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Re: [Qemu-devel] [PATCH] ppc: Avoid decrementer related kvm exits
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH] ppc: Avoid decrementer related kvm exits |
Date: |
Thu, 20 Oct 2011 10:08:36 -0700 |
On 16.10.2011, at 22:26, David Gibson wrote:
> In __cpu_ppc_store_decr(), we set up a regular timer used to trigger
> decrementer interrupts. This is necessary to implement the decrementer
> properly under TCG, but is unnecessary under KVM (true for both Book3S-PR
> and Book3S-HV KVM variants), because the kernel handles generating and
> delivering decrementer exceptions.
>
> Under kvm, in fact, the timer causes expensive and unnecessary exits from
> kvm to qemu. This patch, therefore, disables setting the timer when kvm
> is in use.
>
> Signed-off-by: Anton Blanchard <address@hidden>
> Signed-off-by: David Gibson <address@hidden>
Thanks, applied to ppc-next.
Alex