From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3184158-1518109987-2-9174553935426326316 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='com', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518109987; b=eWWSKfK9EYAssr5g1cFqkeyR6eoxkQU64MbamnxYLQrVHUC pQs7Z3Vqi7KIQ+YaH1gONulBA4FJzq3JqzZYuvALCnjON5APX9LfiBzblYju9bA8 IML5pD1My82Txwwns9qeSbPnyBpGsRIqTe81dpgVgpM3lEoJ+YZYdvBh/fmr3XNP A2+ABEtS2PJSyoKP7z/suAdIb3kD8cqA83h+OgNMxBKta7EDX6olWca1RxyyH0Kf 739uVXJeskt6V2m+R3ncBYQZNKwTDfKp7mJsDX8MPEHzHNsV7pjCN4tLQ73mPaF+ E9fVKJ7THkFguZ73FHp4bNo/uT8XHgxhaTi6/rw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=arctest; t=1518109987; bh=nPaQLkt+wCzTkteHee6D/MjjB6IR4KHCgNxIQJdK7Lk=; b=O3QwZ/b6Z9/R Y3R10kzpqee+IY/9KFmwt5xC9yuzYw9akPeZb5oS6EDnJaz1Z4/lgXVS7RfZHHhF 1oi7OOpNY9+QVFQrxOnR6NXjL6wkhna/1FCspzeCvUhfwvOJnutjYeBY7E3sDoFi JVe7SaTKjnnCKLMmWtVax3rANdneg0r3Gwhv5+uh3mLjmGIdQONMSxBoS0xnbkGq HjNjDaNqaFi5/sER8DYwf+0gXmYpBNYJzjg6TFkRGnrLHZRbr633JT/wLSUMeXfN r6X1z/rEW4eVKG+SohUdJ7O1/1yPlCMFAOPqVzvYhMnpQW5z5syAXei15/dHzGEF +4cJZ2isAw== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=docker.com header.i=@docker.com header.b=C5w94/46 x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=google; dmarc=pass (p=quarantine,has-list-id=yes,d=none) header.from=docker.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=BfAcHykC; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=docker.com header.result=pass header_is_org_domain=yes Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=docker.com header.i=@docker.com header.b=C5w94/46 x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=google; dmarc=pass (p=quarantine,has-list-id=yes,d=none) header.from=docker.com; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=BfAcHykC; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=docker.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752046AbeBHRM0 (ORCPT ); Thu, 8 Feb 2018 12:12:26 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:53952 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751700AbeBHRMZ (ORCPT ); Thu, 8 Feb 2018 12:12:25 -0500 X-Google-Smtp-Source: AH8x224WcUuFxAOOS9N3o99vIId5JD5l+xNVFbKQIV8rKrAcPipzuU6OoT3pwH2bFpV7p4/6B1A5Bw== From: Rolf Neugebauer To: gregkh@linuxfoundation.org Cc: bp@alien8.de, zhang.jia@linux.alibaba.com, tglx@linutronix.de, tony.luck@intel.com, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov , stable@vger.kernel.org, Rolf Neugebauer Subject: [PATCH 1/2] x86/microcode/AMD: Do not load when running on a hypervisor Date: Thu, 8 Feb 2018 17:12:03 +0000 Message-Id: <20180208171204.62005-1-rolf.neugebauer@docker.com> X-Mailer: git-send-email 2.16.0 In-Reply-To: <20180208163940.GD9421@kroah.com> References: <20180208163940.GD9421@kroah.com> Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Borislav Petkov commit a15a753539eca8ba243d576f02e7ca9c4b7d7042 upstream with minor adjustments. Doing so is completely void of sense for multiple reasons so prevent it. Set dis_ucode_ldr to true and thus disable the microcode loader by default to address xen pv guests which execute the AP path but not the BSP path. By having it turned off by default, the APs won't run into the loader either. Also, check CPUID(1).ECX[31] which hypervisors set. Well almost, not the xen pv one. That one gets the aforementioned "fix". Also, improve the detection method by caching the final decision whether to continue loading in dis_ucode_ldr and do it once on the BSP. The APs then simply test that value. Signed-off-by: Borislav Petkov Tested-by: Juergen Gross Tested-by: Boris Ostrovsky Acked-by: Juergen Gross Link: http://lkml.kernel.org/r/20161218164414.9649-4-bp@alien8.de Signed-off-by: Thomas Gleixner Cc: # 4.4.x Signed-off-by: Rolf Neugebauer --- arch/x86/kernel/cpu/microcode/core.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index b3e94ef461fd..1b3e0aa4c511 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -44,7 +44,7 @@ static struct microcode_ops *microcode_ops; -static bool dis_ucode_ldr; +static bool dis_ucode_ldr = true; static int __init disable_loader(char *str) { @@ -81,6 +81,7 @@ struct cpu_info_ctx { static bool __init check_loader_disabled_bsp(void) { + u32 a, b, c, d; #ifdef CONFIG_X86_32 const char *cmdline = (const char *)__pa_nodebug(boot_command_line); const char *opt = "dis_ucode_ldr"; @@ -93,8 +94,23 @@ static bool __init check_loader_disabled_bsp(void) bool *res = &dis_ucode_ldr; #endif - if (cmdline_find_option_bool(cmdline, option)) - *res = true; + if (!have_cpuid_p()) + return *res; + + a = 1; + c = 0; + native_cpuid(&a, &b, &c, &d); + + /* + * 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 + * that's good enough as they don't land on the BSP path anyway. + */ + if (c & BIT(31)) + return *res; + + if (cmdline_find_option_bool(cmdline, option) <= 0) + *res = false; return *res; } @@ -126,9 +142,6 @@ void __init load_ucode_bsp(void) if (check_loader_disabled_bsp()) return; - if (!have_cpuid_p()) - return; - vendor = x86_vendor(); family = x86_family(); @@ -162,9 +175,6 @@ void load_ucode_ap(void) if (check_loader_disabled_ap()) return; - if (!have_cpuid_p()) - return; - vendor = x86_vendor(); family = x86_family(); -- 2.16.0