[RFC 1/7] iommu/vt-d: Set the dma_ops per device so we can remove the iommu_no_mapping code

Tom Murphy
2019-05-04T13:23:17Z

Set the dma_ops per device so we can remove the iommu_no_mapping code.

Signed-off-by: Tom Murphy <tmurphy@arista.com>
---
drivers/iommu/intel-iommu.c | 85 +++----------------------------------
1 file changed, 6 insertions(+), 79 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index eace915602f0..2db1dc47e7e4 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2622,17 +2622,6 @@ static int __init si_domain_init(int hw)
return 0;
}

-static int identity_mapping(struct device *dev)
-{
- struct device_domain_info *info;
-
- info = dev->archdata.iommu;
- if (info && info != DUMMY_DEVICE_DOMAIN_INFO)
- return (info->domain == si_domain);
-
- return 0;
-}
-
static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
{
struct dmar_domain *ndomain;
@@ -3270,43 +3259,6 @@ static unsigned long intel_alloc_iova(struct device *dev,
return iova_pfn;
}

-/* Check if the dev needs to go through non-identity map and unmap process.*/
-static int iommu_no_mapping(struct device *dev)
-{
- int found;
-
- if (iommu_dummy(dev))
- return 1;
-
- found = identity_mapping(dev);
- if (found) {
- /*
- * If the device's dma_mask is less than the system's memory
- * size then this is not a candidate for identity mapping.
- */
- u64 dma_mask = *dev->dma_mask;
-
- if (dev->coherent_dma_mask &&
- dev->coherent_dma_mask < dma_mask)
- dma_mask = dev->coherent_dma_mask;
-
- if (dma_mask < dma_get_required_mask(dev)) {
- /*
- * 32 bit DMA is removed from si_domain and fall back
- * to non-identity mapping.
- */
- dmar_remove_one_dev_info(dev);
- dev_warn(dev, "32bit DMA uses non-identity mapping\n");
-
- return 0;
- }
-
- return 1;
- }
-
- return 0;
-}
-
static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
size_t size, int dir, u64 dma_mask)
{
@@ -3320,9 +3272,6 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,

BUG_ON(dir == DMA_NONE);

- if (iommu_no_mapping(dev))
- return paddr;
-
domain = find_domain(dev);
if (!domain)
return DMA_MAPPING_ERROR;
@@ -3391,9 +3340,6 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
struct intel_iommu *iommu;
struct page *freelist;

- if (iommu_no_mapping(dev))
- return;
-
domain = find_domain(dev);
BUG_ON(!domain);

@@ -3442,9 +3388,7 @@ static void *intel_alloc_coherent(struct device *dev, size_t size,
size = PAGE_ALIGN(size);
order = get_order(size);

- if (!iommu_no_mapping(dev))
- flags &= ~(GFP_DMA | GFP_DMA32);
- else if (dev->coherent_dma_mask < dma_get_required_mask(dev)) {
+ if (dev->coherent_dma_mask < dma_get_required_mask(dev)) {
if (dev->coherent_dma_mask < DMA_BIT_MASK(32))
flags |= GFP_DMA;
else
@@ -3456,11 +3400,6 @@ static void *intel_alloc_coherent(struct device *dev, size_t size,

page = dma_alloc_from_contiguous(dev, count, order,
flags & __GFP_NOWARN);
- if (page && iommu_no_mapping(dev) &&
- page_to_phys(page) + size > dev->coherent_dma_mask) {
- dma_release_from_contiguous(dev, page, count);
- page = NULL;
- }
}

if (!page)
@@ -3510,20 +3449,6 @@ static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist,
intel_unmap(dev, startaddr, nrpages << VTD_PAGE_SHIFT);
}

-static int intel_nontranslate_map_sg(struct device *hddev,
- struct scatterlist *sglist, int nelems, int dir)
-{
- int i;
- struct scatterlist *sg;
-
- for_each_sg(sglist, sg, nelems, i) {
- BUG_ON(!sg_page(sg));
- sg->dma_address = sg_phys(sg);
- sg->dma_length = sg->length;
- }
- return nelems;
-}
-
static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nelems,
enum dma_data_direction dir, unsigned long attrs)
{
@@ -3538,8 +3463,6 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
struct intel_iommu *iommu;

BUG_ON(dir == DMA_NONE);
- if (iommu_no_mapping(dev))
- return intel_nontranslate_map_sg(dev, sglist, nelems, dir);

domain = find_domain(dev);
if (!domain)
@@ -4570,7 +4493,6 @@ int __init intel_iommu_init(void)
#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
swiotlb = 0;
#endif
- dma_ops = &intel_dma_ops;

init_iommu_pm_ops();

@@ -4949,6 +4871,7 @@ static int intel_iommu_add_device(struct device *dev)
{
struct intel_iommu *iommu;
struct iommu_group *group;
+ struct iommu_domain *domain;
u8 bus, devfn;

iommu = device_to_iommu(dev, &bus, &devfn);
@@ -4965,6 +4888,10 @@ static int intel_iommu_add_device(struct device *dev)
if (IS_ERR(group))
return PTR_ERR(group);

+ domain = iommu_get_domain_for_dev(dev);
+ if (domain->type == IOMMU_DOMAIN_DMA)
+ dev->dma_ops = &intel_dma_ops;
+
iommu_group_put(group);
return 0;
}
--
2.17.1