Re: [PATCH v1 4/4] xen/pci: solve compilation error when memory paging is not enabled.

[Jan Beulich <jbeulich@xxxxxxxx>]

On 26.10.2020 18:17, Rahul Singh wrote:
> --- a/xen/drivers/passthrough/pci.c
> +++ b/xen/drivers/passthrough/pci.c
> @@ -1419,13 +1419,15 @@ static int assign_device(struct domain *d, u16 seg, 
> u8 bus, u8 devfn, u32 flag)
>      if ( !is_iommu_enabled(d) )
>          return 0;
>  
> -    /* Prevent device assign if mem paging or mem sharing have been 
> +#if defined(CONFIG_HAS_MEM_PAGING) || defined(CONFIG_MEM_SHARING)
> +    /* Prevent device assign if mem paging or mem sharing have been
>       * enabled for this domain */
>      if ( d != dom_io &&
>           unlikely(mem_sharing_enabled(d) ||
>                    vm_event_check_ring(d->vm_event_paging) ||
>                    p2m_get_hostp2m(d)->global_logdirty) )
>          return -EXDEV;
> +#endif

Besides this also disabling mem-sharing and log-dirty related
logic, I don't think the change is correct: Each item being
checked needs individually disabling depending on its associated
CONFIG_*. For this, perhaps you want to introduce something
like mem_paging_enabled(d), to avoid the need for #ifdef here?

Jan