[PATCH v3 04/10] x86/resctrl: Detect and configure Slow Memory Bandwidth allocation

From: Babu Moger
Date: Mon Aug 22 2022 - 09:43:48 EST


The QoS slow memory configuration details are available via
CPUID_Fn80000020_EDX_x02. Detect the available details and
initialize the rest to defaults.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/resctrl/core.c | 50 +++++++++++++++++++++++++++++
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 2 +
arch/x86/kernel/cpu/resctrl/internal.h | 1 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 9 +++--
4 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 6c38427b71a2..36ad97ab7342 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -253,6 +253,37 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
return true;
}

+static bool __rdt_get_s_mem_config_amd(struct rdt_resource *r)
+{
+ struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
+ union cpuid_0x10_3_eax eax;
+ union cpuid_0x10_x_edx edx;
+ u32 ebx, ecx;
+
+ cpuid_count(0x80000020, 2, &eax.full, &ebx, &ecx, &edx.full);
+ hw_res->num_closid = edx.split.cos_max + 1;
+ r->default_ctrl = MAX_MBA_BW_AMD;
+
+ /* AMD does not use delay */
+ r->membw.delay_linear = false;
+ r->membw.arch_needs_linear = false;
+
+ /*
+ * AMD does not use memory delay throttle model to control
+ * the allocation like Intel does.
+ */
+ r->membw.throttle_mode = THREAD_THROTTLE_UNDEFINED;
+ r->membw.min_bw = 0;
+ r->membw.bw_gran = 1;
+ /* Max value is 2048, Data width should be 4 in decimal */
+ r->data_width = 4;
+
+ r->alloc_capable = true;
+ r->alloc_enabled = true;
+
+ return true;
+}
+
static void rdt_get_cache_alloc_cfg(int idx, struct rdt_resource *r)
{
struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
@@ -787,6 +818,19 @@ static __init bool get_mem_config(void)
return false;
}

+static __init bool get_s_mem_config(void)
+{
+ struct rdt_hw_resource *hw_res = &rdt_resources_all[RDT_RESOURCE_SMBA];
+
+ if (!rdt_cpu_has(X86_FEATURE_SMBA))
+ return false;
+
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+ return __rdt_get_s_mem_config_amd(&hw_res->r_resctrl);
+
+ return false;
+}
+
static __init bool get_rdt_alloc_resources(void)
{
struct rdt_resource *r;
@@ -817,6 +861,9 @@ static __init bool get_rdt_alloc_resources(void)
if (get_mem_config())
ret = true;

+ if (get_s_mem_config())
+ ret = true;
+
return ret;
}

@@ -908,6 +955,9 @@ static __init void rdt_init_res_defs_amd(void)
} else if (r->rid == RDT_RESOURCE_MBA) {
hw_res->msr_base = MSR_IA32_MBA_BW_BASE;
hw_res->msr_update = mba_wrmsr_amd;
+ } else if (r->rid == RDT_RESOURCE_SMBA) {
+ hw_res->msr_base = MSR_IA32_SMBA_BW_BASE;
+ hw_res->msr_update = mba_wrmsr_amd;
}
}
}
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 87666275eed9..11ec3577db40 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -203,7 +203,7 @@ static int parse_line(char *line, struct resctrl_schema *s,
unsigned long dom_id;

if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
- r->rid == RDT_RESOURCE_MBA) {
+ (r->rid == RDT_RESOURCE_MBA || r->rid == RDT_RESOURCE_SMBA)) {
rdt_last_cmd_puts("Cannot pseudo-lock MBA resource\n");
return -EINVAL;
}
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 24a1dfeb6cb2..c049a274383c 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -14,6 +14,7 @@
#define MSR_IA32_L2_CBM_BASE 0xd10
#define MSR_IA32_MBA_THRTL_BASE 0xd50
#define MSR_IA32_MBA_BW_BASE 0xc0000200
+#define MSR_IA32_SMBA_BW_BASE 0xc0000280

#define MSR_IA32_QM_CTR 0x0c8e
#define MSR_IA32_QM_EVTSEL 0x0c8d
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index f276aff521e8..fc5286067201 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1218,7 +1218,7 @@ static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)

list_for_each_entry(s, &resctrl_schema_all, list) {
r = s->res;
- if (r->rid == RDT_RESOURCE_MBA)
+ if (r->rid == RDT_RESOURCE_MBA || r->rid == RDT_RESOURCE_SMBA)
continue;
has_cache = true;
list_for_each_entry(d, &r->domains, list) {
@@ -1399,7 +1399,8 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
ctrl = resctrl_arch_get_config(r, d,
rdtgrp->closid,
schema->conf_type);
- if (r->rid == RDT_RESOURCE_MBA)
+ if (r->rid == RDT_RESOURCE_MBA ||
+ r->rid == RDT_RESOURCE_SMBA)
size = ctrl;
else
size = rdtgroup_cbm_to_size(r, d, ctrl);
@@ -2807,7 +2808,9 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)

list_for_each_entry(s, &resctrl_schema_all, list) {
r = s->res;
- if (r->rid == RDT_RESOURCE_MBA) {
+ if (r->rid == RDT_RESOURCE_MBA ||
+ r->rid == RDT_RESOURCE_SMBA) {
+
rdtgroup_init_mba(r);
} else {
ret = rdtgroup_init_cat(s, rdtgrp->closid);