[PATCH v3 00/14] Add support for AMD hardware feedback interface

[PATCH v3 00/14] Add support for AMD hardware feedback interface

[Mario Limonciello]

The AMD Heterogeneous core design and Hardware Feedback Interface (HFI)
provide behavioral classification and a dynamically updated ranking table
for the scheduler to use when choosing cores for tasks.

Threads are classified during runtime into enumerated classes.
Currently, the driver supports 3 classes (0 through 2). These classes
represent thread performance/power characteristics that may benefit from
special scheduling behaviors. The real-time thread classification is
consumed by the operating system and is used to inform the scheduler of
where the thread should be placed for optimal performance or energy efficiency.

The thread classification helps to select CPU from a ranking table that describes
an efficiency and performance ranking for each classification from two dimensions.

The ranking data provided by the ranking table are numbers ranging from 0 to 255,
where a higher performance value indicates higher performance capability and a higher
efficiency value indicates greater efficiency. All the CPU cores are ranked into
different class IDs. Within each class ranking, the cores may have different ranking
values. Therefore, picking from each classification ID will later allow the scheduler
to select the best core while threads are classified into the specified workload class.

This series was originally submitted by Perry Yuan [1] but he is now doing a different
role and he asked me to take over.

Link: https://lore.kernel.org/all/cover.1724748733.git.perry.yuan@amd.com/

On applicable hardware this series has between a 2% and 5% improvement across various
benchmarks.

There is however a cost associated with clearing history on the process context switch.
On average it increases the delay by 119ns, and also has a wider range in delays
(the standard deviation is 25% greater).

Although this series most prominently has changes to platform-x86 it is based
off of https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git/log/?h=linux-next
due to changes queued up for 6.13-rc1 that are dependencies.

---
v2->v3:
 * Take into mailing list feedback for various patches (see patches for details)
 * Add a patch to show the performance and efficiency rankings in debugfs

Mario Limonciello (4):
  MAINTAINERS: Add maintainer entry for AMD Hardware Feedback Driver
  cpufreq/amd-pstate: Disable preferred cores on designs with workload
    classification
  platform/x86/amd: hfi: Set ITMT priority from ranking data
  platform/x86: hfi: Add debugfs support

Perry Yuan (10):
  Documentation: x86: Add AMD Hardware Feedback Interface documentation
  x86/cpufeatures: add X86_FEATURE_WORKLOAD_CLASS feature bit
  x86/msr-index: define AMD heterogeneous CPU related MSR
  platform/x86: hfi: Introduce AMD Hardware Feedback Interface Driver
  platform/x86: hfi: parse CPU core ranking data from shared memory
  platform/x86: hfi: init per-cpu scores for each class
  platform/x86: hfi: add online and offline callback support
  platform/x86: hfi: add power management callback
  x86/cpu: Enable SD_ASYM_PACKING for DIE Domain on AMD Processors
  x86/process: Clear hardware feedback history for AMD processors

 Documentation/arch/x86/amd-hfi.rst    | 115 ++++++
 Documentation/arch/x86/index.rst      |   1 +
 MAINTAINERS                           |   9 +
 arch/x86/include/asm/cpufeatures.h    |   1 +
 arch/x86/include/asm/hreset.h         |   6 +
 arch/x86/include/asm/msr-index.h      |   5 +
 arch/x86/kernel/cpu/common.c          |  15 +
 arch/x86/kernel/cpu/scattered.c       |   1 +
 arch/x86/kernel/process_32.c          |   3 +
 arch/x86/kernel/process_64.c          |   3 +
 arch/x86/kernel/smpboot.c             |   5 +-
 drivers/cpufreq/amd-pstate.c          |   6 +
 drivers/platform/x86/amd/Kconfig      |   1 +
 drivers/platform/x86/amd/Makefile     |   1 +
 drivers/platform/x86/amd/hfi/Kconfig  |  21 +
 drivers/platform/x86/amd/hfi/Makefile |   7 +
 drivers/platform/x86/amd/hfi/hfi.c    | 552 ++++++++++++++++++++++++++
 17 files changed, 750 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/arch/x86/amd-hfi.rst
 create mode 100644 arch/x86/include/asm/hreset.h
 create mode 100644 drivers/platform/x86/amd/hfi/Kconfig
 create mode 100644 drivers/platform/x86/amd/hfi/Makefile
 create mode 100644 drivers/platform/x86/amd/hfi/hfi.c

-- 
2.43.0

[PATCH v3 01/14] Documentation: x86: Add AMD Hardware Feedback Interface documentation

[Mario Limonciello]

From: Perry Yuan <Perry.Yuan@amd.com>

Introduce a new documentation file, `amd_hfi.rst`, which delves into the
implementation details of the AMD Hardware Feedback Interface and its
associated driver, `amd_hfi`. This documentation describes how the
driver provides hint to the OS scheduling which depends on the capability
of core performance and efficiency ranking data.

This documentation describes
* The design of the driver
* How the driver provides hints to the OS scheduling
* How the driver interfaces with the kernel for efficiency ranking data.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
 * Rewording (Bagas)
 * Fix toctree entry name (Bagas)
---
 Documentation/arch/x86/amd-hfi.rst | 115 +++++++++++++++++++++++++++++
 Documentation/arch/x86/index.rst   |   1 +
 2 files changed, 116 insertions(+)
 create mode 100644 Documentation/arch/x86/amd-hfi.rst

diff --git a/Documentation/arch/x86/amd-hfi.rst b/Documentation/arch/x86/amd-hfi.rst
new file mode 100644
index 000000000000..2f0d493135c1
--- /dev/null
+++ b/Documentation/arch/x86/amd-hfi.rst
@@ -0,0 +1,115 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================================================
+Hardware Feedback Interface For Hetero Core Scheduling On AMD Platform
+======================================================================
+
+:Copyright: 2024 Advanced Micro Devices, Inc. All Rights Reserved.
+
+:Author: Perry Yuan <perry.yuan@amd.com>
+
+Overview
+--------
+
+AMD Heterogeneous Core implementations are comprised of more than one
+architectural class and CPUs are comprised of cores of various efficiency and
+power capabilities: performance-oriented *classic cores* and power-efficient
+*dense cores*. As such, power management strategies must be designed to
+accommodate the complexities introduced by incorporating different core types.
+Heterogeneous systems can also extend to more than two architectural classes as
+well. The purpose of the scheduling feedback mechanism is to provide
+information to the operating system scheduler in real time such that the
+scheduler can direct threads to the optimal core.
+
+The goal of AMD's heterogeneous architecture is to attain power benefit by sending
+background thread to the dense cores while sending high priority threads to the classic
+cores. From a performance perspective, sending background threads to dense cores can free
+up power headroom and allow the classic cores to optimally service demanding threads.
+Furthermore, the area optimized nature of the dense cores allows for an increasing
+number of physical cores. This improved core density will have positive multithreaded
+performance impact.
+
+AMD Heterogeneous Core Driver
+-----------------------------
+
+The ``amd_hfi`` driver delivers the operating system a performance and energy efficiency
+capability data for each CPU in the system. The scheduler can use the ranking data
+from the HFI driver to make task placement decisions.
+
+Thread Classification and Ranking Table Interaction
+----------------------------------------------------
+
+The thread classification is used to select into a ranking table that describes
+an efficiency and performance ranking for each classification.
+
+Threads are classified during runtime into enumerated classes. The classes represent
+thread performance/power characteristics that may benefit from special scheduling behaviors.
+The below table depicts an example of thread classification and a preference where a given thread
+should be scheduled based on its thread class. The real time thread classification is consumed
+by the operating system and is used to inform the scheduler of where the thread should be placed.
+
+Thread Classification Example Table
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
++----------+----------------+-------------------------------+---------------------+---------+
+| class ID | Classification | Preferred scheduling behavior | Preemption priority | Counter |
++----------+----------------+-------------------------------+---------------------+---------+
+| 0        | Default        | Performant                    | Highest             |         |
++----------+----------------+-------------------------------+---------------------+---------+
+| 1        | Non-scalable   | Efficient                     | Lowest              | PMCx1A1 |
++----------+----------------+-------------------------------+---------------------+---------+
+| 2        | I/O bound      | Efficient                     | Lowest              | PMCx044 |
++----------+----------------+-------------------------------+---------------------+---------+
+
+
+AMD Hardware Feedback Interface
+--------------------------------
+
+The Hardware Feedback Interface provides to the operating system information
+about the performance and energy efficiency of each CPU in the system. Each
+capability is given as a unit-less quantity in the range [0-255]. A higher
+performance value indicates higher performance capability, and a higher
+efficiency value indicates more efficiency. Energy efficiency and performance
+are reported in separate capabilities in the shared memory based ranking table.
+
+These capabilities may change at runtime as a result of changes in the
+operating conditions of the system or the action of external factors.
+Power Management FW is responsible for detecting events that would require
+a reordering of the performance and efficiency ranking. Table updates would
+happen relatively infrequently and occur on the time scale of seconds or more.
+
+The following events trigger a table update:
+    * Thermal Stress Events
+    * Silent Compute
+    * Extreme Low Battery Scenarios
+
+The kernel or a userspace policy daemon can use these capabilities to modify
+task placement decisions. For instance, if either the performance or energy
+capabilities of a given logical processor becomes zero, it is an indication that
+the hardware recommends to the operating system to not schedule any tasks on
+that processor for performance or energy efficiency reasons, respectively.
+
+Implementation details for Linux
+--------------------------------
+
+The implementation of threads scheduling consists of the following steps:
+
+1. A thread is spawned and scheduled to the ideal core using the default
+   heterogeneous scheduling policy.
+2. The processor profiles thread execution and assigns an enumerated classification ID.
+   This classification is communicated to the OS via logical processor scope MSR.
+3. During the thread context switch out the operating system consumes the workload(WL)
+   classification which resides in a logical processor scope MSR.
+4. The OS triggers the hardware to clear its history by writing to an MSR,
+   after consuming the WL classification and before switching in the new thread.
+5. If due to the classification, ranking table, and processor availability,
+   the thread is not on its ideal processor, the OS will then consider scheduling
+   the thread on its ideal processor (if available).
+
+Ranking Table update
+---------------------------
+The power management firmware issues an platform interrupt after updating the ranking
+table and is ready for the operating system to consume it. CPUs receive such interrupt
+and read new ranking table from shared memory which PCCT table has provided, then
+``amd_hfi`` driver parse the new table to provide new consume data for scheduling decisions.
+
+
diff --git a/Documentation/arch/x86/index.rst b/Documentation/arch/x86/index.rst
index 8ac64d7de4dc..56f2923f5259 100644
--- a/Documentation/arch/x86/index.rst
+++ b/Documentation/arch/x86/index.rst
@@ -43,3 +43,4 @@ x86-specific Documentation
    features
    elf_auxvec
    xstate
+   amd-hfi
-- 
2.43.0

[PATCH v3 02/14] MAINTAINERS: Add maintainer entry for AMD Hardware Feedback Driver

[Mario Limonciello]

Introduce the `amd_hfi` driver into the MAINTAINERS file.
The driver will support AMD Heterogeneous Core design which provides
hardware feedback to the OS scheduler.

