[PATCH v6 04/25] iommu: Add IOMMU_DOMAIN_PLATFORM for S390

Jason Gunthorpe
2023-08-03T00:09:21Z

The PLATFORM domain will be set as the default domain and attached as
normal during probe. The driver will ignore the initial attach from a NULL
domain to the PLATFORM domain.

After this, the PLATFORM domain's attach_dev will be called whenever we
detach from an UNMANAGED domain (eg for VFIO). This is the same time the
original design would have called op->detach_dev().

This is temporary until the S390 dma-iommu.c conversion is merged.

Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/s390-iommu.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index fbf59a8db29b11..f0c867c57a5b9b 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -142,14 +142,31 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
return 0;
}

-static void s390_iommu_set_platform_dma(struct device *dev)
+/*
+ * Switch control over the IOMMU to S390's internal dma_api ops
+ */
+static int s390_iommu_platform_attach(struct iommu_domain *platform_domain,
+ struct device *dev)
{
struct zpci_dev *zdev = to_zpci_dev(dev);

+ if (!zdev->s390_domain)
+ return 0;
+
__s390_iommu_detach_device(zdev);
zpci_dma_init_device(zdev);
+ return 0;
}

+static struct iommu_domain_ops s390_iommu_platform_ops = {
+ .attach_dev = s390_iommu_platform_attach,
+};
+
+static struct iommu_domain s390_iommu_platform_domain = {
+ .type = IOMMU_DOMAIN_PLATFORM,
+ .ops = &s390_iommu_platform_ops,
+};
+
static void s390_iommu_get_resv_regions(struct device *dev,
struct list_head *list)
{
@@ -428,12 +445,12 @@ void zpci_destroy_iommu(struct zpci_dev *zdev)
}

static const struct iommu_ops s390_iommu_ops = {
+ .default_domain = &s390_iommu_platform_domain,
.capable = s390_iommu_capable,
.domain_alloc = s390_domain_alloc,
.probe_device = s390_iommu_probe_device,
.release_device = s390_iommu_release_device,
.device_group = generic_device_group,
- .set_platform_dma_ops = s390_iommu_set_platform_dma,
.pgsize_bitmap = SZ_4K,
.get_resv_regions = s390_iommu_get_resv_regions,
.default_domain_ops = &(const struct iommu_domain_ops) {
--
2.41.0