linux-hwg/fix_CPU0_microcode_on_resume.patch

From fb86b97300d930b57471068720c52bfa8622eab7 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Tue, 18 Nov 2014 10:46:57 +0100
Subject: [PATCH] x86, microcode: Update BSPs microcode on resume

In the situation when we apply early microcode but do *not* apply late
microcode, we fail to update the BSP's microcode on resume because we
haven't initialized the uci->mc microcode pointer. So, in order to
alleviate that, we go and dig out the stashed microcode patch during
early boot. It is basically the same thing that is done on the APs early
during boot so do that too here.

Tested-by: alex.schnaidt@gmail.com
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=88001
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: <stable@vger.kernel.org> # v3.9
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20141118094657.GA6635@pd.tnic
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/cpu/microcode/core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index dd9d619..2ce9051 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -465,6 +465,14 @@ static void mc_bp_resume(void)
 
 	if (uci->valid && uci->mc)
 		microcode_ops->apply_microcode(cpu);
+	else if (!uci->mc)
+		/*
+		 * We might resume and not have applied late microcode but still
+		 * have a newer patch stashed from the early loader. We don't
+		 * have it in uci->mc so we have to load it the same way we're
+		 * applying patches early on the APs.
+		 */
+		load_ucode_ap();
 }
 
 static struct syscore_ops mc_syscore_ops = {
-- 
2.1.3