[PATCH 21/27] arm_mpam: propagate MSC access errors for mpam_reprogram_ris_partid()

[James Morse <james.morse@arm.com>]

From: Andre Przywara <andre.przywara@arm.com>

Allow the mpam_reprogram_ris_partid() function to check for and return
errors, and propagate MSC read and write errors from the lower level up.
This also covers the callers of this function: mpam_reset_ris() and
apply_config().

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Gavin Shan <gshan@redhat.com> # on NVIDIA Grace Hopper
Reviewed-by: Srivathsa L Rao <srivathsa.rao@oss.qualcomm.com>
[morse: Fixed merge conflicts in mpam_save_mbwu_state() and __ris_msmon_read()]
Signed-off-by: James Morse <james.morse@arm.com>
---
 drivers/resctrl/mpam_devices.c | 137 ++++++++++++++++++++++-----------
 1 file changed, 94 insertions(+), 43 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 39437361ed7a..7e7b483ff900 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1616,7 +1616,7 @@ void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ctx)
 	}
 }
 
-static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd)
+static int mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd)
 {
 	u32 num_words, msb;
 	u32 bm = ~0;
@@ -1625,15 +1625,20 @@ static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd)
 	lockdep_assert_held(&msc->part_sel_lock);
 
 	if (wd == 0)
-		return;
+		return 0;
 
 	/*
 	 * Write all ~0 to all but the last 32bit-word, which may
 	 * have fewer bits...
 	 */
 	num_words = DIV_ROUND_UP(wd, 32);
-	for (i = 0; i < num_words - 1; i++, reg += sizeof(bm))
-		__mpam_write_reg(msc, reg, bm);
+	for (i = 0; i < num_words - 1; i++, reg += sizeof(bm)) {
+		int ret;
+
+		ret = __mpam_write_reg(msc, reg, bm);
+		if (ret)
+			return ret;
+	}
 
 	/*
 	 * ....and then the last (maybe) partial 32bit word. When wd is a
@@ -1641,7 +1646,7 @@ static void mpam_reset_msc_bitmap(struct mpam_msc *msc, u16 reg, u16 wd)
 	 */
 	msb = (wd - 1) % 32;
 	bm = GENMASK(msb, 0);
-	__mpam_write_reg(msc, reg, bm);
+	return __mpam_write_reg(msc, reg, bm);
 }
 
 static void mpam_apply_t241_erratum(struct mpam_msc_ris *ris, u16 partid)
@@ -1714,40 +1719,59 @@ static u16 mpam_wa_t241_calc_min_from_max(struct mpam_props *props,
 }
 
 /* Called via IPI. Call while holding an SRCU reference */
-static void mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 partid,
-				      struct mpam_config *cfg)
+static int mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 partid,
+				     struct mpam_config *cfg)
 {
 	u16 cmax = MPAMCFG_CMAX_CMAX;
 	struct mpam_msc *msc = ris->vmsc->msc;
 	struct mpam_props *rprops = &ris->props;
+	int ret;
 
-	mutex_lock(&msc->part_sel_lock);
-	__mpam_part_sel(ris->ris_idx, partid, msc);
+	guard(mutex)(&msc->part_sel_lock);
+	ret = __mpam_part_sel(ris->ris_idx, partid, msc);
+	if (ret)
+		return ret;
 
 	if (mpam_has_feature(mpam_feat_partid_nrw, rprops)) {
 		/* Update the intpartid mapping */
-		mpam_write_partsel_reg(msc, INTPARTID,
-				       MPAMCFG_INTPARTID_INTERNAL | partid);
+		ret = mpam_write_partsel_reg(msc, INTPARTID,
+					     MPAMCFG_INTPARTID_INTERNAL | partid);
+		if (ret)
+			return ret;
 
 		/*
 		 * Then switch to the 'internal' partid to update the
 		 * configuration.
 		 */
-		__mpam_intpart_sel(ris->ris_idx, partid, msc);
+		ret = __mpam_intpart_sel(ris->ris_idx, partid, msc);
+		if (ret)
+			return ret;
 	}
 
 	if (mpam_has_feature(mpam_feat_cpor_part, rprops)) {
-		if (mpam_has_feature(mpam_feat_cpor_part, cfg))
-			mpam_write_partsel_reg(msc, CPBM, cfg->cpbm);
-		else
-			mpam_reset_msc_bitmap(msc, MPAMCFG_CPBM, rprops->cpbm_wd);
+		if (mpam_has_feature(mpam_feat_cpor_part, cfg)) {
+			ret = mpam_write_partsel_reg(msc, CPBM, cfg->cpbm);
+			if (ret)
+				return ret;
+		} else {
+			ret = mpam_reset_msc_bitmap(msc, MPAMCFG_CPBM,
+						    rprops->cpbm_wd);
+			if (ret)
+				return ret;
+		}
 	}
 
 	if (mpam_has_feature(mpam_feat_mbw_part, rprops)) {
-		if (mpam_has_feature(mpam_feat_mbw_part, cfg))
-			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_part, cfg)) {
+			ret = mpam_write_partsel_reg(msc, MBW_PBM, cfg->mbw_pbm);
+			if (ret)
+				return ret;
+		} else {
+			ret = mpam_reset_msc_bitmap(msc, MPAMCFG_MBW_PBM,
+						    rprops->mbw_pbm_bits);
+			if (ret)
+				return ret;
+		}
 	}
 
 	if (mpam_has_feature(mpam_feat_mbw_min, rprops)) {
@@ -1760,27 +1784,47 @@ static void mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 partid,
 			val = max(val, min);
 		}
 
