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

[Stewart Hildebrand <stewart.hildebrand@xxxxxxx>]

On 7/25/25 04:01, Roger Pau Monné wrote:
> On Thu, Jul 24, 2025 at 01:43:48PM -0400, 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>
>> ---
>> 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
> 
> Since this is tied to specific IOMMU implementations, could you please
> tie it to AMD_IOMMU and INTEL_IOMMU instead of X86?
> 
> depends on AMD_IOMMU || INTEL_IOMMU
> 
> Should do it I think?

Yes, that makes sense. Since the version with X86 was already committed,
I'll send the modification with a Fixes: tag.