[PATCH 4.14 035/135] x86/CPU/AMD: Set the CPB bit unconditionally on F17h

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>

commit 0237199186e7a4aa5310741f0a6498a20c820fd7 upstream.

Some F17h models do not have CPB set in CPUID even though the CPU
supports it. Set the feature bit unconditionally on all F17h.

 [ bp: Rewrite commit message and patch. ]

Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Sherry Hurwitz <sherry.hurwitz@xxxxxxx>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20181120030018.5185-1-jiaxun.yang@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/kernel/cpu/amd.c |    8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -791,11 +791,9 @@ static void init_amd_bd(struct cpuinfo_x
 static void init_amd_zn(struct cpuinfo_x86 *c)
 {
 	set_cpu_cap(c, X86_FEATURE_ZEN);
-	/*
-	 * Fix erratum 1076: CPB feature bit not being set in CPUID. It affects
-	 * all up to and including B1.
-	 */
-	if (c->x86_model <= 1 && c->x86_stepping <= 1)
+
+	/* Fix erratum 1076: CPB feature bit not being set in CPUID. */
+	if (!cpu_has(c, X86_FEATURE_CPB))
 		set_cpu_cap(c, X86_FEATURE_CPB);
 }