Re: [PATCH v6 3/8] vpci: Hide legacy capability when it fails to initialize

["Chen, Jiqian" <Jiqian.Chen@xxxxxxx>]

On 2025/6/18 22:09, Jan Beulich wrote:
> On 12.06.2025 11:29, Jiqian Chen wrote:
>> --- a/xen/drivers/vpci/vpci.c
>> +++ b/xen/drivers/vpci/vpci.c
>> @@ -83,6 +83,88 @@ static int assign_virtual_sbdf(struct pci_dev *pdev)
>>  
>>  #endif /* CONFIG_HAS_VPCI_GUEST_SUPPORT */
>>  
>> +static struct vpci_register *vpci_get_register(struct vpci *vpci,
>> +                                               unsigned int offset,
>> +                                               unsigned int size)
>> +{
>> +    struct vpci_register *r;
>> +
>> +    ASSERT(spin_is_locked(&vpci->lock));
>> +
>> +    list_for_each_entry ( r, &vpci->handlers, node )
>> +    {
>> +        if ( r->offset == offset && r->size == size )
>> +            return r;
>> +
>> +        if ( offset <= r->offset )
>> +            break;
>> +    }
>> +
>> +    return NULL;
>> +}
>> +
>> +static struct vpci_register *vpci_get_previous_cap_register(
>> +    struct vpci *vpci, unsigned int offset)
>> +{
>> +    uint32_t next;
>> +    struct vpci_register *r;
>> +
>> +    if ( offset < 0x40 )
>> +    {
>> +        ASSERT_UNREACHABLE();
>> +        return NULL;
>> +    }
>> +
>> +    for ( r = vpci_get_register(vpci, PCI_CAPABILITY_LIST, 1); r;
>> +          r = next >= 0x40 ? vpci_get_register(vpci,
>> +                                               next + PCI_CAP_LIST_NEXT, 1)
>> +                           : NULL )
>> +    {
>> +        next = (uint32_t)(uintptr_t)r->private;
>> +        ASSERT(next == (uintptr_t)r->private);
>> +        if ( next == offset )
>> +            break;
>> +    }
>> +
>> +    return r;
>> +}
>> +
>> +static int vpci_capability_hide(struct pci_dev *pdev, unsigned int cap)
> 
> I really only noticed it in the next patch, but the question applies equally
> here: Any reason the first parameter isn't pointer-to-const?
Will change the parameters to be const of my new functions in this and next 
patches.

> 
> Jan

-- 
Best regards,
Jiqian Chen.