linux-kernel - [PATCH v2 18/27] x86/cpuid: Parse deterministic cache parameters CPUID leaves

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Message-ID: <20250605192356.82250-19-darwi@linutronix.de>
Date: Thu,  5 Jun 2025 21:23:47 +0200
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Sean Christopherson <seanjc@...gle.com>,
	Sohil Mehta <sohil.mehta@...el.com>,
	Ard Biesheuvel <ardb@...nel.org>,
	John Ogness <john.ogness@...utronix.de>,
	x86@...nel.org,
	x86-cpuid@...ts.linux.dev,
	LKML <linux-kernel@...r.kernel.org>,
	"Ahmed S. Darwish" <darwi@...utronix.de>
Subject: [PATCH v2 18/27] x86/cpuid: Parse deterministic cache parameters CPUID leaves

Add CPUID parser logic for Intel CPUID(0x4) and AMD CPUID(0x8000001d).

Define a single cpuid_read_deterministic_cache() parsing function for
both leaves, as both have the same subleaf cache enumeration logic.

Introduce __define_cpuid_read_function() macro to avoid code duplication
between cpuid_read_generic(), the CPUID parser's default read function,
and the new cpuid_read_deterministic_cache() one.

Signed-off-by: Ahmed S. Darwish <darwi@...utronix.de>
---
 arch/x86/include/asm/cpuid/types.h |  2 ++
 arch/x86/kernel/cpu/cpuid_parser.c | 40 +++++++++++++++++++++++++-----
 arch/x86/kernel/cpu/cpuid_parser.h |  4 ++-
 3 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/cpuid/types.h b/arch/x86/include/asm/cpuid/types.h
index 7bbf0671cb95..89c399629e58 100644
--- a/arch/x86/include/asm/cpuid/types.h
+++ b/arch/x86/include/asm/cpuid/types.h
@@ -216,7 +216,9 @@ struct cpuid_leaves {
 	CPUID_LEAF(0x0,		0,		1);
 	CPUID_LEAF(0x1,		0,		1);
 	CPUID_LEAF(0x2,		0,		1);
+	CPUID_LEAF(0x4,		0,		8);
 	CPUID_LEAF(0x80000000,	0,		1);
+	CPUID_LEAF(0x8000001d,	0,		8);
 };
 
 /*
diff --git a/arch/x86/kernel/cpu/cpuid_parser.c b/arch/x86/kernel/cpu/cpuid_parser.c
index 4b960b23cab4..1f3b4cd6b411 100644
--- a/arch/x86/kernel/cpu/cpuid_parser.c
+++ b/arch/x86/kernel/cpu/cpuid_parser.c
@@ -14,15 +14,43 @@
 
 #include "cpuid_parser.h"
 
+/**
+ * __define_cpuid_read_function() - Generate a CPUID parser read function
+ * @_suffix:	Suffix for the generated function name (full name: cpuid_read_@...ffix())
+ * @_leaf_t:	Type to cast the CPUID query output storage pointer
+ * @_leaf:	Name of the CPUID query storage pointer
+ * @_break_c:	Condition to break the CPUID parsing loop, which may reference @_leaf, and
+ *		where @_leaf stores each iteration's CPUID query output.
+ *
+ * Define a CPUID parser read function according to the requirements stated at
+ * &struct cpuid_parse_entry->read().
+ */
+#define __define_cpuid_read_function(_suffix, _leaf_t, _leaf, _break_c)				\
+static void											\
+cpuid_read_##_suffix(const struct cpuid_parse_entry *e, struct cpuid_read_output *output)	\
+{												\
+	struct _leaf_t *_leaf = (struct _leaf_t *)output->regs;					\
+												\
+	static_assert(sizeof(*_leaf) == 16);							\
+												\
+	output->info->nr_entries = 0;								\
+	for (int i = 0; i < e->maxcnt; i++, _leaf++, output->info->nr_entries++) {		\
+		cpuid_read_subleaf(e->leaf, e->subleaf + i, _leaf);				\
+		if (_break_c)									\
+			break;									\
+	}											\
+}
+
 /*
  * Default CPUID parser read function
  */
-static void cpuid_read_generic(const struct cpuid_parse_entry *e, struct cpuid_read_output *output)
-{
-	output->info->nr_entries = 0;
-	for (int i = 0; i < e->maxcnt; i++, output->regs++, output->info->nr_entries++)
-		cpuid_read_subleaf(e->leaf, e->subleaf + i, output->regs);
-}
+__define_cpuid_read_function(generic, cpuid_regs, ignored, false);
+
+/*
+ * Shared read function for Intel CPUID leaf 0x4 and AMD CPUID leaf 0x8000001d,
+ * as both have the same subleaf enumeration logic and registers output format.
+ */
+__define_cpuid_read_function(deterministic_cache, leaf_0x4_0, leaf, leaf->cache_type == 0);
 
 static void cpuid_read_0x2(const struct cpuid_parse_entry *e, struct cpuid_read_output *output)
 {
diff --git a/arch/x86/kernel/cpu/cpuid_parser.h b/arch/x86/kernel/cpu/cpuid_parser.h
index 3178e760e2b3..c79c77547a1d 100644
--- a/arch/x86/kernel/cpu/cpuid_parser.h
+++ b/arch/x86/kernel/cpu/cpuid_parser.h
@@ -97,7 +97,9 @@ struct cpuid_parse_entry {
 	CPUID_PARSE_ENTRY(0x0,		0,		generic),			\
 	CPUID_PARSE_ENTRY(0x1,		0,		generic),			\
 	CPUID_PARSE_ENTRY(0x2,		0,		0x2),				\
-	CPUID_PARSE_ENTRY(0x80000000,	0,		0x80000000),
+	CPUID_PARSE_ENTRY(0x4,		0,		deterministic_cache),		\
+	CPUID_PARSE_ENTRY(0x80000000,	0,		0x80000000),			\
+	CPUID_PARSE_ENTRY(0x8000001d,	0,		deterministic_cache),
 
 extern const struct cpuid_parse_entry cpuid_common_parse_entries[];
 extern const int cpuid_common_parse_entries_size;
-- 
2.49.0