On 09.06.2009 0:52 Uhr, ron minnich wrote: > Fix attached for qemu. > > Awesome! Thanks for spotting this!
> It would be nice to know if this causes trouble for real hardware, > but it should not. > > ron > > ------------------------------------------------------------------------ > > There are some problems with the way these interrrupts were managed. First, > the CLI erases > any knowledge of whether interrupts were enabled or disabled. Second, the STI > works badly on qemu; we get an immediate INT #0 as soon as the STI happens. > > Is this a Qemu bug? > This doesn't happen on real hardware but, that said, I don't think > this code should be doing cli and sti. > Peter Stuge brought this up, and I think I remembered seeing somewhere that loading the IDT and some other stuff should be guarded by cli+sti because otherwise an interrupt could happen during the switch?!? Not sure. It looks highly unlikely that this would happen for us. Peter? Alex? Do you guys have more insight? > This change fixes the observed qemu failures. > > Signed-off-by: Ronald G. Minnich <[email protected]> > > I hope we find out why this is a problem, because a combination of cli+sti should never cause an interrupt that would not exist without cli+sti. If we can't I suggest we commit this in a few days (Acked-by: Stefan Reinauer <[email protected]>) since it fixes the problem. -- coresystems GmbH • Brahmsstr. 16 • D-79104 Freiburg i. Br. Tel.: +49 761 7668825 • Fax: +49 761 7664613 Email: [email protected] • http://www.coresystems.de/ Registergericht: Amtsgericht Freiburg • HRB 7656 Geschäftsführer: Stefan Reinauer • Ust-IdNr.: DE245674866
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