Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754944Ab3FCKZf (ORCPT ); Mon, 3 Jun 2013 06:25:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56965 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753097Ab3FCKZc (ORCPT ); Mon, 3 Jun 2013 06:25:32 -0400 Date: Mon, 3 Jun 2013 13:25:30 +0300 From: Gleb Natapov To: Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: fix sil/dil/bpl/spl in the mod/rm fields Message-ID: <20130603102530.GH4725@redhat.com> References: <1369924555-30216-1-git-send-email-pbonzini@redhat.com> <51A7717D.6030203@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51A7717D.6030203@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2580 Lines: 70 On Thu, May 30, 2013 at 05:34:21PM +0200, Paolo Bonzini wrote: > 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 > This is 16 bit code that sets them up. So 32bit transition code does not reload them? > 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)? > > Paolo > > > Cc: gnatapov@redhat.com > > Cc: kvm@vger.kernel.org > > Cc: # 3.9 > > Signed-off-by: Paolo Bonzini > > --- > > arch/x86/kvm/emulate.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > > index aa68106..028b34f 100644 > > --- a/arch/x86/kvm/emulate.c > > +++ b/arch/x86/kvm/emulate.c > > @@ -1239,9 +1239,12 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, > > ctxt->modrm_seg = VCPU_SREG_DS; > > > > if (ctxt->modrm_mod == 3) { > > + int highbyte_regs = ctxt->rex_prefix == 0; > > + > > op->type = OP_REG; > > op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes; > > - op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, ctxt->d & ByteOp); > > + op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, > > + highbyte_regs && (ctxt->d & ByteOp)); > > if (ctxt->d & Sse) { > > op->type = OP_XMM; > > op->bytes = 16; > > -- Gleb. -- 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/