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From: "H. Peter Anvin" <hpa@zytor.com>
To: kvm@vger.kernel.org
Subject: Re: KVM crash on unusual PM->RM transition
Date: Mon, 13 Apr 2009 22:42:56 -0700	[thread overview]
Message-ID: <49E42260.7030009@zytor.com> (raw)
In-Reply-To: <49E3CDE1.8010001@zytor.com>

H. Peter Anvin wrote:
> The current test branch of Syslinux does PM->RM transition via a stub
> which can be located in high memory.  This is correct and valid (x86
> CPUs rely on this to boot): after clearing CR0.PE, CS.base retains its
> previous value until CS is reloaded by a far JMP (which in this case is
> the very next instruction).

Some trivial research later...

It looks like KVM will simply crash when it runs into a real-mode state
it can't approximate with V86 mode.  I guess I had the failed notion
that it would kick back such "impossible" states to Qemu.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2009-04-14  5:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-13 23:42 KVM crash on unusual PM->RM transition H. Peter Anvin
2009-04-14  5:42 ` H. Peter Anvin [this message]
2009-04-14  8:14   ` Avi Kivity
2009-04-14 15:48     ` H. Peter Anvin
2009-04-14 16:07       ` Avi Kivity
2009-04-14 16:10         ` H. Peter Anvin
2009-04-14 16:16           ` Avi Kivity
2009-04-14 16:17             ` H. Peter Anvin

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