Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964861Ab3E3QfK (ORCPT ); Thu, 30 May 2013 12:35:10 -0400 Received: from mail-vb0-f48.google.com ([209.85.212.48]:42512 "EHLO mail-vb0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934721Ab3E3QfC (ORCPT ); Thu, 30 May 2013 12:35:02 -0400 Message-ID: <51A77FA8.6010007@redhat.com> Date: Thu, 30 May 2013 18:34:48 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 MIME-Version: 1.0 CC: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, gnatapov@redhat.com Subject: Re: [PATCH] KVM: fix sil/dil/bpl/spl in the mod/rm fields References: <1369924555-30216-1-git-send-email-pbonzini@redhat.com> <51A7717D.6030203@redhat.com> In-Reply-To: <51A7717D.6030203@redhat.com> X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1616 Lines: 40 Il 30/05/2013 17:34, Paolo Bonzini ha scritto: > Il 30/05/2013 16:35, Paolo Bonzini ha scritto: >> The x86-64 extended low-byte registers were fetched correctly from reg, >> but not from mod/rm. >> >> This fixes another bug in the boot of RHEL5.9 64-bit, but it is still >> not enough. > > Well, it is enough but it takes 2 minutes to reach the point where > hardware virtualization is used. It is doing a lot of stuff in > emulation mode because FS and GS have leftovers from the A20 test: > > FS =0000 0000000000000000 0000ffff 00009300 DPL=0 DS16 [-WA] > GS =ffff 00000000000ffff0 0000ffff 00009300 DPL=0 DS16 [-WA] > > 0x00000000000113be: in $0x92,%al > 0x00000000000113c0: or $0x2,%al > 0x00000000000113c2: out %al,$0x92 > 0x00000000000113c4: xor %ax,%ax > 0x00000000000113c6: mov %ax,%fs > 0x00000000000113c8: dec %ax > 0x00000000000113c9: mov %ax,%gs > 0x00000000000113cb: inc %ax > 0x00000000000113cc: mov %ax,%fs:0x200 > 0x00000000000113d0: cmp %gs:0x210,%ax > 0x00000000000113d5: je 0x113cb > > The DPL < RPL test fails. Any ideas? Should we introduce a new > intermediate value for emulate_invalid_guest_state (0=none, 1=some, 2=full)? One idea could be to replace invalid descriptors with NULL ones. Then you can intercept this in the #GP handler and trigger emulation for that instruction only. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/