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arm_mpam: Add missing mon_sel locking in MBWU save and restore

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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: 41e8a14950 ("arm_mpam: Track bandwidth counter state for power management")
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
This commit is contained in:
Ben Horgan 2026-09-17 15:56:09 +01:00 committed by James Morse
parent b010d258f3
commit 0045b87f65
1 changed files with 18 additions and 9 deletions
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27
drivers/resctrl/mpam_devices.c
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@ -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);