[PATCH 4.14 072/146] x86/bugs: Update when to check for the LS_CFG SSBD mitigation

From: Greg Kroah-Hartman
Date: Tue Dec 04 2018 - 06:04:04 EST


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

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

From: Tom Lendacky thomas.lendacky@xxxxxxx

commit 845d382bb15c6e7dc5026c0ff919c5b13fc7e11b upstream

If either the X86_FEATURE_AMD_SSBD or X86_FEATURE_VIRT_SSBD features are
present, then there is no need to perform the check for the LS_CFG SSBD
mitigation support.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Borislav Petkov <bpetkov@xxxxxxx>
Cc: David Woodhouse <dwmw@xxxxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180702213553.29202.21089.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/amd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -554,7 +554,9 @@ static void bsp_init_amd(struct cpuinfo_
nodes_per_socket = ((value >> 3) & 7) + 1;
}

- if (c->x86 >= 0x15 && c->x86 <= 0x17) {
+ if (!boot_cpu_has(X86_FEATURE_AMD_SSBD) &&
+ !boot_cpu_has(X86_FEATURE_VIRT_SSBD) &&
+ c->x86 >= 0x15 && c->x86 <= 0x17) {
unsigned int bit;

switch (c->x86) {