Re: [Xen-devel] [PATCH v3 10/14] AMD/IOMMU: allow enabling with IRQ not yet set up

["Woods, Brian" <Brian.Woods@xxxxxxx>]

On Tue, Jul 16, 2019 at 04:39:34PM +0000, Jan Beulich wrote:
> Early enabling (to enter x2APIC mode) requires deferring of the IRQ
> setup. Code to actually do that setup in the x2APIC case will get added
> subsequently.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Acked-by: Brian Woods <brian.woods@xxxxxxx>

> ---
> v3: Re-base.
> 
> --- a/xen/drivers/passthrough/amd/iommu_init.c
> +++ b/xen/drivers/passthrough/amd/iommu_init.c
> @@ -814,7 +814,6 @@ static void amd_iommu_erratum_746_workar
>   static void enable_iommu(struct amd_iommu *iommu)
>   {
>       unsigned long flags;
> -    struct irq_desc *desc;
>   
>       spin_lock_irqsave(&iommu->lock, flags);
>   
> @@ -834,19 +833,27 @@ static void enable_iommu(struct amd_iomm
>       if ( iommu->features.flds.ppr_sup )
>           register_iommu_ppr_log_in_mmio_space(iommu);
>   
> -    desc = irq_to_desc(iommu->msi.irq);
> -    spin_lock(&desc->lock);
> -    set_msi_affinity(desc, NULL);
> -    spin_unlock(&desc->lock);
> +    if ( iommu->msi.irq > 0 )
> +    {
> +        struct irq_desc *desc = irq_to_desc(iommu->msi.irq);
> +
> +        spin_lock(&desc->lock);
> +        set_msi_affinity(desc, NULL);
> +        spin_unlock(&desc->lock);
> +    }
>   
>       amd_iommu_msi_enable(iommu, IOMMU_CONTROL_ENABLED);
>   
>       set_iommu_ht_flags(iommu);
>       set_iommu_command_buffer_control(iommu, IOMMU_CONTROL_ENABLED);
> -    set_iommu_event_log_control(iommu, IOMMU_CONTROL_ENABLED);
>   
> -    if ( iommu->features.flds.ppr_sup )
> -        set_iommu_ppr_log_control(iommu, IOMMU_CONTROL_ENABLED);
> +    if ( iommu->msi.irq > 0 )
> +    {
> +        set_iommu_event_log_control(iommu, IOMMU_CONTROL_ENABLED);
> +
> +        if ( iommu->features.flds.ppr_sup )
> +            set_iommu_ppr_log_control(iommu, IOMMU_CONTROL_ENABLED);
> +    }
>   
>       if ( iommu->features.flds.gt_sup )
>           set_iommu_guest_translation_control(iommu, IOMMU_CONTROL_ENABLED);
> 

-- 
Brian Woods

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