Re: [PATCH v6 4/5] [FUTURE] xen/arm: enable vPCI for domUs

[Stewart Hildebrand <stewart.hildebrand@xxxxxxx>]

On 11/14/23 04:13, Jan Beulich wrote:
> On 13.11.2023 23:21, Stewart Hildebrand wrote:
>> --- a/xen/arch/x86/include/asm/domain.h
>> +++ b/xen/arch/x86/include/asm/domain.h
>> @@ -503,6 +503,8 @@ struct arch_domain
>>  #define has_vpit(d)        (!!((d)->arch.emulation_flags & X86_EMU_PIT))
>>  #define has_pirq(d)        (!!((d)->arch.emulation_flags & 
>> X86_EMU_USE_PIRQ))
>>  
>> +#define arch_needs_vpci(d) ({ (void)(d); false; })
> 
> See my comments on the v5 thread on both this and ...

So, the goal here is to return true for a PVH dom0, and false otherwise (for 
now). Since dom0 can't feasibly be full HVM, and is_hvm_domain(d) returns true 
for PVH, how about the following?

/* TODO: re-visit when vPCI is enabled for PVH domUs. */
#define arch_needs_vpci(d) ({                       \
    const struct domain *_d = (d);                  \
    is_hardware_domain(_d) && is_hvm_domain(_d); })


Link to v5 thread for reference [1]
[1] https://lists.xenproject.org/archives/html/xen-devel/2023-11/msg00968.html

> 
>> --- a/xen/drivers/passthrough/pci.c
>> +++ b/xen/drivers/passthrough/pci.c
>> @@ -1542,6 +1542,18 @@ void iommu_dev_iotlb_flush_timeout(struct domain *d, 
>> struct pci_dev *pdev)
>>      pcidevs_unlock();
>>  }
>>  
>> +static bool needs_vpci(const struct domain *d)
>> +{
>> +    if ( is_hardware_domain(d) )
>> +        return false;
> 
> ... this.

I'll move this check to the Arm arch_needs_vpci() in 
xen/arch/arm/include/asm/domain.h

> (It is generally a good idea to wait a little with sending new
> versions, when you can't be sure yet whether the earlier discussion has
> settled.)

(Sorry, I'll be better about this going forward.)

> 
> Jan