Logically the HWPT should have the coherency set properly for the device
that it is being created for when it is created.
This was happening implicitly if the immediate_attach was set because
iommufd_hw_pagetable_attach() does it as the first thing.
Do it unconditionally so !immediate_attach works properly.
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Tested-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/iommu/iommufd/device.c | 19 ++++-------------
drivers/iommu/iommufd/hw_pagetable.c | 27 +++++++++++++++++++++++++
drivers/iommu/iommufd/iommufd_private.h | 1 +
3 files changed, 32 insertions(+), 15 deletions(-)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 7db5df11ad9be3..d41e34d1b778dd 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -295,22 +295,11 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
goto err_unlock;
}
- /*
- * Try to upgrade the domain we have, it is an iommu driver bug to
- * report IOMMU_CAP_ENFORCE_CACHE_COHERENCY but fail
- * enforce_cache_coherency when there are no devices attached to the
- * domain.
- */
- if (idev->enforce_cache_coherency && !hwpt->enforce_cache_coherency) {
- if (hwpt->domain->ops->enforce_cache_coherency)
- hwpt->enforce_cache_coherency =
- hwpt->domain->ops->enforce_cache_coherency(
- hwpt->domain);
- if (!hwpt->enforce_cache_coherency) {
- WARN_ON(list_empty(&idev->igroup->device_list));
- rc = -EINVAL;
+ /* Try to upgrade the domain we have */
+ if (idev->enforce_cache_coherency) {
+ rc = iommufd_hw_pagetable_enforce_cc(hwpt);
+ if (rc)
goto err_unlock;
- }
}
rc = iopt_table_enforce_dev_resv_regions(&hwpt->ioas->iopt, idev->dev,
diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index bdb76cdb1dc347..e0699d7f4c64af 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -25,6 +25,20 @@ void iommufd_hw_pagetable_destroy(struct iommufd_object *obj)
refcount_dec(&hwpt->ioas->obj.users);
}
+int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt)
+{
+ if (hwpt->enforce_cache_coherency)
+ return 0;
+
+ if (hwpt->domain->ops->enforce_cache_coherency)
+ hwpt->enforce_cache_coherency =
+ hwpt->domain->ops->enforce_cache_coherency(
+ hwpt->domain);
+ if (!hwpt->enforce_cache_coherency)
+ return -EINVAL;
+ return 0;
+}
+
/**
* iommufd_hw_pagetable_alloc() - Get an iommu_domain for a device
* @ictx: iommufd context
@@ -60,6 +74,19 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
goto out_abort;
}
+ /*
+ * Set the coherency mode before we do iopt_table_add_domain() as some
+ * iommus have a per-PTE bit that controls it and need to decide before
+ * doing any maps. It is an iommu driver bug to report
+ * IOMMU_CAP_ENFORCE_CACHE_COHERENCY but fail enforce_cache_coherency on
+ * a new domain.
+ */
+ if (idev->enforce_cache_coherency) {
+ rc = iommufd_hw_pagetable_enforce_cc(hwpt);
+ if (WARN_ON(rc))
+ goto out_abort;
+ }
+
/*
* immediate_attach exists only to accommodate iommu drivers that cannot
* directly allocate a domain. These drivers do not finish creating the
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 63b2587a37f23d..5ce9eaf5fb88e3 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -254,6 +254,7 @@ struct iommufd_hw_pagetable {
struct iommufd_hw_pagetable *
iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
struct iommufd_device *idev, bool immediate_attach);
+int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt);
int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
struct iommufd_device *idev);
struct iommufd_hw_pagetable *
--
2.41.0
