From patchwork Thu Sep 8 14:11:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 9321479 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8B7FD607D3 for ; Thu, 8 Sep 2016 14:14:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7518329856 for ; Thu, 8 Sep 2016 14:14:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6A0C12989C; Thu, 8 Sep 2016 14:14:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id AF96C29856 for ; Thu, 8 Sep 2016 14:14:20 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bi03g-0008BK-Ly; Thu, 08 Sep 2016 14:12:04 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bi03f-0008AV-2U for xen-devel@lists.xen.org; Thu, 08 Sep 2016 14:12:03 +0000 Received: from [85.158.139.211] by server-15.bemta-5.messagelabs.com id 3E/C3-12460-2B171D75; Thu, 08 Sep 2016 14:12:02 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupnkeJIrShJLcpLzFFi42JxWrohUndT4cV wg479jBZLPi5mcWD0OLr7N1MAYxRrZl5SfkUCa8bl2zMYC/5xVXw/N429gfE8excjJ4eEgL/E 8f7PzCA2m4C+xO4Xn5hAbBEBdYnTHRdZuxg5OJgFdCVW/dQACQsLhErs+HqLFcRmEVCReL9jK iOIzSvgKbH85zFmiJFyEueP/wSzOQW8JBrO3ASrEQKqufpxFguErSZxrf8SO0SvoMTJmU/A4s wCEhIHX7yAmsMtcfv0VOYJjHyzkJTNQlK2gJFpFaN6cWpRWWqRrrleUlFmekZJbmJmjq6hgal ebmpxcWJ6ak5iUrFecn7uJkZgQDEAwQ7GY5OdDzFKcjApifL6FF8IF+JLyk+pzEgszogvKs1J LT7EKMPBoSTBm1JwMVxIsCg1PbUiLTMHGNowaQkOHiUR3pkgad7igsTc4sx0iNQpRkUpcV4Tk IQASCKjNA+uDRZPlxhlpYR5GYEOEeIpSC3KzSxBlX/FKM7BqCTM6w4yhSczrwRu+iugxUxAi4 VOnQdZXJKIkJJqYJRgzbIVCTEQKHVZtKFtcu3Lpg8TM/5csHzFd/DizcjLFZuWvdD872OfeJv Dez0rv7kVowFPaPO6nAtnS0+oqTpsLtwafSl/2pLA/sJtKTyalx5KZZ1/ZnHVZnqy8snOe5Yd s/7GRlWld8vVP+p7qllr2tM64b6mCbfO2nC+zfy5XIyOpUEzlViKMxINtZiLihMBsVgS6qICA AA= X-Env-Sender: prvs=052df9534=Andrew.Cooper3@citrix.com X-Msg-Ref: server-10.tower-206.messagelabs.com!1473343918!41330951!3 X-Originating-IP: [66.165.176.89] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni44OSA9PiAyMDMwMDc=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 8.84; banners=-,-,- X-VirusChecked: Checked Received: (qmail 63264 invoked from network); 8 Sep 2016 14:12:01 -0000 Received: from smtp.citrix.com (HELO SMTP.CITRIX.COM) (66.165.176.89) by server-10.tower-206.messagelabs.com with RC4-SHA encrypted SMTP; 8 Sep 2016 14:12:01 -0000 X-IronPort-AV: E=Sophos;i="5.30,301,1470700800"; d="scan'208";a="377074143" From: Andrew Cooper To: Xen-devel Date: Thu, 8 Sep 2016 15:11:50 +0100 Message-ID: <1473343910-15335-4-git-send-email-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1473343910-15335-1-git-send-email-andrew.cooper3@citrix.com> References: <1473343910-15335-1-git-send-email-andrew.cooper3@citrix.com> MIME-Version: 1.0 X-DLP: MIA2 Cc: Andrew Cooper Subject: [Xen-devel] [PATCH 4/4] x86/hvm: Perform a user instruction fetch for a FEP in userspace X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP This matches hardware behaviour, and prevents erroneous failures when a guest has SMEP/SMAP active and issues a FEP from userspace. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich --- xen/arch/x86/hvm/hvm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 596a903..159671e 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -3978,6 +3978,8 @@ void hvm_ud_intercept(struct cpu_user_regs *regs) { struct vcpu *cur = current; const struct segment_register *cs = &ctxt.seg_reg[x86_seg_cs]; + uint32_t walk = (ctxt.seg_reg[x86_seg_ss].attr.fields.dpl == 3) + ? PFEC_user_mode : 0; unsigned long addr; char sig[5]; /* ud2; .ascii "xen" */ @@ -3987,7 +3989,7 @@ void hvm_ud_intercept(struct cpu_user_regs *regs) cs->attr.fields.l) ? 64 : cs->attr.fields.db ? 32 : 16, &addr) && (hvm_fetch_from_guest_virt_nofault(sig, addr, sizeof(sig), - 0) == HVMCOPY_okay) && + walk) == HVMCOPY_okay) && (memcmp(sig, "\xf\xbxen", sizeof(sig)) == 0) ) { regs->eip += sizeof(sig);