From: Ben Horgan <ben.horgan@arm.com>
To: ben.horgan@arm.com
Cc: james.morse@arm.com, reinette.chatre@intel.com,
fenghuay@nvidia.com, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, dave.martin@arm.com,
andre.przywara@arm.com
Subject: [PATCH v1 06/11] arm_mpam: Use __ris_msmon_read() for saving MBWU state
Date: Fri, 10 Jul 2026 12:55:40 +0100 [thread overview]
Message-ID: <20260710115546.29644-7-ben.horgan@arm.com> (raw)
In-Reply-To: <20260710115546.29644-1-ben.horgan@arm.com>
mbwu_save_mbwu_state() reads the MBWU counters and adds that to a saved
correction value. However, the type of counter to read is determined by the
RIS rather than the class and overflow is not taken into account. Fix this
and mitigate against further divergence by using the same helper as used
for user reads, __ris_msmon_read().
Fixes: 41e8a14950e1 ("arm_mpam: Track bandwidth counter state for power management")
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
---
drivers/resctrl/mpam_devices.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 222fc248067e..a49f426aefc0 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1029,12 +1029,6 @@ struct mon_read {
bool waited_timeout;
};
-static bool mpam_ris_has_mbwu_long_counter(struct mpam_msc_ris *ris)
-{
- return (mpam_has_feature(mpam_feat_msmon_mbwu_63counter, &ris->props) ||
- mpam_has_feature(mpam_feat_msmon_mbwu_44counter, &ris->props));
-}
-
static u64 mpam_msc_read_mbwu_l(struct mpam_msc *msc)
{
int retry = 3;
@@ -1687,6 +1681,7 @@ static int mpam_save_mbwu_state(void *arg)
struct mpam_msc_ris *ris = arg;
struct msmon_mbwu_state *mbwu_state;
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++) {
mbwu_state = &ris->mbwu_state[i];
@@ -1702,18 +1697,32 @@ static int mpam_save_mbwu_state(void *arg)
cur_flt = mpam_read_monsel_reg(msc, CFG_MBWU_FLT);
cur_ctl = mpam_read_monsel_reg(msc, CFG_MBWU_CTL);
- if (mpam_ris_has_mbwu_long_counter(ris))
- val = mpam_msc_read_mbwu_l(msc);
- else
- val = mpam_read_monsel_reg(msc, MBWU);
-
cfg->mon = i;
cfg->pmg = FIELD_GET(MSMON_CFG_x_FLT_PMG, cur_flt);
cfg->match_pmg = FIELD_GET(MSMON_CFG_x_CTL_MATCH_PMG, cur_ctl);
cfg->partid = FIELD_GET(MSMON_CFG_x_FLT_PARTID, cur_flt);
- mbwu_state->correction += val;
mbwu_state->enabled = FIELD_GET(MSMON_CFG_x_CTL_EN, cur_ctl);
mpam_mon_sel_unlock(msc);
+
+ if (mbwu_state->enabled) {
+ struct mon_read mbwu_arg = {
+ mbwu_arg.ris = ris,
+ mbwu_arg.ctx = cfg,
+ mbwu_arg.type = mpam_msmon_choose_counter(class),
+ mbwu_arg.val = &val,
+ };
+
+ val = 0;
+ __ris_msmon_read(&mbwu_arg);
+
+ if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc)))
+ return -EIO;
+
+ mbwu_state->reset_on_next_read = true;
+ if (!mbwu_arg.err)
+ mbwu_state->correction = val;
+ mpam_mon_sel_unlock(msc);
+ }
}
return 0;
--
2.43.0
next prev parent reply other threads:[~2026-07-10 11:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-10 11:55 [PATCH v1 00/11] arm_mpam: minor fixes at v7.2 Ben Horgan
2026-07-10 11:55 ` [PATCH v1 01/11] arm_mpam: Move MPAMF_ECR write helpers to allow reuse Ben Horgan
2026-07-10 11:55 ` [PATCH v1 02/11] arm_mpam: Restore the error interrupt enable from mpam_cpu_online() Ben Horgan
2026-07-10 11:55 ` [PATCH v1 03/11] arm_mpam: Set mpam_feat_msmon_mbwu_31counter when there are bandwidth counters Ben Horgan
2026-07-10 11:55 ` [PATCH v1 04/11] arm_mpam: Add missing mon_sel locking in MBWU restore Ben Horgan
2026-07-10 11:55 ` [PATCH v1 05/11] arm_mpam: Ensure MBWU counters are reset on restore Ben Horgan
2026-07-10 11:55 ` Ben Horgan [this message]
2026-07-10 11:55 ` [PATCH v1 07/11] arm_mpam: Initialize all of struct mon_read in mpam_restore_mbwu_state() Ben Horgan
2026-07-10 11:55 ` [PATCH v1 08/11] arm_mpam: resctrl: Correct check that existing class is L3 Ben Horgan
2026-07-10 11:55 ` [PATCH v1 09/11] arm_mpam: resctrl: Make read_mon_cdp_safe() self consistent Ben Horgan
2026-07-10 11:55 ` [PATCH v1 10/11] arm_mpam: Don't loop forever if there is the maximum possible amount of PARTIDs Ben Horgan
2026-07-10 11:55 ` [PATCH v1 11/11] arm_mpam: Switch to kvzmalloc_objs() for allocation of component cfg Ben Horgan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260710115546.29644-7-ben.horgan@arm.com \
--to=ben.horgan@arm.com \
--cc=andre.przywara@arm.com \
--cc=dave.martin@arm.com \
--cc=fenghuay@nvidia.com \
--cc=james.morse@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=reinette.chatre@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox