[PATCH V5 3/5] iommu/dma-iommu: Handle deferred devices

Tom Murphy
2019-08-15T11:10:42Z

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

Signed-off-by: Tom Murphy <murphyt7@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 2712fbc68b28..906b7fa14d3c 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.
@@ -463,6 +479,9 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
size_t iova_off = iova_offset(iovad, phys);
dma_addr_t iova;

+ if (unlikely(handle_deferred_device(dev, domain)))
+ return DMA_MAPPING_ERROR;
+
size = iova_align(iovad, size + iova_off);

iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
@@ -581,6 +600,9 @@ 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;
@@ -713,7 +735,7 @@ 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);
@@ -823,6 +845,9 @@ 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