The Intel Hardware Feedback Interface provides guidance to the operating
system about the performance and energy efficiency capabilities of each
CPU in the system. Capabilities are numbers between 0 and 255 where a
higher number represents a higher capability. For each CPU, energy
efficiency and performance are reported as separate capabilities.
Hardware computes these capabilities based on the operating conditions of
the system such as power and thermal limits. These capabilities are shared
with the operating system in a table resident in memory. Each package in
the system has its own HFI instance. Every logical CPU in the package is
represented in the table. More than one logical CPUs may be represented in
a single table entry. When the hardware updates the table, it generates a
package-level thermal interrupt.
The size and format of the HFI table depend on the supported features and
can only be determined at runtime. To minimally initialize the HFI, parse
its features and allocate one instance per package of a data structure with
the necessary parameters to read and navigate individual HFI tables.
A subsequent changeset will provide per-CPU initialization and interrupt
handling.
Cc: Andi Kleen <[email protected]>
Cc: Aubrey Li <[email protected]>
Cc: Srinivas Pandruvada <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: "Ravi V. Shankar" <[email protected]>
Reviewed-by: Len Brown <[email protected]>
Co-developed by: Aubrey Li <[email protected]>
Signed-off-by: Aubrey Li <[email protected]>
Signed-off-by: Ricardo Neri <[email protected]>
---
drivers/thermal/intel/Kconfig | 12 +++
drivers/thermal/intel/Makefile | 1 +
drivers/thermal/intel/intel_hfi.c | 155 ++++++++++++++++++++++++++++
drivers/thermal/intel/intel_hfi.h | 34 ++++++
drivers/thermal/intel/therm_throt.c | 3 +
5 files changed, 205 insertions(+)
create mode 100644 drivers/thermal/intel/intel_hfi.c
create mode 100644 drivers/thermal/intel/intel_hfi.h
diff --git a/drivers/thermal/intel/Kconfig b/drivers/thermal/intel/Kconfig
index c83ea5d04a1d..d4c6bdcacddb 100644
--- a/drivers/thermal/intel/Kconfig
+++ b/drivers/thermal/intel/Kconfig
@@ -99,3 +99,15 @@ config INTEL_MENLOW
Intel Menlow platform.
If unsure, say N.
+
+config INTEL_HFI
+ bool "Intel Hardware Feedback Interface"
+ depends on CPU_SUP_INTEL
+ depends on SCHED_MC && X86_THERMAL_VECTOR
+ help
+ Select this option to enable the Hardware Feedback Interface. If
+ selected, hardware provides guidance to the operating system on
+ the performance and energy efficiency capabilities of each CPU.
+ These capabilities may change as a result of changes in the operating
+ conditions of the system such power and thermal limits. If selected,
+ the kernel relays updates in CPUs' capabilities to userspace.
diff --git a/drivers/thermal/intel/Makefile b/drivers/thermal/intel/Makefile
index 960b56268b4a..1a80bffcd699 100644
--- a/drivers/thermal/intel/Makefile
+++ b/drivers/thermal/intel/Makefile
@@ -13,3 +13,4 @@ obj-$(CONFIG_INTEL_PCH_THERMAL) += intel_pch_thermal.o
obj-$(CONFIG_INTEL_TCC_COOLING) += intel_tcc_cooling.o
obj-$(CONFIG_X86_THERMAL_VECTOR) += therm_throt.o
obj-$(CONFIG_INTEL_MENLOW) += intel_menlow.o
+obj-$(CONFIG_INTEL_HFI) += intel_hfi.o
diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
new file mode 100644
index 000000000000..edfe343507b3
--- /dev/null
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Hardware Feedback Interface Driver
+ *
+ * Copyright (c) 2021, Intel Corporation.
+ *
+ * Authors: Aubrey Li <[email protected]>
+ * Ricardo Neri <[email protected]>
+ *
+ *
+ * The Hardware Feedback Interface provides a performance and energy efficiency
+ * capability information for each CPU in the system. Depending on the processor
+ * model, hardware may periodically update these capabilities as a result of
+ * changes in the operating conditions (e.g., power limits or thermal
+ * constraints). On other processor models, there is a single HFI update
+ * at boot.
+ *
+ * This file provides functionality to process HFI updates and relay these
+ * updates to userspace.
+ */
+
+#define pr_fmt(fmt) "intel-hfi: " fmt
+
+#include <linux/slab.h>
+
+#include "intel_hfi.h"
+
+/**
+ * struct hfi_cpu_data - HFI capabilities per CPU
+ * @perf_cap: Performance capability
+ * @ee_cap: Energy efficiency capability
+ *
+ * Capabilities of a logical processor in the HFI table. These capabilities are
+ * unitless.
+ */
+struct hfi_cpu_data {
+ u8 perf_cap;
+ u8 ee_cap;
+} __packed;
+
+/**
+ * struct hfi_hdr - Header of the HFI table
+ * @perf_updated: Hardware updated performance capabilities
+ * @ee_updated: Hardware updated energy efficiency capabilities
+ *
+ * Properties of the data in an HFI table.
+ */
+struct hfi_hdr {
+ u8 perf_updated;
+ u8 ee_updated;
+} __packed;
+
+/**
+ * struct hfi_instance - Representation of an HFI instance (i.e., a table)
+ * @ts_counter: Time stamp of the last update of the table
+ * @hdr: Base address of the table header
+ * @data: Base address of the table data
+ *
+ * A set of parameters to parse and navigate a specific HFI table.
