linux-kernel - Re: [PATCH] KVM: fix sil/dil/bpl/spl in the mod/rm fields

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Date:	Mon, 3 Jun 2013 11:04:16 +0300
From:	Gleb Natapov <gleb@...hat.com>
To:	Paolo Bonzini <pbonzini@...hat.com>
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH] KVM: fix sil/dil/bpl/spl in the mod/rm fields

On Mon, Jun 03, 2013 at 08:27:57AM +0200, Paolo Bonzini wrote:
> Il 02/06/2013 20:12, Gleb Natapov ha scritto:
> > On Thu, May 30, 2013 at 04:35:55PM +0200, Paolo Bonzini wrote:
> >> 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.
> >>
> > Did I missed unit test patch? :)
> 
> I wanted to ask the GSoC student to do it.  If it doesn't come in a
> couple of weeks, I'll send it.
> 
Which instruction you saw the bug happening with? It this 3.10 regression?

> Paolo
> 
> >> Cc: gnatapov@...hat.com
Please use my other email :)

> >> Cc: kvm@...r.kernel.org
> >> Cc: <stable@...r.kernel.org> # 3.9
> >> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> >> ---
> >>  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;
> >> -- 
> >> 1.8.1.4
> > 
> > --
> > 			Gleb.
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 

--
			Gleb.
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