[PATCH] vfio/type1: check pfn valid before converting to struct page

[Yan Zhao]

vfio_pin_page_external() can return a phys_pfn for vma with VM_PFNMAP,
e.g. for MMIO PFNs.

It's necessary to check if it's a valid pfn before calling pfn_to_page().

Fixes: 34a255e67615 ("vfio: Replace phys_pfn with pages for vfio_pin_pages()")
Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
---
 drivers/vfio/vfio_iommu_type1.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 493c31de0edb..0620dbe5cca0 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -860,6 +860,11 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
 		if (ret)
 			goto pin_unwind;
 
+		if (!pfn_valid(phys_pfn)) {
+			ret = -EINVAL;
+			goto pin_unwind;
+		}
+
 		ret = vfio_add_to_pfn_list(dma, iova, phys_pfn);
 		if (ret) {
 			if (put_pfn(phys_pfn, dma->prot) && do_accounting)

base-commit: b3c98052d46948a8d65d2778c7f306ff38366aac
-- 
2.17.1