On Fri, May 15, 2020 at 12:44:01PM +0200, Jean-Philippe Brucker wrote:
> The new pci_ats_supported() function checks if a device supports ATS and
> is allowed to use it.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
> ---
> I dropped the Ack because I slightly changed the patch to keep the
> fwspec check, since last version:
> https://lore.kernel.org/linux-iommu/20200311124506.208376-8-jean-phili...@linaro.org/
> ---
>  drivers/iommu/arm-smmu-v3.c | 20 +++++---------------
>  1 file changed, 5 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 82508730feb7a1..39b935e86ab203 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2652,26 +2652,16 @@ static void arm_smmu_install_ste_for_dev(struct 
> arm_smmu_master *master)
>       }
>  }
>  
> -#ifdef CONFIG_PCI_ATS
>  static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
>  {
> -     struct pci_dev *pdev;
> +     struct device *dev = master->dev;
>       struct arm_smmu_device *smmu = master->smmu;
> -     struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
> -
> -     if (!(smmu->features & ARM_SMMU_FEAT_ATS) || !dev_is_pci(master->dev) ||
> -         !(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS) || pci_ats_disabled())
> -             return false;
> +     struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>  
> -     pdev = to_pci_dev(master->dev);
> -     return !pdev->untrusted && pdev->ats_cap;
> +     return (smmu->features & ARM_SMMU_FEAT_ATS) &&
> +             !(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS) &&
> +             dev_is_pci(dev) && pci_ats_supported(to_pci_dev(dev));

nit, but I think this is clearer if you leave it split up (untested diff
below).

Will

--->8

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 82508730feb7..c5730557dbe3 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2652,26 +2652,20 @@ static void arm_smmu_install_ste_for_dev(struct 
arm_smmu_master *master)
        }
 }
 
-#ifdef CONFIG_PCI_ATS
 static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
 {
-       struct pci_dev *pdev;
+       struct device *dev = master->dev;
        struct arm_smmu_device *smmu = master->smmu;
-       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
+       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 
-       if (!(smmu->features & ARM_SMMU_FEAT_ATS) || !dev_is_pci(master->dev) ||
-           !(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS) || pci_ats_disabled())
+       if (!(smmu->features & ARM_SMMU_FEAT_ATS))
                return false;
 
-       pdev = to_pci_dev(master->dev);
-       return !pdev->untrusted && pdev->ats_cap;
-}
-#else
-static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
-{
-       return false;
+       if (!(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS))
+               return false;
+
+       return dev_is_pci(dev) && pci_ats_supported(to_pci_dev(dev));
 }
-#endif
 
 static void arm_smmu_enable_ats(struct arm_smmu_master *master)
 {
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