VM fails to boot with 256 vCPUs, the detailed command is
qemu-system-loongarch64 -smp 256 and there is error reported as follows:
  KVM_LOONGARCH_EXTIOI_INIT_NUM_CPU failed: Invalid argument

There is typo issue in function kvm_eiointc_ctrl_access() when set
max supported vCPUs.

Cc: stable@vger.kernel.org
Fixes: 47256c4c8b1b ("LoongArch: KVM: Avoid copy_*_user() with lock hold in kvm_eiointc_ctrl_access()")

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 arch/loongarch/kvm/intc/eiointc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/loongarch/kvm/intc/eiointc.c b/arch/loongarch/kvm/intc/eiointc.c
index c32333695381..a1cc116b4dac 100644
--- a/arch/loongarch/kvm/intc/eiointc.c
+++ b/arch/loongarch/kvm/intc/eiointc.c
@@ -439,7 +439,7 @@ static int kvm_eiointc_ctrl_access(struct kvm_device *dev,
 	spin_lock_irqsave(&s->lock, flags);
 	switch (type) {
 	case KVM_DEV_LOONGARCH_EXTIOI_CTRL_INIT_NUM_CPU:
-		if (val >= EIOINTC_ROUTE_MAX_VCPUS)
+		if (val > EIOINTC_ROUTE_MAX_VCPUS)
 			ret = -EINVAL;
 		else
 			s->num_cpu = val;

base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
-- 
2.39.3

Applied, thanks.

Huacai

On Tue, Oct 14, 2025 at 5:51 PM Bibo Mao <maobibo@loongson.cn> wrote:
>
> VM fails to boot with 256 vCPUs, the detailed command is
> qemu-system-loongarch64 -smp 256 and there is error reported as follows:
>   KVM_LOONGARCH_EXTIOI_INIT_NUM_CPU failed: Invalid argument
>
> There is typo issue in function kvm_eiointc_ctrl_access() when set
> max supported vCPUs.
>
> Cc: stable@vger.kernel.org
> Fixes: 47256c4c8b1b ("LoongArch: KVM: Avoid copy_*_user() with lock hold in kvm_eiointc_ctrl_access()")
>
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
>  arch/loongarch/kvm/intc/eiointc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/loongarch/kvm/intc/eiointc.c b/arch/loongarch/kvm/intc/eiointc.c
> index c32333695381..a1cc116b4dac 100644
> --- a/arch/loongarch/kvm/intc/eiointc.c
> +++ b/arch/loongarch/kvm/intc/eiointc.c
> @@ -439,7 +439,7 @@ static int kvm_eiointc_ctrl_access(struct kvm_device *dev,
>         spin_lock_irqsave(&s->lock, flags);
>         switch (type) {
>         case KVM_DEV_LOONGARCH_EXTIOI_CTRL_INIT_NUM_CPU:
> -               if (val >= EIOINTC_ROUTE_MAX_VCPUS)
> +               if (val > EIOINTC_ROUTE_MAX_VCPUS)
>                         ret = -EINVAL;
>                 else
>                         s->num_cpu = val;
>
> base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
> --
> 2.39.3
>