Hi.

I have xen running on my Macbook. The problem is cause by grub.
When i start the xen entry in grub with the key "return" xen
fails too boot. When i use the "Cursor key right" to start
the xen entry xen boots fine. I used the atached patch against
grub 0.97 for the Intel Macs.

cu

Edgar (gimli) Hucek

Marco Gerards schrieb:
> Hi,
> 
> For a while now I have been trying to debug an issue with Xen on the
> MacBook, doing this is part of my Summer of Code project to get Xen
> working properly on the Intel Mac.  In case some of you don't know,
> the MacBook is an Intel Core Duo based laptop from Apple, which lacks
> some legacy hardware.
> 
> Xen (testing) works perfectly for me when starting it with "nosmp",
> however when not using it, it crashes while starting up the second
> core.  There have been some bug report on this issue already.
> 
> Below I will explain the problem in more detail and with some
> observations.  I will be very grateful if someone can come up with
> ideas of how to fix this or give me some ideas that can lead to a
> solution.  Not only Xen has this problem, but so has FreeBSD and
> NetBSD, so a solution will be beneficial to these projects as well.
> 
> What happens is the following: The first core sends two IPI
> messages(INIT and STARTUP) to start the second core.  When the second
> core is started, it notifies the first core of this so it can continue
> with the boot process.  However, the second core is not started by
> these messages, the loop that waits for the second core times out,
> continues and Xen crashes.
> 
> One strange thing is that Xen initializes the second core properly
> when you press a key on the keyboard after the IPIs are sent.  I am
> expecting this interrupt somehow wakes up the second core so it can
> accept and process the IPIs.  Because it is a laptop the second core
> is put in deep sleep mode to save power in case an OS does not use
> this core at all.  But as I understand it, it should wake up when an
> INIT IPI arrives.
> 
> The problems I am having with Xen can be reproduced with linux when
> booting with "acpi=ht", which means the ACPI interpreter is not
> started.
> 
> Hopefully someone has some ideas how to deal with this issue and how
> to properly fix this.  If you want more information or want me to test
> things, feel free to ask.
> 
> Thanks,
> Marco
> 
> 
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