From: Jason Wang jasowang@redhat.com
commit 3a3e0fad16d40a2aa68ddf7eea4acdf48b22dd44 upstream.
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 Link: https://lore.kernel.org/r/20210413091557.29008-1-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vhost/vdpa.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -993,6 +993,7 @@ static int vhost_vdpa_mmap(struct file * 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; }