+ */
+struct hfi_instance {
+ u64 *ts_counter;
+ void *hdr;
+ void *data;
+};
+
+/**
+ * struct hfi_features - Supported HFI features
+ * @capabilities: Bitmask of supported capabilities
+ * @nr_table_pages: Size of the HFI table in 4KB pages
+ * @cpu_stride: Stride size to locate capability data of a logical
+ * processor within the table (i.e., row stride)
+ * @hdr_size: Size of table header
+ * @parsed: True if HFI features have been parsed
+ *
+ * Parameters and supported features that are common to all HFI instances
+ */
+struct hfi_features {
+ unsigned long capabilities;
+ unsigned int nr_table_pages;
+ unsigned int cpu_stride;
+ unsigned int hdr_size;
+ bool parsed;
+};
+
+static int max_hfi_instances;
+static struct hfi_instance *hfi_instances;
+
+static struct hfi_features hfi_features;
+
+static __init int hfi_parse_features(void)
+{
+ unsigned int nr_capabilities, reg;
+
+ if (!boot_cpu_has(X86_FEATURE_INTEL_HFI))
+ return -ENODEV;
+
+ if (hfi_features.parsed)
+ return 0;
+
+ /*
+ * If we are here we know that CPUID_HFI_LEAF exists. Parse the
+ * supported capabilities and the size of the HFI table.
+ */
+ reg = cpuid_edx(CPUID_HFI_LEAF);
+
+ hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
+ if (!(hfi_features.capabilities & HFI_CAPABILITIES_PERFORMANCE)) {
+ pr_err("Performance reporting not supported! Not using HFI\n");
+ return -ENODEV;
+ }
+
+ /* The number of 4KB pages required by the table */
+ hfi_features.nr_table_pages = ((reg & CPUID_HFI_TABLE_SIZE_MASK) >>
+ CPUID_HFI_TABLE_SIZE_SHIFT) + 1;
+
+ /*
+ * The number of supported capabilities determines the number of
+ * columns in the HFI table.
+ */
+ nr_capabilities = bitmap_weight(&hfi_features.capabilities,
+ HFI_CAPABILITIES_NR);
+
+ /*
+ * The header contains change indications for each supported feature.
+ * The size of the table header is rounded up to be a multiple of 8
+ * bytes.
+ */
+ hfi_features.hdr_size = DIV_ROUND_UP(nr_capabilities, 8) * 8;
+
+ /*
+ * Data of each logical processor is also rounded up to be a multiple
+ * of 8 bytes.
+ */
+ hfi_features.cpu_stride = DIV_ROUND_UP(nr_capabilities, 8) * 8;
+
+ hfi_features.parsed = true;
+ return 0;
+}
+
+void __init intel_hfi_init(void)
+{
+ if (hfi_parse_features())
+ return;
+
+ max_hfi_instances = topology_max_packages() *
+ topology_max_die_per_package();
+
+ /*
+ * This allocation may fail. CPU hotplug callbacks must check
+ * for a null pointer.
+ */
+ hfi_instances = kcalloc(max_hfi_instances, sizeof(*hfi_instances),
+ GFP_KERNEL);
+}
diff --git a/drivers/thermal/intel/intel_hfi.h b/drivers/thermal/intel/intel_hfi.h
new file mode 100644
index 000000000000..42529d3ac92d
--- /dev/null
+++ b/drivers/thermal/intel/intel_hfi.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _INTEL_HFI_H
+#define _INTEL_HFI_H
+
+#include <linux/bits.h>
+
+/* Hardware Feedback Interface Enumeration */
+#define CPUID_HFI_LEAF 6
+#define CPUID_HFI_CAP_MASK 0xff
+#define CPUID_HFI_TABLE_SIZE_MASK 0x0f00
+#define CPUID_HFI_TABLE_SIZE_SHIFT 8
+#define CPUID_HFI_CPU_INDEX_MASK 0xffff0000
+#define CPUID_HFI_CPU_INDEX_SHIFT 16
+
+/* Hardware Feedback Interface Pointer */
+#define HFI_PTR_VALID_BIT BIT(0)
+#define HFI_PTR_ADDR_SHIFT 12
+
+/* Hardware Feedback Interface Configuration */
+#define HFI_CONFIG_ENABLE_BIT BIT(0)
+
+/* Hardware Feedback Interface Capabilities */
+#define HFI_CAPABILITIES_MASK 0xff
+#define HFI_CAPABILITIES_NR 8
+#define HFI_CAPABILITIES_PERFORMANCE BIT(0)
+#define HFI_CAPABILITIES_ENERGY_EFF BIT(1)
+
+#if defined(CONFIG_INTEL_HFI)
+void __init intel_hfi_init(void);
+#else
+static inline void intel_hfi_init(void) { }
+#endif
+
+#endif /* _INTEL_HFI_H */
diff --git a/drivers/thermal/intel/therm_throt.c b/drivers/thermal/intel/therm_throt.c
index dab7e8fb1059..ac408714d52b 100644
--- a/drivers/thermal/intel/therm_throt.c
+++ b/drivers/thermal/intel/therm_throt.c
@@ -32,6 +32,7 @@
#include <asm/irq.h>
#include <asm/msr.h>
+#include "intel_hfi.h"
#include "thermal_interrupt.h"
/* How long to wait between reporting thermal events */
@@ -509,6 +510,8 @@ static __init int thermal_throttle_init_device(void)
if (!atomic_read(&therm_throt_en))
return 0;
+ intel_hfi_init();
+
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/therm:online",
thermal_throttle_online,
thermal_throttle_offline);
--
2.17.1
On Fri, Nov 05, 2021 at 06:33:08PM -0700, Ricardo Neri wrote:
> +static __init int hfi_parse_features(void)
> +{
> + unsigned int nr_capabilities, reg;
> +
> + /*
> + * If we are here we know that CPUID_HFI_LEAF exists. Parse the
> + * supported capabilities and the size of the HFI table.
