Isaku,
We are on same page now; I also consider the qdev_find way. Both ways can
work and let's wait for others' opinions...
Wei
On 10/28/10 4:25 AM, "Isaku Yamahata" <yamah...@valinux.co.jp> wrote:
> On Thu, Oct 28, 2010 at 03:37:27AM -0700, Wei Xu wrote:
>> Isaku,
>>
>> To make things clear, let me rephrase the problem. With q35/vPCIe, in VMM
>> monitor, we can do hotplug like:
>> pci_add auto|<bus:dev> nic|storage
>> to hotplug a device to PCIe/PCI bus.
>>
>> But we have two problems here:
>> (1) command line for example, "-net nic,addr=<bus:dev>" always failed
>> because it cannot find the bus.
>> (2) If "pci_add auto" in monitor or no "addr=<bus:dev" in command line, the
>> device will be attached to PCI bus, in stead of PCIe ports
>>
>> I solved the first problem. The root cause is pcie_root_write_config (which
>> init SECONDARY_BUS config) happened after pci_nic_init. The latter use
>> pci_find_bus to find the parent bus but failed because config space for
>> secondary bus still not initialized.
>
> Okay, now the issue is clear to me.
> When I tried to clean up pci bridge code, I included the similar lines
> in bridge initialization function.
> But Michael complained about it, so I dropped the lines for merge.
>
> I think there are two ways to address it.
> - initialize secondary/subordinate bus register by qemu
> i.e. something like the patch below.
>
> - use qdev device path
> i.e. qbus_find() instead of pci_find_bus().
> I don't know if the corresponding command line option already exists or not.
>
> My preference is the former, but discussion is necessary to get consensus.
> My plan was to raise the issue when I address pv pci bus numbering issue.
> I've expected that other developers wouldn't think the issue important
> because multiple pci bus can't be used easily right now.
>
> thanks,
>
>>
>> The fix is like:
>>
>> [we...@wexu2-lnx contents]$ git diff hw/pci_bridge.c
>> diff --git a/hw/pci_bridge.c b/hw/pci_bridge.c
>> index c048305..042c1f9 100644
>> --- a/hw/pci_bridge.c
>> +++ b/hw/pci_bridge.c
>> @@ -203,6 +203,7 @@ void pci_bridge_set_bus_number(PCIBridge *br,
>> uint16_t domain;
>> uint8_t primary_bus;
>> uint8_t devfn;
>> + uint8_t *conf;
>>
>> if (!pci_bus_number) {
>> pci_bus_number = qemu_mallocz(sizeof(*pci_bus_number));
>> @@ -215,10 +216,15 @@ void pci_bridge_set_bus_number(PCIBridge *br,
>>
>> d = &br->dev;
>> devfn = d->devfn;
>> + conf = d->config;
>>
>> br->sec_bus = secondary;
>> br->sub_bus = subordinate;
>>
>> + //TODO wexu2 workaround of "-net nic,addr=<bus:dev>"
>> + pci_set_byte(conf + PCI_SECONDARY_BUS, secondary);
>> + pci_set_byte(conf + PCI_SUBORDINATE_BUS, subordinate);
>> +
>> bus = d->bus;
>> primary_bus = 0;
>> if ((d = pci_bridge_get_device(bus)) != NULL){
>>
>> The fix is a little bit hacky -- welcome any advice.
>>
>> For 2nd issue, current code assume PCI bus is flat and not straight forward
>> to change the behavior.
>>
>> Wei Xu
>>
>>
>> On 10/27/10 10:16 PM, "Isaku Yamahata" <yamah...@valinux.co.jp> wrote:
>>
>>> Oh, now I'm seeing your point. Some codes of qemu assume that
>>> the pci bus is flat. They need fixes.
>>>
>>> Right now I've found
>>> - parse_pci_devfn in qdev-properties.c
>>> This corresponds to (1)
>>> - pci_get_bus_devfn() in pci.c
>>> This corresponds to (2)
>>>
>>> thanks,
>>>
>>> On Wed, Oct 27, 2010 at 08:51:29PM -0700, Wei Xu wrote:
>>>> Isaku,
>>>>
>>>> I found two issues:
>>>> (1) command line option is not working: even with addr=<bus>, it complained
>>>> bus cannot be found;
>>>> (2) monitor: pci_add auto ... cannot work.
>>>>
>>>> Wei
>>>>
>>>>
>>>> On 10/27/10 8:03 PM, "Isaku Yamahata" <yamah...@valinux.co.jp> wrote:
>>>>
>>>>> On Wed, Oct 27, 2010 at 09:51:47AM -0700, Wei Xu wrote:
>>>>>> Isaku,
>>>>>>
>>>>>> I have one question regarding EP and PCIe bus: now only way is to use
>>>>>> "pci_add <bus:dev> .." to hot-plug the device to a PCIe port. Looks like
>>>>>> command line with -device parameter automatically use PCI bus? Is it
>>>>>> possible to support it? Have to provide the <bus:dev> in -device
>>>>>> parameter?
>>>>>
>>>>> I'm not sure I got your question right.
>>>>> We can populate the device under an express port with -device command line
>>>>> option. At least it should be possible.
>>>>>
>>>>> For implementation detail, qemu doesn't distinguish pci express
>>>>> from conventional pci so strictly.
>>>>> The only difference is whether the bridge(pci host bridge or
>>>>> pci-to-pci bridge) is just express port because I implemented express
>>>>> ports as pci-to-pci bridge.
>>>>>
>>>>> Or do you want to add express port with command line option?
>>>>> If so, not possible at the moment.
>>>>
>>
