[PATCH v2 2/2] x86/resctrl: Remove hard-coded memory bandwidth event configuration
From: Babu Moger
Date: Tue Dec 12 2023 - 13:03:18 EST
If the BMEC (Bandwidth Monitoring Event Configuration) feature is
supported, the bandwidth events can be configured. The maximum supported
bandwidth bitmask can be determined by following CPUID command.
CPUID_Fn80000020_ECX_x03 [Platform QoS Monitoring Bandwidth Event
Configuration] Read-only. Reset: 0000_007Fh.
Bits Description
31:7 Reserved
6:0 Identifies the bandwidth sources that can be tracked.
The bandwidth sources can change with the processor generations.
Currently, this information is hard-coded. Remove the hard-coded value
and detect using CPUID command. Also print the valid bitmask when the
user tries to configure invalid value.
The CPUID details are documentation in the PPR listed below [1].
[1] Processor Programming Reference (PPR) Vol 1.1 for AMD Family 19h Model
11h B1 - 55901 Rev 0.25.
Fixes: dc2a3e857981 ("x86/resctrl: Add interface to read mbm_total_bytes_config")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v2: Earlier Sent as a part of ABMC feature.
https://lore.kernel.org/lkml/20231201005720.235639-1-babu.moger@xxxxxxx/
But this is not related to ABMC. Sending it separate now.
Removed the global resctrl_max_evt_bitmask. Added event_mask as part of
the resource.
---
arch/x86/kernel/cpu/resctrl/internal.h | 5 ++---
arch/x86/kernel/cpu/resctrl/monitor.c | 6 ++++++
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 18 ++++++++++--------
3 files changed, 18 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index d2979748fae4..3e2f505614d8 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -50,9 +50,6 @@
/* Dirty Victims to All Types of Memory */
#define DIRTY_VICTIMS_TO_ALL_MEM BIT(6)
-/* Max event bits supported */
-#define MAX_EVT_CONFIG_BITS GENMASK(6, 0)
-
struct rdt_fs_context {
struct kernfs_fs_context kfc;
bool enable_cdpl2;
@@ -394,6 +391,7 @@ struct rdt_parse_data {
* @msr_update: Function pointer to update QOS MSRs
* @mon_scale: cqm counter * mon_scale = occupancy in bytes
* @mbm_width: Monitor width, to detect and correct for overflow.
+ * @event_mask: Max supported event bitmask.
* @cdp_enabled: CDP state of this resource
*
* Members of this structure are either private to the architecture
@@ -408,6 +406,7 @@ struct rdt_hw_resource {
struct rdt_resource *r);
unsigned int mon_scale;
unsigned int mbm_width;
+ unsigned int event_mask;
bool cdp_enabled;
};
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index f136ac046851..30bf919edfda 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -813,6 +813,12 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
return ret;
if (rdt_cpu_has(X86_FEATURE_BMEC)) {
+ u32 eax, ebx, ecx, edx;
+
+ /* Detect list of bandwidth sources that can be tracked */
+ cpuid_count(0x80000020, 3, &eax, &ebx, &ecx, &edx);
+ hw_res->event_mask = ecx;
+
if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL)) {
mbm_total_event.configurable = true;
mbm_config_rftype_init("mbm_total_bytes_config");
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 69a1de92384a..8a1e9fdab974 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1537,17 +1537,14 @@ static void mon_event_config_read(void *info)
{
struct mon_config_info *mon_info = info;
unsigned int index;
- u64 msrval;
+ u32 h;
index = mon_event_config_index_get(mon_info->evtid);
if (index == INVALID_CONFIG_INDEX) {
pr_warn_once("Invalid event id %d\n", mon_info->evtid);
return;
}
- rdmsrl(MSR_IA32_EVT_CFG_BASE + index, msrval);
-
- /* Report only the valid event configuration bits */
- mon_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
+ rdmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, h);
}
static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mon_info)
@@ -1557,6 +1554,7 @@ static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mo
static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid)
{
+ struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct mon_config_info mon_info = {0};
struct rdt_domain *dom;
bool sep = false;
@@ -1571,7 +1569,9 @@ static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid
mon_info.evtid = evtid;
mondata_config_read(dom, &mon_info);
- seq_printf(s, "%d=0x%02x", dom->id, mon_info.mon_config);
+ /* Report only the valid event configuration bits */
+ seq_printf(s, "%d=0x%02x", dom->id,
+ mon_info.mon_config & hw_res->event_mask);
sep = true;
}
seq_puts(s, "\n");
@@ -1617,12 +1617,14 @@ static void mon_event_config_write(void *info)
static int mbm_config_write_domain(struct rdt_resource *r,
struct rdt_domain *d, u32 evtid, u32 val)
{
+ struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct mon_config_info mon_info = {0};
int ret = 0;
/* mon_config cannot be more than the supported set of events */
- if (val > MAX_EVT_CONFIG_BITS) {
- rdt_last_cmd_puts("Invalid event configuration\n");
+ if ((val & hw_res->event_mask) != val) {
+ rdt_last_cmd_printf("Invalid input: The maximum valid bitmask is 0x%02x\n",
+ hw_res->event_mask);
return -EINVAL;
}