Re: [RFC 6/7] iommu/vt-d: convert the intel iommu driver to the dma-iommu ops api

From: Lu Baolu
Date: Sun May 05 2019 - 21:42:12 EST


On 5/6/19 1:03 AM, Tom Murphy wrote:
On Sun, May 5, 2019 at 3:44 AM Lu Baolu<> wrote:

On 5/4/19 9:23 PM, Tom Murphy wrote:
static int intel_iommu_add_device(struct device *dev)
+ struct dmar_domain *dmar_domain;
+ struct iommu_domain *domain;
struct intel_iommu *iommu;
struct iommu_group *group;
- struct iommu_domain *domain;
+ dma_addr_t base;
u8 bus, devfn;

iommu = device_to_iommu(dev, &bus, &devfn);
@@ -4871,9 +4514,12 @@ static int intel_iommu_add_device(struct device *dev)
if (IS_ERR(group))
return PTR_ERR(group);

domain = iommu_get_domain_for_dev(dev);
+ dmar_domain = to_dmar_domain(domain);
if (domain->type == IOMMU_DOMAIN_DMA)
- dev->dma_ops = &intel_dma_ops;
+ iommu_setup_dma_ops(dev, base,
+ __DOMAIN_MAX_ADDR(dmar_domain->gaw) - base);
I didn't find the implementation of iommu_setup_dma_ops() in this
series. Will the iova resource be initialized in this function?
Ah sorry, I should've mentioned this is based on the
branch with the "iommu/vt-d: Delegate DMA domain to generic iommu" and
"iommu/amd: Convert the AMD iommu driver to the dma-iommu api" patch
sets applied.

If so, will this block iommu_group_create_direct_mappings() which
reserves and maps the reserved iova ranges.
The reserved regions will be reserved by the
iova_reserve_iommu_regions function instead:
iommu_setup_dma_ops calls iommu_dma_init_domain which calls
iommu_group_create_direct_mappings will still execute normally but it
won't be able to call the intel_iommu_apply_resv_region function
because it's been removed in this patchset.
This shouldn't change any behavior and the same regions should be reserved.

Okay, I understand it now. Thanks for the explanation.

Best regards,
Lu Baolu