Current vfio_pgsize_bitmap code hides the supported IOMMU page
sizes smaller than PAGE_SIZE. As a result, in case the IOMMU
does not support PAGE_SIZE page, the alignment check on map/unmap
is done with larger page sizes, if any. This can fail although
mapping could be done with pages smaller than PAGE_SIZE.
vfio_pgsize_bitmap is modified to expose the IOMMU page sizes,
supported by all domains, even those smaller than PAGE_SIZE. The
alignment check on map is performed against PAGE_SIZE if the minimum
IOMMU size is less than PAGE_SIZE or against the min page size greater
than PAGE_SIZE.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
This was tested on AMD Seattle with 64kB page host. ARM MMU 401
currently expose 4kB, 2MB and 1GB page support. With a 64kB page host,
the map/unmap check is done against 2MB. Some alignment check fail
so VFIO_IOMMU_MAP_DMA fail while we could map using 4kB IOMMU page
size.
---
drivers/vfio/vfio_iommu_type1.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 57d8c37..13fb974 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -403,7 +403,7 @@ 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)
@@ -416,20 +416,18 @@ static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
struct vfio_iommu_type1_dma_unmap *unmap)
{
- uint64_t mask;
struct vfio_dma *dma;
size_t unmapped = 0;
int ret = 0;
+ unsigned int min_pagesz = __ffs(vfio_pgsize_bitmap(iommu));
+ unsigned int requested_alignment = (min_pagesz < PAGE_SIZE) ?
+ PAGE_SIZE : min_pagesz;
- mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
-
- if (unmap->iova & mask)
+ if (!IS_ALIGNED(unmap->iova, requested_alignment))
return -EINVAL;
- if (!unmap->size || unmap->size & mask)
+ if (!unmap->size || !IS_ALIGNED(unmap->size, requested_alignment))
return -EINVAL;
- WARN_ON(mask & PAGE_MASK);
-
mutex_lock(&iommu->lock);
/*
@@ -553,25 +551,24 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
size_t size = map->size;
long npage;
int ret = 0, prot = 0;
- uint64_t mask;
struct vfio_dma *dma;
unsigned long pfn;
+ unsigned int min_pagesz = __ffs(vfio_pgsize_bitmap(iommu));
+ unsigned int requested_alignment = (min_pagesz < PAGE_SIZE) ?
+ PAGE_SIZE : min_pagesz;
/* Verify that none of our __u64 fields overflow */
if (map->size != size || map->vaddr != vaddr || map->iova != iova)
return -EINVAL;
- mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
-
- WARN_ON(mask & PAGE_MASK);
-
/* READ/WRITE from device perspective */
if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
prot |= IOMMU_WRITE;
if (map->flags & VFIO_DMA_MAP_FLAG_READ)
prot |= IOMMU_READ;
- if (!prot || !size || (size | iova | vaddr) & mask)
+ if (!prot || !size ||
+ !IS_ALIGNED(size | iova | vaddr, requested_alignment))
return -EINVAL;
/* Don't allow IOVA or virtual address wrap */
--
1.9.1
--
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