Re: [PATCH v2] LoongArch: KVM: Return the actual error code in kvm_ipi_create()

[Huacai Chen]

Applied, thanks.


Huacai

On Thu, Sep 24, 2026 at 2:51 PM Chaithanya Lagisetty
<nagachaithanya9911@xxxxxxxxx> wrote:
>
> kvm_ipi_create() registers the IPI device on the IOCSR bus. The error
> path currently discards the error code returned by
> kvm_io_bus_register_dev() and returns -EFAULT instead:
>
>         ret = kvm_io_bus_register_dev(kvm, KVM_IOCSR_BUS, IOCSR_IPI_BASE,
>                                       IOCSR_IPI_SIZE, device);
>         mutex_unlock(&kvm->slots_lock);
>         if (ret < 0) {
>                 kvm_pr_unimpl("%s: Initialize IOCSR dev failed, ret = %d\n",
>                               __func__, ret);
>                 goto err;
>         }
>         ...
> err:
>         kfree(s);
>         return -EFAULT;
>
> kvm_io_bus_register_dev() fails with -ENOMEM or -ENOSPC, so userspace
> creating a KVM_DEV_TYPE_LOONGARCH_IPI device is told that it passed a
> bad address when the real problem is that the host is out of memory or
> out of IOCSR bus slots. -EFAULT is reserved for faulting user addresses,
> and the remaining -EFAULT returns in this file are get_user() failures,
> where it is correct.
>
> Free the IPI state and propagate the error directly after cleanup. The
> error label had a single user, so handling the failure in place removes
> the label as well. This matches kvm_eiointc_create(), which already frees
> its state and propagates the kvm_io_bus_register_dev() error code
> unchanged.
>
> Only compile-tested.
>
> Fixes: c532de5a67a7 ("LoongArch: KVM: Add IPI device support")
> Suggested-by: Huacai Chen <chenhuacai@xxxxxxxxxx>
> Assisted-by: Cursor:claude-opus-5
> Signed-off-by: Chaithanya Lagisetty <nagachaithanya9911@xxxxxxxxx>
> ---
> v2:
>  - Handle the failure in place and drop the now unused err label instead
>    of only correcting the returned value (Huacai Chen).
>  - Reworded the commit message accordingly.
>  - Dropped Bibo Mao's Reviewed-by from v1, as the error path is
>    restructured in this version rather than only returning ret.
>
> Link to v1:
> https://lore.kernel.org/all/20260922103931.215091-1-nagachaithanya9911@xxxxxxxxx/
>
>  arch/loongarch/kvm/intc/ipi.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/arch/loongarch/kvm/intc/ipi.c b/arch/loongarch/kvm/intc/ipi.c
> index 7b333a4a0430..80faa770c0cd 100644
> --- a/arch/loongarch/kvm/intc/ipi.c
> +++ b/arch/loongarch/kvm/intc/ipi.c
> @@ -423,15 +423,12 @@ static int kvm_ipi_create(struct kvm_device *dev, u32 type)
>         mutex_unlock(&kvm->slots_lock);
>         if (ret < 0) {
>                 kvm_pr_unimpl("%s: Initialize IOCSR dev failed, ret = %d\n", __func__, ret);
> -               goto err;
> +               kfree(s);
> +               return ret;
>         }
>
>         kvm->arch.ipi = s;
>         return 0;
> -
> -err:
> -       kfree(s);
> -       return -EFAULT;
>  }
>
>  static void kvm_ipi_destroy(struct kvm_device *dev)
> --
> 2.43.0
>