From: Avi Kivity <avi@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Mohammed Gamal <m.gamal005@gmail.com>,
mtosatti@redhat.com, kvm@vger.kernel.org
Subject: Re: [PATCH] x86 emulator: Add IRET instruction
Date: Mon, 26 Jul 2010 12:00:48 +0300 [thread overview]
Message-ID: <4C4D4EC0.9070804@redhat.com> (raw)
In-Reply-To: <4C4D4BB7.6010309@redhat.com>
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
> emulate_popf avoids magic hex constants).
Moreover, vmx will fail the next entry if this is not done. 23.3.1.4 says:
> RFLAGS.
> — Reserved bits 63:22 (bits 31:22 on processors that do not support
> Intel 64
> architecture), bit 15, bit 5 and bit 3 must be 0 in the field, and
> reserved bit 1
> must be 1.
Looks like a note is missing in the manual. I'll alert the authors.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-07-26 9:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-25 19:20 [PATCH] x86 emulator: Add IRET instruction Mohammed Gamal
2010-07-25 23:59 ` Paolo Bonzini
2010-07-26 0:07 ` Mohammed Gamal
2010-07-26 3:09 ` Wei Yongjun
2010-07-26 8:47 ` Paolo Bonzini
2010-07-26 9:00 ` Avi Kivity [this message]
2010-07-26 9:31 ` Paolo Bonzini
2010-07-26 9:32 ` Paolo Bonzini
2010-07-26 11:38 ` Avi Kivity
-- strict thread matches above, loose matches on Subject: below --
2010-07-28 9:38 Mohammed Gamal
2010-07-28 10:30 ` Avi Kivity
2010-07-28 13:30 ` Paolo Bonzini
2010-07-28 13:49 ` Paolo Bonzini
2010-07-28 17:15 ` Marcelo Tosatti
2010-07-27 23:06 Mohammed Gamal
2010-07-28 4:20 ` Avi Kivity
2010-07-25 19:18 Mohammed Gamal
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