From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754188AbcEBPaR (ORCPT ); Mon, 2 May 2016 11:30:17 -0400 Received: from mail.skyhub.de ([78.46.96.112]:55889 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753965AbcEBPaM (ORCPT ); Mon, 2 May 2016 11:30:12 -0400 Date: Mon, 2 May 2016 17:30:02 +0200 From: Borislav Petkov To: Henrique de Moraes Holschuh Cc: LKML , X86 ML Subject: Re: [PATCH 0/2] x86/microcode/amd: Do not overwrite specific patch levels Message-ID: <20160502153002.GD25521@pd.tnic> References: <1435781656-1890-1-git-send-email-bp@alien8.de> <20160326233157.GA11398@khazad-dum.debian.net> <20160327083159.GA32241@pd.tnic> <20160327123218.GA28778@khazad-dum.debian.net> <20160327154748.GD32241@pd.tnic> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="M9NhX3UHpAaciwkO" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160327154748.GD32241@pd.tnic> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --M9NhX3UHpAaciwkO Content-Type: text/plain; charset=utf-8 Content-Disposition: inline On Sun, Mar 27, 2016 at 05:47:48PM +0200, Borislav Petkov wrote: > But ok. I'll put it on my TODO, will get to it eventually. Unless you > beat me to it... :) Ok, I'm attaching the backports for 3.2. Care to give them a run too, just in case? Seem to work here on my test box... Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --M9NhX3UHpAaciwkO Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="0001-x86-microcode-amd-Extract-current-patch-level-read-t.patch" >>From 2eff73c0a11f19ff082a566e3429fbaaca7b8e7b Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 12 Oct 2015 11:22:41 +0200 Subject: [PATCH] x86/microcode/amd: Extract current patch level read to a function Commit 2eff73c0a11f19ff082a566e3429fbaaca7b8e7b upstream. Pave the way for checking the current patch level of the microcode in a core. We want to be able to do stuff depending on the patch level - in this case decide whether to update or not. But that will be added in a later patch. Drop unused local var uci assignment, while at it. Integrate a fix for 32-bit and CONFIG_PARAVIRT from Takashi Iwai: Use native_rdmsr() in check_current_patch_level() because with CONFIG_PARAVIRT enabled and on 32-bit, where we run before paging has been enabled, we cannot deref pv_info yet. Or we could, but we'd need to access its physical address. This way of fixing it is simpler. See: https://bugzilla.suse.com/show_bug.cgi?id=943179 for the background. Signed-off-by: Borislav Petkov Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Takashi Iwai : Cc: Thomas Gleixner Cc: Tony Luck Link: http://lkml.kernel.org/r/1444641762-9437-6-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/microcode.h | 1 + arch/x86/kernel/microcode_amd.c | 24 ++++++++++++++++++++++-- 3 files changed, 30 insertions(+), 12 deletions(-) Index: linux/arch/x86/include/asm/microcode.h =================================================================== --- linux.orig/arch/x86/include/asm/microcode.h 2016-05-02 12:20:08.364728800 +0200 +++ linux/arch/x86/include/asm/microcode.h 2016-05-02 12:20:31.944728581 +0200 @@ -61,4 +61,5 @@ static inline struct microcode_ops * __i } #endif +extern bool check_current_patch_level(u32 *rev); #endif /* _ASM_X86_MICROCODE_H */ Index: linux/arch/x86/kernel/microcode_amd.c =================================================================== --- linux.orig/arch/x86/kernel/microcode_amd.c 2016-05-02 12:20:08.364728800 +0200 +++ linux/arch/x86/kernel/microcode_amd.c 2016-05-02 12:24:35.768726320 +0200 @@ -123,13 +123,32 @@ static int get_matching_microcode(int cp return 1; } +/* + * Check the current patch level on this CPU. + * + * @rev: Use it to return the patch level. It is set to 0 in the case of + * error. + * + * Returns: + * - true: if update should stop + * - false: otherwise + */ +bool check_current_patch_level(u32 *rev) +{ + u32 dummy; + + rdmsr(MSR_AMD64_PATCH_LEVEL, *rev, dummy); + + return false; +} + static int apply_microcode_amd(int