On Thu, 13 Aug 2026 15:06:14 +0530 <[email protected]> wrote: > From: Manish Honap <[email protected]> > > The guest drives a single virtual decoder whose memory maps 1:1, so a > device with more than one HDM decoder, or an interleaved one, cannot be > represented. Turn that assumption into an explicit refusal at bind rather > than a silent misprogramming later. > > Signed-off-by: Manish Honap <[email protected]> > --- > drivers/vfio/pci/cxl/vfio_cxl_core.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/vfio/pci/cxl/vfio_cxl_core.c > b/drivers/vfio/pci/cxl/vfio_cxl_core.c > index 125e11354a46..7edc53b25576 100644 > --- a/drivers/vfio/pci/cxl/vfio_cxl_core.c > +++ b/drivers/vfio/pci/cxl/vfio_cxl_core.c > @@ -36,10 +36,30 @@ static int vfio_cxl_init_device(struct > vfio_pci_core_device *vdev) > if (!pdev->hdm) > return -EPROBE_DEFER; > > + /* The guest drives one virtual decoder; multiple are unsupported. */ > + if (pdev->hdm->decoder_count != 1) > + return -EOPNOTSUPP; > + > hdm_size = range_len(&pdev->hdm->settings[0].hpa_range); > if (!hdm_size) > return -ENXIO; > > + /* Interleaved decoders are unsupported. */ > + if (pdev->hdm->settings[0].interleave_ways != 1) > + return -EOPNOTSUPP; > + > + /* > + * The guest drives resets through the CXL Device DVSEC and polls the > + * shadow for completion. If the host cannot service a function-scoped > + * CXL reset (no reset DVSEC, a multifunction device, or no HDM reset > + * support), that guest request could never complete, so refuse the > + * device rather than advertise a reset the guest would poll on forever. > + */ > + if (!cxl_reset_capable(pdev)) { > + pci_err(pdev, "vfio-cxl: Unsupported device: host cannot > service a CXL reset request\n"); > + return -EOPNOTSUPP; > + }
Why does this particular error deserve such a high priority log while we silently fail the other two cases added here? These don't seem particularly noteworthy to split into a separate patch versus rolling them into the previous. I'd probably also group the easily testable EOPNOTSUPP errors before we actually start evaluating things like the hdm_size. Thanks, Alex > + > dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL, > PCI_DVSEC_CXL_DEVICE); > serial = pci_get_dsn(pdev);
