2016-11-09 02:51:03

by Longpeng(Mike)

Subject: [PATCH] arm/arm64: KVM: clean up useless code in kvm_timer_enable

1) Since commit:41a54482 changed timer enabled variable to per-vcpu,
the correlative comment in kvm_timer_enable is useless now.

2) After the kvm module init successfully, the timecounter is always
non-null, so we can remove the checking of timercounter.

Signed-off-by: Longpeng(Mike) <[email protected]>
---
virt/kvm/arm/arch_timer.c | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
index 27a1f63..17b8fa5 100644
--- a/virt/kvm/arm/arch_timer.c
+++ b/virt/kvm/arm/arch_timer.c
@@ -498,17 +498,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
if (ret)
return ret;

-
- /*
- * There is a potential race here between VCPUs starting for the first
- * time, which may be enabling the timer multiple times. That doesn't
- * hurt though, because we're just setting a variable to the same
- * variable that it already was. The important thing is that all
- * VCPUs have the enabled variable set, before entering the guest, if
- * the arch timers are enabled.
- */
- if (timecounter)
- timer->enabled = 1;
+ timer->enabled = 1;

return 0;
}
--
1.8.3.1

2016-11-15 11:42:00

by Christoffer Dall

Subject: Re: [PATCH] arm/arm64: KVM: clean up useless code in kvm_timer_enable

On Wed, Nov 09, 2016 at 10:50:14AM +0800, Longpeng(Mike) wrote:
> 1) Since commit:41a54482 changed timer enabled variable to per-vcpu,
> the correlative comment in kvm_timer_enable is useless now.
>
> 2) After the kvm module init successfully, the timecounter is always
> non-null, so we can remove the checking of timercounter.
>
> Signed-off-by: Longpeng(Mike) <[email protected]>

Acked-by: Christoffer Dall <[email protected]>

> ---
> virt/kvm/arm/arch_timer.c | 12 +-----------
> 1 file changed, 1 insertion(+), 11 deletions(-)
>
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 27a1f63..17b8fa5 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -498,17 +498,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
> if (ret)
> return ret;
>
> -
> - /*
> - * There is a potential race here between VCPUs starting for the first
> - * time, which may be enabling the timer multiple times. That doesn't
> - * hurt though, because we're just setting a variable to the same
> - * variable that it already was. The important thing is that all
> - * VCPUs have the enabled variable set, before entering the guest, if
> - * the arch timers are enabled.
> - */
> - if (timecounter)
> - timer->enabled = 1;
> + timer->enabled = 1;
>
> return 0;
> }
> --
> 1.8.3.1
>
>
> --
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