Re: kvm-88: KVM_APIC_READ: read reserved register b0

[Daniel Bareiro <daniel-listas@gmx.net>]

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On Sunday, 30 August 2009 14:49:59 +0300,
Gleb Natapov wrote:

> > > This printk no longer exists in upstream kvm.

Between emails of the list, I found the suggestion to apply this [1]
patch, but I suppose that not yet it must be applied in the download
version.

> > just to be curious: What was the reason to add that debugging
> > message?

> Because well behaved OS shouldn't read write only register.
> Unfortunately older Linux kernels sometimes uses xchg to access
> eoi(b0) apic register which will generate read/write.

According to I see, guest kernel is 2.6.26-2-486. Apparently, after a
reboot, the OS boots with it instead of amd64 kernel. After boot with
amd64 kernel, no longer flooding in syslog takes place.

I didn't test yet, but I think that with a 686 kernel also the problem
had been solved from the moment that the kernel is nearer the hardware
architecture which I'm using.

Thanks to both for your replies.

Regards,
Daniel

[1] http://thread.gmane.org/gmane.comp.emulators.qemu/24029
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