Re: [Xen-devel] [PATCH] xen: add support for MSI message groups

["Roger Pau Monné" <roger.pau@citrix.com>]

On 27/02/14 17:33, Boris Ostrovsky wrote:
> On 02/27/2014 10:45 AM, Roger Pau Monné wrote:
>>>
>>> @@ -291,7 +290,10 @@ static int xen_initdom_setup_msi_irqs(struct
>>> pci_dev *dev, int nvec, int type)
>>>                      (pci_domain_nr(dev->bus) << 16);
>>>            map_irq.devfn = dev->devfn;
>>>    -        if (type == PCI_CAP_ID_MSIX) {
>>> +        if (type == PCI_CAP_ID_MSI && nvec > 1) {
>>> +            map_irq.type = MAP_PIRQ_TYPE_MULTI_MSI;
>>> +            map_irq.entry_nr = nvec;
>>>
>>> Are we overloading entry_nr here with a different meaning? I thought it
>>> was meant to be entry number (in MSI-X table for example), not number of
>>> entries.
>> In the case of MSI message groups (MAP_PIRQ_TYPE_MULTI_MSI) entry_nr is
>> the number of vectors to setup, so yes, it's an overloading of entry_nr.
> 
> Then I think we should at least make a note of this in physdev.h. (Or
> maybe even make entry_nr a union with nvec or some such, although that
> would look rather hacky).

OK, I can add a comment to that effect in physdev.h.

> 
>> ....
>>
>>>
>>> index 42721d1..eb13326d 100644
>>> --- a/include/xen/interface/physdev.h
>>> +++ b/include/xen/interface/physdev.h
>>> @@ -131,6 +131,7 @@ struct physdev_irq {
>>>    #define MAP_PIRQ_TYPE_GSI        0x1
>>>    #define MAP_PIRQ_TYPE_UNKNOWN        0x2
>>>    #define MAP_PIRQ_TYPE_MSI_SEG        0x3
>>> +#define MAP_PIRQ_TYPE_MULTI_MSI        0x4
>>> Formatting.
>> I don't get the formatting problem, it's the same formatting that the
>> other MAP_PIRQ_TYPE_* use, and if the patch is applied formatting is OK.
>>
> 
> That's because my client messed up whitespaces. You can look for example
> at https://lkml.org/lkml/2014/2/26/352 to see the extra tab.

It looks like an extra tab because there's a "+" in front of the line,
which makes the tab jump. If you remove the extra "+" and the spaces in
front of the preceding lines it is going to be aligned.

Roger.