[PATCH v4 3/3] iommu/vt-d: Apply per-device dma_ops

From: Lu Baolu
Date: Tue May 05 2020 - 22:03:28 EST


Current Intel IOMMU driver sets the system level dma_ops. This causes
each dma API to go through the IOMMU driver even the devices are using
identity mapped domains. This sets per-device dma_ops only if a device
is using a DMA domain. Otherwise, use the default system level dma_ops
for direct dma.

Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 82 ++++++++++++-------------------------
1 file changed, 26 insertions(+), 56 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index af309e8fa6f5..29d3940847d3 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2720,17 +2720,6 @@ 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)
- return (info->domain == si_domain);
-
- return 0;
-}
-
static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
{
struct dmar_domain *ndomain;
@@ -3315,18 +3304,6 @@ 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 bool iommu_need_mapping(struct device *dev)
-{
- if (iommu_dummy(dev))
- return false;
-
- if (unlikely(attach_deferred(dev)))
- do_deferred_attach(dev);
-
- return !identity_mapping(dev);
-}
-
static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
size_t size, int dir, u64 dma_mask)
{
@@ -3340,6 +3317,9 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,

BUG_ON(dir == DMA_NONE);

+ if (unlikely(attach_deferred(dev)))
+ do_deferred_attach(dev);
+
domain = find_domain(dev);
if (!domain)
return DMA_MAPPING_ERROR;
@@ -3391,20 +3371,15 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page,
enum dma_data_direction dir,
unsigned long attrs)
{
- if (iommu_need_mapping(dev))
- return __intel_map_single(dev, page_to_phys(page) + offset,
- size, dir, *dev->dma_mask);
- return dma_direct_map_page(dev, page, offset, size, dir, attrs);
+ return __intel_map_single(dev, page_to_phys(page) + offset,
+ size, dir, *dev->dma_mask);
}

static dma_addr_t intel_map_resource(struct device *dev, phys_addr_t phys_addr,
size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
- if (iommu_need_mapping(dev))
- return __intel_map_single(dev, phys_addr, size, dir,
- *dev->dma_mask);
- return dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
+ return __intel_map_single(dev, phys_addr, size, dir, *dev->dma_mask);
}

static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
@@ -3455,17 +3430,13 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
- if (iommu_need_mapping(dev))
- intel_unmap(dev, dev_addr, size);
- else
- dma_direct_unmap_page(dev, dev_addr, size, dir, attrs);
+ intel_unmap(dev, dev_addr, size);
}

static void intel_unmap_resource(struct device *dev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
- if (iommu_need_mapping(dev))
- intel_unmap(dev, dev_addr, size);
+ intel_unmap(dev, dev_addr, size);
}

static void *intel_alloc_coherent(struct device *dev, size_t size,
@@ -3475,8 +3446,8 @@ static void *intel_alloc_coherent(struct device *dev, size_t size,
struct page *page = NULL;
int order;

- if (!iommu_need_mapping(dev))
- return dma_direct_alloc(dev, size, dma_handle, flags, attrs);
+ if (unlikely(attach_deferred(dev)))
+ do_deferred_attach(dev);

size = PAGE_ALIGN(size);
order = get_order(size);
@@ -3511,9 +3482,6 @@ static void intel_free_coherent(struct device *dev, size_t size, void *vaddr,
int order;
struct page *page = virt_to_page(vaddr);

- if (!iommu_need_mapping(dev))
- return dma_direct_free(dev, size, vaddr, dma_handle, attrs);
-
size = PAGE_ALIGN(size);
order = get_order(size);

@@ -3531,9 +3499,6 @@ static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist,
struct scatterlist *sg;
int i;

- if (!iommu_need_mapping(dev))
- return dma_direct_unmap_sg(dev, sglist, nelems, dir, attrs);
-
for_each_sg(sglist, sg, nelems, i) {
nrpages += aligned_nrpages(sg_dma_address(sg), sg_dma_len(sg));
}
@@ -3557,8 +3522,9 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
struct intel_iommu *iommu;

BUG_ON(dir == DMA_NONE);
- if (!iommu_need_mapping(dev))
- return dma_direct_map_sg(dev, sglist, nelems, dir, attrs);
+
+ if (unlikely(attach_deferred(dev)))
+ do_deferred_attach(dev);

domain = find_domain(dev);
if (!domain)
@@ -3605,8 +3571,6 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele

static u64 intel_get_required_mask(struct device *dev)
{
- if (!iommu_need_mapping(dev))
- return dma_direct_get_required_mask(dev);
return DMA_BIT_MASK(32);
}

@@ -4888,8 +4852,6 @@ int __init intel_iommu_init(void)
}
up_write(&dmar_global_lock);

- dma_ops = &intel_dma_ops;
-
init_iommu_pm_ops();

down_read(&dmar_global_lock);
@@ -5479,11 +5441,6 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
if (translation_pre_enabled(iommu))
dev->archdata.iommu = DEFER_DEVICE_DOMAIN_INFO;

- if (device_needs_bounce(dev)) {
- dev_info(dev, "Use Intel IOMMU bounce page dma_ops\n");
- set_dma_ops(dev, &bounce_dma_ops);
- }
-
return &iommu->iommu;
}

@@ -5498,7 +5455,19 @@ static void intel_iommu_release_device(struct device *dev)

dmar_remove_one_dev_info(dev);

+ set_dma_ops(dev, NULL);
+}
+
+static void intel_iommu_probe_finalize(struct device *dev)
+{
+ struct iommu_domain *domain;
+
+ domain = iommu_get_domain_for_dev(dev);
if (device_needs_bounce(dev))
+ set_dma_ops(dev, &bounce_dma_ops);
+ else if (domain && domain->type == IOMMU_DOMAIN_DMA)
+ set_dma_ops(dev, &intel_dma_ops);
+ else
set_dma_ops(dev, NULL);
}

@@ -5830,6 +5799,7 @@ const struct iommu_ops intel_iommu_ops = {
.unmap = intel_iommu_unmap,
.iova_to_phys = intel_iommu_iova_to_phys,
.probe_device = intel_iommu_probe_device,
+ .probe_finalize = intel_iommu_probe_finalize,
.release_device = intel_iommu_release_device,
.get_resv_regions = intel_iommu_get_resv_regions,
.put_resv_regions = generic_iommu_put_resv_regions,
--
2.17.1