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Message-ID: <31b14155abb7a66aace3dabfa4cc481bfd9e6647.1749848715.git.babu.moger@amd.com>
Date: Fri, 13 Jun 2025 16:04:53 -0500
From: Babu Moger <babu.moger@....com>
To: <babu.moger@....com>, <corbet@....net>, <tony.luck@...el.com>,
<reinette.chatre@...el.com>, <Dave.Martin@....com>, <james.morse@....com>,
<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
<dave.hansen@...ux.intel.com>
CC: <x86@...nel.org>, <hpa@...or.com>, <akpm@...ux-foundation.org>,
<rostedt@...dmis.org>, <paulmck@...nel.org>, <thuth@...hat.com>,
<ardb@...nel.org>, <gregkh@...uxfoundation.org>, <seanjc@...gle.com>,
<thomas.lendacky@....com>, <pawan.kumar.gupta@...ux.intel.com>,
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<linux-kernel@...r.kernel.org>
Subject: [PATCH v14 09/32] x86/resctrl: Detect Assignable Bandwidth Monitoring feature details
ABMC feature details are reported via CPUID Fn8000_0020_EBX_x5.
Bits Description
15:0 MAX_ABMC Maximum Supported Assignable Bandwidth
Monitoring Counter ID + 1
The feature details are documented in APM listed below [1].
[1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth
Monitoring (ABMC).
Detect the feature and number of assignable counters supported. Also,
enable QOS_L3_MBM_TOTAL_EVENT_ID and QOS_L3_MBM_LOCAL_EVENT_ID upon
detecting the ABMC feature. The current expectation is to support
these two events by default when ABMC is enabled.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Babu Moger <babu.moger@....com>
---
v14: Updated enumeration to support ABMC regardless of MBM total and local support.
Updated the changelog accordingly.
v13: No changes.
v12: Resolved conflicts because of latest merge.
Removed Reviewed-by as the patch has changed.
v11: No changes.
v10: No changes.
v9: Added Reviewed-by tag. No code changes
v8: Used GENMASK for the mask.
v7: Removed WARN_ON for num_mbm_cntrs. Decided to dynamically allocate the
bitmap. WARN_ON is not required anymore.
Removed redundant comments.
v6: Commit message update.
Renamed abmc_capable to mbm_cntr_assignable.
v5: Name change num_cntrs to num_mbm_cntrs.
Moved abmc_capable to resctrl_mon.
v4: Removed resctrl_arch_has_abmc(). Added all the code inline. We dont
need to separate this as arch code.
v3: Removed changes related to mon_features.
Moved rdt_cpu_has to core.c and added new function resctrl_arch_has_abmc.
Also moved the fields mbm_assign_capable and mbm_assign_cntrs to
rdt_resource. (James)
v2: Changed the field name to mbm_assign_capable from abmc_capable.
---
arch/x86/kernel/cpu/resctrl/core.c | 4 ++--
arch/x86/kernel/cpu/resctrl/monitor.c | 11 ++++++++---
include/linux/resctrl.h | 4 ++++
3 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 22a414802cbb..01b210febc7d 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -873,11 +873,11 @@ static __init bool get_rdt_mon_resources(void)
resctrl_enable_mon_event(QOS_L3_OCCUP_EVENT_ID);
ret = true;
}
- if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL)) {
+ if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL) || rdt_cpu_has(X86_FEATURE_ABMC)) {
resctrl_enable_mon_event(QOS_L3_MBM_TOTAL_EVENT_ID);
ret = true;
}
- if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL)) {
+ if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL) || rdt_cpu_has(X86_FEATURE_ABMC)) {
resctrl_enable_mon_event(QOS_L3_MBM_LOCAL_EVENT_ID);
ret = true;
}
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 42a9e3cc6654..a6b9a6ba036d 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -339,6 +339,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;
struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
unsigned int threshold;
+ u32 eax, ebx, ecx, edx;
snc_nodes_per_l3_cache = snc_get_config();
@@ -368,14 +369,18 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
*/
resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(threshold);
- if (rdt_cpu_has(X86_FEATURE_BMEC)) {
- u32 eax, ebx, ecx, edx;
-
+ if (rdt_cpu_has(X86_FEATURE_BMEC) || rdt_cpu_has(X86_FEATURE_ABMC)) {
/* Detect list of bandwidth sources that can be tracked */
cpuid_count(0x80000020, 3, &eax, &ebx, &ecx, &edx);
r->mon.mbm_cfg_mask = ecx & MAX_EVT_CONFIG_BITS;
}
+ if (rdt_cpu_has(X86_FEATURE_ABMC)) {
+ r->mon.mbm_cntr_assignable = true;
+ cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
+ r->mon.num_mbm_cntrs = (ebx & GENMASK(15, 0)) + 1;
+ }
+
r->mon_capable = true;
return 0;
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 22766b8b670b..c0195498bd4a 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -260,10 +260,14 @@ enum resctrl_schema_fmt {
* @num_rmid: Number of RMIDs available.
* @mbm_cfg_mask: Memory transactions that can be tracked when bandwidth
* monitoring events are configured.
+ * @num_mbm_cntrs: Number of assignable counters.
+ * @mbm_cntr_assignable:Is system capable of supporting counter assignment?
*/
struct resctrl_mon {
int num_rmid;
unsigned int mbm_cfg_mask;
+ int num_mbm_cntrs;
+ bool mbm_cntr_assignable;
};
/**
--
2.34.1
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