Re: [PATCH for-4.21?] AMD/IOMMU: unshare IRQ .ack and .disable handlers

[Oleksii Kurochko <oleksii.kurochko@gmail.com>]

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On 10/20/25 4:16 PM, Jan Beulich wrote:
> A .disable handler can't typically be re-used for .ack: The latter needs
> to deal with IRQ migration, while the former shouldn't. Furthermore
> invoking just irq_complete_move() isn't enough; one of
> move_{native,masked}_irq() also need invoking.
>
> Fixes: 487a1cffd71a ("x86: Implement per-cpu vector for xen hypervisor")
> Fixes: f821102450a1 ("x86: IRQ Migration logic enhancement")
> Signed-off-by: Jan Beulich<jbeulich@suse.com>

Release-Acked-by: Oleksii Kurochko<oleksii.kurochko@gmail.com>

~ Oleksii

>
> --- a/xen/drivers/passthrough/amd/iommu_init.c
> +++ b/xen/drivers/passthrough/amd/iommu_init.c
> @@ -428,8 +428,6 @@ static void cf_check iommu_msi_mask(stru
>       unsigned long flags;
>       struct amd_iommu *iommu = desc->action->dev_id;
>   
> -    irq_complete_move(desc);
> -
>       spin_lock_irqsave(&iommu->lock, flags);
>       amd_iommu_msi_enable(iommu, IOMMU_CONTROL_DISABLED);
>       spin_unlock_irqrestore(&iommu->lock, flags);
> @@ -442,6 +440,13 @@ static unsigned int cf_check iommu_msi_s
>       return 0;
>   }
>   
> +static void cf_check iommu_msi_ack(struct irq_desc *desc)
> +{
> +    irq_complete_move(desc);
> +    iommu_msi_mask(desc);
> +    move_masked_irq(desc);
> +}
> +
>   static void cf_check iommu_msi_end(struct irq_desc *desc, u8 vector)
>   {
>       iommu_msi_unmask(desc);
> @@ -455,7 +460,7 @@ static hw_irq_controller iommu_msi_type
>       .shutdown = iommu_msi_mask,
>       .enable = iommu_msi_unmask,
>       .disable = iommu_msi_mask,
> -    .ack = iommu_msi_mask,
> +    .ack = iommu_msi_ack,
>       .end = iommu_msi_end,
>       .set_affinity = set_msi_affinity,
>   };

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