Moving forward, Mario will be responsible for the maintenance
and Perry will assist on review of patches related to this driver.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 MAINTAINERS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index a097afd76ded..90094e064d94 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1083,6 +1083,15 @@ F:	arch/x86/include/asm/amd_hsmp.h
 F:	arch/x86/include/uapi/asm/amd_hsmp.h
 F:	drivers/platform/x86/amd/hsmp.c
 
+AMD HETERO CORE HARDWARE FEEDBACK DRIVER
+M:	Mario Limonciello <mario.limonciello@amd.com>
+R:	Perry Yuan <perry.yuan@amd.com>
+L:	platform-driver-x86@vger.kernel.org
+S:	Supported
+B:	https://gitlab.freedesktop.org/drm/amd/-/issues
+F:	Documentation/arch/x86/amd-hfi.rst
+F:	drivers/platform/x86/amd/hfi/
+
 AMD IOMMU (AMD-VI)
 M:	Joerg Roedel <joro@8bytes.org>
 R:	Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
-- 
2.43.0

[PATCH v3 03/14] x86/cpufeatures: add X86_FEATURE_WORKLOAD_CLASS feature bit

[Mario Limonciello]

From: Perry Yuan <perry.yuan@amd.com>

Add new feature bit that indicates support for workload based
heuristic feedback to OS for scheduling decisions.
When the bit set, threads are classified during runtime into
enumerated classes. The classes represent thread performance/power
characteristics that may benefit from special scheduling behaviors.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 arch/x86/kernel/cpu/scattered.c    | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index cea1ed82aeb4..3e8e67b8ec7a 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -474,6 +474,7 @@
 #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* Clear branch history at vmexit using SW loop */
 #define X86_FEATURE_FAST_CPPC		(21*32 + 5) /* AMD Fast CPPC */
 #define X86_FEATURE_HETERO_CORE_TOPOLOGY	(21*32 + 6) /* Heterogeneous Core Topology */
+#define X86_FEATURE_WORKLOAD_CLASS	(21*32 + 7) /* Workload Classification */
 
 /*
  * BUG word(s)
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index 3bba55323163..b6547bab9e23 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -49,6 +49,7 @@ static const struct cpuid_bit cpuid_bits[] = {
 	{ X86_FEATURE_MBA,		CPUID_EBX,  6, 0x80000008, 0 },
 	{ X86_FEATURE_SMBA,		CPUID_EBX,  2, 0x80000020, 0 },
 	{ X86_FEATURE_BMEC,		CPUID_EBX,  3, 0x80000020, 0 },
+	{ X86_FEATURE_WORKLOAD_CLASS,   CPUID_EAX,  22, 0x80000021, 0 },
 	{ X86_FEATURE_PERFMON_V2,	CPUID_EAX,  0, 0x80000022, 0 },
 	{ X86_FEATURE_AMD_LBR_V2,	CPUID_EAX,  1, 0x80000022, 0 },
 	{ X86_FEATURE_AMD_LBR_PMC_FREEZE,	CPUID_EAX,  2, 0x80000022, 0 },
-- 
2.43.0

[PATCH v3 04/14] x86/msr-index: define AMD heterogeneous CPU related MSR

[Mario Limonciello]

From: Perry Yuan <perry.yuan@amd.com>

Introduces new MSR registers for AMD hardware feedback support.
These registers enable the system to provide workload classification
and configuration capabilities.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 arch/x86/include/asm/msr-index.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 3ae84c3b8e6d..0cd5ffe50f4a 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -712,6 +712,11 @@
 #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
 #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
 
+/* AMD Hardware Feedback Support MSRs */
+#define AMD_WORKLOAD_CLASS_CONFIG      0xc0000500
+#define AMD_WORKLOAD_CLASS_ID          0xc0000501
+#define AMD_WORKLOAD_HRST              0xc0000502
+
 /* AMD Last Branch Record MSRs */
 #define MSR_AMD64_LBR_SELECT			0xc000010e
 
-- 
2.43.0

[PATCH v3 05/14] platform/x86: hfi: Introduce AMD Hardware Feedback Interface Driver

[Mario Limonciello]

From: Perry Yuan <Perry.Yuan@amd.com>

The AMD Heterogeneous core design and Hardware Feedback Interface (HFI)
provide behavioral classification and a dynamically updated ranking table
for the scheduler to use when choosing cores for tasks.

There are two CPU core types defined: `Classic Core` and `Dense Core`.
"Classic" cores are the standard performance cores, while "Dense" cores
are optimized for area and efficiency.

Heterogeneous compute refers to CPU implementations that are comprised
of more than one architectural class, each with two capabilities. This
means each CPU reports two separate capabilities: "perf" and "eff".

Each capability lists all core ranking numbers between 0 and 255, where
a higher number represents a higher capability.

Heterogeneous systems can also extend to more than two architectural
classes.

The purpose of the scheduling feedback mechanism is to provide information
to the operating system scheduler in real time, allowing the scheduler to
direct threads to the optimal core during task scheduling.

All core ranking data are provided by the BIOS via a shared memory ranking
table, which the driver reads and uses to update core capabilities to the
scheduler. When the hardware updates the table, it generates a platform
interrupt to notify the OS to read the new ranking table.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
 * Whitespace (Ilpo)
 * kmalloc -> kzalloc (Ilpo)
 * Drop needless include (Ilpo)
 * Capitalization (Ilpo)
 * Drop needless comment (Ilpo)
---
 drivers/platform/x86/amd/Kconfig      |   1 +
 drivers/platform/x86/amd/Makefile     |   1 +
 drivers/platform/x86/amd/hfi/Kconfig  |  20 +++
 drivers/platform/x86/amd/hfi/Makefile |   7 ++
 drivers/platform/x86/amd/hfi/hfi.c    | 168 ++++++++++++++++++++++++++
 5 files changed, 197 insertions(+)
 create mode 100644 drivers/platform/x86/amd/hfi/Kconfig
 create mode 100644 drivers/platform/x86/amd/hfi/Makefile
 create mode 100644 drivers/platform/x86/amd/hfi/hfi.c

diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig
index f88682d36447..c3f69dbe3037 100644
--- a/drivers/platform/x86/amd/Kconfig
+++ b/drivers/platform/x86/amd/Kconfig
@@ -5,6 +5,7 @@
 
 source "drivers/platform/x86/amd/pmf/Kconfig"
 source "drivers/platform/x86/amd/pmc/Kconfig"
+source "drivers/platform/x86/amd/hfi/Kconfig"
 
 config AMD_HSMP
 	tristate "AMD HSMP Driver"
diff --git a/drivers/platform/x86/amd/Makefile b/drivers/platform/x86/amd/Makefile
index dcec0a46f8af..2676fc81fee5 100644
--- a/drivers/platform/x86/amd/Makefile
+++ b/drivers/platform/x86/amd/Makefile
@@ -9,3 +9,4 @@ amd_hsmp-y			:= hsmp.o
 obj-$(CONFIG_AMD_HSMP)		+= amd_hsmp.o
 obj-$(CONFIG_AMD_PMF)		+= pmf/
 obj-$(CONFIG_AMD_WBRF)		+= wbrf.o
+obj-$(CONFIG_AMD_HFI)		+= hfi/
diff --git a/drivers/platform/x86/amd/hfi/Kconfig b/drivers/platform/x86/amd/hfi/Kconfig
new file mode 100644
index 000000000000..08051cd4f74d
--- /dev/null
+++ b/drivers/platform/x86/amd/hfi/Kconfig
@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# AMD Hardware Feedback Interface Driver
+#
+
+config AMD_HFI
+	bool "AMD Hetero Core Hardware Feedback Driver"
+	depends on ACPI
+	depends on CPU_SUP_AMD
+	help
+	 Select this option to enable the AMD Heterogeneous Core Hardware Feedback Interface. If
+	 selected, hardware provides runtime thread classification guidance to the operating system
+	 on the performance and energy efficiency capabilities of each heterogeneous CPU core.
+	 These capabilities may vary due to the inherent differences in the core types and can
+	 also change as a result of variations in the operating conditions of the system such
+	 as power and thermal limits. If selected, the kernel relays updates in heterogeneous
+	 CPUs' capabilities to userspace, allowing for more optimal task scheduling and
+	 resource allocation, leveraging the diverse set of cores available.
+
+
diff --git a/drivers/platform/x86/amd/hfi/Makefile b/drivers/platform/x86/amd/hfi/Makefile
new file mode 100644
index 000000000000..672c6ac106e9
--- /dev/null
+++ b/drivers/platform/x86/amd/hfi/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# AMD Hardware Feedback Interface Driver
+#
+
+obj-$(CONFIG_AMD_HFI) += amd_hfi.o
+amd_hfi-objs := hfi.o
diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
new file mode 100644
index 000000000000..fbbc2c119a64
--- /dev/null
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Hardware Feedback Interface Driver
+ *
+ * Copyright (C) 2024 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ * Authors: Perry Yuan <Perry.Yuan@amd.com>
+ *          Mario Limonciello <mario.limonciello@amd.com>
+ */
+
+#define pr_fmt(fmt)  "amd-hfi: " fmt
+
+#include <linux/acpi.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/smp.h>
+
+#define AMD_HFI_DRIVER		"amd_hfi"
+#define AMD_HETERO_CPUID_27	0x80000027
+static struct platform_device *device;
+
+struct amd_hfi_data {
+	const char	*name;
+	struct device	*dev;
+	struct mutex	lock;
+};
+
+struct amd_hfi_classes {
+	u32	perf;
+	u32	eff;
+};
+
+/**
+ * struct amd_hfi_cpuinfo - HFI workload class info per CPU
+ * @cpu:		cpu index
+ * @cpus:		mask of cpus associated with amd_hfi_cpuinfo
+ * @class_index:	workload class ID index
+ * @nr_class:		max number of workload class supported
+ * @amd_hfi_classes:	current cpu workload class ranking data
+ *
+ * Parameters of a logical processor linked with hardware feedback class
+ */
+struct amd_hfi_cpuinfo {
+	int		cpu;
+	cpumask_var_t	cpus;
+	s16		class_index;
+	u8		nr_class;
+	struct amd_hfi_classes	*amd_hfi_classes;
+};
+
+static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
+
+static int amd_hfi_alloc_class_data(struct platform_device *pdev)
+{
+	struct amd_hfi_cpuinfo *hfi_cpuinfo;
+	struct device *dev = &pdev->dev;
+	int idx;
+	int nr_class_id;
+
+	nr_class_id = cpuid_eax(AMD_HETERO_CPUID_27);
+	if (nr_class_id < 0 || nr_class_id > 255) {
+		dev_err(dev, "failed to get number of supported classes: %d\n",
+			nr_class_id);
+		return -EINVAL;
+	}
+
+	for_each_present_cpu(idx) {
+		struct amd_hfi_classes *classes;
+
+		classes = devm_kzalloc(dev,
+				       nr_class_id * sizeof(struct amd_hfi_classes),
+				       GFP_KERNEL);
+		if (!classes)
+			return -ENOMEM;
+		hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, idx);
+		hfi_cpuinfo->amd_hfi_classes = classes;
+		hfi_cpuinfo->nr_class = nr_class_id;
+	}
+
+	return 0;
+}
+
+static void amd_hfi_remove(struct platform_device *pdev)
+{
+	struct amd_hfi_data *dev = platform_get_drvdata(pdev);
+
+	mutex_destroy(&dev->lock);
+}
+
+static const struct acpi_device_id amd_hfi_platform_match[] = {
+	{ "AMDI0104", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, amd_hfi_platform_match);
+
+static int amd_hfi_probe(struct platform_device *pdev)
+{
+	struct amd_hfi_data *amd_hfi_data;
+	int ret;
+
+	if (!acpi_match_device(amd_hfi_platform_match, &pdev->dev))
+		return -ENODEV;
+
+	amd_hfi_data = devm_kzalloc(&pdev->dev, sizeof(*amd_hfi_data), GFP_KERNEL);
+	if (!amd_hfi_data)
+		return -ENOMEM;
+
+	amd_hfi_data->dev = &pdev->dev;
+	mutex_init(&amd_hfi_data->lock);
+	platform_set_drvdata(pdev, amd_hfi_data);
+
+	ret = amd_hfi_alloc_class_data(pdev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static struct platform_driver amd_hfi_driver = {
+	.driver = {
+		.name = AMD_HFI_DRIVER,
+		.owner = THIS_MODULE,
+		.acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
+	},
+	.probe = amd_hfi_probe,
+	.remove_new = amd_hfi_remove,
+};
+
+static int __init amd_hfi_init(void)
+{
+	int ret;
+
+	if (acpi_disabled ||
+	    !boot_cpu_has(X86_FEATURE_HETERO_CORE_TOPOLOGY) ||
+	    !boot_cpu_has(X86_FEATURE_WORKLOAD_CLASS))
+		return -ENODEV;
+
+	device = platform_device_register_simple(AMD_HFI_DRIVER, -1, NULL, 0);
+	if (IS_ERR(device)) {
+		pr_err("unable to register HFI platform device\n");
+		return PTR_ERR(device);
+	}
+
+	ret = platform_driver_register(&amd_hfi_driver);
+	if (ret)
+		pr_err("failed to register HFI driver\n");
+
+	return ret;
+}
+
+static __exit void amd_hfi_exit(void)
+{
+	platform_device_unregister(device);
+	platform_driver_unregister(&amd_hfi_driver);
+}
+module_init(amd_hfi_init);
+module_exit(amd_hfi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AMD Hardware Feedback Interface Driver");
-- 
2.43.0

