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.vetter@intel.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Kees Cook keescook@chromium.org Cc: Dan Williams dan.j.williams@intel.com Cc: Andrew Morton akpm@linux-foundation.org Cc: John Hubbard jhubbard@nvidia.com Cc: Jérôme Glisse jglisse@redhat.com Cc: Jan Kara jack@suse.cz Cc: Dan Williams dan.j.williams@intel.com Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Alex Williamson alex.williamson@redhat.com Cc: Cornelia Huck cohuck@redhat.com Cc: kvm@vger.kernel.org Signed-off-by: Daniel Vetter daniel.vetter@ffwll.com --- 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 5fbf0c1f7433..a4d53f3d0a35 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;