linux-kernel - [PATCH] x86/cpu/amd: Move TOPOEXT enablement into the topology parser

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Date: Thu, 11 Apr 2024 18:55:38 +0200
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: x86@...nel.org
Subject: [PATCH] x86/cpu/amd: Move TOPOEXT enablement into the topology parser

The topology rework missed that early_init_amd() tries to re-enable the
Topology Extensions when the BIOS disabled them.

The new parser is invoked before early_init_amd() so the re-enable attempt
happens too late.

Move it into the AMD specific topology parser code where it belongs.

Fixes: f7fb3b2dd92c ("x86/cpu: Provide an AMD/HYGON specific topology parser")
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/cpu/amd.c          |   15 ---------------
 arch/x86/kernel/cpu/topology_amd.c |   21 +++++++++++++++++++++
 2 files changed, 21 insertions(+), 15 deletions(-)

--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -535,7 +535,6 @@ static void early_detect_mem_encrypt(str
 
 static void early_init_amd(struct cpuinfo_x86 *c)
 {
-	u64 value;
 	u32 dummy;
 
 	if (c->x86 >= 0xf)
@@ -603,20 +602,6 @@ static void early_init_amd(struct cpuinf
 
 	early_detect_mem_encrypt(c);
 
-	/* Re-enable TopologyExtensions if switched off by BIOS */
-	if (c->x86 == 0x15 &&
-	    (c->x86_model >= 0x10 && c->x86_model <= 0x6f) &&
-	    !cpu_has(c, X86_FEATURE_TOPOEXT)) {
-
-		if (msr_set_bit(0xc0011005, 54) > 0) {
-			rdmsrl(0xc0011005, value);
-			if (value & BIT_64(54)) {
-				set_cpu_cap(c, X86_FEATURE_TOPOEXT);
-				pr_info_once(FW_INFO "CPU: Re-enabling disabled Topology Extensions Support.\n");
-			}
-		}
-	}
-
 	if (!cpu_has(c, X86_FEATURE_HYPERVISOR) && !cpu_has(c, X86_FEATURE_IBPB_BRTYPE)) {
 		if (c->x86 == 0x17 && boot_cpu_has(X86_FEATURE_AMD_IBPB))
 			setup_force_cpu_cap(X86_FEATURE_IBPB_BRTYPE);
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -147,6 +147,26 @@ static void legacy_set_llc(struct topo_s
 	tscan->c->topo.llc_id = apicid >> tscan->dom_shifts[TOPO_CORE_DOMAIN];
 }
 
+static void topoext_fixup(struct topo_scan *tscan)
+{
+	struct cpuinfo_x86 *c = tscan->c;
+	u64 msrval;
+
+	/* Try to re-enable TopologyExtensions if switched off by BIOS */
+	if (cpu_has(c, X86_FEATURE_TOPOEXT) || c->x86_vendor != X86_VENDOR_AMD ||
+	    c->x86 != 0x15 || c->x86_model < 0x10 || c->x86_model > 0x6f)
+		return;
+
+	if (msr_set_bit(0xc0011005, 54) <= 0)
+		return;
+
+	rdmsrl(0xc0011005, msrval);
+	if (msrval & BIT_64(54)) {
+		set_cpu_cap(c, X86_FEATURE_TOPOEXT);
+		pr_info_once(FW_INFO "CPU: Re-enabling disabled Topology Extensions Support.\n");
+	}
+}
+
 static void parse_topology_amd(struct topo_scan *tscan)
 {
 	bool has_0xb = false;
@@ -176,6 +196,7 @@ static void parse_topology_amd(struct to
 void cpu_parse_topology_amd(struct topo_scan *tscan)
 {
 	tscan->amd_nodes_per_pkg = 1;
+	topoext_fixup(tscan);
 	parse_topology_amd(tscan);
 
 	if (tscan->amd_nodes_per_pkg > 1)