diff mbox series

[v3,13/13] iommu/arm-smmu-v3: Add support for PCI PASID

Message ID 20191209180514.272727-14-jean-philippe@linaro.org (mailing list archive)
State New, archived
Headers show
Series iommu: Add PASID support to Arm SMMUv3 | expand

Commit Message

Jean-Philippe Brucker Dec. 9, 2019, 6:05 p.m. UTC 
Enable PASID for PCI devices that support it. Since the SSID tables are
allocated by arm_smmu_attach_dev(), PASID has to be enabled early enough.
arm_smmu_dev_feature_enable() would be too late, since by that time the
main DMA domain has already been attached. Do it in add_device() instead.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 drivers/iommu/arm-smmu-v3.c | 51 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

Comments

Eric Auger Dec. 18, 2019, 10:17 a.m. UTC | #1 
Hi Jean,

On 12/9/19 7:05 PM, Jean-Philippe Brucker wrote:
> Enable PASID for PCI devices that support it. Since the SSID tables are
> allocated by arm_smmu_attach_dev(), PASID has to be enabled early enough.
> arm_smmu_dev_feature_enable() would be too late, since by that time the
> main DMA domain has already been attached. Do it in add_device() instead.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
>  drivers/iommu/arm-smmu-v3.c | 51 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index d20a79108f8a..cde7af39681c 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2643,6 +2643,49 @@ static void arm_smmu_disable_ats(struct arm_smmu_master *master)
>  	atomic_dec(&smmu_domain->nr_ats_masters);
>  }
>  
> +static int arm_smmu_enable_pasid(struct arm_smmu_master *master)
> +{
> +	int ret;
> +	int features;
> +	int num_pasids;
> +	struct pci_dev *pdev;
> +
> +	if (!dev_is_pci(master->dev))
> +		return -ENODEV;
> +
> +	pdev = to_pci_dev(master->dev);
> +
> +	features = pci_pasid_features(pdev);
> +	if (features < 0)
> +		return -ENODEV;
why -ENODEV?
> +
> +	num_pasids = pci_max_pasids(pdev);
> +	if (num_pasids <= 0)
> +		return -ENODEV;
> +
> +	ret = pci_enable_pasid(pdev, features);
> +	if (!ret)
> +		master->ssid_bits = min_t(u8, ilog2(num_pasids),
> +					  master->smmu->ssid_bits);
so here we are ;-)
> +	return ret;
> +}
> +
> +static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
> +{
> +	struct pci_dev *pdev;
> +
> +	if (!dev_is_pci(master->dev))
> +		return;
> +
> +	pdev = to_pci_dev(master->dev);
> +
> +	if (!pdev->pasid_enabled)
> +		return;
> +
> +	master->ssid_bits = 0;
> +	pci_disable_pasid(pdev);
> +}
> +
>  static void arm_smmu_detach_dev(struct arm_smmu_master *master)
>  {
>  	unsigned long flags;
> @@ -2851,13 +2894,16 @@ static int arm_smmu_add_device(struct device *dev)
>  
>  	master->ssid_bits = min(smmu->ssid_bits, fwspec->num_pasid_bits);
>  
> +	/* Note that PASID must be enabled before, and disabled after ATS */
> +	arm_smmu_enable_pasid(master);
No error handling?
> +
>  	if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB))
>  		master->ssid_bits = min_t(u8, master->ssid_bits,
>  					  CTXDESC_LINEAR_CDMAX);
>  
>  	ret = iommu_device_link(&smmu->iommu, dev);
>  	if (ret)
> -		goto err_free_master;
> +		goto err_disable_pasid;
>  
>  	group = iommu_group_get_for_dev(dev);
>  	if (IS_ERR(group)) {
> @@ -2870,6 +2916,8 @@ static int arm_smmu_add_device(struct device *dev)
>  
>  err_unlink:
>  	iommu_device_unlink(&smmu->iommu, dev);
> +err_disable_pasid:
> +	arm_smmu_disable_pasid(master);
>  err_free_master:
>  	kfree(master);
>  	fwspec->iommu_priv = NULL;
> @@ -2890,6 +2938,7 @@ static void arm_smmu_remove_device(struct device *dev)
>  	arm_smmu_detach_dev(master);
>  	iommu_group_remove_device(dev);
>  	iommu_device_unlink(&smmu->iommu, dev);
> +	arm_smmu_disable_pasid(master);
>  	kfree(master);
>  	iommu_fwspec_free(dev);
>  }
> 

Thanks

Eric
Jean-Philippe Brucker Dec. 18, 2019, 4:13 p.m. UTC | #2 
On Wed, Dec 18, 2019 at 11:17:55AM +0100, Auger Eric wrote:
> > +static int arm_smmu_enable_pasid(struct arm_smmu_master *master)
> > +{
> > +	int ret;
> > +	int features;
> > +	int num_pasids;
> > +	struct pci_dev *pdev;
> > +
> > +	if (!dev_is_pci(master->dev))
> > +		return -ENODEV;
> > +
> > +	pdev = to_pci_dev(master->dev);
> > +
> > +	features = pci_pasid_features(pdev);
> > +	if (features < 0)
> > +		return -ENODEV;
> why -ENODEV?