> + */
> + reg = cpuid_edx(CPUID_HFI_LEAF);
> +
> + hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
> + if (!(hfi_features.capabilities & HFI_CAPABILITIES_PERFORMANCE)) {
> + pr_err("Performance reporting not supported! Not using HFI\n");
> + return -ENODEV;
> + }
> +
> + /* The number of 4KB pages required by the table */
> + hfi_features.nr_table_pages = ((reg & CPUID_HFI_TABLE_SIZE_MASK) >>
> + CPUID_HFI_TABLE_SIZE_SHIFT) + 1;
> +
> +/* Hardware Feedback Interface Enumeration */
> +#define CPUID_HFI_LEAF 6
> +#define CPUID_HFI_CAP_MASK 0xff
> +#define CPUID_HFI_TABLE_SIZE_MASK 0x0f00
> +#define CPUID_HFI_TABLE_SIZE_SHIFT 8
> +#define CPUID_HFI_CPU_INDEX_MASK 0xffff0000
Also, *if* you're going to do something like this, then at least write
out the masks in full so you can easily see how they relate. The above
is crap.
> +#define CPUID_HFI_CPU_INDEX_SHIFT 16
> +
> +/* Hardware Feedback Interface Pointer */
> +#define HFI_PTR_VALID_BIT BIT(0)
> +#define HFI_PTR_ADDR_SHIFT 12
> +
> +/* Hardware Feedback Interface Configuration */
> +#define HFI_CONFIG_ENABLE_BIT BIT(0)
> +
> +/* Hardware Feedback Interface Capabilities */
> +#define HFI_CAPABILITIES_MASK 0xff
> +#define HFI_CAPABILITIES_NR 8
> +#define HFI_CAPABILITIES_PERFORMANCE BIT(0)
> +#define HFI_CAPABILITIES_ENERGY_EFF BIT(1)
So personally I prefer a bitfield union a-la cpuid10_eax, cpuid10_ebx
cpuid10_edx etc.. Barring that, the above can also be written more
concise using FIELD_GET() from bitfields.
union cpuid6_edx {
struct {
unsigned int capabilities : 8;
unsigned int table_size : 4;
unsigned int __reserved : 4;
unsigned int cpu_index : 16;
};
unsigned int full;
};
On Mon, Nov 08, 2021 at 09:47:54AM +0100, Peter Zijlstra wrote:
> On Fri, Nov 05, 2021 at 06:33:08PM -0700, Ricardo Neri wrote:
> > +static __init int hfi_parse_features(void)
> > +{
> > + unsigned int nr_capabilities, reg;
> > +
>
> > + /*
> > + * If we are here we know that CPUID_HFI_LEAF exists. Parse the
> > + * supported capabilities and the size of the HFI table.
> > + */
> > + reg = cpuid_edx(CPUID_HFI_LEAF);
> > +
> > + hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
> > + if (!(hfi_features.capabilities & HFI_CAPABILITIES_PERFORMANCE)) {
> > + pr_err("Performance reporting not supported! Not using HFI\n");
> > + return -ENODEV;
> > + }
> > +
> > + /* The number of 4KB pages required by the table */
> > + hfi_features.nr_table_pages = ((reg & CPUID_HFI_TABLE_SIZE_MASK) >>
> > + CPUID_HFI_TABLE_SIZE_SHIFT) + 1;
> > +
>
> > +/* Hardware Feedback Interface Enumeration */
> > +#define CPUID_HFI_LEAF 6
> > +#define CPUID_HFI_CAP_MASK 0xff
> > +#define CPUID_HFI_TABLE_SIZE_MASK 0x0f00
> > +#define CPUID_HFI_TABLE_SIZE_SHIFT 8
> > +#define CPUID_HFI_CPU_INDEX_MASK 0xffff0000
>
> Also, *if* you're going to do something like this, then at least write
> out the masks in full so you can easily see how they relate. The above
> is crap.
>
> > +#define CPUID_HFI_CPU_INDEX_SHIFT 16
> > +
> > +/* Hardware Feedback Interface Pointer */
> > +#define HFI_PTR_VALID_BIT BIT(0)
> > +#define HFI_PTR_ADDR_SHIFT 12
> > +
> > +/* Hardware Feedback Interface Configuration */
> > +#define HFI_CONFIG_ENABLE_BIT BIT(0)
> > +
> > +/* Hardware Feedback Interface Capabilities */
> > +#define HFI_CAPABILITIES_MASK 0xff
> > +#define HFI_CAPABILITIES_NR 8
> > +#define HFI_CAPABILITIES_PERFORMANCE BIT(0)
> > +#define HFI_CAPABILITIES_ENERGY_EFF BIT(1)
>
>
> So personally I prefer a bitfield union a-la cpuid10_eax, cpuid10_ebx
> cpuid10_edx etc.. Barring that, the above can also be written more
> concise using FIELD_GET() from bitfields.
