Re: [PATCH 4/7] VT-d: replace find_ats_dev_drhd()

["Roger Pau Monné" <roger.pau@citrix.com>]

On Mon, Feb 05, 2024 at 02:56:36PM +0100, Jan Beulich wrote:
> All callers only care about boolean outcome. For this there's no point
> in allocating a duplicate of the respective DRHD structure; a simple
> boolean suffices (which eventually may wantg to become a count, such
                                         ^ want
> that the "any ATS devices assigned state" can also clear again). With
> that boolean, remove respective parameters from internal helper
> functions right away, as those have access to the flag through another
> parameter.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

AFAICT the intention is that this is a non-functional change?

> 
> --- a/xen/drivers/passthrough/vtd/extern.h
> +++ b/xen/drivers/passthrough/vtd/extern.h
> @@ -65,8 +65,6 @@ struct acpi_drhd_unit *ioapic_to_drhd(un
>  struct acpi_drhd_unit *hpet_to_drhd(unsigned int hpet_id);
>  struct acpi_rhsa_unit *drhd_to_rhsa(const struct acpi_drhd_unit *drhd);
>  
> -struct acpi_drhd_unit *find_ats_dev_drhd(struct vtd_iommu *iommu);
> -
>  int ats_device(const struct pci_dev *, const struct acpi_drhd_unit *);
>  
>  int dev_invalidate_iotlb(struct vtd_iommu *iommu, u16 did,
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -624,8 +624,7 @@ int cf_check vtd_flush_iotlb_reg(
>  }
>  
>  static int __must_check iommu_flush_iotlb_global(struct vtd_iommu *iommu,
> -                                                 bool flush_non_present_entry,
> -                                                 bool flush_dev_iotlb)
> +                                                 bool flush_non_present_entry)
>  {
>      int status;
>  
> @@ -633,7 +632,7 @@ static int __must_check iommu_flush_iotl
>      vtd_ops_preamble_quirk(iommu);
>  
>      status = iommu->flush.iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH,
> -                                flush_non_present_entry, flush_dev_iotlb);
> +                                flush_non_present_entry, iommu->flush_dev_iotlb);

Any reason to not also remove the parameter from here also?  As the handler
gets iommu passed as the first parameter anyway.

Thanks, Roger.