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path: root/drivers/vfio/vfio_iommu_type1.c
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Diffstat (limited to 'drivers/vfio/vfio_iommu_type1.c')
-rw-r--r--drivers/vfio/vfio_iommu_type1.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 57d8c37a002b..59d47cb638d5 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -403,13 +403,26 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
{
struct vfio_domain *domain;
- unsigned long bitmap = PAGE_MASK;
+ unsigned long bitmap = ULONG_MAX;
mutex_lock(&iommu->lock);
list_for_each_entry(domain, &iommu->domain_list, next)
bitmap &= domain->domain->ops->pgsize_bitmap;
mutex_unlock(&iommu->lock);
+ /*
+ * In case the IOMMU supports page sizes smaller than PAGE_SIZE
+ * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
+ * That way the user will be able to map/unmap buffers whose size/
+ * start address is aligned with PAGE_SIZE. Pinning code uses that
+ * granularity while iommu driver can use the sub-PAGE_SIZE size
+ * to map the buffer.
+ */
+ if (bitmap & ~PAGE_MASK) {
+ bitmap &= PAGE_MASK;
+ bitmap |= PAGE_SIZE;
+ }
+
return bitmap;
}