Re: [Xen-devel] [PATCH v10] VT-d: use correct BDF for VF to search VT-d unit

[Chao Gao <chao.gao@xxxxxxxxx>]

On Mon, Aug 28, 2017 at 02:16:18AM -0600, Jan Beulich wrote:
>>>> On 28.08.17 at 04:42, <chao.gao@xxxxxxxxx> wrote:
>> When SR-IOV is enabled, 'Virtual Functions' of a 'Physical Function'
>> are under the scope of the same VT-d unit as the 'Physical Function'.
>> A 'Physical Function' can be a 'Traditional Function' or an ARI
>> 'Extended Function'. And furthermore, 'Extended Functions' on an
>> endpoint are under the scope of the same VT-d unit as the 'Traditional
>> Functions' on the endpoint. To search VT-d unit for a VF, if its PF
>> isn't an extended function, the BDF of PF should be used. Otherwise
>> the BDF of a traditional function in the same device with the PF
>> should be used.
>> 
>> Current code uses PCI_SLOT() to recognize an ARI 'Extended Funcion'.
>> But it is conceptually wrong w/o checking whether PF is an extended
>> function and would lead to match VFs of a RC integrated PF to a wrong
>> VT-d unit.
>> 
>> This patch overrides VF 'is_extfn' field and uses this field to
>> indicate whether the PF of this VF is an extended function. The field
>> helps to use correct BDF to search VT-d unit.
>> 
>> Reported-by: Crawford, Eric R <Eric.R.Crawford@xxxxxxxxx>
>> Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
>
>Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
>albeit ...
>
>> --- a/xen/drivers/passthrough/vtd/dmar.c
>> +++ b/xen/drivers/passthrough/vtd/dmar.c
>> @@ -211,15 +211,15 @@ struct acpi_drhd_unit 
>> *acpi_find_matched_drhd_unit(const struct pci_dev *pdev)
>>      if ( pdev == NULL )
>>          return NULL;
>>  
>> -    if ( pdev->info.is_extfn )
>> +    if ( pdev->info.is_virtfn )
>>      {
>> -        bus = pdev->bus;
>> -        devfn = 0;
>> +        bus = pdev->info.physfn.bus;
>> +        devfn = (!pdev->info.is_extfn) ? pdev->info.physfn.devfn : 0;
>
>... if I end up committing this and if I don't forget, I'll likely take the
>liberty to remove the pointless parentheses here.
>

Hi, Eric.

Could you test this patch again and give your Tested-by if it fixes the
problem you reported?

Thanks
Chao

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