[PATCH v3 11/12] iommu: Add ops->domain_alloc_sva()

From: Lu Baolu
Date: Tue Apr 16 2024 - 04:11:24 EST


From: Jason Gunthorpe <jgg@xxxxxxxxxx>

Make a new op that receives the device and the mm_struct that the SVA
domain should be created for. Unlike domain_alloc_paging() the dev
argument is never NULL here.

This allows drivers to fully initialize the SVA domain and allocate the
mmu_notifier during allocation. It allows the notifier lifetime to follow
the lifetime of the iommu_domain.

Since we have only one call site, upgrade the new op to return ERR_PTR
instead of NULL.

Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
[Removed smmu3 related changes - Vasant]
Signed-off-by: Vasant Hegde <vasant.hegde@xxxxxxx>
Reviewed-by: Tina Zhang <tina.zhang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240311090843.133455-15-vasant.hegde@xxxxxxx
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
include/linux/iommu.h | 3 +++
drivers/iommu/iommu-sva.c | 16 +++++++++++-----
2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 2e925b5eba53..8aabe83af8f2 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -518,6 +518,7 @@ static inline int __iommu_copy_struct_from_user_array(
* Upon failure, ERR_PTR must be returned.
* @domain_alloc_paging: Allocate an iommu_domain that can be used for
* UNMANAGED, DMA, and DMA_FQ domain types.
+ * @domain_alloc_sva: Allocate an iommu_domain for Shared Virtual Addressing.
* @probe_device: Add device to iommu driver handling
* @release_device: Remove device from iommu driver handling
* @probe_finalize: Do final setup work after the device is added to an IOMMU
@@ -558,6 +559,8 @@ struct iommu_ops {
struct device *dev, u32 flags, struct iommu_domain *parent,
const struct iommu_user_data *user_data);
struct iommu_domain *(*domain_alloc_paging)(struct device *dev);
+ struct iommu_domain *(*domain_alloc_sva)(struct device *dev,
+ struct mm_struct *mm);

struct iommu_device *(*probe_device)(struct device *dev);
void (*release_device)(struct device *dev);
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 640acc804e8c..18a35e798b72 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -108,8 +108,8 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm

/* Allocate a new domain and set it on device pasid. */
domain = iommu_sva_domain_alloc(dev, mm);
- if (!domain) {
- ret = -ENOMEM;
+ if (IS_ERR(domain)) {
+ ret = PTR_ERR(domain);
goto out_free_handle;
}

@@ -283,9 +283,15 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
const struct iommu_ops *ops = dev_iommu_ops(dev);
struct iommu_domain *domain;

- domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
- if (!domain)
- return NULL;
+ if (ops->domain_alloc_sva) {
+ domain = ops->domain_alloc_sva(dev, mm);
+ if (IS_ERR(domain))
+ return domain;
+ } else {
+ domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
+ if (!domain)
+ return ERR_PTR(-ENOMEM);
+ }

domain->type = IOMMU_DOMAIN_SVA;
mmgrab(mm);
--
2.34.1