>
> union cpuid6_edx {
> struct {
> unsigned int capabilities : 8;
> unsigned int table_size : 4;
> unsigned int __reserved : 4;
> unsigned int cpu_index : 16;
> };
> unsigned int full;
> };
Sure Peter. This looks more readable. I'll implement it like this.
Thanks and BR,
Ricardo
On Sat, Nov 6, 2021 at 2:34 AM Ricardo Neri
<[email protected]> wrote:
>
> The Intel Hardware Feedback Interface provides guidance to the operating
> system about the performance and energy efficiency capabilities of each
> CPU in the system. Capabilities are numbers between 0 and 255 where a
> higher number represents a higher capability. For each CPU, energy
> efficiency and performance are reported as separate capabilities.
>
> Hardware computes these capabilities based on the operating conditions of
> the system such as power and thermal limits. These capabilities are shared
> with the operating system in a table resident in memory. Each package in
> the system has its own HFI instance. Every logical CPU in the package is
> represented in the table. More than one logical CPUs may be represented in
> a single table entry. When the hardware updates the table, it generates a
> package-level thermal interrupt.
>
> The size and format of the HFI table depend on the supported features and
> can only be determined at runtime. To minimally initialize the HFI, parse
> its features and allocate one instance per package of a data structure with
> the necessary parameters to read and navigate individual HFI tables.
>
> A subsequent changeset will provide per-CPU initialization and interrupt
> handling.
>
> Cc: Andi Kleen <[email protected]>
> Cc: Aubrey Li <[email protected]>
> Cc: Srinivas Pandruvada <[email protected]>
> Cc: Tim Chen <[email protected]>
> Cc: "Ravi V. Shankar" <[email protected]>
> Reviewed-by: Len Brown <[email protected]>
> Co-developed by: Aubrey Li <[email protected]>
> Signed-off-by: Aubrey Li <[email protected]>
> Signed-off-by: Ricardo Neri <[email protected]>
> ---
> drivers/thermal/intel/Kconfig | 12 +++
> drivers/thermal/intel/Makefile | 1 +
> drivers/thermal/intel/intel_hfi.c | 155 ++++++++++++++++++++++++++++
> drivers/thermal/intel/intel_hfi.h | 34 ++++++
> drivers/thermal/intel/therm_throt.c | 3 +
> 5 files changed, 205 insertions(+)
> create mode 100644 drivers/thermal/intel/intel_hfi.c
> create mode 100644 drivers/thermal/intel/intel_hfi.h
>
> diff --git a/drivers/thermal/intel/Kconfig b/drivers/thermal/intel/Kconfig
> index c83ea5d04a1d..d4c6bdcacddb 100644
> --- a/drivers/thermal/intel/Kconfig
> +++ b/drivers/thermal/intel/Kconfig
> @@ -99,3 +99,15 @@ config INTEL_MENLOW
> Intel Menlow platform.
>
> If unsure, say N.
> +
> +config INTEL_HFI
> + bool "Intel Hardware Feedback Interface"
> + depends on CPU_SUP_INTEL
> + depends on SCHED_MC && X86_THERMAL_VECTOR
> + help
> + Select this option to enable the Hardware Feedback Interface. If
> + selected, hardware provides guidance to the operating system on
> + the performance and energy efficiency capabilities of each CPU.
> + These capabilities may change as a result of changes in the operating
> + conditions of the system such power and thermal limits. If selected,
> + the kernel relays updates in CPUs' capabilities to userspace.
> diff --git a/drivers/thermal/intel/Makefile b/drivers/thermal/intel/Makefile
> index 960b56268b4a..1a80bffcd699 100644
> --- a/drivers/thermal/intel/Makefile
> +++ b/drivers/thermal/intel/Makefile
> @@ -13,3 +13,4 @@ obj-$(CONFIG_INTEL_PCH_THERMAL) += intel_pch_thermal.o
> obj-$(CONFIG_INTEL_TCC_COOLING) += intel_tcc_cooling.o
> obj-$(CONFIG_X86_THERMAL_VECTOR) += therm_throt.o
> obj-$(CONFIG_INTEL_MENLOW) += intel_menlow.o
> +obj-$(CONFIG_INTEL_HFI) += intel_hfi.o
> diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
> new file mode 100644
> index 000000000000..edfe343507b3
> --- /dev/null
> +++ b/drivers/thermal/intel/intel_hfi.c
> @@ -0,0 +1,155 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Hardware Feedback Interface Driver
> + *
> + * Copyright (c) 2021, Intel Corporation.
> + *
> + * Authors: Aubrey Li <[email protected]>
> + * Ricardo Neri <[email protected]>
> + *
> + *
> + * The Hardware Feedback Interface provides a performance and energy efficiency
> + * capability information for each CPU in the system. Depending on the processor
> + * model, hardware may periodically update these capabilities as a result of
> + * changes in the operating conditions (e.g., power limits or thermal
> + * constraints). On other processor models, there is a single HFI update
> + * at boot.
