2021-11-14 06:41:26

by Jason Wang

Subject: [PATCH] KVM: arm64: remove unneeded comparison

The unsigned expression compared with zero `target < 0' is
unneeded and its result is always false. we can also check the
target's value returned from `kvm_target_cpu' is one of the
KVM_* macros, and these macros are defined greater than or equal
to 0.
Therefore, the comparison code block:
if (target < 0)
return -ENODEV;
is unneeded. We can safely remove it.

Signed-off-by: Jason Wang <[email protected]>
---
arch/arm64/kvm/guest.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 5ce26bedf23c..1605cb71dd52 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -873,9 +873,6 @@ int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
{
u32 target = kvm_target_cpu();

- if (target < 0)
- return -ENODEV;
-
memset(init, 0, sizeof(*init));

/*
--
2.33.0

2021-11-14 07:12:11

by Zenghui Yu

Subject: Re: [PATCH] KVM: arm64: remove unneeded comparison

Hi,

On 2021/11/14 14:40, Jason Wang wrote:
> The unsigned expression compared with zero `target < 0' is
> unneeded and its result is always false. we can also check the
> target's value returned from `kvm_target_cpu' is one of the
> KVM_* macros, and these macros are defined greater than or equal
> to 0.
> Therefore, the comparison code block:
> if (target < 0)
> return -ENODEV;
> is unneeded. We can safely remove it.
>
> Signed-off-by: Jason Wang <[email protected]>
> ---
> arch/arm64/kvm/guest.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 5ce26bedf23c..1605cb71dd52 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -873,9 +873,6 @@ int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
> {
> u32 target = kvm_target_cpu();
>
> - if (target < 0)
> - return -ENODEV;
> -
> memset(init, 0, sizeof(*init));
>
> /*

FYI there's already a similar change in mainline now:

https://git.kernel.org/torvalds/c/08e873cb70f3

Thanks,
Zenghui