From: "H. Peter Anvin" <hpa@zytor.com>
To: Avi Kivity <avi@redhat.com>
Cc: Glauber Costa <glommer@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] do not keep interrupt window closed by sti in real mode
Date: Tue, 07 Apr 2009 23:25:48 -0700 [thread overview]
Message-ID: <49DC436C.2050309@zytor.com> (raw)
In-Reply-To: <49DC39EE.1070606@redhat.com>
Avi Kivity wrote:
>
> I'm guessing the problem is due to the second instruction. We don't
> clear the 'blocked by interrupt shadow' flag when we emulate, which
> extends interrupt shadow by one more instruction. If the instruction
> sequence is 'sti hlt' we end in an inconsistent state.
>
Ah, and since we're in real mode, we have to emulate everything (at
least on some hardware), right? So we really do need to clear the
interrupt shadow bit in the interpreter... I don't see a way around that.
Otherwise not just STI but MOV SS shadows will break, and in real mode
MOV SS shadow is crucial.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2009-04-08 6:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-08 3:23 [PATCH] do not keep interrupt window closed by sti in real mode Glauber Costa
2009-04-08 4:14 ` H. Peter Anvin
2009-04-08 5:45 ` Avi Kivity
2009-04-08 6:25 ` H. Peter Anvin [this message]
2009-04-08 8:16 ` Avi Kivity
2009-04-08 14:55 ` Glauber Costa
2009-04-08 16:11 ` H. Peter Anvin
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