linux-kernel - [PATCH 3.16 164/328] x86/spectre: Add missing family 6 check to microcode check

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Message-ID: <lsq.1544392233.84682158@decadent.org.uk>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Andi Kleen" <ak@...ux.intel.com>,
        "Thomas Gleixner" <tglx@...utronix.de>, x86@...nel.org
Subject: [PATCH 3.16 164/328] x86/spectre: Add missing family 6 check to
 microcode check

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Andi Kleen <ak@...ux.intel.com>

commit 1ab534e85c93945f7862378d8c8adcf408205b19 upstream.

The check for Spectre microcodes does not check for family 6, only the
model numbers.

Add a family 6 check to avoid ambiguity with other families.

Fixes: a5b296636453 ("x86/cpufeature: Blacklist SPEC_CTRL/PRED_CMD on early Spectre v2 microcodes")
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: x86@...nel.org
Cc: linux-kernel@...r.kernel.org
Link: https://lkml.kernel.org/r/20180824170351.34874-2-andi@firstfloor.org
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/kernel/cpu/intel.c | 3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -75,6 +75,9 @@ static bool bad_spectre_microcode(struct
 	if (cpu_has(c, X86_FEATURE_HYPERVISOR))
 		return false;
 
+	if (c->x86 != 6)
+		return false;
+
 	for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) {
 		if (c->x86_model == spectre_bad_microcodes[i].model &&
 		    c->x86_mask == spectre_bad_microcodes[i].stepping)