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Re: [Qemu-devel] [PATCH 2/2] kvm: use per-cpu lock to free vcpu thread o
From: |
Jan Kiszka |
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 |
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 |
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
- Re: [Qemu-devel] [PATCH 2/2] kvm: use per-cpu lock to free vcpu thread out of the big lock,
Jan Kiszka <=