[PATCH v5 05/29] x86/rectrl: Fake OOBMSM interface

[Tony Luck <tony.luck@intel.com>]

Real version is coming soon[1] ... this is here so the remaining parts
will build (and run ... assuming a 2 socket system that supports RDT
monitoring ... only missing part is that the event counters just
report fixed values).

Faked values are provided to exercise some special conditions:
1) Multiple counter aggregators for an event per-socket.
2) Different number of supported RMIDs for each group.

Just for ease of testing and RFC discussion.

[1]
Link: https://lore.kernel.org/all/20250430212106.369208-1-david.e.box@linux.intel.com/

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 .../cpu/resctrl/fake_intel_aet_features.h     | 73 ++++++++++++++
 .../cpu/resctrl/fake_intel_aet_features.c     | 97 +++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/Makefile          |  1 +
 3 files changed, 171 insertions(+)
 create mode 100644 arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.h
 create mode 100644 arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.c

diff --git a/arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.h b/arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.h
new file mode 100644
index 000000000000..c835c4108abc
--- /dev/null
+++ b/arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Bits stolen from OOBMSM VSEC discovery code */
+
+enum pmt_feature_id {
+	FEATURE_INVALID			= 0x0,
+	FEATURE_PER_CORE_PERF_TELEM	= 0x1,
+	FEATURE_PER_CORE_ENV_TELEM	= 0x2,
+	FEATURE_PER_RMID_PERF_TELEM	= 0x3,
+	FEATURE_ACCEL_TELEM		= 0x4,
+	FEATURE_UNCORE_TELEM		= 0x5,
+	FEATURE_CRASH_LOG		= 0x6,
+	FEATURE_PETE_LOG		= 0x7,
+	FEATURE_TPMI_CTRL		= 0x8,
+	FEATURE_RESERVED		= 0x9,
+	FEATURE_TRACING			= 0xA,
+	FEATURE_PER_RMID_ENERGY_TELEM	= 0xB,
+	FEATURE_MAX			= 0xB,
+};
+
+/**
+ * struct oobmsm_plat_info - Platform information for a device instance
+ * @cdie_mask:       Mask of all compute dies in the partition
+ * @package_id:      CPU Package id
+ * @partition:       Package partition id when multiple VSEC PCI devices per package
+ * @segment:         PCI segment ID
+ * @bus_number:      PCI bus number
+ * @device_number:   PCI device number
+ * @function_number: PCI function number
+ *
+ * Structure to store platform data for a OOBMSM device instance.
+ */
+struct oobmsm_plat_info {
+	u16 cdie_mask;
+	u8 package_id;
+	u8 partition;
+	u8 segment;
+	u8 bus_number;
+	u8 device_number;
+	u8 function_number;
+};
+
+enum oobmsm_supplier_type {
+	OOBMSM_SUP_PLAT_INFO,
+	OOBMSM_SUP_DISC_INFO,
+	OOBMSM_SUP_S3M_SIMICS,
+	OOBMSM_SUP_TYPE_MAX
+};
+
+struct oobmsm_mapping_supplier {
+	struct device *supplier_dev[OOBMSM_SUP_TYPE_MAX];
+	struct oobmsm_plat_info plat_info;
+	unsigned long features;
+};
+
+struct telemetry_region {
+	struct oobmsm_plat_info	plat_info;
+	void __iomem		*addr;
+	size_t			size;
+	u32			guid;
+	u32			num_rmids;
+};
+
+struct pmt_feature_group {
+	enum pmt_feature_id	id;
+	int			count;
+	struct kref		kref;
+	struct telemetry_region	regions[];
+};
+
+struct pmt_feature_group *intel_pmt_get_regions_by_feature(enum pmt_feature_id id);
+
+void intel_pmt_put_feature_group(struct pmt_feature_group *feature_group);
diff --git a/arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.c b/arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.c
new file mode 100644
index 000000000000..80f38f1ee3df
--- /dev/null
