Re: [PATCH v3 3/5] xen/arm: make has_vpci() depend on d->arch.has_vpci

[Stewart Hildebrand <stewart.hildebrand@xxxxxxx>]

On 10/20/23 13:29, Julien Grall wrote:
> Hi,
> 
> On 09/10/2023 20:57, Stewart Hildebrand wrote:
>> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
>>
>> VPCI is disabled on ARM. Make it depend on d->arch.has_vpci to enable the PCI
>> passthrough support on ARM.
>>
>> While here, remove the comment on the preceding line.
>>
>> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
>> Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
>> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
> 
> I think this patch should be folded in patch #2. With that the
> hypervisor part would be properly plumbed as soon as the flag is introduced.

Will do. If moving the vpci flag to xen_domctl_createdomain.flags, there is not 
much arch specific about has_vpci(d), so I think this could also be moved to a 
common header, like xen/include/xen/domain.h.

> 
>> ---
>> There are two downstreams [1] [2] that have independently made a version this
>> change, each with different Signed-off-by's. I simply picked one at random 
>> for
>> the Author: field, and added both Signed-off-by lines. Please let me know if
>> there are any objections.
>>
>> v2->v3:
>> * use d->arch.has_vpci since plumbing struct arch_domain with a vPCI flag
>>
>> v1->v2:
>> * add is_hardware_domain check. This will need to be removed after the vPCI
>>    series [3] is merged.
>>
>> downstream->v1:
>> * change to IS_ENABLED(CONFIG_HAS_VPCI) instead of hardcoded to true
>> * remove the comment on the preceding line
>>
>> [1] 
>> https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc/-/commit/27be1729ce8128dbe37275ce7946b2fbd2e5a382
>> [2] 
>> https://github.com/xen-troops/xen/commit/bf12185e6fb2e31db0d8e6ea9ccd8a02abadec17
>> [3] 
>> https://lists.xenproject.org/archives/html/xen-devel/2023-08/msg02361.html
>> ---
>>   xen/arch/arm/include/asm/domain.h | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/xen/arch/arm/include/asm/domain.h 
>> b/xen/arch/arm/include/asm/domain.h
>> index 0a66ed09a617..ebba2c25dceb 100644
>> --- a/xen/arch/arm/include/asm/domain.h
>> +++ b/xen/arch/arm/include/asm/domain.h
>> @@ -300,8 +300,7 @@ static inline void arch_vcpu_block(struct vcpu *v) {}
>>
>>   #define arch_vm_assist_valid_mask(d) (1UL << 
>> VMASST_TYPE_runstate_update_flag)
>>
>> -/* vPCI is not available on Arm */
>> -#define has_vpci(d)    ({ (void)(d); false; })
>> +#define has_vpci(d) ( (d)->arch.has_vpci )
> 
> Coding style: I don't believe we add space after ( and before ) in this
> situation.

OK

> 
> Cheers,
> 
> -- 
> Julien Grall