Re: [PATCH v1 14/14] xen/arm: Add linux,pci-domain property for hwdom if not available.

[Rahul Singh <Rahul.Singh@arm.com>]

Hi Stefano,

> On 10 Sep 2021, at 2:00 am, Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> On Thu, 19 Aug 2021, Rahul Singh wrote:
>> If the property is not present in the device tree node for host bridge,
>> XEN while creating the dtb for hwdom will create this property and
>> assigns the already allocated segment to the host bridge
>> so that XEN and linux will have the same segment for the host bridges.
>> 
>> Signed-off-by: Rahul Singh <rahul.singh@arm.com>
>> ---
>> xen/arch/arm/domain_build.c        | 18 ++++++++++++++++++
>> xen/arch/arm/pci/pci-host-common.c | 21 +++++++++++++++++++++
>> xen/include/asm-arm/pci.h          |  3 +++
>> 3 files changed, 42 insertions(+)
>> 
>> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
>> index 6c86d52781..e0cf2ff19d 100644
>> --- a/xen/arch/arm/domain_build.c
>> +++ b/xen/arch/arm/domain_build.c
>> @@ -581,6 +581,24 @@ static int __init write_properties(struct domain *d, struct kernel_info *kinfo,
>>             return res;
>>     }
>> 
>> +#ifdef CONFIG_HAS_PCI
>> +    if ( dt_device_type_is_equal(node, "pci") )
>> +    {
>> +        if ( !dt_find_property(node, "linux,pci-domain", NULL) )
>> +        {
>> +            uint16_t segment;
>> +
>> +            res = pci_get_host_bridge_segment(node, &segment);
>> +            if ( res < 0 )
>> +                return res;
>> +
>> +            res = fdt_property_cell(kinfo->fdt, "linux,pci-domain", segment);
>> +            if ( res )
>> +                return res;
>> +        }
>> +    }
>> +#endif
> 
> If param_pci_enable is false it might be possible that Xen didn't
> allocate a segment. In that case, we should just let Linux do whatever
> it wants in terms of segment allocation. So I think the code here should
> not return error if param_pci_enable is false.
> returning an error instead.

Ack. I will modify the code as per your request in next version.

Regards,
Rahul