Re: [PATCH] iommu: restrict scratch page quarantining to x86

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 24 Jul 2025, Stewart Hildebrand wrote:
> All IOMMU_QUARANTINE_* options are exposed on Arm since 163c6b589879
> ("xen/arm: pci: introduce PCI_PASSTHROUGH Kconfig option"). However,
> only NONE and BASIC are implemented in any Arm iommu driver since
> 63919fc4d1ca ("xen/arm: smmuv3: Add PCI devices support for SMMUv3") and
> ca8f6ffeb6e3 ("xen/arm: smmuv2: Add PCI devices support for SMMUv2").
> SCRATCH_PAGE is not yet implemented in any Arm iommu driver. Restrict
> scratch page quarantining to x86 for now.
> 
> Reported-by: Jan Beulich <jbeulich@xxxxxxxx>
> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> Cc'ing Arm maintainers to request an Arm ack.
> ---
>  xen/drivers/passthrough/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/xen/drivers/passthrough/Kconfig b/xen/drivers/passthrough/Kconfig
> index 78edd805365e..11aece5f7bda 100644
> --- a/xen/drivers/passthrough/Kconfig
> +++ b/xen/drivers/passthrough/Kconfig
> @@ -90,4 +90,5 @@ choice
>               bool "basic"
>       config IOMMU_QUARANTINE_SCRATCH_PAGE
>               bool "scratch page"
> +             depends on X86
>  endchoice
> 
> base-commit: 150b773a484c911e2926f65adb576e1cdf9de7cf
> -- 
> 2.50.1
>