+++ b/arch/x86/kernel/cpu/resctrl/fake_intel_aet_features.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/cleanup.h>
+#include <linux/minmax.h>
+#include <linux/slab.h>
+#include "fake_intel_aet_features.h"
+#include <linux/intel_vsec.h>
+#include <linux/resctrl.h>
+
+#include "internal.h"
+
+/*
+ * Amount of memory for each fake MMIO space
+ * Magic numbers here match values for XML ID 0x26696143 and 0x26557651
+ * 576: Number of RMIDs
+ * 2: Energy events in 0x26557651
+ * 7: Perf events in 0x26696143
+ * 3: Qwords for status counters after the event counters
+ * 8: Bytes for each counter
+ */
+
+#define ENERGY_QWORDS	((576 * 2) + 3)
+#define ENERGY_SIZE	(ENERGY_QWORDS * 8)
+#define PERF_QWORDS	((576 * 7) + 3)
+#define PERF_SIZE	(PERF_QWORDS * 8)
+
+static long pg[4 * ENERGY_QWORDS + 2 * PERF_QWORDS];
+
+/*
+ * Fill the fake MMIO space with all different values,
+ * all with BIT(63) set to indicate valid entries.
+ */
+static int __init fill(void)
+{
+	u64 val = 0;
+
+	for (int i = 0; i < sizeof(pg); i += sizeof(val)) {
+		pg[i / sizeof(val)] = BIT_ULL(63) + val;
+		val++;
+	}
+	return 0;
+}
+device_initcall(fill);
+
+#define PKG_REGION(_entry, _guid, _addr, _size, _pkg, _num_rmids)	\
+	[_entry] = { .guid = _guid, .addr = (void __iomem *)_addr, \
+		     .num_rmids = _num_rmids, \
+		     .size = _size, .plat_info = { .package_id = _pkg }}
+
+/*
+ * Set up a fake return for call to:
+ *   intel_pmt_get_regions_by_feature(FEATURE_PER_RMID_ENERGY_TELEM);
+ * Pretend there are two aggregators on each of the sockets to test
+ * the code that sums over multiple aggregators.
+ * Pretend this group only supports 64 RMIDs to exercise the code
+ * that reconciles support for different RMID counts.
+ */
+static struct pmt_feature_group fake_energy = {
+	.count = 4,
+	.regions = {
+		PKG_REGION(0, 0x26696143, &pg[0 * ENERGY_QWORDS], ENERGY_SIZE, 0, 64),
+		PKG_REGION(1, 0x26696143, &pg[1 * ENERGY_QWORDS], ENERGY_SIZE, 0, 64),
+		PKG_REGION(2, 0x26696143, &pg[2 * ENERGY_QWORDS], ENERGY_SIZE, 1, 64),
+		PKG_REGION(3, 0x26696143, &pg[3 * ENERGY_QWORDS], ENERGY_SIZE, 1, 64)
+	}
+};
+
+/*
+ * Fake return for:
+ *   intel_pmt_get_regions_by_feature(FEATURE_PER_RMID_PERF_TELEM);
+ */
+static struct pmt_feature_group fake_perf = {
+	.count = 2,
+	.regions = {
+		PKG_REGION(0, 0x26557651, &pg[4 * ENERGY_QWORDS + 0 * PERF_QWORDS], PERF_SIZE, 0, 576),
+		PKG_REGION(1, 0x26557651, &pg[4 * ENERGY_QWORDS + 1 * PERF_QWORDS], PERF_SIZE, 1, 576)
+	}
+};
+
+struct pmt_feature_group *
+intel_pmt_get_regions_by_feature(enum pmt_feature_id id)
+{
+	switch (id) {
+	case FEATURE_PER_RMID_ENERGY_TELEM:
+		return &fake_energy;
+	case FEATURE_PER_RMID_PERF_TELEM:
+		return &fake_perf;
+	default:
+		return ERR_PTR(-ENOENT);
+	}
+}
+
+/*
+ * Nothing needed for the "put" function.
+ */
+void intel_pmt_put_feature_group(struct pmt_feature_group *feature_group)
+{
+}
diff --git a/arch/x86/kernel/cpu/resctrl/Makefile b/arch/x86/kernel/cpu/resctrl/Makefile
index d8a04b195da2..cf4fac58d068 100644
--- a/arch/x86/kernel/cpu/resctrl/Makefile
+++ b/arch/x86/kernel/cpu/resctrl/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_X86_CPU_RESCTRL)		+= core.o rdtgroup.o monitor.o
 obj-$(CONFIG_X86_CPU_RESCTRL)		+= ctrlmondata.o
+obj-$(CONFIG_X86_CPU_RESCTRL)		+= fake_intel_aet_features.o
 obj-$(CONFIG_RESCTRL_FS_PSEUDO_LOCK)	+= pseudo_lock.o
 
 # To allow define_trace.h's recursive include:
-- 
2.49.0