Right that should return features. The below should return num_pasids.

> > +
> > +	num_pasids = pci_max_pasids(pdev);
> > +	if (num_pasids <= 0)
> > +		return -ENODEV;
> > +
> > +	ret = pci_enable_pasid(pdev, features);
> > +	if (!ret)
> > +		master->ssid_bits = min_t(u8, ilog2(num_pasids),
> > +					  master->smmu->ssid_bits);
> so here we are ;-)
> > +	return ret;
> > +}
> > +
> > +static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
> > +{
> > +	struct pci_dev *pdev;
> > +
> > +	if (!dev_is_pci(master->dev))
> > +		return;
> > +
> > +	pdev = to_pci_dev(master->dev);
> > +
> > +	if (!pdev->pasid_enabled)
> > +		return;
> > +
> > +	master->ssid_bits = 0;
> > +	pci_disable_pasid(pdev);
> > +}
> > +
> >  static void arm_smmu_detach_dev(struct arm_smmu_master *master)
> >  {
> >  	unsigned long flags;
> > @@ -2851,13 +2894,16 @@ static int arm_smmu_add_device(struct device *dev)
> >  
> >  	master->ssid_bits = min(smmu->ssid_bits, fwspec->num_pasid_bits);
> >  
> > +	/* Note that PASID must be enabled before, and disabled after ATS */
> > +	arm_smmu_enable_pasid(master);
> No error handling?

The device still works if PASID isn't supported or cannot be enabled, it
just won't have some capabilities (IOMMU_DEV_FEAT_AUX and
IOMMU_DEV_FEAT_SVA), so I don't think add_device should return an error.

But it's a good point, I think at least printing an error like
arm_smmu_enable_ats() does would be better.

Thanks,
Jean
diff mbox series

Patch

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index d20a79108f8a..cde7af39681c 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2643,6 +2643,49 @@  static void arm_smmu_disable_ats(struct arm_smmu_master *master)
 	atomic_dec(&smmu_domain->nr_ats_masters);
 }
 
+static int arm_smmu_enable_pasid(struct arm_smmu_master *master)
+{
+	int ret;
+	int features;
+	int num_pasids;
+	struct pci_dev *pdev;
+
+	if (!dev_is_pci(master->dev))
+		return -ENODEV;
+
+	pdev = to_pci_dev(master->dev);
+
+	features = pci_pasid_features(pdev);
+	if (features < 0)
+		return -ENODEV;
+
+	num_pasids = pci_max_pasids(pdev);
+	if (num_pasids <= 0)
+		return -ENODEV;
+
+	ret = pci_enable_pasid(pdev, features);
+	if (!ret)
+		master->ssid_bits = min_t(u8, ilog2(num_pasids),
+					  master->smmu->ssid_bits);
+	return ret;
+}
+
+static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
+{
+	struct pci_dev *pdev;
+
+	if (!dev_is_pci(master->dev))
+		return;
+
+	pdev = to_pci_dev(master->dev);
+
+	if (!pdev->pasid_enabled)
+		return;
+
+	master->ssid_bits = 0;
+	pci_disable_pasid(pdev);
+}
+
 static void arm_smmu_detach_dev(struct arm_smmu_master *master)
 {
 	unsigned long flags;
@@ -2851,13 +2894,16 @@  static int arm_smmu_add_device(struct device *dev)
 
 	master->ssid_bits = min(smmu->ssid_bits, fwspec->num_pasid_bits);
 
+	/* Note that PASID must be enabled before, and disabled after ATS */
+	arm_smmu_enable_pasid(master);
+
 	if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB))
 		master->ssid_bits = min_t(u8, master->ssid_bits,
 					  CTXDESC_LINEAR_CDMAX);
 
 	ret = iommu_device_link(&smmu->iommu, dev);
 	if (ret)
-		goto err_free_master;
+		goto err_disable_pasid;
 
 	group = iommu_group_get_for_dev(dev);
 	if (IS_ERR(group)) {
@@ -2870,6 +2916,8 @@  static int arm_smmu_add_device(struct device *dev)
 
 err_unlink:
 	iommu_device_unlink(&smmu->iommu, dev);
+err_disable_pasid:
+	arm_smmu_disable_pasid(master);
 err_free_master:
 	kfree(master);
 	fwspec->iommu_priv = NULL;
@@ -2890,6 +2938,7 @@  static void arm_smmu_remove_device(struct device *dev)
 	arm_smmu_detach_dev(master);
 	iommu_group_remove_device(dev);
 	iommu_device_unlink(&smmu->iommu, dev);
+	arm_smmu_disable_pasid(master);
 	kfree(master);
 	iommu_fwspec_free(dev);
 }