> On 04-Jul-2023, at 5:32 PM, Akihiko Odaki <akihiko.od...@daynix.com> wrote:
>
> On 2023/07/04 20:59, Ani Sinha wrote:
>>> On 04-Jul-2023, at 5:24 PM, Akihiko Odaki <akihiko.od...@daynix.com> wrote:
>>>
>>> On 2023/07/04 20:25, Ani Sinha wrote:
>>>> PCI Express ports only have one slot, so PCI Express devices can only be
>>>> plugged into slot 0 on a PCIE port. Add a warning to let users know when
>>>> the
>>>> invalid configuration is used. We may enforce this more strongly later on
>>>> once
>>>> we get more clarity on whether we are introducing a bad regression for
>>>> users
>>>> currenly using the wrong configuration.
>>>> The change has been tested to not break or alter behaviors of ARI capable
>>>> devices by instantiating seven vfs on an emulated igb device (the maximum
>>>> number of vfs the linux igb driver supports). The vfs instantiated
>>>> correctly
>>>> and are seen to have non-zero device/slot numbers in the conventional PCI
>>>> BDF
>>>> representation.
>>>> CC: jus...@redhat.com
>>>> CC: imamm...@redhat.com
>>>> CC: m...@redhat.com
>>>> CC: akihiko.od...@daynix.com
>>>> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929
>>>> Signed-off-by: Ani Sinha <anisi...@redhat.com>
>>>> Reviewed-by: Julia Suvorova <jus...@redhat.com>
>>>> ---
>>>> hw/pci/pci.c | 15 +++++++++++++++
>>>> 1 file changed, 15 insertions(+)
>>>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>>>> index e2eb4c3b4a..47517ba3db 100644
>>>> --- a/hw/pci/pci.c
>>>> +++ b/hw/pci/pci.c
>>>> @@ -65,6 +65,7 @@ bool pci_available = true;
>>>> static char *pcibus_get_dev_path(DeviceState *dev);
>>>> static char *pcibus_get_fw_dev_path(DeviceState *dev);
>>>> static void pcibus_reset(BusState *qbus);
>>>> +static bool pcie_has_upstream_port(PCIDevice *dev);
>>>> static Property pci_props[] = {
>>>> DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
>>>> @@ -2121,6 +2122,20 @@ static void pci_qdev_realize(DeviceState *qdev,
>>>> Error **errp)
>>>> }
>>>> }
>>>> + /*
>>>> + * With SRIOV and ARI, vfs can have non-zero slot in the conventional
>>>> + * PCI interpretation as all five bits reserved for slot addresses are
>>>> + * also used for function bits for the various vfs. Ignore that case.
>>>
>>> You don't have to mention SR/IOV; it affects all ARI-capable devices. A PF
>>> can also have non-zero slot number in the conventional interpretation so
>>> you shouldn't call it vf either.
>> Can you please help write a comment that explains this properly for all
>> cases - ARI/non-ARI, PFs and VFs? Once everyone agrees that its clear and
>> correct, I will re-spin.
>
> Simply, you can say:
> With ARI, the slot number field in the conventional PCI interpretation can
> have a non-zero value as the field bits are reused to extend the function
> number bits. Ignore that case.
but we are not checking for ARI capability here in the code. So the comment is
confusing.
>
>>>
>>>> + */
>>>> + if (pci_is_express(pci_dev) &&
>>>> + !pcie_find_capability(pci_dev, PCI_EXT_CAP_ID_ARI) &&
>>>> + pcie_has_upstream_port(pci_dev) &&
>>>> + PCI_SLOT(pci_dev->devfn)) {
>>>> + warn_report("PCI: slot %d is not valid for %s,"
>>>> + " parent device only allows plugging into slot 0.",
>>>> + PCI_SLOT(pci_dev->devfn), pci_dev->name);
>>>> + }
>>>> +
>>>> if (pci_dev->failover_pair_id) {
>>>> if (!pci_bus_is_express(pci_get_bus(pci_dev))) {
>>>> error_setg(errp, "failover primary device must be on "