[PATCH v3 06/14] platform/x86: hfi: parse CPU core ranking data from shared memory

[Mario Limonciello]

From: Perry Yuan <Perry.Yuan@amd.com>

When `amd_hfi` driver is loaded, it will use PCCT subspace type 4 table
to retrieve the shared memory address which contains the CPU core ranking
table. This table includes a header that specifies the number of ranking
data entries to be parsed and rank each CPU core with the Performance and
Energy Efficiency capability as implemented by the CPU power management
firmware.

Once the table has been parsed, each CPU is assigned a ranking score
within its class. Subsequently, when the scheduler selects cores, it
chooses from the ranking list based on the assigned scores in each class,
thereby ensuring the optimal selection of CPU cores according to their
predefined classifications and priorities.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/platform/x86/amd/hfi/hfi.c | 200 +++++++++++++++++++++++++++++
 1 file changed, 200 insertions(+)

diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
index fbbc2c119a64..d2952233442b 100644
--- a/drivers/platform/x86/amd/hfi/hfi.c
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -18,21 +18,77 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/mailbox_client.h>
 #include <linux/mutex.h>
+#include <linux/percpu-defs.h>
 #include <linux/platform_device.h>
 #include <linux/printk.h>
 #include <linux/smp.h>
+#include <linux/topology.h>
+#include <linux/workqueue.h>
+
+#include <asm/cpu_device_id.h>
+
+#include <acpi/pcc.h>
+#include <acpi/cppc_acpi.h>
 
 #define AMD_HFI_DRIVER		"amd_hfi"
+#define AMD_HFI_MAILBOX_COUNT	1
+#define AMD_HETERO_RANKING_TABLE_VER	2
+
 #define AMD_HETERO_CPUID_27	0x80000027
+
 static struct platform_device *device;
 
+/**
+ * struct amd_shmem_info - Shared memory table for AMD HFI
+ *
+ * @signature:	The PCC signature. The signature of a subspace is computed by
+ *		a bitwise of the value 0x50434300 with the subspace ID.
+ * @flags:	Notify on completion
+ * @length:	Length of payload being transmitted including command field
+ * @command:	Command being sent over the subspace
+ * @version_number:		Version number of the table
+ * @n_logical_processors:	Number of logical processors
+ * @n_capabilities:		Number of ranking dimensions (performance, efficiency, etc)
+ * @table_update_context:	Command being sent over the subspace
+ * @n_bitmaps:			Number of 32-bit bitmaps to enumerate all the APIC IDs
+ *				This is based on the maximum APIC ID enumerated in the system
+ * @reserved:			24 bit spare
+ * @table_data:			Bit Map(s) of enabled logical processors
+ *				Followed by the ranking data for each logical processor
+ */
+struct amd_shmem_info {
+	struct acpi_pcct_ext_pcc_shared_memory header;
+	u32	version_number		:8,
+		n_logical_processors	:8,
+		n_capabilities		:8,
+		table_update_context	:8;
+	u32	n_bitmaps		:8,
+		reserved		:24;
+	u32	table_data[];
+} __packed;
+
 struct amd_hfi_data {
 	const char	*name;
 	struct device	*dev;
 	struct mutex	lock;
+
+	/* PCCT table related*/
+	struct pcc_mbox_chan	*pcc_chan;
+	void __iomem		*pcc_comm_addr;
+	struct acpi_subtable_header	*pcct_entry;
+	struct amd_shmem_info	*shmem;
 };
 
+/**
+ * struct amd_hfi_classes - HFI class capabilities per CPU
+ * @perf:	Performance capability
+ * @eff:	Power efficiency capability
+ *
+ * Capabilities of a logical processor in the ranking table. These capabilities
+ * are unitless and specific to each HFI class.
+ */
 struct amd_hfi_classes {
 	u32	perf;
 	u32	eff;
@@ -41,23 +97,105 @@ struct amd_hfi_classes {
 /**
  * struct amd_hfi_cpuinfo - HFI workload class info per CPU
  * @cpu:		cpu index
+ * @apic_id:		apic id of the current cpu
  * @cpus:		mask of cpus associated with amd_hfi_cpuinfo
  * @class_index:	workload class ID index
  * @nr_class:		max number of workload class supported
+ * @ipcc_scores:	ipcc scores for each class
  * @amd_hfi_classes:	current cpu workload class ranking data
  *
  * Parameters of a logical processor linked with hardware feedback class
  */
 struct amd_hfi_cpuinfo {
 	int		cpu;
+	u32		apic_id;
 	cpumask_var_t	cpus;
 	s16		class_index;
 	u8		nr_class;
+	int		*ipcc_scores;
 	struct amd_hfi_classes	*amd_hfi_classes;
 };
 
 static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
 
+static int find_cpu_index_by_apicid(unsigned int target_apicid)
+{
+	int cpu_index;
+
+	for_each_present_cpu(cpu_index) {
+		struct cpuinfo_x86 *info = &cpu_data(cpu_index);
+
+		if (info->topo.apicid == target_apicid) {
+			pr_debug("match APIC id %d for CPU index: %d\n",
+				 info->topo.apicid, cpu_index);
+			return cpu_index;
+		}
+	}
+
+	return -ENODEV;
+}
+
+static int amd_hfi_fill_metadata(struct amd_hfi_data *amd_hfi_data)
+{
+	struct acpi_pcct_ext_pcc_slave *pcct_ext =
+		(struct acpi_pcct_ext_pcc_slave *)amd_hfi_data->pcct_entry;
+	void __iomem *pcc_comm_addr;
+
+	pcc_comm_addr = acpi_os_ioremap(amd_hfi_data->pcc_chan->shmem_base_addr,
+					amd_hfi_data->pcc_chan->shmem_size);
+	if (!pcc_comm_addr) {
+		pr_err("failed to ioremap PCC common region mem\n");
+		return -ENOMEM;
+	}
+
+	memcpy_fromio(amd_hfi_data->shmem, pcc_comm_addr, pcct_ext->length);
+	iounmap(pcc_comm_addr);
+
+	if (amd_hfi_data->shmem->header.signature != PCC_SIGNATURE) {
+		pr_err("invalid signature in shared memory\n");
+		return -EINVAL;
+	}
+	if (amd_hfi_data->shmem->version_number != AMD_HETERO_RANKING_TABLE_VER) {
+		pr_err("invalid version %d\n", amd_hfi_data->shmem->version_number);
+		return -EINVAL;
+	}
+
+	for (unsigned int i = 0; i < amd_hfi_data->shmem->n_bitmaps; i++) {
+		u32 bitmap = amd_hfi_data->shmem->table_data[i];
+
+		for (unsigned int j = 0; j < BITS_PER_TYPE(u32); j++) {
+			struct amd_hfi_cpuinfo *info;
+			int apic_id = i * BITS_PER_TYPE(u32) + j;
+			int cpu_index;
+
+			if (!(bitmap & BIT(j)))
+				continue;
+
+			cpu_index = find_cpu_index_by_apicid(apic_id);
+			if (cpu_index < 0) {
+				pr_warn("APIC ID %d not found\n", apic_id);
+				continue;
+			}
+
+			info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu_index);
+			info->apic_id = apic_id;
+
+			/* Fill the ranking data for each logical processor */
+			info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu_index);
+			for (unsigned int k = 0; k < info->nr_class; k++) {
+				u32 *table = amd_hfi_data->shmem->table_data +
+					     amd_hfi_data->shmem->n_bitmaps +
+					     i * info->nr_class;
+
+				info->amd_hfi_classes[k].eff = table[apic_id + 2 * k];
+				info->amd_hfi_classes[k].perf = table[apic_id + 2 * k + 1];
+			}
+		}
+	}
+
+	return 0;
+}
+
 static int amd_hfi_alloc_class_data(struct platform_device *pdev)
 {
 	struct amd_hfi_cpuinfo *hfi_cpuinfo;
@@ -74,14 +212,19 @@ static int amd_hfi_alloc_class_data(struct platform_device *pdev)
 
 	for_each_present_cpu(idx) {
 		struct amd_hfi_classes *classes;
+		int *ipcc_scores;
 
 		classes = devm_kzalloc(dev,
 				       nr_class_id * sizeof(struct amd_hfi_classes),
 				       GFP_KERNEL);
 		if (!classes)
 			return -ENOMEM;
+		ipcc_scores = devm_kcalloc(dev, nr_class_id, sizeof(int), GFP_KERNEL);
+		if (!ipcc_scores)
+			return -ENOMEM;
 		hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, idx);
 		hfi_cpuinfo->amd_hfi_classes = classes;
+		hfi_cpuinfo->ipcc_scores = ipcc_scores;
 		hfi_cpuinfo->nr_class = nr_class_id;
 	}
 
@@ -95,6 +238,59 @@ static void amd_hfi_remove(struct platform_device *pdev)
 	mutex_destroy(&dev->lock);
 }
 
