From 021118ce5ea954ec316d7e30bcf4506e12eb5222 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Sat, 6 Jun 2026 22:09:25 -0700 Subject: [PATCH] arm_mpam: Fix MPAMCFG_MBW_PBM register setting MPAMCFG_MBW_PBM is written from cfg if cfg has the MBW partition feature. It is reset when cfg does not have the MBW partition feature. But the register handling is reversed. This may cause an incorrect register setting. For example, during an MPAM reset, reset_cfg is empty (no MBW partition feature set), and cfg->mbw_pbm is 0. Instead of resetting MPAMCFG_MBW_PBM to all 1's, the current logic will set it to cfg->mbw_pbm, which is 0. Fix the issue by swapping the if/else branches. Fixes: a1cb6577f575 ("arm_mpam: Reset when feature configuration bit unset") Reported-by: Matt Ochs Signed-off-by: Fenghua Yu Reviewed-by: Gavin Shan Reviewed-by: Ben Horgan Signed-off-by: Will Deacon --- drivers/resctrl/mpam_devices.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 37ce11d7db92..8e48b918ae54 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -1580,9 +1580,9 @@ static void mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 partid, if (mpam_has_feature(mpam_feat_mbw_part, rprops)) { if (mpam_has_feature(mpam_feat_mbw_part, cfg)) - mpam_reset_msc_bitmap(msc, MPAMCFG_MBW_PBM, rprops->mbw_pbm_bits); - else mpam_write_partsel_reg(msc, MBW_PBM, cfg->mbw_pbm); + else + mpam_reset_msc_bitmap(msc, MPAMCFG_MBW_PBM, rprops->mbw_pbm_bits); } if (mpam_has_feature(mpam_feat_mbw_min, rprops)) {