Messages in this thread | | | Date | Fri, 19 Aug 2022 15:26:45 +0100 | From | Jean-Philippe Brucker <> | Subject | Re: [PATCH v2 8/9] iommu/of: Delete usage of driver_deferred_probe_check_state() |
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Hi Saravana,
On Wed, Jun 01, 2022 at 12:07:04AM -0700, Saravana Kannan via iommu wrote: > Now that fw_devlink=on and fw_devlink.strict=1 by default and fw_devlink > supports iommu DT properties, the execution will never get to the point > where driver_deferred_probe_check_state() is called before the supplier > has probed successfully or before deferred probe timeout has expired. > > So, delete the call and replace it with -ENODEV. > > Signed-off-by: Saravana Kannan <saravanak@google.com> > --- > drivers/iommu/of_iommu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c > index 5696314ae69e..41f4eb005219 100644 > --- a/drivers/iommu/of_iommu.c > +++ b/drivers/iommu/of_iommu.c > @@ -40,7 +40,7 @@ static int of_iommu_xlate(struct device *dev, > * a proper probe-ordering dependency mechanism in future. > */ > if (!ops) > - return driver_deferred_probe_check_state(dev); > + return -ENODEV;
Unfortunately this breaks virtio-iommu on v6.0-rc1. Could you add it to your revert series [1]?
Eventually I'd really like to use fw_devlink in order to enable module support, so I'm looking for a proper fix. Our DT description is peculiar because the virtio-iommu, when it uses the virtio-pci transport, can appear on the same PCI bus than the endpoints it manages. So the PCI node looks like this:
pcie@10000000 { compatible = "pci-host-ecam-generic"; ... iommu-map = <0x00 &viommu 0x00 0x20> <0x21 &viommu 0x21 0xffdf>;
viommu: virtio_iommu@32 { #iommu-cells = <0x01>; reg = <0x2000 0x00 0x00 0x00 0x00>; compatible = "virtio,pci-iommu"; }; };
The iommu-map property points to the IOMMU sub-node for all endpoints except the IOMMU itself (device 0x20 - 00:04.0). fw_devlink currently rejects this:
[ 0.270150] OF: Not linking pcie@10000000 to virtio_iommu@32 - is descendant [ 0.270324] OF: Not linking pcie@10000000 to virtio_iommu@32 - is descendant
I don't know yet if this kind of topology could ever work with fw_devlink, but I thought I'd notify you before digging further.
Thanks, Jean
[1] https://lore.kernel.org/all/20220727185012.3255200-1-saravanak@google.com/#t
> > if (!try_module_get(ops->owner)) > return -ENODEV; > -- > 2.36.1.255.ge46751e96f-goog > > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu
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