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Message-Id: <20211001160302.31189-18-james.morse@arm.com>
Date: Fri, 1 Oct 2021 16:02:56 +0000
From: James Morse <james.morse@....com>
To: x86@...nel.org, linux-kernel@...r.kernel.org
Cc: Fenghua Yu <fenghua.yu@...el.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
H Peter Anvin <hpa@...or.com>,
Babu Moger <Babu.Moger@....com>,
James Morse <james.morse@....com>,
shameerali.kolothum.thodi@...wei.com,
Jamie Iles <jamie@...iainc.com>,
D Scott Phillips OS <scott@...amperecomputing.com>,
lcherian@...vell.com, bobo.shaobowang@...wei.com,
tan.shaopeng@...itsu.com
Subject: [PATCH v2 17/23] x86/resctrl: Abstract __rmid_read()
__rmid_read() selects the specified eventid and returns the counter
value from the msr. The error handling is architecture specific, and
handled by the callers, rdtgroup_mondata_show() and __mon_event_count().
Error handling should be handled by architecture specific code, as
a different architecture may have different requirements. MPAM's
counters can report that they are 'not ready', requiring a second
read after a short delay. This should be hidden from resctrl.
Make __rmid_read() the architecture specific function for reading
a counter. Rename it resctrl_arch_rmid_read() and move the error
handling into it.
Signed-off-by: James Morse <james.morse@....com>
---
Changes since v1:
* Return EINVAL from the impossible case in __mon_event_count() instead
of an x86 hardware specific value.
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 4 +--
arch/x86/kernel/cpu/resctrl/internal.h | 2 +-
arch/x86/kernel/cpu/resctrl/monitor.c | 42 +++++++++++++++--------
include/linux/resctrl.h | 1 +
4 files changed, 31 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 25baacd331e0..c8ca7184c6d9 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -579,9 +579,9 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
mon_event_read(&rr, r, d, rdtgrp, evtid, false);
- if (rr.val & RMID_VAL_ERROR)
+ if (rr.err == -EIO)
seq_puts(m, "Error\n");
- else if (rr.val & RMID_VAL_UNAVAIL)
+ else if (rr.err == -EINVAL)
seq_puts(m, "Unavailable\n");
else
seq_printf(m, "%llu\n", rr.val * hw_res->mon_scale);
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index f3f31315a907..eca7793d3342 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -40,7 +40,6 @@
*/
#define MBM_CNTR_WIDTH_OFFSET_MAX (62 - MBM_CNTR_WIDTH_BASE)
-
struct rdt_fs_context {
struct kernfs_fs_context kfc;
bool enable_cdpl2;
@@ -94,6 +93,7 @@ struct rmid_read {
struct rdt_domain *d;
enum resctrl_event_id evtid;
bool first;
+ int err;
u64 val;
};
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 35eef49954b0..cf35eaf01042 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -167,9 +167,9 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d,
memset(am, 0, sizeof(*am));
}
-static u64 __rmid_read(u32 rmid, enum resctrl_event_id eventid)
+int resctrl_arch_rmid_read(u32 rmid, enum resctrl_event_id eventid, u64 *val)
{
- u64 val;
+ u64 msr_val;
/*
* As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured
@@ -180,14 +180,24 @@ static u64 __rmid_read(u32 rmid, enum resctrl_event_id eventid)
* are error bits.
*/
wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid);
- rdmsrl(MSR_IA32_QM_CTR, val);
+ rdmsrl(MSR_IA32_QM_CTR, msr_val);
- return val;
+ if (msr_val & RMID_VAL_ERROR)
+ return -EIO;
+ if (msr_val & RMID_VAL_UNAVAIL)
+ return -EINVAL;
+
+ *val = msr_val;
+
+ return 0;
}
static bool rmid_dirty(struct rmid_entry *entry)
{
- u64 val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID);
+ u64 val = 0;
+
+ if (resctrl_arch_rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID, &val))
+ return true;
return val >= resctrl_cqm_threshold;
}
@@ -259,8 +269,8 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
{
struct rdt_resource *r;
struct rdt_domain *d;
- int cpu;
- u64 val;
+ int cpu, err;
+ u64 val = 0;
r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
@@ -268,8 +278,10 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
cpu = get_cpu();
list_for_each_entry(d, &r->domains, list) {
if (cpumask_test_cpu(cpu, &d->cpu_mask)) {
- val = __rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID);
- if (val <= resctrl_cqm_threshold)
+ err = resctrl_arch_rmid_read(entry->rmid,
+ QOS_L3_OCCUP_EVENT_ID,
+ &val);
+ if (err || val <= resctrl_cqm_threshold)
continue;
}
@@ -319,15 +331,15 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
{
struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);
struct mbm_state *m;
- u64 chunks, tval;
+ u64 chunks, tval = 0;
if (rr->first)
resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid);
- tval = __rmid_read(rmid, rr->evtid);
- if (tval & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL)) {
- return tval;
- }
+ rr->err = resctrl_arch_rmid_read(rmid, rr->evtid, &tval);
+ if (rr->err)
+ return rr->err;
+
switch (rr->evtid) {
case QOS_L3_OCCUP_EVENT_ID:
rr->val += tval;
@@ -343,7 +355,7 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
* Code would never reach here because an invalid
* event id would fail the __rmid_read.
*/
- return RMID_VAL_ERROR;
+ return -EINVAL;
}
if (rr->first) {
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 04f30d80fc67..01bdd8be590b 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -218,6 +218,7 @@ u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
u32 closid, enum resctrl_conf_type type);
int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d);
void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
+int resctrl_arch_rmid_read(u32 rmid, enum resctrl_event_id eventid, u64 *res);
/**
* resctrl_arch_reset_rmid() - Reset any private state associated with rmid
--
2.30.2
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