Re: [PATCH 2/2] vpci: use named rangeset for BARs

[Jan Beulich <jbeulich@xxxxxxxx>]

On 22.11.2021 11:59, Oleksandr Andrushchenko wrote:
> On 22.11.21 12:54, Jan Beulich wrote:
>> On 22.11.2021 11:50, Oleksandr Andrushchenko wrote:
>>>
>>> On 22.11.21 12:43, Jan Beulich wrote:
>>>> On 22.11.2021 11:27, Roger Pau Monné wrote:
>>>>> On Mon, Nov 22, 2021 at 11:28:25AM +0200, Oleksandr Andrushchenko wrote:
>>>>>> --- a/xen/drivers/vpci/header.c
>>>>>> +++ b/xen/drivers/vpci/header.c
>>>>>> @@ -206,12 +206,16 @@ static void defer_map(struct domain *d, struct 
>>>>>> pci_dev *pdev,
>>>>>>    static int modify_bars(const struct pci_dev *pdev, uint16_t cmd, bool 
>>>>>> rom_only)
>>>>>>    {
>>>>>>        struct vpci_header *header = &pdev->vpci->header;
>>>>>> -    struct rangeset *mem = rangeset_new(NULL, NULL, 0);
>>>>>> +    struct rangeset *mem;
>>>>>> +    char str[32];
>>>>>>        struct pci_dev *tmp, *dev = NULL;
>>>>>>        const struct vpci_msix *msix = pdev->vpci->msix;
>>>>>>        unsigned int i;
>>>>>>        int rc;
>>>>>>    
>>>>>> +    snprintf(str, sizeof(str), "%pp", &pdev->sbdf);
>>>>>> +    mem = rangeset_new(NULL, str, RANGESETF_no_print);
>>>>> You are still not adding the rangeset to the domain list, as the first
>>>>> parameter passed here in NULL instead of a domain struct.
>>>>>
>>>>> Given the current short living of the rangesets I'm not sure it makes
>>>>> much sense to link them to the domain ATM, but I guess this is kind of
>>>>> a preparatory change as other patches you have will have the
>>>>> rangesets permanent as long as the device is assigned to a domain.
>>>>>
>>>>> Likely the above reasoning (or the appropriate one) should be added to
>>>>> the commit message.
>>> If I fold then there is no reason to add the comment, right?
>> I'd say you still want to justify the change from "anonymous" to "named and
>> accounted".
> "Make the range sets permanent, e.g. create them when a PCI device is
> added and destroy when it is removed. Also make the range sets named
> and accounted."

Making them permanent is a requirement of your change iirc, so I'd start with
"Because the range sets now become permanent, make them ...".

Jan