From: Jan Kiszka <jan.kiszka@web.de>
To: Gleb Natapov <gleb@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, kvm <kvm@vger.kernel.org>
Subject: Re: [PATCH] KVM: x86: Avoid busy loops over uninjectable pending APIC timers
Date: Sun, 28 Apr 2013 12:20:12 +0200 [thread overview]
Message-ID: <517CF7DC.7010109@web.de> (raw)
In-Reply-To: <20130428101905.GH30504@redhat.com>
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On 2013-04-28 12:19, Gleb Natapov wrote:
> On Sun, Apr 28, 2013 at 12:15:05PM +0200, Jan Kiszka wrote:
>> On 2013-03-17 09:47, Gleb Natapov wrote:
>>> On Sat, Mar 16, 2013 at 09:49:07PM +0100, Jan Kiszka wrote:
>>>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>>>
>>>> If the guest didn't take the last APIC timer interrupt yet and generates
>>>> another one on top, e.g. via periodic mode, we do not block the VCPU
>>>> even if the guest state is halted. The reason is that
>>>> apic_has_pending_timer continues to return a non-zero value.
>>>>
>>>> Fix this busy loop by taking the IRR content for the LVT vector in
>>>> apic_has_pending_timer into account.
>>>>
>>> Just drop coalescing tacking for lapic interrupt. After posted interrupt
>>> will be merged __apic_accept_irq() will not longer return coalescing
>>> information, so the code will be dead anyway.
>>
>> If I understood the follow-up discussion correctly, we aren't dropping
>> de-coalescing support yet. So how to proceed with this fix here?
>>
> We do. It does not work if you run on CPU with apicv support already.
But isn't the code still there and working when apicv is absent?
Jan
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next prev parent reply other threads:[~2013-04-28 10:20 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-16 20:49 [PATCH] KVM: x86: Avoid busy loops over uninjectable pending APIC timers Jan Kiszka
2013-03-17 8:47 ` Gleb Natapov
2013-03-17 10:45 ` Jan Kiszka
2013-03-17 10:47 ` Gleb Natapov
2013-03-20 19:30 ` Marcelo Tosatti
2013-03-20 20:03 ` Marcelo Tosatti
2013-03-20 21:32 ` Gleb Natapov
2013-03-20 23:19 ` Marcelo Tosatti
2013-03-21 4:54 ` Gleb Natapov
2013-03-21 14:02 ` Marcelo Tosatti
2013-03-21 14:18 ` Gleb Natapov
2013-03-21 14:27 ` Zhang, Yang Z
2013-03-21 16:27 ` Gleb Natapov
2013-03-21 20:51 ` Marcelo Tosatti
2013-03-21 21:13 ` Gleb Natapov
2013-03-21 23:06 ` Marcelo Tosatti
2013-03-22 1:50 ` Zhang, Yang Z
2013-03-22 6:53 ` Gleb Natapov
2013-03-22 10:43 ` Marcelo Tosatti
2013-03-22 11:19 ` Gleb Natapov
2013-03-24 10:45 ` Zhang, Yang Z
2013-03-24 19:03 ` Gleb Natapov
2013-04-28 10:15 ` Jan Kiszka
2013-04-28 10:19 ` Gleb Natapov
2013-04-28 10:20 ` Jan Kiszka [this message]
2013-04-28 10:23 ` Gleb Natapov
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