On Tue, 2 Jul 2024 16:04:17 +1000 Alistair Francis <alistair23@xxxxxxxxx> wrote: > The PCIe 6 specification added support for the Data Object > Exchange (DOE). > When DOE is supported the DOE Discovery Feature must be implemented per > PCIe r6.1 sec 6.30.1.1. The protocol allows a requester to obtain > information about the other DOE features supported by the device. > > The kernel is already querying the DOE features supported and cacheing > the values. Expose the values in sysfs to allow user space to > determine which DOE features are supported by the PCIe device. > > By exposing the information to userspace tools like lspci can relay the > information to users. By listing all of the supported features we can > allow userspace to parse the list, which might include > vendor specific features as well as yet to be supported features. > > After this patch is supported you can see something like this when > attaching a DOE device > > $ ls /sys/devices/pci0000:00/0000:00:02.0//doe* > 0001:00 0001:01 0001:02 > > Signed-off-by: Alistair Francis <alistair.francis@xxxxxxx> > --- > v13: > - Drop pci_doe_sysfs_init() and use pci_doe_sysfs_group > - As discussed in https://lore.kernel.org/all/20231019165829.GA1381099@bhelgaas/ > we can just modify pci_doe_sysfs_group at the DOE init and let Can't do that as it is global so you expose the same DOE features for all DOEs. Also, I think that this is only processing features on last doe_mb found for a given device. Fix that and the duplicates problem resurfaces. > device_add() handle the sysfs attributes. > diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c > index defc4be81bd4..e7b702afce88 100644 > --- a/drivers/pci/doe.c > +++ b/drivers/pci/doe.c > + > static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout) > { > if (wait_event_timeout(doe_mb->wq, > @@ -687,6 +747,12 @@ void pci_doe_init(struct pci_dev *pdev) > { > struct pci_doe_mb *doe_mb; > u16 offset = 0; > + struct attribute **sysfs_attrs; > + struct device_attribute *attrs; > + unsigned long num_features = 0; > + unsigned long i; > + unsigned long vid, type; > + void *entry; > int rc; > > xa_init(&pdev->doe_mbs); > @@ -707,6 +773,45 @@ void pci_doe_init(struct pci_dev *pdev) > pci_doe_destroy_mb(doe_mb); > } > } The above is looping over multiple DOEs but this just considers last one. That doesn't look right... I think this needs to be in the loop and having done that the duplicate handing may be an issue. I'm not sure what happens in that path with a presupplied set of attributes. > + > + if (doe_mb) { > + xa_for_each(&doe_mb->feats, i, entry) > + num_features++; > + > + sysfs_attrs = kcalloc(num_features + 1, sizeof(*sysfs_attrs), GFP_KERNEL); > + if (!sysfs_attrs) > + return; > + > + attrs = kcalloc(num_features, sizeof(*attrs), GFP_KERNEL); > + if (!attrs) { > + kfree(sysfs_attrs); > + return; > + } > + > + doe_mb->device_attrs = attrs; > + doe_mb->sysfs_attrs = sysfs_attrs; > + > + xa_for_each(&doe_mb->feats, i, entry) { > + sysfs_attr_init(&attrs[i].attr); > + > + vid = xa_to_value(entry) >> 8; > + type = xa_to_value(entry) & 0xFF; > + > + attrs[i].attr.name = kasprintf(GFP_KERNEL, "%04lx:%02lx", vid, type); > + if (!attrs[i].attr.name) { > + pci_doe_sysfs_feature_remove(pdev, doe_mb); > + return; > + } > + attrs[i].attr.mode = 0444; > + attrs[i].show = pci_doe_sysfs_feature_show; > + > + sysfs_attrs[i] = &attrs[i].attr; > + } > + > + sysfs_attrs[num_features] = NULL; > + > + pci_doe_sysfs_group.attrs = sysfs_attrs; Hmm. Isn't this global? What if you have multiple devices. > + } > } >
