Re: [PATCH v2 1/3] x86/apic: remove delivery and destination mode fields from drivers

[Jan Beulich <jbeulich@suse.com>]

On 06.03.2025 16:54, Roger Pau Monné wrote:
> On Thu, Mar 06, 2025 at 04:33:37PM +0100, Jan Beulich wrote:
>> On 06.03.2025 15:57, Roger Pau Monne wrote:
>>> --- a/xen/arch/x86/genapic/bigsmp.c
>>> +++ b/xen/arch/x86/genapic/bigsmp.c
>>> @@ -46,8 +46,6 @@ static int __init cf_check probe_bigsmp(void)
>>>  
>>>  const struct genapic __initconst_cf_clobber apic_bigsmp = {
>>>  	APIC_INIT("bigsmp", probe_bigsmp),
>>> -	.int_delivery_mode = dest_Fixed,
>>> -	.int_dest_mode = 0, /* physical delivery */
>>>  	.init_apic_ldr = init_apic_ldr_phys,
>>>  	.vector_allocation_cpumask = vector_allocation_cpumask_phys,
>>>  	.cpu_mask_to_apicid = cpu_mask_to_apicid_phys,
>>> --- a/xen/arch/x86/genapic/default.c
>>> +++ b/xen/arch/x86/genapic/default.c
>>> @@ -16,8 +16,6 @@
>>>  /* should be called last. */
>>>  const struct genapic __initconst_cf_clobber apic_default = {
>>>  	APIC_INIT("default", NULL),
>>> -	.int_delivery_mode = dest_Fixed,
>>> -	.int_dest_mode = 0, /* physical delivery */
>>>  	.init_apic_ldr = init_apic_ldr_flat,
>>>  	.vector_allocation_cpumask = vector_allocation_cpumask_phys,
>>>  	.cpu_mask_to_apicid = cpu_mask_to_apicid_phys,
>>> --- a/xen/arch/x86/genapic/x2apic.c
>>> +++ b/xen/arch/x86/genapic/x2apic.c
>>> @@ -140,8 +140,6 @@ static void cf_check send_IPI_mask_x2apic_cluster(
>>>  
>>>  static const struct genapic __initconst_cf_clobber apic_x2apic_phys = {
>>>      APIC_INIT("x2apic_phys", NULL),
>>> -    .int_delivery_mode = dest_Fixed,
>>> -    .int_dest_mode = 0 /* physical delivery */,
>>>      .init_apic_ldr = init_apic_ldr_phys,
>>>      .vector_allocation_cpumask = vector_allocation_cpumask_phys,
>>>      .cpu_mask_to_apicid = cpu_mask_to_apicid_phys,
>>> @@ -163,8 +161,6 @@ static const struct genapic __initconst_cf_clobber apic_x2apic_mixed = {
>>>       * The following fields are exclusively used by external interrupts and
>>>       * hence are set to use Physical destination mode handlers.
>>>       */
>>> -    .int_delivery_mode = dest_Fixed,
>>> -    .int_dest_mode = 0 /* physical delivery */,
>>>      .vector_allocation_cpumask = vector_allocation_cpumask_phys,
>>>      .cpu_mask_to_apicid = cpu_mask_to_apicid_phys,
>>
>> Like we had it everywhere above, ...
>>
>>> --- a/xen/arch/x86/io_apic.c
>>> +++ b/xen/arch/x86/io_apic.c
>>> @@ -1080,8 +1080,8 @@ static void __init setup_IO_APIC_irqs(void)
>>>               */
>>>              memset(&entry,0,sizeof(entry));
>>>  
>>> -            entry.delivery_mode = INT_DELIVERY_MODE;
>>> -            entry.dest_mode = INT_DEST_MODE;
>>> +            entry.delivery_mode = dest_Fixed;
>>> +            entry.dest_mode = 0;
>>
>> ... here and below these zeros would better gain a comment, or be expressed
>> as e.g. (untested) MASK_EXTR(APIC_DEST_PHYSICAL, APIC_DEST_MASK).
> 
> I've started adding those comments, but then I got the impression they
> where a bit redundant, many of the setting of the fields didn't have a
> matching comment.  I was even tempted to just not setting the field at
> all, seeing as the structure is zeroed.
> 
> Also this is the IO-APIC RTE, so it feels a bit out of place to use
> the local APIC defines?

Maybe. There is a certain level of correlation, but yes, it may end up
being confusing.

> I will add a comment if you are fine with it.

I am.

Jan