> + *
> + * This file provides functionality to process HFI updates and relay these
> + * updates to userspace.
> + */
> +
> +#define pr_fmt(fmt) "intel-hfi: " fmt
> +
> +#include <linux/slab.h>
> +
> +#include "intel_hfi.h"
> +
> +/**
> + * struct hfi_cpu_data - HFI capabilities per CPU
> + * @perf_cap: Performance capability
> + * @ee_cap: Energy efficiency capability
> + *
> + * Capabilities of a logical processor in the HFI table. These capabilities are
> + * unitless.
> + */
> +struct hfi_cpu_data {
> + u8 perf_cap;
> + u8 ee_cap;
> +} __packed;
> +
> +/**
> + * struct hfi_hdr - Header of the HFI table
> + * @perf_updated: Hardware updated performance capabilities
> + * @ee_updated: Hardware updated energy efficiency capabilities
> + *
> + * Properties of the data in an HFI table.
> + */
> +struct hfi_hdr {
> + u8 perf_updated;
> + u8 ee_updated;
> +} __packed;
> +
> +/**
> + * struct hfi_instance - Representation of an HFI instance (i.e., a table)
> + * @ts_counter: Time stamp of the last update of the table
> + * @hdr: Base address of the table header
> + * @data: Base address of the table data
> + *
> + * A set of parameters to parse and navigate a specific HFI table.
> + */
> +struct hfi_instance {
> + u64 *ts_counter;
> + void *hdr;
> + void *data;
> +};
> +
> +/**
> + * struct hfi_features - Supported HFI features
> + * @capabilities: Bitmask of supported capabilities
> + * @nr_table_pages: Size of the HFI table in 4KB pages
> + * @cpu_stride: Stride size to locate capability data of a logical
> + * processor within the table (i.e., row stride)
> + * @hdr_size: Size of table header
> + * @parsed: True if HFI features have been parsed
> + *
> + * Parameters and supported features that are common to all HFI instances
> + */
> +struct hfi_features {
> + unsigned long capabilities;
> + unsigned int nr_table_pages;
> + unsigned int cpu_stride;
> + unsigned int hdr_size;
> + bool parsed;
I'm not sure why this field is needed.
It looks like it is only checked by hfi_parse_features() which is only
called by intel_hfi_init() which is invoked by
thermal_throttle_init_device() which can happen only once if I'm not
mistaken.
> +};
> +
> +static int max_hfi_instances;
> +static struct hfi_instance *hfi_instances;
> +
> +static struct hfi_features hfi_features;
> +
> +static __init int hfi_parse_features(void)
> +{
> + unsigned int nr_capabilities, reg;
> +
> + if (!boot_cpu_has(X86_FEATURE_INTEL_HFI))
> + return -ENODEV;
> +
> + if (hfi_features.parsed)
> + return 0;
> +
> + /*
> + * If we are here we know that CPUID_HFI_LEAF exists. Parse the
> + * supported capabilities and the size of the HFI table.
> + */
> + reg = cpuid_edx(CPUID_HFI_LEAF);
> +
> + hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
> + if (!(hfi_features.capabilities & HFI_CAPABILITIES_PERFORMANCE)) {
> + pr_err("Performance reporting not supported! Not using HFI\n");
This doesn't need to be pr_err().
> + return -ENODEV;
> + }
> +
> + /* The number of 4KB pages required by the table */
> + hfi_features.nr_table_pages = ((reg & CPUID_HFI_TABLE_SIZE_MASK) >>
> + CPUID_HFI_TABLE_SIZE_SHIFT) + 1;
> +
> + /*
> + * The number of supported capabilities determines the number of
> + * columns in the HFI table.
> + */
> + nr_capabilities = bitmap_weight(&hfi_features.capabilities,
> + HFI_CAPABILITIES_NR);
> +
> + /*
> + * The header contains change indications for each supported feature.
> + * The size of the table header is rounded up to be a multiple of 8
> + * bytes.
> + */
> + hfi_features.hdr_size = DIV_ROUND_UP(nr_capabilities, 8) * 8;
> +
> + /*
> + * Data of each logical processor is also rounded up to be a multiple
> + * of 8 bytes.
> + */
> + hfi_features.cpu_stride = DIV_ROUND_UP(nr_capabilities, 8) * 8;
> +
> + hfi_features.parsed = true;
> + return 0;
> +}
> +
> +void __init intel_hfi_init(void)
> +{
> + if (hfi_parse_features())
> + return;
> +
> + max_hfi_instances = topology_max_packages() *
> + topology_max_die_per_package();
> +
> + /*
> + * This allocation may fail. CPU hotplug callbacks must check
> + * for a null pointer.
