From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH] x86 emulator: Add IRET instruction
Date: Mon, 26 Jul 2010 12:00:48 +0300
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Cc: Mohammed Gamal <m.gamal005@gmail.com>, mtosatti@redhat.com,
	kvm@vger.kernel.org
To: Paolo Bonzini <pbonzini@redhat.com>
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  On 07/26/2010 11:47 AM, Paolo Bonzini wrote:
>> I don't think this is needed. The temp_eflags value is assigned
>> directly to eflags if we're operand size is 16 bits. At least that's
>> what the Intel manual says!
>
>
> That's fine, but please make sure that
>
> mov %sp, %bp
> orw $2, 4(%bp)
> iret
>
> followed at return site by
>
> pushf
> popw %ax
>
> does not set bit 1 in %ax. That's the important point (also see how=20
> emulate_popf avoids magic hex constants).

Moreover, vmx will fail the next entry if this is not done. 23.3.1.4 sa=
ys:

> RFLAGS.
> =97 Reserved bits 63:22 (bits 31:22 on processors that do not support=
=20
> Intel 64
> architecture), bit 15, bit 5 and bit 3 must be 0 in the field, and=20
> reserved bit 1
> must be 1.

Looks like a note is missing in the manual. I'll alert the authors.

--=20
error compiling committee.c: too many arguments to function