The code seems to stuff these pfns into iommu pts (or something like
that, I didn't follow), but there's no mmu_notifier to ensure that
access is synchronized with pte updates.
Hence mark these as unsafe. This means that with
CONFIG_STRICT_FOLLOW_PFN, these will be rejected.
Real fix is to wire up an mmu_notifier ... somehow. Probably means any
invalidate is a fatal fault for this vfio device, but then this
shouldn't ever happen if userspace is reasonable.
Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
Cc: Jason Gunthorpe <j...@ziepe.ca>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: John Hubbard <jhubb...@nvidia.com>
Cc: Jérôme Glisse <jgli...@redhat.com>
Cc: Jan Kara <j...@suse.cz>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: linux...@kvack.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-samsung-...@vger.kernel.org
Cc: linux-me...@vger.kernel.org
Cc: Alex Williamson <alex.william...@redhat.com>
Cc: Cornelia Huck <coh...@redhat.com>
Cc: k...@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch>
---
drivers/vfio/vfio_iommu_type1.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index bb2684cc245e..eccfee900033 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -421,7 +421,7 @@ static int follow_fault_pfn(struct vm_area_struct *vma,
struct mm_struct *mm,
{
int ret;
- ret = follow_pfn(vma, vaddr, pfn);
+ ret = unsafe_follow_pfn(vma, vaddr, pfn);
if (ret) {
bool unlocked = false;
@@ -435,7 +435,7 @@ static int follow_fault_pfn(struct vm_area_struct *vma,
struct mm_struct *mm,
if (ret)
return ret;
- ret = follow_pfn(vma, vaddr, pfn);
+ ret = unsafe_follow_pfn(vma, vaddr, pfn);
}
return ret;
--
2.28.0
