On Thu, Feb 06, 2020 at 03:23:03PM +1100, Alexey Kardashevskiy wrote:
>
>
> 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 <sbobr...@linux.ibm.com>
> > ---
> > 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 <a...@ozlabs.ru>
>
Thanks,
I'll change it if there's some reason to do another version but
otherwise leave it as is.
Sam.
>
>
>
> > + 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
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