From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35504 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753808AbdJPQUo (ORCPT ); Mon, 16 Oct 2017 12:20:44 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Borislav Petkov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.13 51/53] x86/microcode: Do the family check first Date: Mon, 16 Oct 2017 18:16:48 +0200 Message-Id: <20171016161444.379414406@linuxfoundation.org> In-Reply-To: <20171016161442.263947886@linuxfoundation.org> References: <20171016161442.263947886@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Borislav Petkov commit 1f161f67a272cc4f29f27934dd3f74cb657eb5c4 upstream. On CPUs like AMD's Geode, for example, we shouldn't even try to load microcode because they do not support the modern microcode loading interface. However, we do the family check *after* the other checks whether the loader has been disabled on the command line or whether we're running in a guest. So move the family checks first in order to exit early if we're being loaded on an unsupported family. Reported-and-tested-by: Sven Glodowski Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://bugzilla.suse.com/show_bug.cgi?id=1061396 Link: http://lkml.kernel.org/r/20171012112316.977-1-bp@alien8.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/microcode/core.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -122,9 +122,6 @@ static bool __init check_loader_disabled bool *res = &dis_ucode_ldr; #endif - if (!have_cpuid_p()) - return *res; - /* * CPUID(1).ECX[31]: reserved for hypervisor use. This is still not * completely accurate as xen pv guests don't see that CPUID bit set but @@ -166,24 +163,36 @@ bool get_builtin_firmware(struct cpio_da void __init load_ucode_bsp(void) { unsigned int cpuid_1_eax; + bool intel = true; - if (check_loader_disabled_bsp()) + if (!have_cpuid_p()) return; cpuid_1_eax = native_cpuid_eax(1); switch (x86_cpuid_vendor()) { case X86_VENDOR_INTEL: - if (x86_family(cpuid_1_eax) >= 6) - load_ucode_intel_bsp(); + if (x86_family(cpuid_1_eax) < 6) + return; break; + case X86_VENDOR_AMD: - if (x86_family(cpuid_1_eax) >= 0x10) - load_ucode_amd_bsp(cpuid_1_eax); + if (x86_family(cpuid_1_eax) < 0x10) + return; + intel = false; break; + default: - break; + return; } + + if (check_loader_disabled_bsp()) + return; + + if (intel) + load_ucode_intel_bsp(); + else + load_ucode_amd_bsp(cpuid_1_eax); } static bool check_loader_disabled_ap(void)