Re: [Xen-devel] [PATCH 1/2] xen-pciback: return proper values during BAR sizing

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 06/06/2016 09:51 AM, Jan Beulich wrote:
>>>> On 06.06.16 at 15:03, <boris.ostrovsky@xxxxxxxxxx> wrote:
>> On 06/06/2016 04:11 AM, Jan Beulich wrote:
>>> @@ -225,38 +225,42 @@ static inline void read_dev_bar(struct p
>>>                        (PCI_BASE_ADDRESS_SPACE_MEMORY |
>>>                             PCI_BASE_ADDRESS_MEM_TYPE_64))) {
>>>                     bar_info->val = res[pos - 1].start >> 32;
>>> -                   bar_info->len_val = res[pos - 1].end >> 32;
>>> +                   bar_info->len_val = -resource_size(&res[pos - 1]) >> 32;
>>>                     return;
>>>             }
>>>     }
>>>  
>>> +   if (!res[pos].flags ||
>>> +       (res[pos].flags & (IORESOURCE_DISABLED | IORESOURCE_UNSET |
>>> +                          IORESOURCE_BUSY)))
>>> +           return;
>> Why are you not making this check first thing in the routine?
> For one, pos isn't set there yet. And I'd also rather avoid the
> complications resulting from 64-bit memory resources spanning
> two entries.

I thought that both words of a 64-bit BAR would result in a return under
this check so both would be zero. But yes, pos needs to be initialized
anyway (I didn't see this in the diff).

Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>


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