On Fri, 29 Jan 2021, Ben Widawsky wrote: > +static int cxl_mem_setup_mailbox(struct cxl_mem *cxlm) > +{ > + const int cap = cxl_read_mbox_reg32(cxlm, CXLDEV_MB_CAPS_OFFSET); > + > + cxlm->mbox.payload_size = > + 1 << CXL_GET_FIELD(cap, CXLDEV_MB_CAP_PAYLOAD_SIZE); > + > + /* 8.2.8.4.3 */ > + if (cxlm->mbox.payload_size < 256) { > + dev_err(&cxlm->pdev->dev, "Mailbox is too small (%zub)", > + cxlm->mbox.payload_size); > + return -ENXIO; > + } Any reason not to check cxlm->mbox.payload_size > (1 << 20) as well and return ENXIO if true?