Re: [PATCH v2 2/2] xen/pci: replace call to is_memory_hole to pci_check_bar

[Rahul Singh <Rahul.Singh@xxxxxxx>]

Hello Jan,

> On 17 Aug 2022, at 4:18 pm, Jan Beulich <jbeulich@xxxxxxxx> wrote:
> 
> On 17.08.2022 16:45, Rahul Singh wrote:
>> @@ -363,6 +373,42 @@ int __init pci_host_bridge_mappings(struct domain *d)
>>     return 0;
>> }
>> 
>> +static int is_bar_valid(const struct dt_device_node *dev,
>> +                        u64 addr, u64 len, void *data)
> 
> s/u64/uint64_t/g please.

Ack. 
> 
>> +{
>> +    struct pdev_bar *bar_data = data;
>> +    unsigned long s = mfn_x(bar_data->start);
>> +    unsigned long e = mfn_x(bar_data->end);
>> +
>> +    if ( (s < e) && (s >= PFN_UP(addr)) && (e <= PFN_UP(addr + len - 1)) )
> 
> Doesn't this need to be s >= PFN_DOWN(addr)? Or else why is e checked
> against PFN_UP()?

Ack. I will modify as if ( (s < e) && (s >= PFN_DOWN(addr)) && (e <= 
PFN_UP(addr + len - 1)) )

> 
>> +        bar_data->is_valid =  true;
>> +
>> +    return 0;
>> +}
>> +
>> +bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end)
>> +{
>> +    int ret;
>> +    const struct dt_device_node *dt_node;
>> +    struct pdev_bar bar_data =  {
>> +        .start = start,
>> +        .end = end,
>> +        .is_valid = false
>> +    };
>> +
>> +    dt_node = pci_find_host_bridge_node(pdev);
>> +    if ( !dt_node )
>> +        return false;
>> +
>> +    ret = dt_for_each_range(dt_node, &is_bar_valid, &bar_data);
> 
> Just as a side note - I find such (the first instance here) uses of the
> unary & operator odd. The same effect will be had without it. So all it
> does (in my opinion) is make things harder to read (just very slightly,
> of course).

I follow the same calling method as used in map_device_children() function in 
file arch/arm/domain_build.c

> 
>> +    if ( ret < 0 )
>> +        return false;
>> +
>> +    if ( !bar_data.is_valid )
>> +        return false;
>> +
>> +    return true;
> 
> Simply "return bar_data.is_valid;"?

Ack. 
 
Regards,
Rahul