Re: [PATCH v2] xen/pci: Refactor PCI MSI interrupts related code

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Apr 19, 2021 at 07:16:52AM +0000, Rahul Singh wrote:
> Thanks you everyone for reviewing the code. I will summarise what I have 
> understood from all the comments 
> and what I will be doing for the next version of the patch.  Please let me 
> know your view on this.
> 
> 1. Create a separate non-arch specific file "msi-intercept.c"  for the below 
> newly introduced function and 
>     compile that file if CONFIG_PCI_MSI_INTERCEPT is 
> enabled.CONFIG_PCI_MSI_INTERCEPT  will  be 
>     enabled for x86 by default. Also Mention in the commit message that these 
> function will be needed for Xen to 
>     support MSI interrupt within XEN.
> 
>       pdev_msi_initi(..)
>       pdev_msi_deiniti(..)

I would drop the last 'i' from both function names above, as we use
init/deinit in the rest of the code base.

>       pdev_dump_msi(..),
>       pdev_msix_assign(..)
> 
> 2. Create separate patch for iommu_update_ire_from_msi() related code. There 
> are two suggestion please help me which one to choose. 
>  
>      - Move the iommu_update_ire_from_msi() function to asm-x86/iommu.h and 
> also move the hook from iommu_ops under CONFIG_X86.

I would go for this one.

> 
>       - Implement a more generic function "arch_register_msi()"). This could 
> call iommu_update_ire_from_msi() on x86 and the 
>         ITS related code once implemented on Arm. Introduce the new Kconfig 
> CONFIG_HAS_IOMMU_INTERRUPT_REMAP for this option.

I think it's best to introduce this hook when you actually have to
implement the Arm version of it.

Thanks, Roger.