From: Jan Kiszka <jan.kiszka@siemens.com>
To: Avi Kivity <avi@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v3 1/3] Introduce a workqueue to deliver PIT timer interrupts.
Date: Tue, 17 Apr 2012 18:15:05 +0200 [thread overview]
Message-ID: <4F8D9709.3020409@siemens.com> (raw)
In-Reply-To: <4F8D5CBD.1070004@redhat.com>
On 2012-04-17 14:06, Avi Kivity wrote:
> On 04/17/2012 03:03 PM, Gleb Natapov wrote:
>>>
>>> KVM_MAX_VCPUS.
>>>
>> Ah, so you are worried about malicious guest configuring pit to
>> broadcast to all its vcpus.
>
> Yes - it can introduce huge amounts of latency this way which is exactly
> what Jan is trying to prevent.
>
> Though I'm not sure spin_lock_irq() in the realtime tree actually
> disables irqs (but it's certainly not a good idea in mainline; it's
> nasty even with just the spinlock).
This depends on how you declare the spin lock type - raw or normal. The
former will disable irqs, the latter not even preemption (but become a
mutex).
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2012-04-17 16:15 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-16 21:11 [PATCH v3 0/3]: Fixes to IRQ routing Chris Lalancette
2010-06-16 21:11 ` [PATCH v3 1/3] Introduce a workqueue to deliver PIT timer interrupts Chris Lalancette
2012-04-16 16:33 ` Jan Kiszka
2012-04-16 17:07 ` Avi Kivity
2012-04-17 9:31 ` Gleb Natapov
2012-04-17 10:23 ` Avi Kivity
2012-04-17 10:26 ` Gleb Natapov
2012-04-17 10:29 ` Avi Kivity
2012-04-17 10:31 ` Gleb Natapov
2012-04-17 10:42 ` Avi Kivity
2012-04-17 10:43 ` Avi Kivity
2012-04-17 11:05 ` Gleb Natapov
2012-04-17 12:00 ` Avi Kivity
2012-04-17 12:03 ` Gleb Natapov
2012-04-17 12:06 ` Avi Kivity
2012-04-17 16:15 ` Jan Kiszka [this message]
2012-04-17 16:17 ` Avi Kivity
2012-04-18 8:04 ` Gleb Natapov
2012-04-18 8:25 ` Avi Kivity
2012-04-18 8:27 ` Gleb Natapov
2010-06-16 21:11 ` [PATCH v3 2/3] Allow any LAPIC to accept PIC interrupts Chris Lalancette
2010-06-16 21:11 ` [PATCH v3 3/3] In DM_LOWEST, only deliver interrupts to vcpus with enabled LAPIC's Chris Lalancette
2010-06-18 17:44 ` [PATCH v3 0/3]: Fixes to IRQ routing Marcelo Tosatti
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