2023-10-01 22:47:24

by Dongli Zhang

Subject: [PATCH 1/1] KVM: x86: remove always-false condition in kvmclock_sync_fn

The 'kvmclock_periodic_sync' is a readonly param that cannot change after
bootup.

The kvm_arch_vcpu_postcreate() is not going to schedule the
kvmclock_sync_work if kvmclock_periodic_sync == false.

As a result, the "if (!kvmclock_periodic_sync)" can never be true if the
kvmclock_sync_work = kvmclock_sync_fn() is scheduled.

Inspired by: https://lore.kernel.org/kvm/[email protected]/
Signed-off-by: Dongli Zhang <[email protected]>
---
arch/x86/kvm/x86.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9f18b06bbda6..38fd04a286c7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3290,9 +3290,6 @@ static void kvmclock_sync_fn(struct work_struct *work)
kvmclock_sync_work);
struct kvm *kvm = container_of(ka, struct kvm, arch);

- if (!kvmclock_periodic_sync)
- return;
-
schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
KVMCLOCK_SYNC_PERIOD);
--
2.34.1

2023-10-20 22:57:43

by Sean Christopherson

Subject: Re: [PATCH 1/1] KVM: x86: remove always-false condition in kvmclock_sync_fn

On Sun, 01 Oct 2023 14:36:37 -0700, Dongli Zhang wrote:
> The 'kvmclock_periodic_sync' is a readonly param that cannot change after
> bootup.
>
> The kvm_arch_vcpu_postcreate() is not going to schedule the
> kvmclock_sync_work if kvmclock_periodic_sync == false.
>
> As a result, the "if (!kvmclock_periodic_sync)" can never be true if the
> kvmclock_sync_work = kvmclock_sync_fn() is scheduled.
>
> [...]

Applied to kvm-x86 misc, thanks!

[1/1] KVM: x86: remove always-false condition in kvmclock_sync_fn
https://github.com/kvm-x86/linux/commit/2081a8450ef8

--
https://github.com/kvm-x86/linux/tree/next