> + */
> + hfi_instances = kcalloc(max_hfi_instances, sizeof(*hfi_instances),
> + GFP_KERNEL);
> +}
> diff --git a/drivers/thermal/intel/intel_hfi.h b/drivers/thermal/intel/intel_hfi.h
> new file mode 100644
> index 000000000000..42529d3ac92d
> --- /dev/null
> +++ b/drivers/thermal/intel/intel_hfi.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _INTEL_HFI_H
> +#define _INTEL_HFI_H
> +
> +#include <linux/bits.h>
> +
> +/* Hardware Feedback Interface Enumeration */
> +#define CPUID_HFI_LEAF 6
> +#define CPUID_HFI_CAP_MASK 0xff
> +#define CPUID_HFI_TABLE_SIZE_MASK 0x0f00
> +#define CPUID_HFI_TABLE_SIZE_SHIFT 8
> +#define CPUID_HFI_CPU_INDEX_MASK 0xffff0000
> +#define CPUID_HFI_CPU_INDEX_SHIFT 16
> +
> +/* Hardware Feedback Interface Pointer */
> +#define HFI_PTR_VALID_BIT BIT(0)
> +#define HFI_PTR_ADDR_SHIFT 12
> +
> +/* Hardware Feedback Interface Configuration */
> +#define HFI_CONFIG_ENABLE_BIT BIT(0)
> +
> +/* Hardware Feedback Interface Capabilities */
> +#define HFI_CAPABILITIES_MASK 0xff
> +#define HFI_CAPABILITIES_NR 8
> +#define HFI_CAPABILITIES_PERFORMANCE BIT(0)
> +#define HFI_CAPABILITIES_ENERGY_EFF BIT(1)
> +
> +#if defined(CONFIG_INTEL_HFI)
> +void __init intel_hfi_init(void);
> +#else
> +static inline void intel_hfi_init(void) { }
> +#endif
> +
> +#endif /* _INTEL_HFI_H */
> diff --git a/drivers/thermal/intel/therm_throt.c b/drivers/thermal/intel/therm_throt.c
> index dab7e8fb1059..ac408714d52b 100644
> --- a/drivers/thermal/intel/therm_throt.c
> +++ b/drivers/thermal/intel/therm_throt.c
> @@ -32,6 +32,7 @@
> #include <asm/irq.h>
> #include <asm/msr.h>
>
> +#include "intel_hfi.h"
> #include "thermal_interrupt.h"
>
> /* How long to wait between reporting thermal events */
> @@ -509,6 +510,8 @@ static __init int thermal_throttle_init_device(void)
> if (!atomic_read(&therm_throt_en))
> return 0;
>
> + intel_hfi_init();
> +
> ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/therm:online",
> thermal_throttle_online,
> thermal_throttle_offline);
> --
> 2.17.1
>
On Wed, Nov 24, 2021 at 03:09:20PM +0100, Rafael J. Wysocki wrote:
> On Sat, Nov 6, 2021 at 2:34 AM Ricardo Neri
> <[email protected]> wrote:
> >
> > The Intel Hardware Feedback Interface provides guidance to the operating
> > system about the performance and energy efficiency capabilities of each
> > CPU in the system. Capabilities are numbers between 0 and 255 where a
> > higher number represents a higher capability. For each CPU, energy
> > efficiency and performance are reported as separate capabilities.
> >
> > Hardware computes these capabilities based on the operating conditions of
> > the system such as power and thermal limits. These capabilities are shared
> > with the operating system in a table resident in memory. Each package in
> > the system has its own HFI instance. Every logical CPU in the package is
> > represented in the table. More than one logical CPUs may be represented in
> > a single table entry. When the hardware updates the table, it generates a
> > package-level thermal interrupt.
> >
> > The size and format of the HFI table depend on the supported features and
> > can only be determined at runtime. To minimally initialize the HFI, parse
> > its features and allocate one instance per package of a data structure with
> > the necessary parameters to read and navigate individual HFI tables.
> >
> > A subsequent changeset will provide per-CPU initialization and interrupt
> > handling.
> >
> > Cc: Andi Kleen <[email protected]>
> > Cc: Aubrey Li <[email protected]>
> > Cc: Srinivas Pandruvada <[email protected]>
> > Cc: Tim Chen <[email protected]>
> > Cc: "Ravi V. Shankar" <[email protected]>
> > Reviewed-by: Len Brown <[email protected]>
> > Co-developed by: Aubrey Li <[email protected]>
> > Signed-off-by: Aubrey Li <[email protected]>
> > Signed-off-by: Ricardo Neri <[email protected]>
> > ---
> > drivers/thermal/intel/Kconfig | 12 +++
> > drivers/thermal/intel/Makefile | 1 +
> > drivers/thermal/intel/intel_hfi.c | 155 ++++++++++++++++++++++++++++
> > drivers/thermal/intel/intel_hfi.h | 34 ++++++
> > drivers/thermal/intel/therm_throt.c | 3 +
> > 5 files changed, 205 insertions(+)
> > create mode 100644 drivers/thermal/intel/intel_hfi.c
> > create mode 100644 drivers/thermal/intel/intel_hfi.h
> >
> > diff --git a/drivers/thermal/intel/Kconfig b/drivers/thermal/intel/Kconfig
> > index c83ea5d04a1d..d4c6bdcacddb 100644
> > --- a/drivers/thermal/intel/Kconfig
> > +++ b/drivers/thermal/intel/Kconfig
> > @@ -99,3 +99,15 @@ config INTEL_MENLOW
> > Intel Menlow platform.
> >
> > If unsure, say N.
> > +
> > +config INTEL_HFI
> > + bool "Intel Hardware Feedback Interface"
> > + depends on CPU_SUP_INTEL
> > + depends on SCHED_MC && X86_THERMAL_VECTOR
> > + help
> > + Select this option to enable the Hardware Feedback Interface. If
> > + selected, hardware provides guidance to the operating system on
> > + the performance and energy efficiency capabilities of each CPU.