+static int amd_hfi_metadata_parser(struct platform_device *pdev,
+				   struct amd_hfi_data *amd_hfi_data)
+{
+	struct acpi_pcct_ext_pcc_slave *pcct_ext;
+	struct acpi_subtable_header *pcct_entry;
+	struct mbox_chan *pcc_mbox_channels;
+	struct acpi_table_header *pcct_tbl;
+	struct pcc_mbox_chan *pcc_chan;
+	acpi_status status;
+	int ret;
+
+	pcc_mbox_channels = devm_kcalloc(&pdev->dev, AMD_HFI_MAILBOX_COUNT,
+					 sizeof(*pcc_mbox_channels), GFP_KERNEL);
+	if (!pcc_mbox_channels)
+		return -ENOMEM;
+
+	pcc_chan = devm_kcalloc(&pdev->dev, AMD_HFI_MAILBOX_COUNT,
+				sizeof(*pcc_chan), GFP_KERNEL);
+	if (!pcc_chan)
+		return -ENOMEM;
+
+	status = acpi_get_table(ACPI_SIG_PCCT, 0, &pcct_tbl);
+	if (ACPI_FAILURE(status) || !pcct_tbl)
+		return -ENODEV;
+
+	/* get pointer to the first PCC subspace entry */
+	pcct_entry = (struct acpi_subtable_header *) (
+			(unsigned long)pcct_tbl + sizeof(struct acpi_table_pcct));
+
+	pcc_chan->mchan = &pcc_mbox_channels[0];
+
+	amd_hfi_data->pcc_chan = pcc_chan;
+	amd_hfi_data->pcct_entry = pcct_entry;
+	pcct_ext = (struct acpi_pcct_ext_pcc_slave *)pcct_entry;
+
+	if (pcct_ext->length <= 0)
+		return -EINVAL;
+
+	amd_hfi_data->shmem = devm_kzalloc(amd_hfi_data->dev, pcct_ext->length, GFP_KERNEL);
+	if (!amd_hfi_data->shmem)
+		return -ENOMEM;
+
+	pcc_chan->shmem_base_addr = pcct_ext->base_address;
+	pcc_chan->shmem_size = pcct_ext->length;
+
+	/* parse the shared memory info from the pcct table */
+	ret = amd_hfi_fill_metadata(amd_hfi_data);
+
+	acpi_put_table(pcct_tbl);
+
+	return ret;
+}
+
 static const struct acpi_device_id amd_hfi_platform_match[] = {
 	{ "AMDI0104", 0},
 	{ }
@@ -121,6 +317,10 @@ static int amd_hfi_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = amd_hfi_metadata_parser(pdev, amd_hfi_data);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
-- 
2.43.0

[PATCH v3 07/14] platform/x86: hfi: init per-cpu scores for each class

[Mario Limonciello]

From: Perry Yuan <Perry.Yuan@amd.com>

Initialize per cpu score `amd_hfi_ipcc_scores` which store energy score
and performance score data for each class.

`Classic core` and `Dense core` are ranked according to those values as
energy efficiency capability or performance capability.
OS scheduler will pick cores from the ranking list on each class ID for
the thread which provide the class id got from hardware feedback
interface.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
 * Drop jump label (Ilpo)
---
 drivers/platform/x86/amd/hfi/hfi.c | 31 ++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
index d2952233442b..63e66ab60655 100644
--- a/drivers/platform/x86/amd/hfi/hfi.c
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -118,6 +118,8 @@ struct amd_hfi_cpuinfo {
 
 static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
 
+static DEFINE_MUTEX(hfi_cpuinfo_lock);
+
 static int find_cpu_index_by_apicid(unsigned int target_apicid)
 {
 	int cpu_index;
@@ -238,6 +240,31 @@ static void amd_hfi_remove(struct platform_device *pdev)
 	mutex_destroy(&dev->lock);
 }
 
+static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
+{
+	for (int i = 0; i < hfi_cpuinfo->nr_class; i++)
+		WRITE_ONCE(hfi_cpuinfo->ipcc_scores[i],
+			   hfi_cpuinfo->amd_hfi_classes[i].perf);
+
+	return 0;
+}
+
+static int update_hfi_ipcc_scores(void)
+{
+	int cpu;
+	int ret;
+
+	for_each_present_cpu(cpu) {
+		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
+
+		ret = amd_set_hfi_ipcc_score(hfi_cpuinfo, cpu);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int amd_hfi_metadata_parser(struct platform_device *pdev,
 				   struct amd_hfi_data *amd_hfi_data)
 {
@@ -321,6 +348,10 @@ static int amd_hfi_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = update_hfi_ipcc_scores();
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
-- 
2.43.0

[PATCH v3 08/14] platform/x86: hfi: add online and offline callback support

[Mario Limonciello]

From: Perry Yuan <Perry.Yuan@amd.com>

There are some firmware parameters that need to be configured
when a CPU core is brought online or offline.

when CPU is online, it will initialize the workload classification
parameters to CPU firmware which will trigger the workload class ID
updating function.

Once the CPU is going to offline, it will need to disable the workload
classification function and clear the history.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
 * Use guard() (Ilpo)
 * Whitespace changes (Ilpo)
 * Remove labels for unwind (Ilpo)
---
 drivers/platform/x86/amd/hfi/hfi.c | 79 ++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
index 63e66ab60655..d971ec1124af 100644
--- a/drivers/platform/x86/amd/hfi/hfi.c
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -249,6 +249,80 @@ static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
 	return 0;
 }
 
+static int amd_hfi_set_state(unsigned int cpu, bool state)
+{
+	int ret;
+
+	ret = wrmsrl_on_cpu(cpu, AMD_WORKLOAD_CLASS_CONFIG, state);
+	if (ret)
+		return ret;
+
+	return wrmsrl_on_cpu(cpu, AMD_WORKLOAD_HRST, 0x1);
+}
+
+/**
+ * amd_hfi_online() - Enable workload classification on @cpu
+ * @cpu: CPU in which the workload classification will be enabled
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int amd_hfi_online(unsigned int cpu)
+{
+	struct amd_hfi_cpuinfo *hfi_info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
+	struct amd_hfi_classes *hfi_classes;
+	int ret;
+
+	if (WARN_ON_ONCE(!hfi_info))
+		return -EINVAL;
+
+	/*
+	 * Check if @cpu as an associated, initialized and ranking data must be filled
+	 */
+	hfi_classes = hfi_info->amd_hfi_classes;
+	if (!hfi_classes)
+		return -EINVAL;
+
+	guard(mutex)(&hfi_cpuinfo_lock);
+
+	if (!zalloc_cpumask_var(&hfi_info->cpus, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpumask_set_cpu(cpu, hfi_info->cpus);
+
+	ret = amd_hfi_set_state(cpu, true);
+	if (ret)
+		pr_err("WCT enable failed for cpu %d\n", cpu);
+
+	return ret;
+}
+
+/**
+ * amd_hfi_offline() - Disable workload classification on @cpu
+ * @cpu: CPU in which the workload classification will be disabled
+ *
+ * Remove @cpu from those covered by its HFI instance.
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int amd_hfi_offline(unsigned int cpu)
+{
+	struct amd_hfi_cpuinfo *hfi_info = &per_cpu(amd_hfi_cpuinfo, cpu);
+	int ret;
+
+	if (WARN_ON_ONCE(!hfi_info))
+		return -EINVAL;
+
+	guard(mutex)(&hfi_cpuinfo_lock);
+
+	ret = amd_hfi_set_state(cpu, false);
+	if (ret)
+		pr_err("WCT disable failed for CPU %d\n", cpu);
+
+	free_cpumask_var(hfi_info->cpus);
+
+	return ret;
+}
+
 static int update_hfi_ipcc_scores(void)
 {
 	int cpu;
@@ -352,6 +426,11 @@ static int amd_hfi_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/amd_hfi:online",
+				amd_hfi_online, amd_hfi_offline);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
-- 
2.43.0

[PATCH v3 09/14] platform/x86: hfi: add power management callback

[Mario Limonciello]

From: Perry Yuan <Perry.Yuan@amd.com>

Introduces power management callbacks for the `amd_hfi` driver.
Specifically, the `suspend` and `resume` callbacks have been added
to handle the necessary operations during system low power states
and wake-up.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
 * Whitespace (Ilpo)
---
 drivers/platform/x86/amd/hfi/hfi.c | 33 ++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
index d971ec1124af..79963c423d35 100644
--- a/drivers/platform/x86/amd/hfi/hfi.c
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -392,6 +392,38 @@ static int amd_hfi_metadata_parser(struct platform_device *pdev,
 	return ret;
 }
 
+static int amd_hfi_pm_resume(struct device *dev)
+{
+	int ret, cpu;
+
+	for_each_present_cpu(cpu) {
+		ret = amd_hfi_set_state(cpu, true);
+		if (ret < 0) {
+			dev_err(dev, "failed to enable workload class config: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int amd_hfi_pm_suspend(struct device *dev)
+{
+	int ret, cpu;
+
+	for_each_present_cpu(cpu) {
+		ret = amd_hfi_set_state(cpu, false);
+		if (ret < 0) {
+			dev_err(dev, "failed to disable workload class config: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(amd_hfi_pm_ops, amd_hfi_pm_suspend, amd_hfi_pm_resume);
+
 static const struct acpi_device_id amd_hfi_platform_match[] = {
 	{ "AMDI0104", 0},
 	{ }
@@ -438,6 +470,7 @@ static struct platform_driver amd_hfi_driver = {
 	.driver = {
 		.name = AMD_HFI_DRIVER,
 		.owner = THIS_MODULE,
+		.pm = &amd_hfi_pm_ops,
 		.acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
 	},
 	.probe = amd_hfi_probe,
-- 
2.43.0

[PATCH v3 10/14] x86/cpu: Enable SD_ASYM_PACKING for DIE Domain on AMD Processors

[Mario Limonciello]

From: Perry Yuan <perry.yuan@amd.com>

Enable the SD_ASYM_PACKING domain flag for the DIE domain on AMD
heterogeneous processors.
This flag is beneficial for processors with one or more CCDs and
relies on x86_sched_itmt_flags().

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 arch/x86/kernel/smpboot.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 766f092dab80..c01bb75d0375 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -497,8 +497,9 @@ static int x86_cluster_flags(void)
 
 static int x86_die_flags(void)
 {
-	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
-	       return x86_sched_itmt_flags();
+	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU) ||
+	    cpu_feature_enabled(X86_FEATURE_HETERO_CORE_TOPOLOGY))
+		return x86_sched_itmt_flags();
 
 	return 0;
 }
-- 
2.43.0

[PATCH v3 11/14] x86/process: Clear hardware feedback history for AMD processors

[Mario Limonciello]

From: Perry Yuan <perry.yuan@amd.com>

Incorporate a mechanism within the context switching code to reset
the hardware history for AMD processors. Specifically, when a task
is switched in, the class ID was read and reset the hardware workload
classification history of CPU firmware and then it start to trigger
workload classification for the next running thread.

