From: Jan Kiszka <jan.kiszka@web.de>
To: Abel Gordon <ABELG@il.ibm.com>
Cc: Alex Landau <LALEX@il.ibm.com>,
Dan Tsafrir <dan.tsafrir@gmail.com>,
sheng qiu <herbert1984106@gmail.com>, kvm <kvm@vger.kernel.org>,
Muli Ben-Yehuda <muli@cs.technion.ac.il>,
Nadav Har'El <NYH@il.ibm.com>, Nadav Amit <nadav.amit@gmail.com>
Subject: Re: KVM handling external interrupts
Date: Thu, 07 Jun 2012 14:19:14 +0200 [thread overview]
Message-ID: <4FD09C42.8080201@web.de> (raw)
In-Reply-To: <OFE1FFF5F1.85E3FEFB-ONC2257A16.0042A2FA-C2257A16.00437C64@il.ibm.com>
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On 2012-06-07 14:17, Abel Gordon wrote:
>
>
> Jan Kiszka <jan.kiszka@web.de> wrote on 07/06/2012 14:40:57:
>
>> But even if we consider the IDT unsafe, what does that IDT limiting buy
>> us?
>
> The limit lets you force an exit (#GP exception) whenever the shadow IDT
> is ok or not. In this case, you simple shadow the GUEST_IDTR register
> and not a memory area
>
>> The guest can still mask interrupts above that limit via cli, no?
>> So the only measures that save us from CPU hogging guests are the
>> preemption timer and kicking via NMI. Or what am I missing?
>
> Nothing :) As we described in the paper, this is what we do to avoid
> this situation.
So the other measures are redundant, right? They only seem to complicate
the approach without any gain, that is my point.
Jan
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next prev parent reply other threads:[~2012-06-07 12:19 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-07 0:12 KVM handling external interrupts sheng qiu
2012-06-07 7:51 ` Abel Gordon
2012-06-07 8:13 ` Jan Kiszka
2012-06-07 9:02 ` Jan Kiszka
2012-06-07 10:47 ` Abel Gordon
2012-06-07 10:51 ` Jan Kiszka
2012-06-07 11:05 ` Abel Gordon
2012-06-07 11:13 ` Jan Kiszka
2012-06-07 11:51 ` Abel Gordon
2012-06-07 11:54 ` Jan Kiszka
2012-06-07 12:02 ` Abel Gordon
2012-06-07 11:10 ` Jan Kiszka
2012-06-07 11:49 ` Abel Gordon
2012-06-07 12:11 ` Jan Kiszka
2012-06-07 12:25 ` Abel Gordon
2012-06-07 15:05 ` Jan Kiszka
2012-06-10 8:41 ` Abel Gordon
2012-06-10 10:16 ` Jan Kiszka
2012-06-10 10:43 ` Abel Gordon
2012-06-10 12:16 ` Jan Kiszka
2012-06-10 13:30 ` Abel Gordon
2012-06-07 9:55 ` Abel Gordon
2012-06-07 10:23 ` Jan Kiszka
2012-06-07 10:34 ` Nadav Har'El
2012-06-07 10:48 ` Jan Kiszka
2012-06-07 11:40 ` Jan Kiszka
2012-06-07 12:17 ` Abel Gordon
2012-06-07 12:19 ` Jan Kiszka [this message]
2012-06-07 12:32 ` Abel Gordon
2012-06-07 15:07 ` Jan Kiszka
2012-06-10 10:12 ` Abel Gordon
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