Re: [PATCH] Dom0 PCI: fix SR-IOV function dependency link problem

[Yu Zhao <yu.zhao@intel.com>]

Isaku Yamahata wrote:
> On Wed, Jun 03, 2009 at 01:41:34PM +0800, Yu Zhao wrote:
>> PCIe Root Complex Integrated Endpoint does not implement ARI, so this
>> kind of endpoint uses 3-bit function number. The function dependency
>> link of the integrated endpoint should be calculated using the device
>> number field in conjunction with the value from function dependency
>> link register.
>>
>> Normal SR-IOV endpoint always implements ARI and the function dependency
>> link register contains 8-bit function number (i.e. `devfn' from software
>> perspective).
>>
>> Signed-off-by: Yu Zhao <yu.zhao@intel.com>
> 
>> # HG changeset patch
>> # User Yu Zhao <yu.zhao@intel.com>
>> # Date 1244007161 -28800
>> # Node ID 3a959a6975152b741389d2eed1823d55be4f2889
>> # Parent  ec3442c2ed48eb11fcacd3fe31af48932f0a6645
>> PCI: fix SR-IOV function dependency link problem
>>
>> PCIe Root Complex Integrated Endpoint does not implement ARI, so this
>> kind of endpoint uses 3-bit function number. The function dependency
>> link of the integrated endpoint should be calculated using the device
>> number field in conjunction with the value from function dependency
>> link register.
>>
>> Normal SR-IOV endpoint always implements ARI and the function dependency
>> link register contains 8-bit function number (i.e. `devfn' from software
>> perspective).
>>
>> Signed-off-by: Yu Zhao <yu.zhao@intel.com>
>>
>> diff -r ec3442c2ed48 -r 3a959a697515 drivers/pci/iov.c
>> --- a/drivers/pci/iov.c	Wed Jun 03 13:30:08 2009 +0800
>> +++ b/drivers/pci/iov.c	Wed Jun 03 13:32:41 2009 +0800
>> @@ -366,6 +366,8 @@
>>  	iov->self = dev;
>>  	pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
>>  	pci_read_config_byte(dev, pos + PCI_SRIOV_FUNC_LINK, &iov->link);
>> +	if (!dev->bus->number)	/* Root Complex Integrated Endpoint */
>> +		iov->link = PCI_DEVFN(PCI_SLOT(dev->devfn), iov->link);
>>  
>>  	if (pdev)
>>  		iov->dev = pci_dev_get(pdev);
> 
> Possibly the above check may work.
> But pci capability list should be examined.
> something like
>   rpcap = pci_find_capability(pdev, PCI_CAP_ID_EXP);
>   if (!rpcap)
> 	  pci_read_config_word(pdev, rpcap + PCI_CAP_FLAGS, &cap);
> 	  if (cap == PCI_EXP_TYPE_RC_END)

It will works well since the capability check is already done before 
doing anything else:

int pci_iov_init(struct pci_dev *dev)
{
         int pos;

         pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
         if (pos)
                 return sriov_init(dev, pos);

         return -ENODEV;
}

Thanks,
Yu