> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Wednesday, October 26, 2022 2:12 AM
>
> This queries if a domain linked to a device should expect to support
> enforce_cache_coherency() so iommufd can negotiate the rules for when a
> domain should be shared or not.
>
> For iommufd a device that declares
> IOMMU_CAP_ENFORCE_CACHE_COHERENCY will
> not be attached to a domain that does not support it.
>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>, with one nit
> @@ -4458,7 +4458,11 @@ static bool intel_iommu_capable(struct device
> *dev, enum iommu_cap cap)
> return irq_remapping_enabled == 1;
> if (cap == IOMMU_CAP_PRE_BOOT_PROTECTION)
> return dmar_platform_optin();
> + if (cap == IOMMU_CAP_ENFORCE_CACHE_COHERENCY) {
> + struct device_domain_info *info = dev_iommu_priv_get(dev);
>
> + return ecap_sc_support(info->iommu->ecap);
> + }
> return false;
> }
use switch/case while making this change.