-		mpam_write_partsel_reg(msc, MBW_MIN, val);
+		ret = mpam_write_partsel_reg(msc, MBW_MIN, val);
+		if (ret)
+			return ret;
 	}
 
 	if (mpam_has_feature(mpam_feat_mbw_max, rprops)) {
-		if (mpam_has_feature(mpam_feat_mbw_max, cfg))
-			mpam_write_partsel_reg(msc, MBW_MAX, cfg->mbw_max);
-		else
-			mpam_write_partsel_reg(msc, MBW_MAX, MPAMCFG_MBW_MAX_MAX);
+		if (mpam_has_feature(mpam_feat_mbw_max, cfg)) {
+			ret = mpam_write_partsel_reg(msc, MBW_MAX, cfg->mbw_max);
+			if (ret)
+				return ret;
+		} else {
+			ret = mpam_write_partsel_reg(msc, MBW_MAX,
+						     MPAMCFG_MBW_MAX_MAX);
+			if (ret)
+				return ret;
+		}
 	}
 
-	if (mpam_has_feature(mpam_feat_mbw_prop, rprops))
-		mpam_write_partsel_reg(msc, MBW_PROP, 0);
+	if (mpam_has_feature(mpam_feat_mbw_prop, rprops)) {
+		ret = mpam_write_partsel_reg(msc, MBW_PROP, 0);
+		if (ret)
+			return ret;
+	}
 
-	if (mpam_has_feature(mpam_feat_cmax_cmax, rprops))
-		mpam_write_partsel_reg(msc, CMAX, cmax);
+	if (mpam_has_feature(mpam_feat_cmax_cmax, rprops)) {
+		ret = mpam_write_partsel_reg(msc, CMAX, cmax);
+		if (ret)
+			return ret;
+	}
 
-	if (mpam_has_feature(mpam_feat_cmax_cmin, rprops))
-		mpam_write_partsel_reg(msc, CMIN, 0);
+	if (mpam_has_feature(mpam_feat_cmax_cmin, rprops)) {
+		ret = mpam_write_partsel_reg(msc, CMIN, 0);
+		if (ret)
+			return ret;
+	}
 
-	if (mpam_has_feature(mpam_feat_cmax_cassoc, rprops))
-		mpam_write_partsel_reg(msc, CASSOC, MPAMCFG_CASSOC_CASSOC);
+	if (mpam_has_feature(mpam_feat_cmax_cassoc, rprops)) {
+		ret = mpam_write_partsel_reg(msc, CASSOC, MPAMCFG_CASSOC_CASSOC);
+		if (ret)
+			return ret;
+	}
 
 	if (mpam_has_feature(mpam_feat_intpri_part, rprops) ||
 	    mpam_has_feature(mpam_feat_dspri_part, rprops)) {
@@ -1804,12 +1848,14 @@ static void mpam_reprogram_ris_partid(struct mpam_msc_ris *ris, u16 partid,
 			pri_val |= FIELD_PREP(MPAMCFG_PRI_DSPRI, dspri);
 		}
 
-		mpam_write_partsel_reg(msc, PRI, pri_val);
+		ret = mpam_write_partsel_reg(msc, PRI, pri_val);
+		if (ret)
+			return ret;
 	}
 
 	mpam_quirk_post_config_change(ris, partid, cfg);
 
-	mutex_unlock(&msc->part_sel_lock);
+	return 0;
 }
 
 /* Call with msc cfg_lock held */
@@ -1936,6 +1982,7 @@ static int mpam_reset_ris(void *arg)
 	u16 partid_max;
 	struct mpam_config reset_cfg = {};
 	struct mpam_msc_ris *ris = arg;
+	int ret;
 
 	if (ris->in_reset_state)
 		return 0;
@@ -1943,8 +1990,11 @@ static int mpam_reset_ris(void *arg)
 	spin_lock(&partid_max_lock);
 	partid_max = mpam_partid_max;
 	spin_unlock(&partid_max_lock);
-	for (u32 partid = 0; partid <= partid_max; partid++)
-		mpam_reprogram_ris_partid(ris, partid, &reset_cfg);
+	for (u32 partid = 0; partid <= partid_max; partid++) {
+		ret = mpam_reprogram_ris_partid(ris, partid, &reset_cfg);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
@@ -1983,9 +2033,8 @@ static int __write_config(void *arg)
 {
 	struct mpam_write_config_arg *c = arg;
 
-	mpam_reprogram_ris_partid(c->ris, c->partid, &c->comp->cfg[c->partid]);
-
-	return 0;
+	return mpam_reprogram_ris_partid(c->ris, c->partid,
+					 &c->comp->cfg[c->partid]);
 }
 
 static void mpam_reprogram_msc(struct mpam_msc *msc)
@@ -3144,6 +3193,7 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid,
 	struct mpam_msc_ris *ris;
 	struct mpam_vmsc *vmsc;
 	struct mpam_msc *msc;
+	int ret;
 
 	lockdep_assert_cpus_held();
 
@@ -3161,14 +3211,15 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid,
 				 srcu_read_lock_held(&mpam_srcu)) {
 		msc = vmsc->msc;
 
-		mutex_lock(&msc->cfg_lock);
+		guard(mutex)(&msc->cfg_lock);
 		list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list,
 					 srcu_read_lock_held(&mpam_srcu)) {
 			arg.ris = ris;
-			mpam_touch_msc(msc, __write_config, &arg);
+			ret = mpam_touch_msc(msc, __write_config, &arg);
+			if (ret)
+				return ret;
 			ris->in_reset_state = false;
 		}
-		mutex_unlock(&msc->cfg_lock);
 	}
 
 	return 0;
-- 
2.53.0