Re: [RESEND PATCH v5 5/5] hw/pci: ensure PCIE devices are plugged into only slot 0 of PCIE port

[Ani Sinha]

> On 27-Jun-2023, at 5:53 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> 
> On Tue, Jun 27, 2023 at 01:58:49PM +0200, Igor Mammedov wrote:
>> On Tue, 27 Jun 2023 15:23:04 +0530
>> Ani Sinha <anisinha@redhat.com> wrote:
>> 
>>>> On 27-Jun-2023, at 2:32 PM, Igor Mammedov <imammedo@redhat.com> wrote:
>>>> 
>>>> On Mon, 26 Jun 2023 21:42:44 +0530
>>>> Ani Sinha <anisinha@redhat.com> wrote:
>>>> 
>>>>> PCI Express ports only have one slot, so PCI Express devices can only be
>>>>> plugged into slot 0 on a PCIE port. Enforce it.  
>>>> 
>>>> btw, previously you mentioned ARI.
>>>> So if we turn it on, wouldn't this patch actually become regression?  
>>> 
>>> If ARI breaks this, it will break other areas in QEMU too, ex anywhere 
>>> pci_get_function_0() is used.
>>> Regardless, I think at least the tests are worth fixing, particularly the 
>>> mess with hd-geo-test.
>> 
>> I'm fine with this patch if you test it with ARI enabled and it won't break
>> something that has been working before this patch. Just mention what testing
>> you've done in commit message.
> 
> Oh yes. That's why it was checking !vf originally. It's because the most
> common use of ARI is SRIOV, so it works a a kind of hack.

Ok so should I put it back?
Also I was thinking of running the qtest and avocado test mentioned in 
https://www.qemu.org/docs/master/system/devices/igb.html . Not sure if it would 
be enough to test ARI.

> 
>>> 
>>>> 
>>>>> 
>>>>> CC: jusual@redhat.com
>>>>> CC: imammedo@redhat.com
>>>>> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929
>>>>> Signed-off-by: Ani Sinha <anisinha@redhat.com>
>>>>> Reviewed-by: Julia Suvorova <jusual@redhat.com>
>>>>> ---
>>>>> hw/pci/pci.c | 6 ++++++
>>>>> 1 file changed, 6 insertions(+)
>>>>> 
>>>>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>>>>> index bf38905b7d..426af133b0 100644
>>>>> --- a/hw/pci/pci.c
>>>>> +++ b/hw/pci/pci.c
>>>>> @@ -64,6 +64,7 @@ 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),
>>>>> @@ -1189,6 +1190,11 @@ static PCIDevice *do_pci_register_device(PCIDevice 
>>>>> *pci_dev,
>>>>>                   name);
>>>>> 
>>>>>       return NULL;
>>>>> +    } else if (pcie_has_upstream_port(pci_dev) && PCI_SLOT(devfn)) {
>>>>> +        error_setg(errp, "PCI: slot %d is not valid for %s,"
>>>>> +                   " parent device only allows plugging into slot 0.",
>>>>> +                   PCI_SLOT(devfn), name);
>>>>> +        return NULL;
>>>>>    }
>>>>> 
>>>>>    pci_dev->devfn = devfn;