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[Qemu-devel] Re: [PATCH] HPET fixes for reg writes
From: |
Andriy Gapon |
Subject: |
[Qemu-devel] Re: [PATCH] HPET fixes for reg writes |
Date: |
Fri, 24 Jul 2009 20:08:21 +0300 |
User-agent: |
Thunderbird 2.0.0.22 (X11/20090630) |
on 24/07/2009 19:26 Beth Kon said the following:
> This patch addresses the problems found by Andriy Gapon:
>
> - The code was incorrectly overwriting the high order 32
> bits of the timer and hpet config registers. This didn't show up
> in testing because linux and windows use hpet in legacy mode,
> where the high order 32 bits (advertising available interrupts)
> of the timer config register are ignored, and the high order 32
> bits of the hpet config register are reserved and unused.
>
>
> - The mask for level-triggered interrupts was off by a bit. (hpet
> doesn't currently support level-triggered interrupts).
>
> In addition, I removed some unused #defines, and corrected the ioapic
> interrupt values advertised. I'd set this up early in hpet development
> and never went back to correct it, and no bugs resulted since linux and
> windows use hpet in legacy mode where available interrupts are ignored.
>
Beth,
thanks a lot!
And a comment: it seems that the code doesn't verify interrupt configured by
software, it happily uses any interrupt even if it's not advertised in interrupt
capabilities. I know, the software should not do that, but it happens :)
Also, maybe it would be a good idea to keep support for some additional
interrupts? E.g. irq 10, 11 or some such, or maybe something >= 16 for APIC mode
(if possible at all). But I know that this needs some careful thinking to not
interfere with other emulated devices.
--
Andriy Gapon