From 4d044c521a63b2cd394ea6e3547012032145e47e Mon Sep 17 00:00:00 2001 From: James Morse Date: Fri, 2 Sep 2022 15:48:23 +0000 Subject: 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. A read from a counter that hardware supports but resctrl does not now returns -EINVAL instead of -EIO from the default case in __mon_event_count(). It isn't possible for user-space to see this change as resctrl doesn't expose counters it doesn't support. Signed-off-by: James Morse Signed-off-by: Borislav Petkov Reviewed-by: Jamie Iles Reviewed-by: Shaopeng Tan Reviewed-by: Reinette Chatre Tested-by: Xin Hao Tested-by: Shaopeng Tan Tested-by: Cristian Marussi Link: https://lore.kernel.org/r/20220902154829.30399-16-james.morse@arm.com --- arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 4 +- arch/x86/kernel/cpu/resctrl/internal.h | 1 + arch/x86/kernel/cpu/resctrl/monitor.c | 62 +++++++++++++++++++------------ 3 files changed, 42 insertions(+), 25 deletions(-) (limited to 'arch/x86/kernel/cpu') diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index 0ab92320de71..42a1abb378f0 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 b34a1403f033..1d2e7bd6305f 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -94,6 +94,7 @@ 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 e9755143492b..51ab76f2dfbc 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; } @@ -315,19 +327,19 @@ static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int width) return chunks >> shift; } -static u64 __mon_event_count(u32 rmid, struct rmid_read *rr) +static int __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; @@ -341,9 +353,9 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr) default: /* * Code would never reach here because an invalid - * event id would fail the __rmid_read. + * event id would fail in resctrl_arch_rmid_read(). */ - return RMID_VAL_ERROR; + return -EINVAL; } if (rr->first) { @@ -399,11 +411,11 @@ void mon_event_count(void *info) struct rdtgroup *rdtgrp, *entry; struct rmid_read *rr = info; struct list_head *head; - u64 ret_val; + int ret; rdtgrp = rr->rgrp; - ret_val = __mon_event_count(rdtgrp->mon.rmid, rr); + ret = __mon_event_count(rdtgrp->mon.rmid, rr); /* * For Ctrl groups read data from child monitor groups and @@ -415,13 +427,17 @@ void mon_event_count(void *info) if (rdtgrp->type == RDTCTRL_GROUP) { list_for_each_entry(entry, head, mon.crdtgrp_list) { if (__mon_event_count(entry->mon.rmid, rr) == 0) - ret_val = 0; + ret = 0; } } - /* Report error if none of rmid_reads are successful */ - if (ret_val) - rr->val = ret_val; + /* + * __mon_event_count() calls for newly created monitor groups may + * report -EINVAL/Unavailable if the monitor hasn't seen any traffic. + * Discard error if any of the monitor event reads succeeded. + */ + if (ret == 0) + rr->err = 0; } /* -- cgit v1.2.3