[tip:x86/pti] x86/bugs: Update when to check for the LS_CFG SSBD mitigation

[tip-bot for Tom Lendacky]

Commit-ID:  845d382bb15c6e7dc5026c0ff919c5b13fc7e11b
Gitweb:     https://git.kernel.org/tip/845d382bb15c6e7dc5026c0ff919c5b13fc7e11b
Author:     Tom Lendacky <thomas.lendacky@xxxxxxx>
AuthorDate: Mon, 2 Jul 2018 16:35:53 -0500
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 3 Jul 2018 09:45:48 +0200

x86/bugs: Update when to check for the LS_CFG SSBD mitigation

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>
---
 arch/x86/kernel/cpu/amd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 082d7875cef8..38915fbfae73 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -543,7 +543,9 @@ static void bsp_init_amd(struct cpuinfo_x86 *c)
 		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) {