> > + These capabilities may change as a result of changes in the operating
> > + conditions of the system such power and thermal limits. If selected,
> > + the kernel relays updates in CPUs' capabilities to userspace.
> > diff --git a/drivers/thermal/intel/Makefile b/drivers/thermal/intel/Makefile
> > index 960b56268b4a..1a80bffcd699 100644
> > --- a/drivers/thermal/intel/Makefile
> > +++ b/drivers/thermal/intel/Makefile
> > @@ -13,3 +13,4 @@ obj-$(CONFIG_INTEL_PCH_THERMAL) += intel_pch_thermal.o
> > obj-$(CONFIG_INTEL_TCC_COOLING) += intel_tcc_cooling.o
> > obj-$(CONFIG_X86_THERMAL_VECTOR) += therm_throt.o
> > obj-$(CONFIG_INTEL_MENLOW) += intel_menlow.o
> > +obj-$(CONFIG_INTEL_HFI) += intel_hfi.o
> > diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
> > new file mode 100644
> > index 000000000000..edfe343507b3
> > --- /dev/null
> > +++ b/drivers/thermal/intel/intel_hfi.c
> > @@ -0,0 +1,155 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Hardware Feedback Interface Driver
> > + *
> > + * Copyright (c) 2021, Intel Corporation.
> > + *
> > + * Authors: Aubrey Li <[email protected]>
> > + * Ricardo Neri <[email protected]>
> > + *
> > + *
> > + * The Hardware Feedback Interface provides a performance and energy efficiency
> > + * capability information for each CPU in the system. Depending on the processor
> > + * model, hardware may periodically update these capabilities as a result of
> > + * changes in the operating conditions (e.g., power limits or thermal
> > + * constraints). On other processor models, there is a single HFI update
> > + * at boot.
> > + *
> > + * This file provides functionality to process HFI updates and relay these
> > + * updates to userspace.
> > + */
> > +
> > +#define pr_fmt(fmt) "intel-hfi: " fmt
> > +
> > +#include <linux/slab.h>
> > +
> > +#include "intel_hfi.h"
> > +
> > +/**
> > + * struct hfi_cpu_data - HFI capabilities per CPU
> > + * @perf_cap: Performance capability
> > + * @ee_cap: Energy efficiency capability
> > + *
> > + * Capabilities of a logical processor in the HFI table. These capabilities are
> > + * unitless.
> > + */
> > +struct hfi_cpu_data {
> > + u8 perf_cap;
> > + u8 ee_cap;
> > +} __packed;
> > +
> > +/**
> > + * struct hfi_hdr - Header of the HFI table
> > + * @perf_updated: Hardware updated performance capabilities
> > + * @ee_updated: Hardware updated energy efficiency capabilities
> > + *
> > + * Properties of the data in an HFI table.
> > + */
> > +struct hfi_hdr {
> > + u8 perf_updated;
> > + u8 ee_updated;
> > +} __packed;
> > +
> > +/**
> > + * struct hfi_instance - Representation of an HFI instance (i.e., a table)
> > + * @ts_counter: Time stamp of the last update of the table
> > + * @hdr: Base address of the table header
> > + * @data: Base address of the table data
> > + *
> > + * A set of parameters to parse and navigate a specific HFI table.
> > + */
> > +struct hfi_instance {
> > + u64 *ts_counter;
> > + void *hdr;
> > + void *data;
> > +};
> > +
> > +/**
> > + * struct hfi_features - Supported HFI features
> > + * @capabilities: Bitmask of supported capabilities
> > + * @nr_table_pages: Size of the HFI table in 4KB pages
> > + * @cpu_stride: Stride size to locate capability data of a logical
> > + * processor within the table (i.e., row stride)
> > + * @hdr_size: Size of table header
> > + * @parsed: True if HFI features have been parsed
> > + *
> > + * Parameters and supported features that are common to all HFI instances
> > + */
> > +struct hfi_features {
> > + unsigned long capabilities;
> > + unsigned int nr_table_pages;
> > + unsigned int cpu_stride;
> > + unsigned int hdr_size;
> > + bool parsed;
Thank you very much for your feedback, Rafael!
>
> I'm not sure why this field is needed.
>
> It looks like it is only checked by hfi_parse_features() which is only
> called by intel_hfi_init() which is invoked by
> thermal_throttle_init_device() which can happen only once if I'm not
> mistaken.
This is very true. It is not needed. I will remove it.
> > +};
> > +
> > +static int max_hfi_instances;
> > +static struct hfi_instance *hfi_instances;
> > +
> > +static struct hfi_features hfi_features;
> > +
> > +static __init int hfi_parse_features(void)
> > +{
> > + unsigned int nr_capabilities, reg;
> > +
> > + if (!boot_cpu_has(X86_FEATURE_INTEL_HFI))
> > + return -ENODEV;
> > +
> > + if (hfi_features.parsed)
> > + return 0;
> > +
> > + /*
> > + * If we are here we know that CPUID_HFI_LEAF exists. Parse the
> > + * supported capabilities and the size of the HFI table.
> > + */
> > + reg = cpuid_edx(CPUID_HFI_LEAF);
> > +
> > + hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
> > + if (!(hfi_features.capabilities & HFI_CAPABILITIES_PERFORMANCE)) {
> > + pr_err("Performance reporting not supported! Not using HFI\n");
>
> This doesn't need to be pr_err().
