linux-kernel - Re: [PATCH] KVM: arm64: vgic: fix incorrect spinlock API usage

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Message-ID: <86v7ltcqb9.wl-maz@kernel.org>
Date: Mon, 08 Sep 2025 09:16:10 +0100
From: Marc Zyngier <maz@...nel.org>
To: Alok Tiwari <alok.a.tiwari@...cle.com>
Cc: 	jintack@...columbia.edu,
	christoffer.dall@....com,
	oliver.upton@...ux.dev,
	joey.gouly@....com,
	suzuki.poulose@....com,
	yuzenghui@...wei.com,
	catalin.marinas@....com,
	will@...nel.org,
	linux-arm-kernel@...ts.infradead.org,
	kvmarm@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: arm64: vgic: fix incorrect spinlock API usage

[removing @arm.com addresses that haven't been in use for a very long
time]

On Sun, 07 Sep 2025 21:14:13 +0100,
Alok Tiwari <alok.a.tiwari@...cle.com> wrote:
> 
> The function vgic_flush_lr_state() was calling _raw_spin_unlock()

s/was/is/

> instead of the proper raw_spin_unlock().
>
> _raw_spin_unlock() is an internal low-level API and should not
> be used directly; using raw_spin_unlock() ensures proper locking
> semantics in the vgic code.
> 
> This change replaces low-level API usage with the general kernel
> spinlock API, avoiding misuse of internal functions and aligning
> with kernel locking conventions.

This paragraph doesn't add much, please drop it.

> 
> Fixes: 8fa3adb8c6be ("KVM: arm/arm64: vgic: Make vgic_irq->irq_lock a raw_spinlock")
> Signed-off-by: Alok Tiwari <alok.a.tiwari@...cle.com>
> ---
>  arch/arm64/kvm/vgic/vgic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
> index f5148b38120a..c74d6120a12c 100644
> --- a/arch/arm64/kvm/vgic/vgic.c
> +++ b/arch/arm64/kvm/vgic/vgic.c
> @@ -818,7 +818,7 @@ static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
>  		 * the AP list has been sorted already.
>  		 */
>  		if (multi_sgi && irq->priority > prio) {
> -			_raw_spin_unlock(&irq->irq_lock);
> +			raw_spin_unlock(&irq->irq_lock);
>  			break;
>  		}
>  

With the above fixed:

Acked-by: Marc Zyngier <maz@...nel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.