From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752778AbeCVIeU (ORCPT ); Thu, 22 Mar 2018 04:34:20 -0400 Received: from mail-pl0-f65.google.com ([209.85.160.65]:40631 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751768AbeCVIeQ (ORCPT ); Thu, 22 Mar 2018 04:34:16 -0400 X-Google-Smtp-Source: AG47ELsUGP3umth8CSZf7McefXooCWdgAWjJ2jsKJ23t0DdBF8CAI2yohtYHxX27af6vsl65vXCobA== From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH] KVM: X86: Fix the decoding of segment overrides in 64bit mode Date: Thu, 22 Mar 2018 16:34:11 +0800 Message-Id: <1521707651-9375-1-git-send-email-wanpengli@tencent.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li Explicit segment overides other than %fs and %gs are documented as ignored by both Intel and AMD. In practice, this means that: * Explicit uses of %ss don't actually yield #SS[0] for non-canonical memory references. * Explicit uses of %{e,c,d}s don't override %rbp/%rsp-based memory references to yield #GP[0] for non-canonical memory references. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li --- arch/x86/kvm/emulate.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index dd88158..5091255 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5148,8 +5148,10 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) case 0x2e: /* CS override */ case 0x36: /* SS override */ case 0x3e: /* DS override */ - has_seg_override = true; - ctxt->seg_override = (ctxt->b >> 3) & 3; + if (mode != X86EMUL_MODE_PROT64) { + has_seg_override = true; + ctxt->seg_override = (ctxt->b >> 3) & 3; + } break; case 0x64: /* FS override */ case 0x65: /* GS override */ -- 2.7.4