__IOMMU_DOMAIN_LP (large pages) indicates that a domain can handle
conditions where PAGE_SIZE might be smaller than the IOMMU page size.
Always allow attaching devices to such domains and set the flag for
IOMMU_DOMAIN_DMA, which can now handle these situations.
Signed-off-by: Sven Peter <s...@svenpeter.dev>
---
drivers/iommu/iommu.c | 2 ++
include/linux/iommu.h | 8 ++++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index f02b727d3054..77d1ee14c7d0 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1980,6 +1980,8 @@ static int iommu_check_page_size(struct iommu_domain
*domain)
{
if (!(domain->type & __IOMMU_DOMAIN_PAGING))
return 0;
+ if (domain->type & __IOMMU_DOMAIN_LP)
+ return 0;
if ((1 << __ffs(domain->pgsize_bitmap)) > PAGE_SIZE) {
pr_warn("IOMMU page size cannot represent CPU pages.\n");
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 6633040a13f9..40c1ad6be4e7 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -62,6 +62,8 @@ struct iommu_domain_geometry {
implementation */
#define __IOMMU_DOMAIN_PT (1U << 2) /* Domain is identity mapped */
#define __IOMMU_DOMAIN_DMA_FQ (1U << 3) /* DMA-API uses flush queue */
+#define __IOMMU_DOMAIN_LP (1U << 4) /* Support for PAGE_SIZE smaller
+ than IOMMU page size */
/*
* This are the possible domain-types
@@ -81,10 +83,12 @@ struct iommu_domain_geometry {
#define IOMMU_DOMAIN_IDENTITY (__IOMMU_DOMAIN_PT)
#define IOMMU_DOMAIN_UNMANAGED (__IOMMU_DOMAIN_PAGING)
#define IOMMU_DOMAIN_DMA (__IOMMU_DOMAIN_PAGING | \
- __IOMMU_DOMAIN_DMA_API)
+ __IOMMU_DOMAIN_DMA_API | \
+ __IOMMU_DOMAIN_LP)
#define IOMMU_DOMAIN_DMA_FQ (__IOMMU_DOMAIN_PAGING | \
__IOMMU_DOMAIN_DMA_API | \
- __IOMMU_DOMAIN_DMA_FQ)
+ __IOMMU_DOMAIN_DMA_FQ | \
+ __IOMMU_DOMAIN_LP)
struct iommu_domain {
unsigned type;
--
2.25.1
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