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 arch/x86/include/asm/hreset.h |  6 ++++++
 arch/x86/kernel/cpu/common.c  | 15 +++++++++++++++
 arch/x86/kernel/process_32.c  |  3 +++
 arch/x86/kernel/process_64.c  |  3 +++
 4 files changed, 27 insertions(+)
 create mode 100644 arch/x86/include/asm/hreset.h

diff --git a/arch/x86/include/asm/hreset.h b/arch/x86/include/asm/hreset.h
new file mode 100644
index 000000000000..ae1f72602bbd
--- /dev/null
+++ b/arch/x86/include/asm/hreset.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_HRESET_H
+
+void reset_hardware_history_hetero(void);
+
+#endif /* _ASM_X86_HRESET_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 07a34d723505..887821e97e54 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -57,6 +57,7 @@
 #include <asm/mce.h>
 #include <asm/msr.h>
 #include <asm/cacheinfo.h>
+#include <asm/hreset.h>
 #include <asm/memtype.h>
 #include <asm/microcode.h>
 #include <asm/intel-family.h>
@@ -403,6 +404,7 @@ static const unsigned long cr4_pinned_mask = X86_CR4_SMEP | X86_CR4_SMAP | X86_C
 					     X86_CR4_FSGSBASE | X86_CR4_CET | X86_CR4_FRED;
 static DEFINE_STATIC_KEY_FALSE_RO(cr_pinning);
 static unsigned long cr4_pinned_bits __ro_after_init;
+static DEFINE_STATIC_KEY_FALSE_RO(hardware_history_features);
 
 void native_write_cr0(unsigned long val)
 {
@@ -481,6 +483,12 @@ void cr4_init(void)
 	this_cpu_write(cpu_tlbstate.cr4, cr4);
 }
 
+static void __init setup_hreset(struct cpuinfo_x86 *c)
+{
+	if (cpu_feature_enabled(X86_FEATURE_WORKLOAD_CLASS))
+		static_key_enable_cpuslocked(&hardware_history_features.key);
+}
+
 /*
  * Once CPU feature detection is finished (and boot params have been
  * parsed), record any of the sensitive CR bits that are set, and
@@ -1844,6 +1852,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 	setup_smep(c);
 	setup_smap(c);
 	setup_umip(c);
+	setup_hreset(c);
 
 	/* Enable FSGSBASE instructions if available. */
 	if (cpu_has(c, X86_FEATURE_FSGSBASE)) {
@@ -2410,3 +2419,9 @@ void __init arch_cpu_finalize_init(void)
 	 */
 	mem_encrypt_init();
 }
+
+__always_inline void reset_hardware_history_hetero(void)
+{
+	if (static_branch_unlikely(&hardware_history_features))
+		wrmsrl(AMD_WORKLOAD_HRST, 0x1);
+}
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 0917c7f25720..6a3a1339f7a7 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -52,6 +52,7 @@
 #include <asm/switch_to.h>
 #include <asm/vm86.h>
 #include <asm/resctrl.h>
+#include <asm/hreset.h>
 #include <asm/proto.h>
 
 #include "process.h"
@@ -213,6 +214,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	/* Load the Intel cache allocation PQR MSR. */
 	resctrl_sched_in(next_p);
 
+	reset_hardware_history_hetero();
+
 	return prev_p;
 }
 
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 226472332a70..ea7f765c6262 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -54,6 +54,7 @@
 #include <asm/xen/hypervisor.h>
 #include <asm/vdso.h>
 #include <asm/resctrl.h>
+#include <asm/hreset.h>
 #include <asm/unistd.h>
 #include <asm/fsgsbase.h>
 #include <asm/fred.h>
@@ -709,6 +710,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	/* Load the Intel cache allocation PQR MSR. */
 	resctrl_sched_in(next_p);
 
+	reset_hardware_history_hetero();
+
 	return prev_p;
 }
 
-- 
2.43.0

[PATCH v3 12/14] cpufreq/amd-pstate: Disable preferred cores on designs with workload classification

[Mario Limonciello]

On designs that have workload classification, it's preferred that
the amd-hfi driver is used to provide hints to the scheduler of
which cores to use instead of the amd-pstate driver.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
 * Disable prefcore sysfs file too
---
 drivers/cpufreq/amd-pstate.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 90868c8b214e..f2a23f622843 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -763,6 +763,12 @@ static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
 	/* user disabled or not detected */
 	if (!amd_pstate_prefcore)
 		return;
+	/* should use amd-hfi instead */
+	if (boot_cpu_has(X86_FEATURE_WORKLOAD_CLASS) &&
+	    IS_ENABLED(CONFIG_AMD_HFI)) {
+		amd_pstate_prefcore = false;
+		return;
+	}
 
 	cpudata->hw_prefcore = true;
 
-- 
2.43.0

[PATCH v3 13/14] platform/x86/amd: hfi: Set ITMT priority from ranking data

[Mario Limonciello]

The static ranking data that is read at module load should be used
to set up the priorities for the cores relative to the performance
values.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/platform/x86/amd/hfi/Kconfig |  1 +
 drivers/platform/x86/amd/hfi/hfi.c   | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/drivers/platform/x86/amd/hfi/Kconfig b/drivers/platform/x86/amd/hfi/Kconfig
index 08051cd4f74d..4dfa7641b35b 100644
--- a/drivers/platform/x86/amd/hfi/Kconfig
+++ b/drivers/platform/x86/amd/hfi/Kconfig
@@ -7,6 +7,7 @@ config AMD_HFI
 	bool "AMD Hetero Core Hardware Feedback Driver"
 	depends on ACPI
 	depends on CPU_SUP_AMD
+	depends on SCHED_MC_PRIO
 	help
 	 Select this option to enable the AMD Heterogeneous Core Hardware Feedback Interface. If
 	 selected, hardware provides runtime thread classification guidance to the operating system
diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
index 79963c423d35..6c90b50f0a40 100644
--- a/drivers/platform/x86/amd/hfi/hfi.c
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -120,6 +120,12 @@ static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index =
 
 static DEFINE_MUTEX(hfi_cpuinfo_lock);
 
+static void amd_hfi_sched_itmt_work(struct work_struct *work)
+{
+	sched_set_itmt_support();
+}
+static DECLARE_WORK(sched_amd_hfi_itmt_work, amd_hfi_sched_itmt_work);
+
 static int find_cpu_index_by_apicid(unsigned int target_apicid)
 {
 	int cpu_index;
@@ -246,6 +252,8 @@ static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
 		WRITE_ONCE(hfi_cpuinfo->ipcc_scores[i],
 			   hfi_cpuinfo->amd_hfi_classes[i].perf);
 
+	sched_set_itmt_core_prio(hfi_cpuinfo->ipcc_scores[0], cpu);
+
 	return 0;
 }
 
@@ -463,6 +471,8 @@ static int amd_hfi_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
+	schedule_work(&sched_amd_hfi_itmt_work);
+
 	return 0;
 }
 
-- 
2.43.0

[PATCH v3 14/14] platform/x86: hfi: Add debugfs support

[Mario Limonciello]

Add a dump of the class and capabilities table to debugfs to assist
with debugging scheduler issues.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v2->v3:
  * New patch
---
 drivers/platform/x86/amd/hfi/hfi.c | 31 ++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
index 6c90b50f0a40..6df80f6ac73c 100644
--- a/drivers/platform/x86/amd/hfi/hfi.c
+++ b/drivers/platform/x86/amd/hfi/hfi.c
@@ -13,6 +13,7 @@
 #include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
+#include <linux/debugfs.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/io.h>
@@ -79,6 +80,8 @@ struct amd_hfi_data {
 	void __iomem		*pcc_comm_addr;
 	struct acpi_subtable_header	*pcct_entry;
 	struct amd_shmem_info	*shmem;
+
+	struct dentry *dbgfs_dir;
 };
 
 /**
@@ -243,6 +246,8 @@ static void amd_hfi_remove(struct platform_device *pdev)
 {
 	struct amd_hfi_data *dev = platform_get_drvdata(pdev);
 
+	debugfs_remove_recursive(dev->dbgfs_dir);
+
 	mutex_destroy(&dev->lock);
 }
 
@@ -400,6 +405,28 @@ static int amd_hfi_metadata_parser(struct platform_device *pdev,
 	return ret;
 }
 
+static int class_capabilities_show(struct seq_file *s, void *unused)
+{
+	int cpu, idx;
+
+	seq_puts(s, "CPU #\tWLC\tPerf\tEff\n");
+	for_each_present_cpu(cpu) {
+		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
+
+		seq_printf(s, "%d\t", cpu);
+		for (idx = 0; idx < hfi_cpuinfo->nr_class; idx++) {
+			seq_printf(s, "%s%d\t%d\t%d\n",
+				   idx == 0 ? "" : "\t",
+				   idx,
+				   hfi_cpuinfo->amd_hfi_classes[idx].perf,
+				   hfi_cpuinfo->amd_hfi_classes[idx].eff);
+		}
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(class_capabilities);
+
 static int amd_hfi_pm_resume(struct device *dev)
 {
 	int ret, cpu;
@@ -473,6 +500,10 @@ static int amd_hfi_probe(struct platform_device *pdev)
 
 	schedule_work(&sched_amd_hfi_itmt_work);
 
+	amd_hfi_data->dbgfs_dir = debugfs_create_dir("amd_hfi", arch_debugfs_dir);
+	debugfs_create_file("class_capabilities", 0644, amd_hfi_data->dbgfs_dir, pdev,
+			    &class_capabilities_fops);
+
 	return 0;
 }
 
-- 
2.43.0

Re: [PATCH v3 14/14] platform/x86: hfi: Add debugfs support

[Ilpo Järvinen]

On Tue, 15 Oct 2024, Mario Limonciello wrote:

> Add a dump of the class and capabilities table to debugfs to assist
> with debugging scheduler issues.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> v2->v3:
>   * New patch
> ---
>  drivers/platform/x86/amd/hfi/hfi.c | 31 ++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
> index 6c90b50f0a40..6df80f6ac73c 100644
> --- a/drivers/platform/x86/amd/hfi/hfi.c
> +++ b/drivers/platform/x86/amd/hfi/hfi.c
> @@ -13,6 +13,7 @@
>  #include <linux/acpi.h>
>  #include <linux/cpu.h>
>  #include <linux/cpumask.h>
> +#include <linux/debugfs.h>
>  #include <linux/gfp.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
> @@ -79,6 +80,8 @@ struct amd_hfi_data {
>  	void __iomem		*pcc_comm_addr;
>  	struct acpi_subtable_header	*pcct_entry;
>  	struct amd_shmem_info	*shmem;
> +
> +	struct dentry *dbgfs_dir;
>  };
>  
>  /**
> @@ -243,6 +246,8 @@ static void amd_hfi_remove(struct platform_device *pdev)
>  {
>  	struct amd_hfi_data *dev = platform_get_drvdata(pdev);
>  
> +	debugfs_remove_recursive(dev->dbgfs_dir);
> +
>  	mutex_destroy(&dev->lock);
>  }
>  
> @@ -400,6 +405,28 @@ static int amd_hfi_metadata_parser(struct platform_device *pdev,
>  	return ret;
>  }
>  
> +static int class_capabilities_show(struct seq_file *s, void *unused)
> +{
> +	int cpu, idx;
> +
> +	seq_puts(s, "CPU #\tWLC\tPerf\tEff\n");
> +	for_each_present_cpu(cpu) {
> +		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
> +
> +		seq_printf(s, "%d\t", cpu);
> +		for (idx = 0; idx < hfi_cpuinfo->nr_class; idx++) {
> +			seq_printf(s, "%s%d\t%d\t%d\n",
> +				   idx == 0 ? "" : "\t",

Is this conditional printing really required? Why cannot you just print \t 
always here and remove it from the cpu print line?

-- 
 i.

