_mbwu_mon; i++) { - mbwu_state = &ris->mbwu_state[i]; - cfg = &mbwu_state->cfg; - if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc))) return -EIO; + mbwu_state = &ris->mbwu_state[i]; + cfg = &mbwu_state->cfg; + mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, i) | FIELD_PREP(MSMON_CFG_MON_SEL_RIS, ris->ris_idx); mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel);