From: Robin Murphy robin.murphy@arm.com
Currently, iommu-dma is the only place outside of IOMMUFD and drivers which might need to be aware of the stage 2 domain encapsulated within a nested domain. This would be in the legacy-VFIO-style case where we're using host-managed MSIs with an identity mapping at stage 1, where it is the underlying stage 2 domain which owns an MSI cookie and holds the corresponding dynamic mappings. Hook up the new op to resolve what we need from a nested domain.
Signed-off-by: Robin Murphy robin.murphy@arm.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Kunkun Jiang jiangkunkun@huawei.com --- drivers/iommu/dma-iommu.c | 18 ++++++++++++++++-- include/linux/iommu.h | 4 ++++ 2 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 037fcf826407..f6d904cdcf97 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1796,6 +1796,20 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, return NULL; }
+/* + * Nested domains may not have an MSI cookie or accept mappings, but they may + * be related to a domain which does, so we let them tell us what they need. + */ +static struct iommu_domain *iommu_dma_get_msi_mapping_domain(struct device *dev) +{ + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + + if (domain && domain->type == IOMMU_DOMAIN_NESTED && + domain->ops->get_msi_mapping_domain) + domain = domain->ops->get_msi_mapping_domain(domain); + return domain; +} + /** * iommu_dma_prepare_msi() - Map the MSI page in the IOMMU domain * @desc: MSI descriptor, will store the MSI page @@ -1806,7 +1820,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) { struct device *dev = msi_desc_to_dev(desc); - struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iommu_domain *domain = iommu_dma_get_msi_mapping_domain(dev); struct iommu_dma_msi_page *msi_page; static DEFINE_MUTEX(msi_prepare_lock); /* see below */
@@ -1839,7 +1853,7 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg) { struct device *dev = msi_desc_to_dev(desc); - const struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + const struct iommu_domain *domain = iommu_dma_get_msi_mapping_domain(dev); const struct iommu_dma_msi_page *msi_page;
msi_page = msi_desc_get_iommu_cookie(desc); diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 438b1ed02c6c..dd6b261eccde 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -645,6 +645,8 @@ struct iommu_ops { * @sync_dirty_log: Sync dirty log from IOMMU into a dirty bitmap * @clear_dirty_log: Clear dirty log of IOMMU by a mask bitmap * @free: Release the domain after use. + * @get_msi_mapping_domain: Return the related iommu_domain that should hold the + * MSI cookie and accept mapping(s). */ struct iommu_domain_ops { int (*attach_dev)(struct iommu_domain *domain, struct device *dev); @@ -689,6 +691,8 @@ struct iommu_domain_ops { unsigned long *bitmap, unsigned long base_iova, unsigned long bitmap_pgshift); void (*free)(struct iommu_domain *domain); + struct iommu_domain * + (*get_msi_mapping_domain)(struct iommu_domain *domain); };
/**