The virtqueue doorbell is usually implemented via registeres but we don't provide the necessary vma->flags like VM_PFNMAP. This may cause several issues e.g when userspace tries to map the doorbell via vhost IOTLB, kernel may panic due to the page is not backed by page structure. This patch fixes this by setting the necessary vm_flags. With this patch, try to map doorbell via IOTLB will fail with bad address.
Cc: stable@vger.kernel.org Fixes: ddd89d0a059d ("vhost_vdpa: support doorbell mapping via mmap") Signed-off-by: Jason Wang jasowang@redhat.com --- drivers/vhost/vdpa.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index e0a27e336293..865eab69cb71 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -989,6 +989,7 @@ static int vhost_vdpa_mmap(struct file *file, struct vm_area_struct *vma) if (vma->vm_end - vma->vm_start != notify.size) return -ENOTSUPP;
+ vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_ops = &vhost_vdpa_vm_ops; return 0; }