linux-kernel - [PATCH 03/13] x86/CPU/AMD: Move the Zen3 BTC

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Message-ID: <20231120104152.13740-4-bp@alien8.de>
Date:   Mon, 20 Nov 2023 11:41:42 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 03/13] x86/CPU/AMD: Move the Zen3 BTC_NO detection to the Zen3 init function

From: "Borislav Petkov (AMD)" <bp@...en8.de>

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
---
 arch/x86/kernel/cpu/amd.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index b3f939101368..92202bad9bd3 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1031,14 +1031,6 @@ static void init_amd_zn(struct cpuinfo_x86 *c)
 		/* Erratum 1076: CPB feature bit not being set in CPUID. */
 		if (!cpu_has(c, X86_FEATURE_CPB))
 			set_cpu_cap(c, X86_FEATURE_CPB);
-
-		/*
-		 * Zen3 (Fam19 model < 0x10) parts are not susceptible to
-		 * Branch Type Confusion, but predate the allocation of the
-		 * BTC_NO bit.
-		 */
-		if (c->x86 == 0x19 && !cpu_has(c, X86_FEATURE_BTC_NO))
-			set_cpu_cap(c, X86_FEATURE_BTC_NO);
 	}
 }
 
@@ -1054,6 +1046,15 @@ static void init_amd_zen2(struct cpuinfo_x86 *c)
 
 static void init_amd_zen3(struct cpuinfo_x86 *c)
 {
+	if (!cpu_has(c, X86_FEATURE_HYPERVISOR)) {
+		/*
+		 * Zen3 (Fam19 model < 0x10) parts are not susceptible to
+		 * Branch Type Confusion, but predate the allocation of the
+		 * BTC_NO bit.
+		 */
+		if (!cpu_has(c, X86_FEATURE_BTC_NO))
+			set_cpu_cap(c, X86_FEATURE_BTC_NO);
+	}
 }
 
 static void init_amd_zen4(struct cpuinfo_x86 *c)
-- 
2.42.0.rc0.25.ga82fb66fed25