Re: PCI Pass-through in Xen ARM - Draft 2.

[Julien Grall <julien.grall@citrix.com>]

On 06/07/15 12:09, Manish Jaggi wrote:
> 
> 
> On Monday 06 July 2015 04:13 PM, Julien Grall wrote:
>> On 05/07/15 06:55, Manish Jaggi wrote:
>>>>> 4.3 Hypercall for bdf mapping notification to xen
>>>>> -----------------------------------------------
>>>>> #define PHYSDEVOP_map_sbdf              43
>>>>> typedef struct {
>>>>>       u32 s;
>>>>>       u8 b;
>>>>>       u8 df;
>>>>>       u16 res;
>>>>> } sbdf_t;
>>>>> struct physdev_map_sbdf {
>>>>>       int domain_id;
>>>>>       sbdf_t    sbdf;
>>>>>       sbdf_t    gsbdf;
>>>>> };
>>>>>
>>>>> Each domain has a pdev list, which contains the list of all pci
>>>>> devices.
>>>>> The
>>>>> pdev structure already has a sbdf information. The arch_pci_dev is
>>>>> updated to
>>>>> contain the gsbdf information. (gs- guest segment id)
>>>>>
>>>>> Whenever there is trap from guest or an interrupt has to be injected,
>>>>> the pdev
>>>>> list is iterated to find the gsbdf.
>>>> Can you give more background for this section? i.e:
>>>>      - Why do you need this?
>>>>      - How xen will translate the gbdf to a vDeviceID?
>>> In the context of the hypercall processing.
>> That wasn't my question. I asked, how Xen will find the mapping between
>> the gdbf and vDeviceID? He doesn't have access to the firmware table and
>> therefore not able to find the right one.
> I believe gsbdf and vDeviceID would be same.

Xen and the guest need to translate the gsbdf the same way. If this is
clearly defined by a spec, then you should give a link to it.

If not, you have to explain in this design doc how you plan to have xen
and the guest using the same vdevID for a given gsbdf.

Regards,

-- 
Julien Grall