Should it be a pr_warn() or perhaps pr_info()?
Thanks and BR,
Ricardo
On Mon, 2021-11-29 at 19:20 -0800, Ricardo Neri wrote:
> On Wed, Nov 24, 2021 at 03:09:20PM +0100, Rafael J. Wysocki wrote:
> > On Sat, Nov 6, 2021 at 2:34 AM Ricardo Neri
> > <[email protected]> wrote:
> > >
> > > The Intel Hardware Feedback Interface provides guidance to the
> > > operating
> > > system about the performance and energy efficiency capabilities
> > > of each
> > > CPU in the system. Capabilities are numbers between 0 and 255
> > > where a
> > > higher number represents a higher capability. For each CPU,
> > > energy
> > > efficiency and performance are reported as separate capabilities.
> > >
> > > Hardware computes these capabilities based on the operating
> > > conditions of
> > > the system such as power and thermal limits. These capabilities
> > > are shared
> > > with the operating system in a table resident in memory. Each
> > > package in
> > > the system has its own HFI instance. Every logical CPU in the
> > > package is
> > > represented in the table. More than one logical CPUs may be
> > > represented in
> > > a single table entry. When the hardware updates the table, it
> > > generates a
> > > package-level thermal interrupt.
> > >
> > > The size and format of the HFI table depend on the supported
> > > features and
> > > can only be determined at runtime. To minimally initialize the
> > > HFI, parse
> > > its features and allocate one instance per package of a data
> > > structure with
> > > the necessary parameters to read and navigate individual HFI
> > > tables.
> > >
> > > A subsequent changeset will provide per-CPU initialization and
> > > interrupt
> > > handling.
> > >
[...]
> > > + /*
> > > + * If we are here we know that CPUID_HFI_LEAF exists.
> > > Parse the
> > > + * supported capabilities and the size of the HFI table.
> > > + */
> > > + reg = cpuid_edx(CPUID_HFI_LEAF);
> > > +
> > > + hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
> > > + if (!(hfi_features.capabilities &
> > > HFI_CAPABILITIES_PERFORMANCE)) {
> > > + pr_err("Performance reporting not supported! Not
> > > using HFI\n");
> >
> > This doesn't need to be pr_err().
>
> Should it be a pr_warn() or perhaps pr_info()?
May be even pr_debug as we can always enable dynamic debug, where we
need to debug.
Thanks,
Srinivas
>
> Thanks and BR,
> Ricardo
>
On Mon, Nov 29, 2021 at 07:55:18PM -0800, Srinivas Pandruvada wrote:
> On Mon, 2021-11-29 at 19:20 -0800, Ricardo Neri wrote:
> > On Wed, Nov 24, 2021 at 03:09:20PM +0100, Rafael J. Wysocki wrote:
> > > On Sat, Nov 6, 2021 at 2:34 AM Ricardo Neri
> > > <[email protected]> wrote:
> > > >
> > > > The Intel Hardware Feedback Interface provides guidance to the
> > > > operating
> > > > system about the performance and energy efficiency capabilities
> > > > of each
> > > > CPU in the system. Capabilities are numbers between 0 and 255
> > > > where a
> > > > higher number represents a higher capability. For each CPU,
> > > > energy
> > > > efficiency and performance are reported as separate capabilities.
> > > >
> > > > Hardware computes these capabilities based on the operating
> > > > conditions of
> > > > the system such as power and thermal limits. These capabilities
> > > > are shared
> > > > with the operating system in a table resident in memory. Each
> > > > package in
> > > > the system has its own HFI instance. Every logical CPU in the
> > > > package is
> > > > represented in the table. More than one logical CPUs may be
> > > > represented in
> > > > a single table entry. When the hardware updates the table, it
> > > > generates a
> > > > package-level thermal interrupt.
> > > >
> > > > The size and format of the HFI table depend on the supported
> > > > features and
> > > > can only be determined at runtime. To minimally initialize the
> > > > HFI, parse
> > > > its features and allocate one instance per package of a data
> > > > structure with
> > > > the necessary parameters to read and navigate individual HFI
> > > > tables.
> > > >
> > > > A subsequent changeset will provide per-CPU initialization and
> > > > interrupt
> > > > handling.
> > > >
>
> [...]
>
> > > > +?????? /*
> > > > +??????? * If we are here we know that CPUID_HFI_LEAF exists.
> > > > Parse the
> > > > +??????? * supported capabilities and the size of the HFI table.
> > > > +??????? */
> > > > +?????? reg = cpuid_edx(CPUID_HFI_LEAF);
> > > > +
> > > > +?????? hfi_features.capabilities = reg & HFI_CAPABILITIES_MASK;
> > > > +?????? if (!(hfi_features.capabilities &
> > > > HFI_CAPABILITIES_PERFORMANCE)) {
> > > > +?????????????? pr_err("Performance reporting not supported! Not
> > > > using HFI\n");
> > >
> > > This doesn't need to be pr_err().
> >
> > Should it be a pr_warn() or perhaps pr_info()?
> May be even pr_debug as we can always enable dynamic debug, where we
> need to debug.
Fair enough. That sounds good. I will make the change.
Thanks and BR,
Ricardo