[PATCH v5 6/6] RISC-V: KVM: use kvm_trylock_all_vcpus when locking all vCPUs

[Anup Patel]

On Mon, May 12, 2025 at 11:35 PM Maxim Levitsky <mlevitsk at redhat.com> wrote:
>
> Use kvm_trylock_all_vcpus instead of a custom implementation when locking
> all vCPUs of a VM.
>
> Compile tested only.
>
> Suggested-by: Paolo Bonzini <pbonzini at redhat.com>
> Signed-off-by: Maxim Levitsky <mlevitsk at redhat.com>

For KVM RISC-V:
Tested-by: Anup Patel <anup at brainfault.org>
Reviewed-by: Anup Patel <anup at brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/kvm/aia_device.c | 34 ++--------------------------------
>  1 file changed, 2 insertions(+), 32 deletions(-)
>
> diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c
> index 39cd26af5a69..6315821f0d69 100644
> --- a/arch/riscv/kvm/aia_device.c
> +++ b/arch/riscv/kvm/aia_device.c
> @@ -12,36 +12,6 @@
>  #include <linux/kvm_host.h>
>  #include <linux/uaccess.h>
>
> -static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
> -{
> -       struct kvm_vcpu *tmp_vcpu;
> -
> -       for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
> -               tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
> -               mutex_unlock(&tmp_vcpu->mutex);
> -       }
> -}
> -
> -static void unlock_all_vcpus(struct kvm *kvm)
> -{
> -       unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
> -}
> -
> -static bool lock_all_vcpus(struct kvm *kvm)
> -{
> -       struct kvm_vcpu *tmp_vcpu;
> -       unsigned long c;
> -
> -       kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
> -               if (!mutex_trylock(&tmp_vcpu->mutex)) {
> -                       unlock_vcpus(kvm, c - 1);
> -                       return false;
> -               }
> -       }
> -
> -       return true;
> -}
> -
>  static int aia_create(struct kvm_device *dev, u32 type)
>  {
>         int ret;
> @@ -53,7 +23,7 @@ static int aia_create(struct kvm_device *dev, u32 type)
>                 return -EEXIST;
>
>         ret = -EBUSY;
> -       if (!lock_all_vcpus(kvm))
> +       if (kvm_trylock_all_vcpus(kvm))
>                 return ret;
>
>         kvm_for_each_vcpu(i, vcpu, kvm) {
> @@ -65,7 +35,7 @@ static int aia_create(struct kvm_device *dev, u32 type)
>         kvm->arch.aia.in_kernel = true;
>
>  out_unlock:
> -       unlock_all_vcpus(kvm);
> +       kvm_unlock_all_vcpus(kvm);
>         return ret;
>  }
>
> --
> 2.46.0
>