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Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups |
Date: |
Mon, 05 Jul 2010 15:28:55 +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 |
Avi Kivity wrote:
> On 07/05/2010 03:16 PM, Jan Kiszka wrote:
>>> It's also architecturally cleaner. Masks and acks are architectural
>>> events. Injections are not - there's the edge on the LINT0 or INTI2
>>> pins, generation of an APIC message, receipt of the APIC message, and
>>> assertion of the APIC-to-core interrupt interface. I'm not sure how the
>>> proposed interface maps to that.
>>>
>> Our emulation does not reflect every architectural detail of the
>> delivery path anyway.
>
> Usually, when that happens, we get an obscure bug.
>
> So if we add a facility, especially across the user/kernel boundary,
> it's better to have it conform to the architecture. That reduces the
> chance it has a serious hidden bug.
Neither ack/mask notifiers (past the IRQ controller) nor injection
return values are part of any architecture we emulate. What is driving
us are the requirements of the de-coalescing workarounds we want to
build on top and the impact on existing design.
>
>> The abstraction is always an IRQ line which can be
>> high or low (sometimes it is only high, but this is a bug).
>>
>
> That's a bug in the use of qemu_irq, not qemu_irq itself.
>
> But qemu_irq needs to remember its state, otherwise when an irq
> controller unmasks a level-triggered line, it won't see the interrupt.
I think it's currently the IRQ controller's job to keep track of the
line state during masked periods. Moving this to qemu_irq is definitely
better but requires some care (e.g. when vmstates are involved).
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, (continued)
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Gleb Natapov, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Avi Kivity, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Jan Kiszka, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Avi Kivity, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Jan Kiszka, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Gleb Natapov, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Jan Kiszka, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Avi Kivity, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Gleb Natapov, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Avi Kivity, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups,
Jan Kiszka <=
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Avi Kivity, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Blue Swirl, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Jan Kiszka, 2010/07/05
- Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Avi Kivity, 2010/07/05
Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups, Anthony Liguori, 2010/07/01