From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3340693-1520824726-2-4382425456916147479 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 0.25, ME_NOAUTH 0.01, 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='CN', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' 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=1520824726; b=dfUv5wm+ZMoxyyshkfHnpNTTWxujA//S/U9VYp4SHXDYqZw FBV+MPUoZguu9BqQX4f1yRihPVk6NbseoAsrbVqo4+cyj8FbqvydyfF/vC/w4d37 MV9LaNcCn9RWEDSc3FIuXlIuCDGFYjNZ7hu4yujhDc5W5eVt5C6bzcMuu0Al1DSz p5wSFbUNhR0mbO5pAgcrZ2vuiCAoaJRs0s78PKbnbiAR/hQjftGgUiqdxUmQoClo v9Jt4IzMPfo35jeFkLktFdKhzcWeHBrADR9A6lZYz2Q33kumEuKRPi1OKABPbSqm gFzd0NWhV5lANMbVazZww05uZTRG0oKVA8693Zg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1520824726; bh=koexOmizIc+M+XJrPhq W6o1tvtOlswovPcVDo9Wb1Fc=; b=bQ3FK+eXL44Gawp8fsnvLJE1cXXY05ByAus cqLgwh7bt0O/lbldICcuS9b4CjmBn+jDsh5OsgkirNgMQqwuvVrxHdb7LJKenqxa Jn3y1+l7pesW3znwYw68fREN7SMwc2TOsxUUctdq78hFFbqFnTwtq76U82/BnW87 SYZQldVVFwJC/He50e6YwBMumwBmAV3U/QdEeBf6yP2lbJt3rYHImQpIAgAqsfIc gBhAsOxgjd1Sy/RAVQ02rZfnCTixvE28pNRGukX9ICFU6HY1WYHpUlNKMAbDk7R6 cBC6PaHPPjmob2TFEi9qYYZowFID2iADqZilqM0R+GJhefm6osw== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; 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-category=clean score=-100 state=0; 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=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; 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-category=clean score=-100 state=0; 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=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933060AbeCLDQZ (ORCPT ); Sun, 11 Mar 2018 23:16:25 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41359 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932742AbeCLDHq (ORCPT ); Sun, 11 Mar 2018 23:07:46 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Thomas Gleixner" , "Paolo Bonzini" , kvm@vger.kernel.org, "Andrew Honig" , "Jim Mattson" , "Dan Williams" Date: Mon, 12 Mar 2018 03:03:34 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 092/104] x86/kvm: Update spectre-v1 mitigation In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false 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: 3.2.101-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams commit 085331dfc6bbe3501fb936e657331ca943827600 upstream. Commit 75f139aaf896 "KVM: x86: Add memory barrier on vmcs field lookup" added a raw 'asm("lfence");' to prevent a bounds check bypass of 'vmcs_field_to_offset_table'. The lfence can be avoided in this path by using the array_index_nospec() helper designed for these types of fixes. Signed-off-by: Dan Williams Signed-off-by: Thomas Gleixner Acked-by: Paolo Bonzini Cc: Andrew Honig Cc: kvm@vger.kernel.org Cc: Jim Mattson Link: https://lkml.kernel.org/r/151744959670.6342.3001723920950249067.stgit@dwillia2-desk3.amr.corp.intel.com [bwh: Backported to 3.2: - Replace max_vmcs_field with the local size variable - Adjust context] Signed-off-by: Ben Hutchings --- --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "kvm_cache_regs.h" #include "x86.h" @@ -570,23 +571,21 @@ static unsigned short vmcs_field_to_offs FIELD(HOST_RSP, host_rsp), FIELD(HOST_RIP, host_rip), }; -static const int max_vmcs_field = ARRAY_SIZE(vmcs_field_to_offset_table); static inline short vmcs_field_to_offset(unsigned long field) { - if (field >= max_vmcs_field) - return -1; + const size_t size = ARRAY_SIZE(vmcs_field_to_offset_table); + unsigned short offset; - /* - * FIXME: Mitigation for CVE-2017-5753. To be replaced with a - * generic mechanism. - */ - asm("lfence"); - - if (vmcs_field_to_offset_table[field] == 0) + BUILD_BUG_ON(size > SHRT_MAX); + if (field >= size) return -1; - return vmcs_field_to_offset_table[field]; + field = array_index_nospec(field, size); + offset = vmcs_field_to_offset_table[field]; + if (offset == 0) + return -1; + return offset; } static inline struct vmcs12 *get_vmcs12(struct kvm_vcpu *vcpu)