linux-kernel - [PATCH v2 3/3] x86/cpu/topology: Check for X86_FEATURE_XTOPOLOGY instead of passing has

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Message-ID: <20250725110622.59743-4-kprateek.nayak@amd.com>
Date: Fri, 25 Jul 2025 11:06:22 +0000
From: K Prateek Nayak <kprateek.nayak@....com>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
	<x86@...nel.org>
CC: Naveen rao <naveen.rao@....com>, Sairaj Kodilkar <sarunkod@....com>, "H.
 Peter Anvin" <hpa@...or.com>, "Peter Zijlstra (Intel)"
	<peterz@...radead.org>, "Xin Li (Intel)" <xin@...or.com>, Pawan Gupta
	<pawan.kumar.gupta@...ux.intel.com>, <linux-kernel@...r.kernel.org>, "Mario
 Limonciello" <mario.limonciello@....com>, "Gautham R. Shenoy"
	<gautham.shenoy@....com>, Babu Moger <babu.moger@....com>, "Suravee
 Suthikulpanit" <suravee.suthikulpanit@....com>, K Prateek Nayak
	<kprateek.nayak@....com>
Subject: [PATCH v2 3/3] x86/cpu/topology: Check for X86_FEATURE_XTOPOLOGY instead of passing has_topoext

cpu_parse_topology_ext() sets X86_FEATURE_XTOPOLOGY before returning
true if any of the XTOPOLOGY leaf could be parsed successfully.

Instead of storing and passing around this return value using
"has_topoext" in parse_topology_amd(), check for X86_FEATURE_XTOPOLOGY
instead in parse_8000_001e() to simplify the flow.

No functional changes intended.

Signed-off-by: K Prateek Nayak <kprateek.nayak@....com>
---
Changelog v1..v2:

o New patch.
---
 arch/x86/kernel/cpu/topology_amd.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/topology_amd.c b/arch/x86/kernel/cpu/topology_amd.c
index b392d91c6df4..1b4f178edd72 100644
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -59,7 +59,7 @@ static void store_node(struct topo_scan *tscan, u16 nr_nodes, u16 node_id)
 	tscan->amd_node_id = node_id;
 }
 
-static bool parse_8000_001e(struct topo_scan *tscan, bool has_topoext)
+static bool parse_8000_001e(struct topo_scan *tscan)
 {
 	struct {
 		// eax
@@ -81,7 +81,7 @@ static bool parse_8000_001e(struct topo_scan *tscan, bool has_topoext)
 
 	cpuid_leaf(0x8000001e, &leaf);
 
-	if (!has_topoext) {
+	if (!boot_cpu_has(X86_FEATURE_XTOPOLOGY)) {
 		/*
 		 * Prefer initial_apicid parsed from XTOPOLOGY leaf
 		 * 0x8000026 or 0xb if available. Otherwise prefer the
@@ -178,6 +178,9 @@ static void topoext_fixup(struct topo_scan *tscan)
 
 static void parse_topology_amd(struct topo_scan *tscan)
 {
+	if (cpu_feature_enabled(X86_FEATURE_AMD_HTR_CORES))
+		tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);
+
 	/*
 	 * Try to get SMT, CORE, TILE, and DIE shifts from extended
 	 * CPUID leaf 0x8000_0026 on supported processors first. If
@@ -185,16 +188,11 @@ static void parse_topology_amd(struct topo_scan *tscan)
 	 * get SMT and CORE shift from leaf 0xb first, then try to
 	 * get the CORE shift from leaf 0x8000_0008.
 	 */
-	bool has_topoext = cpu_parse_topology_ext(tscan);
-
-	if (cpu_feature_enabled(X86_FEATURE_AMD_HTR_CORES))
-		tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);
-
-	if (!has_topoext && !parse_8000_0008(tscan))
+	if (!cpu_parse_topology_ext(tscan) && !parse_8000_0008(tscan))
 		return;
 
 	/* Prefer leaf 0x8000001e if available */
-	if (parse_8000_001e(tscan, has_topoext))
+	if (parse_8000_001e(tscan))
 		return;
 
 	/* Try the NODEID MSR */
-- 
2.34.1