From: Gleb Natapov <gleb@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH 1/3] KVM: emulator: check rex prefix inside decode_register()
Date: Mon, 4 Nov 2013 16:06:03 +0200 [thread overview]
Message-ID: <20131104140603.GG7513@redhat.com> (raw)
In-Reply-To: <5277A986.9070309@redhat.com>
On Mon, Nov 04, 2013 at 03:04:54PM +0100, Paolo Bonzini wrote:
> Il 04/11/2013 14:52, Gleb Natapov ha scritto:
> > All decode_register() callers check if instruction has rex prefix
> > to properly decode one byte operand. It make sense to move the check
> > inside.
> >
> > Signed-off-by: Gleb Natapov <gleb@redhat.com>
>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>
> I guess you'd like to use Linus's extra week and get it in 3.13?
>
Yes, nothing serious here.
> Paolo
>
> > ---
> > arch/x86/kvm/emulate.c | 18 +++++++-----------
> > 1 file changed, 7 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> > index 282d28c..0bd372f 100644
> > --- a/arch/x86/kvm/emulate.c
> > +++ b/arch/x86/kvm/emulate.c
> > @@ -785,9 +785,10 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
> > * @highbyte_regs specifies whether to decode AH,CH,DH,BH.
> > */
> > static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,
> > - int highbyte_regs)
> > + int byteop)
> > {
> > void *p;
> > + int highbyte_regs = (ctxt->rex_prefix == 0) && byteop;
> >
> > if (highbyte_regs && modrm_reg >= 4 && modrm_reg < 8)
> > p = (unsigned char *)reg_rmw(ctxt, modrm_reg & 3) + 1;
> > @@ -1024,7 +1025,6 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
> > struct operand *op)
> > {
> > unsigned reg = ctxt->modrm_reg;
> > - int highbyte_regs = ctxt->rex_prefix == 0;
> >
> > if (!(ctxt->d & ModRM))
> > reg = (ctxt->b & 7) | ((ctxt->rex_prefix & 1) << 3);
> > @@ -1046,10 +1046,10 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
> >
> > op->type = OP_REG;
> > if (ctxt->d & ByteOp) {
> > - op->addr.reg = decode_register(ctxt, reg, highbyte_regs);
> > + op->addr.reg = decode_register(ctxt, reg, true);
> > op->bytes = 1;
> > } else {
> > - op->addr.reg = decode_register(ctxt, reg, 0);
> > + op->addr.reg = decode_register(ctxt, reg, false);
> > op->bytes = ctxt->op_bytes;
> > }
> > fetch_register_operand(op);
> > @@ -1082,12 +1082,10 @@ 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,
> > - highbyte_regs && (ctxt->d & ByteOp));
> > + ctxt->d & ByteOp);
> > if (ctxt->d & Sse) {
> > op->type = OP_XMM;
> > op->bytes = 16;
> > @@ -4117,10 +4115,8 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
> > case OpMem8:
> > ctxt->memop.bytes = 1;
> > if (ctxt->memop.type == OP_REG) {
> > - int highbyte_regs = ctxt->rex_prefix == 0;
> > -
> > - ctxt->memop.addr.reg = decode_register(ctxt, ctxt->modrm_rm,
> > - highbyte_regs);
> > + ctxt->memop.addr.reg = decode_register(ctxt,
> > + ctxt->modrm_rm, true);
> > fetch_register_operand(&ctxt->memop);
> > }
> > goto mem_common;
> >
--
Gleb.
prev parent reply other threads:[~2013-11-04 14:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-04 13:52 [PATCH 1/3] KVM: emulator: check rex prefix inside decode_register() Gleb Natapov
2013-11-04 13:52 ` [PATCH 2/3] KVM: emulator: cleanup decode_register_operand() a bit Gleb Natapov
2013-11-04 14:05 ` Paolo Bonzini
2013-11-04 13:52 ` [PATCH 3/3] KVM: x86: trace cpuid emulation when called from emulator Gleb Natapov
2013-11-04 14:06 ` Paolo Bonzini
2013-11-04 14:04 ` [PATCH 1/3] KVM: emulator: check rex prefix inside decode_register() Paolo Bonzini
2013-11-04 14:06 ` Gleb Natapov [this message]
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