> +				   idx,
> +				   hfi_cpuinfo->amd_hfi_classes[idx].perf,
> +				   hfi_cpuinfo->amd_hfi_classes[idx].eff);
> +		}
> +	}
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(class_capabilities);
> +
>  static int amd_hfi_pm_resume(struct device *dev)
>  {
>  	int ret, cpu;
> @@ -473,6 +500,10 @@ static int amd_hfi_probe(struct platform_device *pdev)
>  
>  	schedule_work(&sched_amd_hfi_itmt_work);
>  
> +	amd_hfi_data->dbgfs_dir = debugfs_create_dir("amd_hfi", arch_debugfs_dir);
> +	debugfs_create_file("class_capabilities", 0644, amd_hfi_data->dbgfs_dir, pdev,
> +			    &class_capabilities_fops);
> +
>  	return 0;
>  }
>  
> 

Re: [PATCH v3 08/14] platform/x86: hfi: add online and offline callback support

[Ilpo Järvinen]

On Tue, 15 Oct 2024, Mario Limonciello wrote:

> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> There are some firmware parameters that need to be configured
> when a CPU core is brought online or offline.
> 
> when CPU is online, it will initialize the workload classification
> parameters to CPU firmware which will trigger the workload class ID
> updating function.
> 
> Once the CPU is going to offline, it will need to disable the workload
> classification function and clear the history.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> v2->v3:
>  * Use guard() (Ilpo)
>  * Whitespace changes (Ilpo)
>  * Remove labels for unwind (Ilpo)
> ---
>  drivers/platform/x86/amd/hfi/hfi.c | 79 ++++++++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
> index 63e66ab60655..d971ec1124af 100644
> --- a/drivers/platform/x86/amd/hfi/hfi.c
> +++ b/drivers/platform/x86/amd/hfi/hfi.c
> @@ -249,6 +249,80 @@ static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
>  	return 0;
>  }
>  
> +static int amd_hfi_set_state(unsigned int cpu, bool state)
> +{
> +	int ret;
> +
> +	ret = wrmsrl_on_cpu(cpu, AMD_WORKLOAD_CLASS_CONFIG, state);
> +	if (ret)
> +		return ret;
> +
> +	return wrmsrl_on_cpu(cpu, AMD_WORKLOAD_HRST, 0x1);
> +}
> +
> +/**
> + * amd_hfi_online() - Enable workload classification on @cpu
> + * @cpu: CPU in which the workload classification will be enabled
> + *
> + * Return: 0 on success, negative error code on failure
> + */
> +static int amd_hfi_online(unsigned int cpu)
> +{
> +	struct amd_hfi_cpuinfo *hfi_info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
> +	struct amd_hfi_classes *hfi_classes;
> +	int ret;
> +
> +	if (WARN_ON_ONCE(!hfi_info))
> +		return -EINVAL;
> +
> +	/*
> +	 * Check if @cpu as an associated, initialized and ranking data must be filled
> +	 */
> +	hfi_classes = hfi_info->amd_hfi_classes;
> +	if (!hfi_classes)
> +		return -EINVAL;
> +
> +	guard(mutex)(&hfi_cpuinfo_lock);
> +
> +	if (!zalloc_cpumask_var(&hfi_info->cpus, GFP_KERNEL))
> +		return -ENOMEM;
> +
> +	cpumask_set_cpu(cpu, hfi_info->cpus);
> +
> +	ret = amd_hfi_set_state(cpu, true);
> +	if (ret)
> +		pr_err("WCT enable failed for cpu %d\n", cpu);

cpu -> CPU

-- 
 i.

> +
> +	return ret;
> +}
> +
> +/**
> + * amd_hfi_offline() - Disable workload classification on @cpu
> + * @cpu: CPU in which the workload classification will be disabled
> + *
> + * Remove @cpu from those covered by its HFI instance.
> + *
> + * Return: 0 on success, negative error code on failure
> + */
> +static int amd_hfi_offline(unsigned int cpu)
> +{
> +	struct amd_hfi_cpuinfo *hfi_info = &per_cpu(amd_hfi_cpuinfo, cpu);
> +	int ret;
> +
> +	if (WARN_ON_ONCE(!hfi_info))
> +		return -EINVAL;
> +
> +	guard(mutex)(&hfi_cpuinfo_lock);
> +
> +	ret = amd_hfi_set_state(cpu, false);
> +	if (ret)
> +		pr_err("WCT disable failed for CPU %d\n", cpu);
> +
> +	free_cpumask_var(hfi_info->cpus);
> +
> +	return ret;
> +}
> +
>  static int update_hfi_ipcc_scores(void)
>  {
>  	int cpu;
> @@ -352,6 +426,11 @@ static int amd_hfi_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/amd_hfi:online",
> +				amd_hfi_online, amd_hfi_offline);
> +	if (ret < 0)
> +		return ret;
> +
>  	return 0;
>  }
>  
> 

Re: [PATCH v3 14/14] platform/x86: hfi: Add debugfs support

[Mario Limonciello]

On 10/16/2024 07:38, Ilpo Järvinen wrote:
> On Tue, 15 Oct 2024, Mario Limonciello wrote:
> 
>> Add a dump of the class and capabilities table to debugfs to assist
>> with debugging scheduler issues.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> ---
>> v2->v3:
>>    * New patch
>> ---
>>   drivers/platform/x86/amd/hfi/hfi.c | 31 ++++++++++++++++++++++++++++++
>>   1 file changed, 31 insertions(+)
>>
>> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
>> index 6c90b50f0a40..6df80f6ac73c 100644
>> --- a/drivers/platform/x86/amd/hfi/hfi.c
>> +++ b/drivers/platform/x86/amd/hfi/hfi.c
>> @@ -13,6 +13,7 @@
>>   #include <linux/acpi.h>
>>   #include <linux/cpu.h>
>>   #include <linux/cpumask.h>
>> +#include <linux/debugfs.h>
>>   #include <linux/gfp.h>
>>   #include <linux/init.h>
>>   #include <linux/io.h>
>> @@ -79,6 +80,8 @@ struct amd_hfi_data {
>>   	void __iomem		*pcc_comm_addr;
>>   	struct acpi_subtable_header	*pcct_entry;
>>   	struct amd_shmem_info	*shmem;
>> +
>> +	struct dentry *dbgfs_dir;
>>   };
>>   
>>   /**
>> @@ -243,6 +246,8 @@ static void amd_hfi_remove(struct platform_device *pdev)
>>   {
>>   	struct amd_hfi_data *dev = platform_get_drvdata(pdev);
>>   
>> +	debugfs_remove_recursive(dev->dbgfs_dir);
>> +
>>   	mutex_destroy(&dev->lock);
>>   }
>>   
>> @@ -400,6 +405,28 @@ static int amd_hfi_metadata_parser(struct platform_device *pdev,
>>   	return ret;
>>   }
>>   
>> +static int class_capabilities_show(struct seq_file *s, void *unused)
>> +{
>> +	int cpu, idx;
>> +
>> +	seq_puts(s, "CPU #\tWLC\tPerf\tEff\n");
>> +	for_each_present_cpu(cpu) {
>> +		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
>> +
>> +		seq_printf(s, "%d\t", cpu);
>> +		for (idx = 0; idx < hfi_cpuinfo->nr_class; idx++) {
>> +			seq_printf(s, "%s%d\t%d\t%d\n",
>> +				   idx == 0 ? "" : "\t",
> 
> Is this conditional printing really required? Why cannot you just print \t
> always here and remove it from the cpu print line?
> 

Thanks for the suggestion, will include in v4.

Re: [PATCH v3 03/14] x86/cpufeatures: add X86_FEATURE_WORKLOAD_CLASS feature bit

[Gautham R. Shenoy]

On Tue, Oct 15, 2024 at 04:36:34PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <perry.yuan@amd.com>
> 
> Add new feature bit that indicates support for workload based
> heuristic feedback to OS for scheduling decisions.
> When the bit set, threads are classified during runtime into
> enumerated classes. The classes represent thread performance/power
> characteristics that may benefit from special scheduling behaviors.
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>


> ---
>  arch/x86/include/asm/cpufeatures.h | 1 +
>  arch/x86/kernel/cpu/scattered.c    | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index cea1ed82aeb4..3e8e67b8ec7a 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -474,6 +474,7 @@
>  #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* Clear branch history at vmexit using SW loop */
>  #define X86_FEATURE_FAST_CPPC		(21*32 + 5) /* AMD Fast CPPC */
>  #define X86_FEATURE_HETERO_CORE_TOPOLOGY	(21*32 + 6) /* Heterogeneous Core Topology */
> +#define X86_FEATURE_WORKLOAD_CLASS	(21*32 + 7) /* Workload Classification */
>  
>  /*
>   * BUG word(s)
> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
> index 3bba55323163..b6547bab9e23 100644
> --- a/arch/x86/kernel/cpu/scattered.c
> +++ b/arch/x86/kernel/cpu/scattered.c
> @@ -49,6 +49,7 @@ static const struct cpuid_bit cpuid_bits[] = {
>  	{ X86_FEATURE_MBA,		CPUID_EBX,  6, 0x80000008, 0 },
>  	{ X86_FEATURE_SMBA,		CPUID_EBX,  2, 0x80000020, 0 },
>  	{ X86_FEATURE_BMEC,		CPUID_EBX,  3, 0x80000020, 0 },
> +	{ X86_FEATURE_WORKLOAD_CLASS,   CPUID_EAX,  22, 0x80000021, 0 },
>  	{ X86_FEATURE_PERFMON_V2,	CPUID_EAX,  0, 0x80000022, 0 },
>  	{ X86_FEATURE_AMD_LBR_V2,	CPUID_EAX,  1, 0x80000022, 0 },
>  	{ X86_FEATURE_AMD_LBR_PMC_FREEZE,	CPUID_EAX,  2, 0x80000022, 0 },
> -- 
> 2.43.0
> 

Re: [PATCH v3 04/14] x86/msr-index: define AMD heterogeneous CPU related MSR

[Gautham R. Shenoy]

On Tue, Oct 15, 2024 at 04:36:35PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <perry.yuan@amd.com>
> 
> Introduces new MSR registers for AMD hardware feedback support.
> These registers enable the system to provide workload classification
> and configuration capabilities.
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

> ---
>  arch/x86/include/asm/msr-index.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
> index 3ae84c3b8e6d..0cd5ffe50f4a 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -712,6 +712,11 @@
>  #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
>  
> +/* AMD Hardware Feedback Support MSRs */
> +#define AMD_WORKLOAD_CLASS_CONFIG      0xc0000500
> +#define AMD_WORKLOAD_CLASS_ID          0xc0000501
> +#define AMD_WORKLOAD_HRST              0xc0000502
> +
>  /* AMD Last Branch Record MSRs */
>  #define MSR_AMD64_LBR_SELECT			0xc000010e
>  
> -- 
> 2.43.0
> 

Re: [PATCH v3 07/14] platform/x86: hfi: init per-cpu scores for each class

[Gautham R. Shenoy]

On Tue, Oct 15, 2024 at 04:36:38PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> Initialize per cpu score `amd_hfi_ipcc_scores` which store energy score
> and performance score data for each class.
> 
> `Classic core` and `Dense core` are ranked according to those values as
> energy efficiency capability or performance capability.
> OS scheduler will pick cores from the ranking list on each class ID for
> the thread which provide the class id got from hardware feedback
> interface.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> v2->v3:
>  * Drop jump label (Ilpo)
> ---
>  drivers/platform/x86/amd/hfi/hfi.c | 31 ++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
> index d2952233442b..63e66ab60655 100644
> --- a/drivers/platform/x86/amd/hfi/hfi.c
> +++ b/drivers/platform/x86/amd/hfi/hfi.c
> @@ -118,6 +118,8 @@ struct amd_hfi_cpuinfo {
>  
>  static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
>  
> +static DEFINE_MUTEX(hfi_cpuinfo_lock);
> +
>  static int find_cpu_index_by_apicid(unsigned int target_apicid)
>  {
>  	int cpu_index;
> @@ -238,6 +240,31 @@ static void amd_hfi_remove(struct platform_device *pdev)
>  	mutex_destroy(&dev->lock);
>  }
>  
> +static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
> +{
> +	for (int i = 0; i < hfi_cpuinfo->nr_class; i++)
> +		WRITE_ONCE(hfi_cpuinfo->ipcc_scores[i],
> +			   hfi_cpuinfo->amd_hfi_classes[i].perf);

@cpu is not used here. But I suppose it will be used in a subsequent
patch to inform the scheduler about the changed score for this cpu.

