[PATCH v4 3/5] iommu/dma-iommu: Handle deferred devices

[Tom Murphy]

Handle devices which defer their attach to the iommu in the dma-iommu api

Signed-off-by: Tom Murphy <murph...@tcd.ie>
---
 drivers/iommu/dma-iommu.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index e64dbbcde63c..f303bbe20e51 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -22,6 +22,7 @@
 #include <linux/pci.h>
 #include <linux/scatterlist.h>
 #include <linux/vmalloc.h>
+#include <linux/crash_dump.h>
 
 struct iommu_dma_msi_page {
        struct list_head        list;
@@ -351,6 +352,21 @@ static int iommu_dma_init_domain(struct iommu_domain 
*domain, dma_addr_t base,
        return iova_reserve_iommu_regions(dev, domain);
 }
 
+static int handle_deferred_device(struct device *dev,
+       struct iommu_domain *domain)
+{
+       const struct iommu_ops *ops = domain->ops;
+
+       if (!is_kdump_kernel())
+               return 0;
+
+       if (unlikely(ops->is_attach_deferred &&
+               ops->is_attach_deferred(domain, dev)))
+               return iommu_attach_device(domain, dev);
+
+       return 0;
+}
+
 /**
  * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
  *                    page flags.
@@ -462,6 +478,9 @@ static dma_addr_t __iommu_dma_map(struct device *dev, 
phys_addr_t phys,
        size_t iova_off = 0;
        dma_addr_t iova;
 
+       if (unlikely(handle_deferred_device(dev, domain)))
+               return DMA_MAPPING_ERROR;
+
        if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
                iova_off = iova_offset(&cookie->iovad, phys);
                size = iova_align(&cookie->iovad, size + iova_off);
@@ -583,6 +602,9 @@ static void *iommu_dma_alloc_remap(struct device *dev, 
size_t size,
 
        *dma_handle = DMA_MAPPING_ERROR;
 
+       if (unlikely(handle_deferred_device(dev, domain)))
+               return NULL;
+
        min_size = alloc_sizes & -alloc_sizes;
        if (min_size < PAGE_SIZE) {
                min_size = PAGE_SIZE;
@@ -715,7 +737,7 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, 
struct page *page,
        int prot = dma_info_to_prot(dir, coherent, attrs);
        dma_addr_t dma_handle;
 
-       dma_handle =__iommu_dma_map(dev, phys, size, prot);
+       dma_handle = __iommu_dma_map(dev, phys, size, prot);
        if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
            dma_handle != DMA_MAPPING_ERROR)
                arch_sync_dma_for_device(dev, phys, size, dir);
@@ -825,6 +847,9 @@ static int iommu_dma_map_sg(struct device *dev, struct 
scatterlist *sg,
        unsigned long mask = dma_get_seg_boundary(dev);
        int i;
 
+       if (unlikely(handle_deferred_device(dev, domain)))
+               return 0;
+
        if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
                iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
 
-- 
2.20.1

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