From: Jan Kiszka <jan.kiszka@siemens.com>
To: Liu Ping Fan <qemulist@gmail.com>
Cc: Liu Ping Fan <pingfank@linux.vnet.ibm.com>,
qemu-devel <qemu-devel@nongnu.org>,
"Anthony.Liguori.anthony@codemonkey.ws"
<Anthony.Liguori.anthony@codemonkey.ws>
Subject: Re: [Qemu-devel] [PATCH 2/2] kvm: use per-cpu lock to free vcpu thread out of the big lock
Date: Thu, 21 Jun 2012 17:02:58 +0200 [thread overview]
Message-ID: <4FE337A2.4030802@siemens.com> (raw)
In-Reply-To: <1340290158-11036-3-git-send-email-qemulist@gmail.com>
On 2012-06-21 16:49, Liu Ping Fan wrote:
> In order to break the big lock, using per-cpu_lock in kvm_cpu_exec()
> to protect the race from other cpu's access to env->apic_state & related
> field in env.
> Also, we need to protect agaist run_on_cpu().
>
> Race condition can be like this:
> 1. vcpu-1 IPI vcpu-2
> vcpu-3 IPI vcpu-2
> Open window exists for accessing to vcpu-2's apic_state & env
>
> 2. run_on_cpu() write env->queued_work_last, while flush_queued_work()
> read
>
How much of this is still relevant with the (nowadays default-on)
in-kernel irqchips?
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
next parent reply other threads:[~2012-06-21 15:03 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1340290158-11036-1-git-send-email-qemulist@gmail.com>
[not found] ` <1340290158-11036-3-git-send-email-qemulist@gmail.com>
2012-06-21 15:02 ` Jan Kiszka [this message]
2012-06-22 20:06 ` [Qemu-devel] [PATCH 2/2] kvm: use per-cpu lock to free vcpu thread out of the big lock Anthony Liguori
2012-06-23 9:32 ` liu ping fan
2012-06-24 14:09 ` liu ping fan
2012-06-21 15:23 ` [Qemu-devel] [RFC] use little granularity lock to substitue qemu_mutex_lock_iothread Jan Kiszka
2012-06-22 10:24 ` liu ping fan
2012-06-22 10:37 ` Jan Kiszka
2012-06-22 20:11 ` Anthony Liguori
2012-06-22 21:14 ` Jan Kiszka
2012-06-22 21:44 ` Anthony Liguori
2012-06-22 22:27 ` Jan Kiszka
2012-06-22 22:56 ` Anthony Liguori
2012-06-23 9:10 ` Jan Kiszka
[not found] ` <1340290158-11036-2-git-send-email-qemulist@gmail.com>
2012-06-22 20:01 ` [Qemu-devel] [PATCH 1/2] CPUArchState: introduce per-cpu lock Anthony Liguori
2012-06-21 15:06 [Qemu-devel] [RFC] use little granularity lock to substitue qemu_mutex_lock_iothread Liu Ping Fan
2012-06-21 15:06 ` [Qemu-devel] [PATCH 2/2] kvm: use per-cpu lock to free vcpu thread out of the big lock Liu Ping Fan
2012-06-22 2:29 ` 陳韋任 (Wei-Ren Chen)
2012-06-22 10:26 ` liu ping fan
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