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From: Will Deacon <will@kernel.org>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: ashok.raj@intel.com, linux-pci@vger.kernel.org,
	alex.williamson@redhat.com, iommu@lists.linux-foundation.org,
	bhelgaas@google.com, robin.murphy@arm.com, dwmw2@infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/4] iommu/arm-smmu-v3: Use pci_ats_supported()
Date: Mon, 18 May 2020 16:37:34 +0100	[thread overview]
Message-ID: <20200518153733.GM32394@willie-the-truck> (raw)
In-Reply-To: <20200515104359.1178606-4-jean-philippe@linaro.org>

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-philippe@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-philippe@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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  reply	other threads:[~2020-05-18 15:37 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15 10:43 [PATCH 0/4] PCI, iommu: Factor 'untrusted' check for ATS enablement Jean-Philippe Brucker
2020-05-15 10:43 ` [PATCH 1/4] PCI/ATS: Only enable ATS for trusted devices Jean-Philippe Brucker
2020-05-15 11:57   ` Joerg Roedel
2020-05-15 21:18   ` Bjorn Helgaas
2020-05-15 10:44 ` [PATCH 2/4] iommu/amd: Use pci_ats_supported() Jean-Philippe Brucker
2020-05-15 12:01   ` Joerg Roedel
2020-05-15 12:11     ` Jean-Philippe Brucker
2020-05-15 12:21       ` Joerg Roedel
2020-05-15 10:44 ` [PATCH 3/4] iommu/arm-smmu-v3: " Jean-Philippe Brucker
2020-05-18 15:37   ` Will Deacon [this message]
2020-05-15 10:44 ` [PATCH 4/4] iommu/vt-d: " Jean-Philippe Brucker
2020-05-15 15:43 ` [PATCH 0/4] PCI, iommu: Factor 'untrusted' check for ATS enablement Christoph Hellwig
2020-05-15 17:19   ` Raj, Ashok
2020-05-15 17:21     ` Will Deacon
2020-05-18 15:47     ` David Woodhouse
2020-05-18 16:29       ` Raj, Ashok
2020-05-18 16:36   ` Jean-Philippe Brucker

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