[PATCH 03/13] x86/CPU/AMD: Move the Zen3 BTC_NO detection to the Zen3 init function

From: Borislav Petkov
Date: Mon Nov 20 2023 - 05:42:27 EST


From: "Borislav Petkov (AMD)" <bp@xxxxxxxxx>

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
---
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