On 10/23/25 10:21, Nicolin Chen wrote:
From: Jason Gunthorpe<[email protected]>
Generally an IOMMU driver should leave the translation as BLOCKED until the
translation entry is probed onto a struct device. When the struct device is
removed, the translation should be put back to BLOCKED.
Drivers that are able to work like this can set their release_domain to the
blocking domain, and the core code handles this work.
The exception is when the device has an IOMMU_RESV_DIRECT region, in which
case the OS should continuously allow translations for the given range. And
the core code generally prevents using a BLOCKED domain with this device.
Continue this logic for the device release and hoist some open coding from
drivers. If the device has dev->iommu->require_direct and the driver uses a
BLOCKED release_domain, override it to IDENTITY to preserve the semantics.
The only remaining required driver code for IOMMU_RESV_DIRECT should preset
an IDENTITY translation during early IOMMU startup for those devices.
Signed-off-by: Jason Gunthorpe<[email protected]>
Signed-off-by: Nicolin Chen<[email protected]>
---
drivers/iommu/iommu.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
Reviewed-by: Lu Baolu <[email protected]>
