The same windows installation CD could be used in xen guest. So why
windows bootloader use Big-Real-Mode for the native installation, but
not use the mode for Xen-HVM guest installation?
On 8/9/07, Brady Chen <chenchp@xxxxxxxxx> wrote:
> Keir, Mats, Archie, and all others
> Thank you guys all.
> I just read this
> seems Randy Thelen tried to fix this issue one year ago, unfortunately
> that patch doesn't work for me.
> Finally I think we have the conclusion that I have to give it up on my
> T60 Laptop now.
> But I'd like to try in this way:
> install windows in xen hvm guest, and then try to boot it in native
> environment. Hope it works.
> BTW, Keir, Mats, Any plan/schedule to support a full functional real
> mode simulator? Or do you know anyone are working on this? thanks
> On 8/9/07, Keir Fraser <keir@xxxxxxxxxxxxx> wrote:
> > On 8/8/07 18:45, "Mats Petersson" <mats@xxxxxxxxxxxxxxxxx> wrote:
> > > At 17:19 08/08/2007, Keir Fraser wrote:
> > >> No, it's a processor mode halfway between real mode and protected mode
> > >> which
> > >> all x86 processors support, but which vmxassist is really rather bad at
> > >> handling. If this is a big-real-mode copy loop then that might explain
> > >> why
> > >> the loop is executing so bizarrely, and may mean you are out of luck
> > >> until
> > >> we retire vmxassist.
> > >
> > > And the fact that EDI is 0xC33FE when it tries to write to the memory
> > > at address of EDI indicates that it's Big-Real-Mode.
> > Yes, that's a giveaway.
> > So I think the 'fix' here is to not try booting your native Windows
> > partition on Xen. It's not likely to work too well anyway, as it'll look
> > like all your hardware has changed, causing activation problems and also big
> > driver changes whenever you switch between running on Xen and running
> > natively.
> > You're better off having a dedicated Xen Windows installation, perhaps on an
> > LVM partition.
> > The problems that others have been seeing are quite likely not the same root
> > cause as yours. Most times there's an early boot problem it will end up with
> > a trap and backtrace in vmxassist, when running on Intel CPUs.
> > -- Keir
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