cpu) { - u32 rev, dummy; int cpu_num = raw_smp_processor_id(); struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num; struct microcode_amd *mc_amd = uci->mc; struct cpuinfo_x86 *c = &cpu_data(cpu); + u32 dummy, rev; /* We should bind the task to the CPU */ BUG_ON(cpu_num != cpu); @@ -137,6 +156,9 @@ static int apply_microcode_amd(int cpu) if (mc_amd == NULL) return 0; + if (check_current_patch_level(&rev)) + return -1; + wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code); /* get patch id after patching */ rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy); --M9NhX3UHpAaciwkO Content-Type: text/x-diff; charset=utf-8 Content-Disposition: attachment; filename="0002-x86-microcode-amd-Do-not-overwrite-final-patch-level.patch" Content-Transfer-Encoding: 8bit >>From 0399f73299f1b7e04de329050f7111b362b7eeb5 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 12 Oct 2015 11:22:42 +0200 Subject: [PATCH] x86/microcode/amd: Do not overwrite final patch levels MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 0399f73299f1b7e04de329050f7111b362b7eeb5 upstream. A certain number of patch levels of applied microcode should not be overwritten by the microcode loader, otherwise bad things will happen. Check those and abort update if the current core has one of those final patch levels applied by the BIOS. 32-bit needs special handling, of course. See https://bugzilla.suse.com/show_bug.cgi?id=913996 for more info. Tested-by: Peter Kirchgeßner Signed-off-by: Borislav Petkov Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Link: http://lkml.kernel.org/r/1444641762-9437-7-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/microcode.h | 2 +- arch/x86/kernel/cpu/microcode/amd.c | 38 +++++++++++++++++++++++++++---- arch/x86/kernel/cpu/microcode/amd_early.c | 13 ++++++++--- 3 files changed, 44 insertions(+), 9 deletions(-) Index: linux/arch/x86/include/asm/microcode.h =================================================================== --- linux.orig/arch/x86/include/asm/microcode.h 2016-05-02 13:40:48.980683909 +0200 +++ linux/arch/x86/include/asm/microcode.h 2016-05-02 13:40:48.976683909 +0200 @@ -61,5 +61,5 @@ static inline struct microcode_ops * __i } #endif -extern bool check_current_patch_level(u32 *rev); +extern bool check_current_patch_level(u32 *rev, bool early); #endif /* _ASM_X86_MICROCODE_H */ Index: linux/arch/x86/kernel/microcode_amd.c =================================================================== --- linux.orig/arch/x86/kernel/microcode_amd.c 2016-05-02 13:40:48.980683909 +0200 +++ linux/arch/x86/kernel/microcode_amd.c 2016-05-02 13:56:56.688674935 +0200 @@ -124,6 +124,16 @@ static int get_matching_microcode(int cp } /* + * Those patch levels cannot be updated to newer ones and thus should be final. + */ +static u32 final_levels[] = { + 0x01000098, + 0x0100009f, + 0x010000af, + 0, /* T-101 terminator */ +}; + +/* * Check the current patch level on this CPU. * * @rev: Use it to return the patch level. It is set to 0 in the case of @@ -133,13 +143,33 @@ static int get_matching_microcode(int cp * - true: if update should stop * - false: otherwise */ -bool check_current_patch_level(u32 *rev) +bool check_current_patch_level(u32 *rev, bool early) { - u32 dummy; + u32 lvl, dummy, i; + bool ret = false; + u32 *levels; + + rdmsr(MSR_AMD64_PATCH_LEVEL, lvl, dummy); + +#ifdef CONFIG_X86_32 + if (early) + levels = (u32 *)__pa_nodebug(&final_levels); + else +#endif + levels = final_levels; + + for (i = 0; levels[i]; i++) { + if (lvl == levels[i]) { + lvl = 0; + ret = true; + break; + } + } - rdmsr(MSR_AMD64_PATCH_LEVEL, *rev, dummy); + if (rev) + *rev = lvl; - return false; + return ret; } static int apply_microcode_amd(int cpu) @@ -156,7 +186,7 @@ static int apply_microcode_amd(int cpu) if (mc_amd == NULL) return 0; - if (check_current_patch_level(&rev)) + if (check_current_patch_level(&rev, false)) return -1; wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code); --M9NhX3UHpAaciwkO--