linux-kernel - [PATCH 2/3] x86/microcode: Fix the ancient deprecated microcode loading method

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Date:   Fri,  5 Apr 2019 15:30:09 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Jann Horn <jannh@...gle.com>, X86 ML <x86@...nel.org>
Subject: [PATCH 2/3] x86/microcode: Fix the ancient deprecated microcode loading method

From: Borislav Petkov <bp@...e.de>

The commit in Fixes: added the new define UCODE_NEW to denote that an
update should happen only when newer microcode (than installed on the
system) has been found.

But it missed adjusting that for the old /dev/cpu/microcode loading
interface. Fix it.

Fixes: 2613f36ed965 ("x86/microcode: Attempt late loading only when new microcode is present")
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Jann Horn <jannh@...gle.com>
---
 arch/x86/kernel/cpu/microcode/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 5260185cbf7b..8a4a7823451a 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -418,8 +418,9 @@ static int do_microcode_update(const void __user *buf, size_t size)
 		if (ustate == UCODE_ERROR) {
 			error = -1;
 			break;
-		} else if (ustate == UCODE_OK)
+		} else if (ustate == UCODE_NEW) {
 			apply_microcode_on_target(cpu);
+		}
 	}
 
 	return error;
-- 
2.21.0