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Re: [Qemu-devel] [PATCH v3 1/5] hpet 'driftfix': add hooks required to d
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH v3 1/5] hpet 'driftfix': add hooks required to detect coalesced interrupts (x86 apic only) |
Date: |
Fri, 29 Apr 2011 12:15:27 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-04-29 11:45, Ulrich Obergfell wrote:
>
>> On 2011-04-28 20:51, Blue Swirl wrote:
>>> On Thu, Apr 28, 2011 at 5:24 PM, Ulrich Obergfell wrote:
>>>> 'target_get_irq_delivered' and 'target_reset_irq_delivered' contain
>>>> entry addresses of functions that are utilized by update_irq() to
>>>> detect coalesced interrupts. apic code loads these pointers during
>>>> initialization.
>>>
>>> I'm not so happy with this approach, but probably then the i386
>>> dependencies can be removed from RTC and it can be compiled only once
>>> for all targets.
>>
>> This whole series is really the minimalistic approach. The callbacks
>> defined here must remain a temporary "shortcut". Just like proper
>> abstraction of periodic tick compensation for reuse in other timers has
>> to be added later on. And the limitation to edge-triggered legacy HPET
>> INTs has to be removed.
>
> Since QEMU doesn't have a generic infrastructure to track interrupt
> delivery, I decided to reuse something that is currently available.
> The only mechanism that I'm aware of is the one that is utilized by
> RTC code ('rtc_td_hack'), i.e. apic_get_irq_delivered() etc.
>
> The changes that would be introduced by part 1/5 and part 4/5 of
> this patch series could be replaced if a generic infrastructure
> to track interrupt delivery becomes available.
Right, and I hope you have the resources to continue working on this
topic in the foreseeable future.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
[Qemu-devel] [PATCH v3 2/5] hpet 'driftfix': add driftfix property to HPETState and DeviceInfo, Ulrich Obergfell, 2011/04/28
[Qemu-devel] [PATCH v3 3/5] hpet 'driftfix': add fields to HPETTimer and VMStateDescription, Ulrich Obergfell, 2011/04/28
[Qemu-devel] [PATCH v3 4/5] hpet 'driftfix': add code in update_irq() to detect coalesced interrupts (x86 apic only), Ulrich Obergfell, 2011/04/28
[Qemu-devel] [PATCH v3 5/5] hpet 'driftfix': add code in hpet_timer() to compensate delayed callbacks and coalesced interrupts, Ulrich Obergfell, 2011/04/28