From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48B63C3A5A3 for ; Tue, 27 Aug 2019 14:54:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2072321881 for ; Tue, 27 Aug 2019 14:54:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730001AbfH0OyA (ORCPT ); Tue, 27 Aug 2019 10:54:00 -0400 Received: from mga07.intel.com ([134.134.136.100]:21708 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726333AbfH0Ox7 (ORCPT ); Tue, 27 Aug 2019 10:53:59 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Aug 2019 07:53:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,437,1559545200"; d="scan'208";a="380943529" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.41]) by fmsmga006.fm.intel.com with ESMTP; 27 Aug 2019 07:53:58 -0700 Date: Tue, 27 Aug 2019 07:53:58 -0700 From: Sean Christopherson To: Jan Dakinevich Cc: "linux-kernel@vger.kernel.org" , Denis Lunev , Roman Kagan , Denis Plotnikov , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , "x86@kernel.org" , "kvm@vger.kernel.org" Subject: Re: [PATCH 2/3] KVM: x86: set ctxt->have_exception in x86_decode_insn() Message-ID: <20190827145358.GD27459@linux.intel.com> References: <1566911210-30059-1-git-send-email-jan.dakinevich@virtuozzo.com> <1566911210-30059-3-git-send-email-jan.dakinevich@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1566911210-30059-3-git-send-email-jan.dakinevich@virtuozzo.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 27, 2019 at 01:07:08PM +0000, Jan Dakinevich wrote: > x86_emulate_instruction() takes into account ctxt->have_exception flag > during instruction decoding, but in practice this flag is never set in > x86_decode_insn(). > > Fixes: 6ea6e84 ("KVM: x86: inject exceptions produced by x86_decode_insn") > Cc: Denis Lunev > Cc: Roman Kagan > Cc: Denis Plotnikov > Signed-off-by: Jan Dakinevich > --- > 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 6170ddf..f93880f 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -5395,6 +5395,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) > ctxt->memopp->addr.mem.ea + ctxt->_eip); > > done: > + if (rc == X86EMUL_PROPAGATE_FAULT) > + ctxt->have_exception = true; We should add a sanity check or two on the vector since the emulator code goes all over the place, e.g. #UD should not be injected/propagated, and trap-like exceptions should not be handled/encountered during decode. Note, exception_type() also warns on illegal vectors. WARN_ON_ONCE(ctxt->exception.vector == UD_VECTOR || exception_type(ctxt->exception.vector) == EXCPT_TRAP); > return (rc != X86EMUL_CONTINUE) ? EMULATION_FAILED : EMULATION_OK; > } > > -- > 2.1.4 >