On 2012-02-09 18:20, Paolo Bonzini wrote: > On 02/09/2012 05:32 PM, Jan Kiszka wrote: >> > I mean just check kpcr.self. >> >> Yes, clear, but that means that Windows must have initialized FS.base to >> point to the KPCR also in UP mode. Is that really the case? E.g. when >> ACPI is off?! I wonder if that explains the reported bug of qemu-kvm >> with -no-acpi and in-kernel irqchip... > > Yes, it does. It's used by some fast-path kernel APIs, and indeed the > canonical way to find the KPCR base from ring 0 is to look at FS:[1Ch].
Yep, can confirm this so far. I briefly tested a non-ACPI installation, and it both works without problems on qemu-kvm and shows that pattern at FS:[1C]. I guess I will simply remove the smp_cpus == 1 special case. Jan PS: Please strip of the newsgroups from CC when picking up a thread via news.gmane.org. Some clients may not be configured to reply to them (like mine - intentionally :) ).
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