Otherwise, looks good to me.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

--
Thanks and Regards
gautham.


> +
> +	return 0;
> +}
> +
> +static int update_hfi_ipcc_scores(void)
> +{
> +	int cpu;
> +	int ret;
> +
> +	for_each_present_cpu(cpu) {
> +		struct amd_hfi_cpuinfo *hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
> +
> +		ret = amd_set_hfi_ipcc_score(hfi_cpuinfo, cpu);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static int amd_hfi_metadata_parser(struct platform_device *pdev,
>  				   struct amd_hfi_data *amd_hfi_data)
>  {
> @@ -321,6 +348,10 @@ static int amd_hfi_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	ret = update_hfi_ipcc_scores();
> +	if (ret)
> +		return ret;
> +
>  	return 0;
>  }
>  
> -- 
> 2.43.0
> 

Re: [PATCH v3 09/14] platform/x86: hfi: add power management callback

[Gautham R. Shenoy]

On Tue, Oct 15, 2024 at 04:36:40PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> Introduces power management callbacks for the `amd_hfi` driver.
> Specifically, the `suspend` and `resume` callbacks have been added
> to handle the necessary operations during system low power states
> and wake-up.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
> v2->v3:
>  * Whitespace (Ilpo)
> ---
>  drivers/platform/x86/amd/hfi/hfi.c | 33 ++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
> index d971ec1124af..79963c423d35 100644
> --- a/drivers/platform/x86/amd/hfi/hfi.c
> +++ b/drivers/platform/x86/amd/hfi/hfi.c
> @@ -392,6 +392,38 @@ static int amd_hfi_metadata_parser(struct platform_device *pdev,
>  	return ret;
>  }
>  
> +static int amd_hfi_pm_resume(struct device *dev)
> +{
> +	int ret, cpu;
> +
> +	for_each_present_cpu(cpu) {

Shouldn't this be for_each_online_cpu() in light of the hotplug
notifier callbacks implemented in Patch 8?

> +		ret = amd_hfi_set_state(cpu, true);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to enable workload class config: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int amd_hfi_pm_suspend(struct device *dev)
> +{
> +	int ret, cpu;
> +
> +	for_each_present_cpu(cpu) {

Ditto..

> +		ret = amd_hfi_set_state(cpu, false);
> +		if (ret < 0) {
> +			dev_err(dev, "failed to disable workload class config: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(amd_hfi_pm_ops, amd_hfi_pm_suspend, amd_hfi_pm_resume);
> +
>  static const struct acpi_device_id amd_hfi_platform_match[] = {
>  	{ "AMDI0104", 0},
>  	{ }
> @@ -438,6 +470,7 @@ static struct platform_driver amd_hfi_driver = {
>  	.driver = {
>  		.name = AMD_HFI_DRIVER,
>  		.owner = THIS_MODULE,
> +		.pm = &amd_hfi_pm_ops,
>  		.acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
>  	},
>  	.probe = amd_hfi_probe,
> -- 
> 2.43.0

--
Thanks and Regards
gautham.

Re: [PATCH v3 10/14] x86/cpu: Enable SD_ASYM_PACKING for DIE Domain on AMD Processors

[Gautham R. Shenoy]

On Tue, Oct 15, 2024 at 04:36:41PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <perry.yuan@amd.com>
> 
> Enable the SD_ASYM_PACKING domain flag for the DIE domain on AMD

Nit: It is called the PKG domain now instead of the DIE domain.

# grep . /sys/kernel/debug/sched/domains/cpu0/domain*/name
/sys/kernel/debug/sched/domains/cpu0/domain0/name:SMT
/sys/kernel/debug/sched/domains/cpu0/domain1/name:MC
/sys/kernel/debug/sched/domains/cpu0/domain2/name:PKG <----
/sys/kernel/debug/sched/domains/cpu0/domain3/name:NUMA


> heterogeneous processors.
> This flag is beneficial for processors with one or more CCDs and
> relies on x86_sched_itmt_flags().
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

Looks good to me otherwise.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

> ---
>  arch/x86/kernel/smpboot.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 766f092dab80..c01bb75d0375 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -497,8 +497,9 @@ static int x86_cluster_flags(void)
>  
>  static int x86_die_flags(void)
>  {
> -	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
> -	       return x86_sched_itmt_flags();
> +	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU) ||
> +	    cpu_feature_enabled(X86_FEATURE_HETERO_CORE_TOPOLOGY))
> +		return x86_sched_itmt_flags();
>  
>  	return 0;
>  }
> -- 
> 2.43.0
> 

Re: [PATCH v3 05/14] platform/x86: hfi: Introduce AMD Hardware Feedback Interface Driver

[Gautham R. Shenoy]

On Tue, Oct 15, 2024 at 04:36:36PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> The AMD Heterogeneous core design and Hardware Feedback Interface (HFI)
> provide behavioral classification and a dynamically updated ranking table
> for the scheduler to use when choosing cores for tasks.
> 
> There are two CPU core types defined: `Classic Core` and `Dense Core`.
> "Classic" cores are the standard performance cores, while "Dense" cores
> are optimized for area and efficiency.
> 
> Heterogeneous compute refers to CPU implementations that are comprised
> of more than one architectural class, each with two capabilities. This
> means each CPU reports two separate capabilities: "perf" and "eff".
> 
> Each capability lists all core ranking numbers between 0 and 255, where
> a higher number represents a higher capability.
> 
> Heterogeneous systems can also extend to more than two architectural
> classes.
> 
> The purpose of the scheduling feedback mechanism is to provide information
> to the operating system scheduler in real time, allowing the scheduler to
> direct threads to the optimal core during task scheduling.
> 
> All core ranking data are provided by the BIOS via a shared memory ranking
> table, which the driver reads and uses to update core capabilities to the
> scheduler. When the hardware updates the table, it generates a platform
> interrupt to notify the OS to read the new ranking table.
> 
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>

This patch looks good to me.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>

--
Thanks and Regards
gautham.


