On 06/02/2020 14:17, Sam Bobroff wrote:
> Older versions of skiboot only provide a single value in the device
> tree property "ibm,mmio-atsd", even when multiple Address Translation
> Shoot Down (ATSD) registers are present. This prevents NVLink2 devices
> (other than the first) from being used with vfio-pci because vfio-pci
> expects to be able to assign a dedicated ATSD register to each NVLink2
> device.
>
> However, ATSD registers can be shared among devices. This change
> allows vfio-pci to fall back to sharing the register at index 0 if
> necessary.
>
> Signed-off-by: Sam Bobroff <sbobroff@xxxxxxxxxxxxx>
> ---
> drivers/vfio/pci/vfio_pci_nvlink2.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_nvlink2.c b/drivers/vfio/pci/vfio_pci_nvlink2.c
> index f2983f0f84be..851ba673882b 100644
> --- a/drivers/vfio/pci/vfio_pci_nvlink2.c
> +++ b/drivers/vfio/pci/vfio_pci_nvlink2.c
> @@ -420,8 +420,17 @@ int vfio_pci_ibm_npu2_init(struct vfio_pci_device *vdev)
>
> if (of_property_read_u64_index(hose->dn, "ibm,mmio-atsd", nvlink_index,
> &mmio_atsd)) {
> - dev_warn(&vdev->pdev->dev, "No available ATSD found\n");
> - mmio_atsd = 0;
> + dev_warn(&vdev->pdev->dev,
> + "No ibm,mmio-atsd[%d] found: trying ibm,mmio-atsd[0]\n",
> + nvlink_index);
We do not really need this warning (nvlink_index doesn't matter that
much, we can work out from the device tree what happened), warnings
below are enough (if you really want, you can print nvlink_index there).
Either way,
Reviewed-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
> + if (of_property_read_u64_index(hose->dn, "ibm,mmio-atsd", 0,
> + &mmio_atsd)) {
> + dev_warn(&vdev->pdev->dev, "No available ATSD found\n");
> + mmio_atsd = 0;
> + } else {
> + dev_warn(&vdev->pdev->dev,
> + "Using fallback ibm,mmio-atsd[0] for ATSD.\n");
> + }
> }
>
> if (of_property_read_u64(npu_node, "ibm,device-tgt-addr", &tgt)) {
>
--
Alexey
