Re: [PATCH RESEND v9 11/13] iommu/arm-smmu-v3: Add SVA device feature

[Auger Eric <eric.auger@redhat.com>]

Hi Jean,

On 8/17/20 7:15 PM, Jean-Philippe Brucker wrote:
> Implement the IOMMU device feature callbacks to support the SVA feature.
> At the moment dev_has_feat() returns false since I/O Page Faults isn't
> yet implemented.
and because we don't advertise BTM, isn't it?
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   | 26 ++++++
>  .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 49 ++++++++++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 79 +++++++++++++++++++
>  3 files changed, 154 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index 7b14b48a26c7..ba34914813ff 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -646,6 +646,8 @@ struct arm_smmu_master {
>  	u32				*sids;
>  	unsigned int			num_sids;
>  	bool				ats_enabled;
> +	bool				sva_enabled;
> +	struct list_head		bonds;
>  	unsigned int			ssid_bits;
>  };
>  
> @@ -687,10 +689,34 @@ bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd);
>  
>  #ifdef CONFIG_ARM_SMMU_V3_SVA
>  bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
> +bool arm_smmu_master_sva_supported(struct arm_smmu_master *master);
> +bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
> +int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
> +int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
>  #else /* CONFIG_ARM_SMMU_V3_SVA */
>  static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
>  {
>  	return false;
>  }
> +
> +static inline bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
> +{
> +	return false;
> +}
> +
> +static inline bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
> +{
> +	return false;
> +}
> +
> +static inline int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
> +{
> +	return -ENODEV;
> +}
> +
> +static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
> +{
> +	return -ENODEV;
> +}
>  #endif /* CONFIG_ARM_SMMU_V3_SVA */
>  #endif /* _ARM_SMMU_V3_H */
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> index bf81d91ce71e..28027620cf2e 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> @@ -10,6 +10,8 @@
>  #include "arm-smmu-v3.h"
>  #include "../../io-pgtable-arm.h"
>  
> +static DEFINE_MUTEX(sva_lock);
> +
>  /*
>   * Try to reserve this ASID in the SMMU. If it is in use, try to steal it from
>   * the private entry. Careful here, we may be modifying the context tables of
> @@ -196,3 +198,50 @@ bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
>  
>  	return true;
>  }
> +
> +static bool arm_smmu_iopf_supported(struct arm_smmu_master *master)
> +{
> +	return false;
> +}
> +
> +bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
> +{
> +	if (!(master->smmu->features & ARM_SMMU_FEAT_SVA))
> +		return false;
> +
> +	/* SSID and IOPF support are mandatory for the moment */
> +	return master->ssid_bits && arm_smmu_iopf_supported(master);
> +}
> +
> +bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
> +{
> +	bool enabled;
> +
> +	mutex_lock(&sva_lock);
> +	enabled = master->sva_enabled;
> +	mutex_unlock(&sva_lock);
> +	return enabled;
> +}
> +
> +int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
> +{
> +	mutex_lock(&sva_lock);
> +	master->sva_enabled = true;
> +	mutex_unlock(&sva_lock);
> +
> +	return 0;
> +}
> +
> +int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
> +{
> +	mutex_lock(&sva_lock);
> +	if (!list_empty(&master->bonds)) {
> +		dev_err(master->dev, "cannot disable SVA, device is bound\n");
> +		mutex_unlock(&sva_lock);
> +		return -EBUSY;
> +	}
> +	master->sva_enabled = false;
> +	mutex_unlock(&sva_lock);
> +
> +	return 0;
> +}
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 15cb3d9c1a5d..5ed5bb42298f 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2163,6 +2163,16 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>  	master = dev_iommu_priv_get(dev);
>  	smmu = master->smmu;
>  
> +	/*
> +	 * Checking that SVA is disabled ensures that this device isn't bound to
> +	 * any mm, and can be safely detached from its old domain. Bonds cannot
> +	 * be removed concurrently since we're holding the group mutex.
> +	 */
> +	if (arm_smmu_master_sva_enabled(master)) {
> +		dev_err(dev, "cannot attach - SVA enabled\n");
> +		return -EBUSY;
> +	}
> +
>  	arm_smmu_detach_dev(master);
>  
>  	mutex_lock(&smmu_domain->init_mutex);
> @@ -2310,6 +2320,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
>  	master->smmu = smmu;
>  	master->sids = fwspec->ids;
>  	master->num_sids = fwspec->num_ids;
> +	INIT_LIST_HEAD(&master->bonds);
>  	dev_iommu_priv_set(dev, master);
>  
>  	/* Check the SIDs are in range of the SMMU and our stream table */
> @@ -2362,6 +2373,7 @@ static void arm_smmu_release_device(struct device *dev)
>  		return;
>  
>  	master = dev_iommu_priv_get(dev);
> +	WARN_ON(arm_smmu_master_sva_enabled(master));
>  	arm_smmu_detach_dev(master);
>  	arm_smmu_disable_pasid(master);
>  	kfree(master);
> @@ -2479,6 +2491,69 @@ static void arm_smmu_get_resv_regions(struct device *dev,
>  	iommu_dma_get_resv_regions(dev, head);
>  }
>  
> +static bool arm_smmu_dev_has_feature(struct device *dev,
> +				     enum iommu_dev_features feat)
> +{
> +	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
> +
> +	if (!master)
> +		return false;
> +
> +	switch (feat) {
> +	case IOMMU_DEV_FEAT_SVA:
> +		return arm_smmu_master_sva_supported(master);
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool arm_smmu_dev_feature_enabled(struct device *dev,
> +					 enum iommu_dev_features feat)
> +{
> +	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
> +
> +	if (!master)
> +		return false;
> +
> +	switch (feat) {
> +	case IOMMU_DEV_FEAT_SVA:
> +		return arm_smmu_master_sva_enabled(master);
> +	default:
> +		return false;
> +	}
> +}
> +
> +static int arm_smmu_dev_enable_feature(struct device *dev,
> +				       enum iommu_dev_features feat)
> +{
> +	if (!arm_smmu_dev_has_feature(dev, feat))
> +		return -ENODEV;
> +
> +	if (arm_smmu_dev_feature_enabled(dev, feat))
> +		return -EBUSY;
> +
> +	switch (feat) {
> +	case IOMMU_DEV_FEAT_SVA:
> +		return arm_smmu_master_enable_sva(dev_iommu_priv_get(dev));
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int arm_smmu_dev_disable_feature(struct device *dev,
> +					enum iommu_dev_features feat)
> +{
> +	if (!arm_smmu_dev_feature_enabled(dev, feat))
> +		return -EINVAL;
> +
> +	switch (feat) {
> +	case IOMMU_DEV_FEAT_SVA:
> +		return arm_smmu_master_disable_sva(dev_iommu_priv_get(dev));
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
>  static struct iommu_ops arm_smmu_ops = {
>  	.capable		= arm_smmu_capable,
>  	.domain_alloc		= arm_smmu_domain_alloc,
> @@ -2497,6 +2572,10 @@ static struct iommu_ops arm_smmu_ops = {
>  	.of_xlate		= arm_smmu_of_xlate,
>  	.get_resv_regions	= arm_smmu_get_resv_regions,
>  	.put_resv_regions	= generic_iommu_put_resv_regions,
> +	.dev_has_feat		= arm_smmu_dev_has_feature,
> +	.dev_feat_enabled	= arm_smmu_dev_feature_enabled,
> +	.dev_enable_feat	= arm_smmu_dev_enable_feature,
> +	.dev_disable_feat	= arm_smmu_dev_disable_feature,
>  	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
>  };
>  
> 
Besides

Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric

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