iommu: Add IOMMU_CAP_ENFORCE_CACHE_COHERENCY

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.

Link: https://lore.kernel.org/r/1-v6-a196d26f289e+11787-iommufd_jgg@nvidia.com
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Lixiao Yang <lixiao.yang@intel.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yu He <yu.he@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe
2022-11-29 16:29:24 -04:00
parent 69e61edebe
commit 4989764d8e
3 changed files with 20 additions and 7 deletions

View File

@@ -124,6 +124,11 @@ enum iommu_cap {
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
IOMMU_CAP_PRE_BOOT_PROTECTION, /* Firmware says it used the IOMMU for
DMA protection and we should too */
/*
* Per-device flag indicating if enforce_cache_coherency() will work on
* this device.
*/
IOMMU_CAP_ENFORCE_CACHE_COHERENCY,
};
/* These are the possible reserved region types */