Re: Can VMX provide real mode support?

From: GaoYi <gaoyi709@gmail.com>
To: Avi Kivity <avi@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	kvm <kvm@vger.kernel.org>
Subject: Re: Can VMX provide real mode support?
Date: Wed, 21 Mar 2012 21:56:27 +0800	[thread overview]
Message-ID: <CABurPedppUNeYRw7qw2dmy+i3qQf-XKfHg-rVKV2pyXNZ9CPug@mail.gmail.com> (raw)
In-Reply-To: <4F69DC3B.3050509@redhat.com>

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Hi,
   Thanks for your prompt response. So if the CPU supports the real
mode, the KVM can support the real mode guest and there is still work to be
done for CPU without real mode support, namely software emulation?

   Again

在 2012年3月21日 下午9:48，Avi Kivity <avi@redhat.com>写道：

> On 03/21/2012 03:40 PM, Jan Kiszka wrote:
> > On 2012-03-21 13:38, GaoYi wrote:
> > > Hi Jan,
> > >
> > >     Since the newest Intel-VT supports the guest OS under the real
> mode, which was already supported in AMD-V, can the VMX in the latest KVM
> support that case?
> >
> > Yes, both with our without that "unrestricted guest" support (as Intel
> > called it), real mode will generally work. Without that CPU feature, I
> > think to recall that there were some limitations for big real mode, not
> > sure.
> >
>
> Yes, big real mode will not work without "unrestricted guest".  There
> was some work to emulate it (module option emulate_invalid_guest_state),
> but it is not complete.
>
> --
> error compiling committee.c: too many arguments to function
>
>

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