From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: KVM: x86: use proper port value when checking io instruction
 permission (v2)
Date: Thu, 26 May 2011 11:00:24 +0200
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Cc: Avi Kivity <avi@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>,
	kvm <kvm@vger.kernel.org>, Joerg Roedel <joerg.roedel@amd.com>
To: Gleb Natapov <gleb@redhat.com>
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On 05/26/2011 10:26 AM, Gleb Natapov wrote:
> Why would c->dst.bytes != c->src.bytes for cwd/cdq/cqo if we'll set
> c->dst.bytes to op_bytes during decode?

Duh, you're right, cwd/cdq/cqo uses SrcAcc which has

                 c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;

so in practice c->src.bytes = c->op_bytes.

I still find it confusing that DstDX would use c->op_bytes without 
honoring ByteOp unlike pretty much everything else; but yes, there is a 
possible use of DstDX outside in/out.

Paolo