> ---
> v2->v3:
>  * Whitespace (Ilpo)
>  * kmalloc -> kzalloc (Ilpo)
>  * Drop needless include (Ilpo)
>  * Capitalization (Ilpo)
>  * Drop needless comment (Ilpo)
> ---
>  drivers/platform/x86/amd/Kconfig      |   1 +
>  drivers/platform/x86/amd/Makefile     |   1 +
>  drivers/platform/x86/amd/hfi/Kconfig  |  20 +++
>  drivers/platform/x86/amd/hfi/Makefile |   7 ++
>  drivers/platform/x86/amd/hfi/hfi.c    | 168 ++++++++++++++++++++++++++
>  5 files changed, 197 insertions(+)
>  create mode 100644 drivers/platform/x86/amd/hfi/Kconfig
>  create mode 100644 drivers/platform/x86/amd/hfi/Makefile
>  create mode 100644 drivers/platform/x86/amd/hfi/hfi.c
> 
> diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig
> index f88682d36447..c3f69dbe3037 100644
> --- a/drivers/platform/x86/amd/Kconfig
> +++ b/drivers/platform/x86/amd/Kconfig
> @@ -5,6 +5,7 @@
>  
>  source "drivers/platform/x86/amd/pmf/Kconfig"
>  source "drivers/platform/x86/amd/pmc/Kconfig"
> +source "drivers/platform/x86/amd/hfi/Kconfig"
>  
>  config AMD_HSMP
>  	tristate "AMD HSMP Driver"
> diff --git a/drivers/platform/x86/amd/Makefile b/drivers/platform/x86/amd/Makefile
> index dcec0a46f8af..2676fc81fee5 100644
> --- a/drivers/platform/x86/amd/Makefile
> +++ b/drivers/platform/x86/amd/Makefile
> @@ -9,3 +9,4 @@ amd_hsmp-y			:= hsmp.o
>  obj-$(CONFIG_AMD_HSMP)		+= amd_hsmp.o
>  obj-$(CONFIG_AMD_PMF)		+= pmf/
>  obj-$(CONFIG_AMD_WBRF)		+= wbrf.o
> +obj-$(CONFIG_AMD_HFI)		+= hfi/
> diff --git a/drivers/platform/x86/amd/hfi/Kconfig b/drivers/platform/x86/amd/hfi/Kconfig
> new file mode 100644
> index 000000000000..08051cd4f74d
> --- /dev/null
> +++ b/drivers/platform/x86/amd/hfi/Kconfig
> @@ -0,0 +1,20 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +# AMD Hardware Feedback Interface Driver
> +#
> +
> +config AMD_HFI
> +	bool "AMD Hetero Core Hardware Feedback Driver"
> +	depends on ACPI
> +	depends on CPU_SUP_AMD
> +	help
> +	 Select this option to enable the AMD Heterogeneous Core Hardware Feedback Interface. If
> +	 selected, hardware provides runtime thread classification guidance to the operating system
> +	 on the performance and energy efficiency capabilities of each heterogeneous CPU core.
> +	 These capabilities may vary due to the inherent differences in the core types and can
> +	 also change as a result of variations in the operating conditions of the system such
> +	 as power and thermal limits. If selected, the kernel relays updates in heterogeneous
> +	 CPUs' capabilities to userspace, allowing for more optimal task scheduling and
> +	 resource allocation, leveraging the diverse set of cores available.
> +
> +
> diff --git a/drivers/platform/x86/amd/hfi/Makefile b/drivers/platform/x86/amd/hfi/Makefile
> new file mode 100644
> index 000000000000..672c6ac106e9
> --- /dev/null
> +++ b/drivers/platform/x86/amd/hfi/Makefile
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# AMD Hardware Feedback Interface Driver
> +#
> +
> +obj-$(CONFIG_AMD_HFI) += amd_hfi.o
> +amd_hfi-objs := hfi.o
> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
> new file mode 100644
> index 000000000000..fbbc2c119a64
> --- /dev/null
> +++ b/drivers/platform/x86/amd/hfi/hfi.c
> @@ -0,0 +1,168 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * AMD Hardware Feedback Interface Driver
> + *
> + * Copyright (C) 2024 Advanced Micro Devices, Inc. All Rights Reserved.
> + *
> + * Authors: Perry Yuan <Perry.Yuan@amd.com>
> + *          Mario Limonciello <mario.limonciello@amd.com>
> + */
> +
> +#define pr_fmt(fmt)  "amd-hfi: " fmt
> +
> +#include <linux/acpi.h>
> +#include <linux/cpu.h>
> +#include <linux/cpumask.h>
> +#include <linux/gfp.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/printk.h>
> +#include <linux/smp.h>
> +
> +#define AMD_HFI_DRIVER		"amd_hfi"
> +#define AMD_HETERO_CPUID_27	0x80000027
> +static struct platform_device *device;
> +
> +struct amd_hfi_data {
> +	const char	*name;
> +	struct device	*dev;
> +	struct mutex	lock;
> +};
> +
> +struct amd_hfi_classes {
> +	u32	perf;
> +	u32	eff;
> +};
> +
> +/**
> + * struct amd_hfi_cpuinfo - HFI workload class info per CPU
> + * @cpu:		cpu index
> + * @cpus:		mask of cpus associated with amd_hfi_cpuinfo
> + * @class_index:	workload class ID index
> + * @nr_class:		max number of workload class supported
> + * @amd_hfi_classes:	current cpu workload class ranking data
> + *
> + * Parameters of a logical processor linked with hardware feedback class
> + */
> +struct amd_hfi_cpuinfo {
> +	int		cpu;
> +	cpumask_var_t	cpus;
> +	s16		class_index;
> +	u8		nr_class;
> +	struct amd_hfi_classes	*amd_hfi_classes;
> +};
> +
> +static DEFINE_PER_CPU(struct amd_hfi_cpuinfo, amd_hfi_cpuinfo) = {.class_index = -1};
> +
> +static int amd_hfi_alloc_class_data(struct platform_device *pdev)
> +{
> +	struct amd_hfi_cpuinfo *hfi_cpuinfo;
> +	struct device *dev = &pdev->dev;
> +	int idx;
> +	int nr_class_id;
> +
> +	nr_class_id = cpuid_eax(AMD_HETERO_CPUID_27);
> +	if (nr_class_id < 0 || nr_class_id > 255) {
> +		dev_err(dev, "failed to get number of supported classes: %d\n",
> +			nr_class_id);
> +		return -EINVAL;
> +	}
> +
> +	for_each_present_cpu(idx) {
> +		struct amd_hfi_classes *classes;
> +
> +		classes = devm_kzalloc(dev,
> +				       nr_class_id * sizeof(struct amd_hfi_classes),
> +				       GFP_KERNEL);
> +		if (!classes)
> +			return -ENOMEM;
> +		hfi_cpuinfo = per_cpu_ptr(&amd_hfi_cpuinfo, idx);
> +		hfi_cpuinfo->amd_hfi_classes = classes;
> +		hfi_cpuinfo->nr_class = nr_class_id;
> +	}
> +
> +	return 0;
> +}
> +
> +static void amd_hfi_remove(struct platform_device *pdev)
> +{
> +	struct amd_hfi_data *dev = platform_get_drvdata(pdev);
> +
> +	mutex_destroy(&dev->lock);
> +}
> +
> +static const struct acpi_device_id amd_hfi_platform_match[] = {
> +	{ "AMDI0104", 0},
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(acpi, amd_hfi_platform_match);
> +
> +static int amd_hfi_probe(struct platform_device *pdev)
> +{
> +	struct amd_hfi_data *amd_hfi_data;
> +	int ret;
> +
> +	if (!acpi_match_device(amd_hfi_platform_match, &pdev->dev))
> +		return -ENODEV;
> +
> +	amd_hfi_data = devm_kzalloc(&pdev->dev, sizeof(*amd_hfi_data), GFP_KERNEL);
> +	if (!amd_hfi_data)
> +		return -ENOMEM;
> +
> +	amd_hfi_data->dev = &pdev->dev;
> +	mutex_init(&amd_hfi_data->lock);
> +	platform_set_drvdata(pdev, amd_hfi_data);
> +
> +	ret = amd_hfi_alloc_class_data(pdev);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static struct platform_driver amd_hfi_driver = {
> +	.driver = {
> +		.name = AMD_HFI_DRIVER,
> +		.owner = THIS_MODULE,
> +		.acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
> +	},
> +	.probe = amd_hfi_probe,
> +	.remove_new = amd_hfi_remove,
> +};
> +
> +static int __init amd_hfi_init(void)
> +{
> +	int ret;
> +
> +	if (acpi_disabled ||
> +	    !boot_cpu_has(X86_FEATURE_HETERO_CORE_TOPOLOGY) ||
> +	    !boot_cpu_has(X86_FEATURE_WORKLOAD_CLASS))
> +		return -ENODEV;
> +
> +	device = platform_device_register_simple(AMD_HFI_DRIVER, -1, NULL, 0);
> +	if (IS_ERR(device)) {
> +		pr_err("unable to register HFI platform device\n");
> +		return PTR_ERR(device);
> +	}
> +
> +	ret = platform_driver_register(&amd_hfi_driver);
> +	if (ret)
> +		pr_err("failed to register HFI driver\n");
> +
> +	return ret;
> +}
> +
> +static __exit void amd_hfi_exit(void)
> +{
> +	platform_device_unregister(device);
> +	platform_driver_unregister(&amd_hfi_driver);
> +}
> +module_init(amd_hfi_init);
> +module_exit(amd_hfi_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("AMD Hardware Feedback Interface Driver");
> -- 
> 2.43.0
> 

Re: [PATCH v3 09/14] platform/x86: hfi: add power management callback

[Mario Limonciello]

On 10/17/2024 01:00, Gautham R. Shenoy wrote:
> On Tue, Oct 15, 2024 at 04:36:40PM -0500, Mario Limonciello wrote:
>> From: Perry Yuan <Perry.Yuan@amd.com>
>>
>> Introduces power management callbacks for the `amd_hfi` driver.
>> Specifically, the `suspend` and `resume` callbacks have been added
>> to handle the necessary operations during system low power states
>> and wake-up.
>>
>> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
>> Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> ---
>> v2->v3:
>>   * Whitespace (Ilpo)
>> ---
>>   drivers/platform/x86/amd/hfi/hfi.c | 33 ++++++++++++++++++++++++++++++
>>   1 file changed, 33 insertions(+)
>>
>> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
>> index d971ec1124af..79963c423d35 100644
>> --- a/drivers/platform/x86/amd/hfi/hfi.c
>> +++ b/drivers/platform/x86/amd/hfi/hfi.c
>> @@ -392,6 +392,38 @@ static int amd_hfi_metadata_parser(struct platform_device *pdev,
>>   	return ret;
>>   }
>>   
>> +static int amd_hfi_pm_resume(struct device *dev)
>> +{
>> +	int ret, cpu;
>> +
>> +	for_each_present_cpu(cpu) {
> 
> Shouldn't this be for_each_online_cpu() in light of the hotplug
> notifier callbacks implemented in Patch 8?

Thx, will fix.

> 
>> +		ret = amd_hfi_set_state(cpu, true);
>> +		if (ret < 0) {
>> +			dev_err(dev, "failed to enable workload class config: %d\n", ret);
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int amd_hfi_pm_suspend(struct device *dev)
>> +{
>> +	int ret, cpu;
>> +
>> +	for_each_present_cpu(cpu) {
> 
> Ditto..
> 
>> +		ret = amd_hfi_set_state(cpu, false);
>> +		if (ret < 0) {
>> +			dev_err(dev, "failed to disable workload class config: %d\n", ret);
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static DEFINE_SIMPLE_DEV_PM_OPS(amd_hfi_pm_ops, amd_hfi_pm_suspend, amd_hfi_pm_resume);
>> +
>>   static const struct acpi_device_id amd_hfi_platform_match[] = {
>>   	{ "AMDI0104", 0},
>>   	{ }
>> @@ -438,6 +470,7 @@ static struct platform_driver amd_hfi_driver = {
>>   	.driver = {
>>   		.name = AMD_HFI_DRIVER,
>>   		.owner = THIS_MODULE,
>> +		.pm = &amd_hfi_pm_ops,
>>   		.acpi_match_table = ACPI_PTR(amd_hfi_platform_match),
>>   	},
>>   	.probe = amd_hfi_probe,
>> -- 
>> 2.43.0
> 
> --
> Thanks and Regards
> gautham.

Re: [PATCH v3 03/14] x86/cpufeatures: add X86_FEATURE_WORKLOAD_CLASS feature bit

[Borislav Petkov]

On Tue, Oct 15, 2024 at 04:36:34PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <perry.yuan@amd.com>
> 
> Add new feature bit that indicates support for workload based
> heuristic feedback to OS for scheduling decisions.
> When the bit set, threads are classified during runtime into
> enumerated classes. The classes represent thread performance/power
> characteristics that may benefit from special scheduling behaviors.
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> ---
>  arch/x86/include/asm/cpufeatures.h | 1 +
>  arch/x86/kernel/cpu/scattered.c    | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index cea1ed82aeb4..3e8e67b8ec7a 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -474,6 +474,7 @@
>  #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* Clear branch history at vmexit using SW loop */
>  #define X86_FEATURE_FAST_CPPC		(21*32 + 5) /* AMD Fast CPPC */
>  #define X86_FEATURE_HETERO_CORE_TOPOLOGY	(21*32 + 6) /* Heterogeneous Core Topology */
> +#define X86_FEATURE_WORKLOAD_CLASS	(21*32 + 7) /* Workload Classification */

As already discussed: X86_FEATURE_AMD_WORKLOAD_CLASS

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH v3 03/14] x86/cpufeatures: add X86_FEATURE_WORKLOAD_CLASS feature bit

[Mario Limonciello]

On 10/22/2024 07:42, Borislav Petkov wrote:
> On Tue, Oct 15, 2024 at 04:36:34PM -0500, Mario Limonciello wrote:
>> From: Perry Yuan <perry.yuan@amd.com>
>>
>> Add new feature bit that indicates support for workload based
>> heuristic feedback to OS for scheduling decisions.
>> When the bit set, threads are classified during runtime into
>> enumerated classes. The classes represent thread performance/power
>> characteristics that may benefit from special scheduling behaviors.
>>
>> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
>> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
>> ---
>>   arch/x86/include/asm/cpufeatures.h | 1 +
>>   arch/x86/kernel/cpu/scattered.c    | 1 +
>>   2 files changed, 2 insertions(+)
>>
>> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
>> index cea1ed82aeb4..3e8e67b8ec7a 100644
>> --- a/arch/x86/include/asm/cpufeatures.h
>> +++ b/arch/x86/include/asm/cpufeatures.h
>> @@ -474,6 +474,7 @@
>>   #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* Clear branch history at vmexit using SW loop */
>>   #define X86_FEATURE_FAST_CPPC		(21*32 + 5) /* AMD Fast CPPC */
>>   #define X86_FEATURE_HETERO_CORE_TOPOLOGY	(21*32 + 6) /* Heterogeneous Core Topology */
>> +#define X86_FEATURE_WORKLOAD_CLASS	(21*32 + 7) /* Workload Classification */
> 
> As already discussed: X86_FEATURE_AMD_WORKLOAD_CLASS
> 

Yes; v4 does this.

https://lore.kernel.org/linux-pm/20241021180252.3531-4-mario.limonciello@amd.com/T/#u