From patchwork Sun Nov 2 09:54:46 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nadav Amit X-Patchwork-Id: 5211501 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 8EE169F295 for ; Sun, 2 Nov 2014 09:55:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CD6ED201BB for ; Sun, 2 Nov 2014 09:55:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0AFCC20173 for ; Sun, 2 Nov 2014 09:55:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751970AbaKBJzv (ORCPT ); Sun, 2 Nov 2014 04:55:51 -0500 Received: from mailgw12.technion.ac.il ([132.68.225.12]:52328 "EHLO mailgw12.technion.ac.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751280AbaKBJz0 (ORCPT ); Sun, 2 Nov 2014 04:55:26 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArMCAAH/VVSERCABjGdsb2JhbABc2R4CgRAWAQEBAQEBEAEBASdChAMBBSdSEFFXGYhBwyuFaAEBAQEGAgEfkRAHFoQ1BbZPIIFcaoJLAQEB X-IPAS-Result: ArMCAAH/VVSERCABjGdsb2JhbABc2R4CgRAWAQEBAQEBEAEBASdChAMBBSdSEFFXGYhBwyuFaAEBAQEGAgEfkRAHFoQ1BbZPIIFcaoJLAQEB X-IronPort-AV: E=Sophos;i="5.07,295,1413234000"; d="scan'208";a="127554975" Received: from csa.cs.technion.ac.il ([132.68.32.1]) by mailgw12.technion.ac.il with ESMTP; 02 Nov 2014 11:55:12 +0200 Received: from csn.cs.technion.ac.il (csn.cs.technion.ac.il [132.68.32.15]) by csa.cs.technion.ac.il (Postfix) with ESMTP id E83EF140050; Sun, 2 Nov 2014 11:55:09 +0200 (IST) Received: from csl-tapuz20.cs.technion.ac.il (csl-tapuz20.cs.technion.ac.il [132.68.206.58]) by csn.cs.technion.ac.il (Postfix) with ESMTPSA id B5965A1BFD; Sun, 2 Nov 2014 11:55:09 +0200 (IST) From: Nadav Amit To: pbonzini@redhat.com Cc: kvm@vger.kernel.org, nadav.amit@gmail.com, Nadav Amit Subject: [PATCH 06/21] KVM: x86: Emulator MOV-sreg uses incorrect size Date: Sun, 2 Nov 2014 11:54:46 +0200 Message-Id: <1414922101-17626-7-git-send-email-namit@cs.technion.ac.il> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1414922101-17626-1-git-send-email-namit@cs.technion.ac.il> References: <1414922101-17626-1-git-send-email-namit@cs.technion.ac.il> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In x86, you cannot MOV-sreg to memory is either 16-bits or 64-bits. When destination is registers, and the operand size is 32-bits, the high 16-bits in modern CPUs is filled with zero. In contrast, KVM may write to memory 32-bits on MOV-sreg. This patch fixes KVM behavior, and sets the destination operand size to two, if the destination is memory. Signed-off-by: Nadav Amit --- arch/x86/kvm/emulate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 273c37e..f456783 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3187,6 +3187,8 @@ static int em_mov_rm_sreg(struct x86_emulate_ctxt *ctxt) return emulate_ud(ctxt); ctxt->dst.val = get_segment_selector(ctxt, ctxt->modrm_reg); + if (ctxt->dst.bytes == 4 && ctxt->dst.type == OP_MEM) + ctxt->dst.bytes = 2; return X86EMUL_CONTINUE; }