Re: [PATCH v10 07/10] iommu/arm-smmu-v3: Maintain a SID->device structure

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

Hi Jean,

On 1/21/21 1:36 PM, Jean-Philippe Brucker wrote:
> When handling faults from the event or PRI queue, we need to find the
> struct device associated with a SID. Add a rb_tree to keep track of
> SIDs.
> 
> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric

> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  13 +-
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 161 ++++++++++++++++----
>  2 files changed, 144 insertions(+), 30 deletions(-)
> 
> 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 96c2e9565e00..8ef6a1c48635 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -636,6 +636,15 @@ struct arm_smmu_device {
>  
>  	/* IOMMU core code handle */
>  	struct iommu_device		iommu;
> +
> +	struct rb_root			streams;
> +	struct mutex			streams_mutex;
> +};
> +
> +struct arm_smmu_stream {
> +	u32				id;
> +	struct arm_smmu_master		*master;
> +	struct rb_node			node;
>  };
>  
>  /* SMMU private data for each master */
> @@ -644,8 +653,8 @@ struct arm_smmu_master {
>  	struct device			*dev;
>  	struct arm_smmu_domain		*domain;
>  	struct list_head		domain_head;
> -	u32				*sids;
> -	unsigned int			num_sids;
> +	struct arm_smmu_stream		*streams;
> +	unsigned int			num_streams;
>  	bool				ats_enabled;
>  	bool				sva_enabled;
>  	struct list_head		bonds;
> 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 6a53b4edf054..db5d6aa76c3a 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -912,8 +912,8 @@ static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain,
>  
>  	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
>  	list_for_each_entry(master, &smmu_domain->devices, domain_head) {
> -		for (i = 0; i < master->num_sids; i++) {
> -			cmd.cfgi.sid = master->sids[i];
> +		for (i = 0; i < master->num_streams; i++) {
> +			cmd.cfgi.sid = master->streams[i].id;
>  			arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
>  		}
>  	}
> @@ -1355,6 +1355,32 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
>  	return 0;
>  }
>  
> +__maybe_unused
> +static struct arm_smmu_master *
> +arm_smmu_find_master(struct arm_smmu_device *smmu, u32 sid)
> +{
> +	struct rb_node *node;
> +	struct arm_smmu_stream *stream;
> +	struct arm_smmu_master *master = NULL;
> +
> +	mutex_lock(&smmu->streams_mutex);
> +	node = smmu->streams.rb_node;
> +	while (node) {
> +		stream = rb_entry(node, struct arm_smmu_stream, node);
> +		if (stream->id < sid) {
> +			node = node->rb_right;
> +		} else if (stream->id > sid) {
> +			node = node->rb_left;
> +		} else {
> +			master = stream->master;
> +			break;
> +		}
> +	}
> +	mutex_unlock(&smmu->streams_mutex);
> +
> +	return master;
> +}
> +
>  /* IRQ and event handlers */
>  static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
>  {
> @@ -1588,8 +1614,8 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
>  
>  	arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);
>  
> -	for (i = 0; i < master->num_sids; i++) {
> -		cmd.atc.sid = master->sids[i];
> +	for (i = 0; i < master->num_streams; i++) {
> +		cmd.atc.sid = master->streams[i].id;
>  		arm_smmu_cmdq_issue_cmd(master->smmu, &cmd);
>  	}
>  
> @@ -1632,8 +1658,8 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
>  		if (!master->ats_enabled)
>  			continue;
>  
> -		for (i = 0; i < master->num_sids; i++) {
> -			cmd.atc.sid = master->sids[i];
> +		for (i = 0; i < master->num_streams; i++) {
> +			cmd.atc.sid = master->streams[i].id;
>  			arm_smmu_cmdq_batch_add(smmu_domain->smmu, &cmds, &cmd);
>  		}
>  	}
> @@ -2040,13 +2066,13 @@ static void arm_smmu_install_ste_for_dev(struct arm_smmu_master *master)
>  	int i, j;
>  	struct arm_smmu_device *smmu = master->smmu;
>  
> -	for (i = 0; i < master->num_sids; ++i) {
> -		u32 sid = master->sids[i];
> +	for (i = 0; i < master->num_streams; ++i) {
> +		u32 sid = master->streams[i].id;
>  		__le64 *step = arm_smmu_get_step_for_sid(smmu, sid);
>  
>  		/* Bridged PCI devices may end up with duplicated IDs */
>  		for (j = 0; j < i; j++)
> -			if (master->sids[j] == sid)
> +			if (master->streams[j].id == sid)
>  				break;
>  		if (j < i)
>  			continue;
> @@ -2319,11 +2345,101 @@ static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
>  	return sid < limit;
>  }
>  
> +static int arm_smmu_insert_master(struct arm_smmu_device *smmu,
> +				  struct arm_smmu_master *master)
> +{
> +	int i;
> +	int ret = 0;
> +	struct arm_smmu_stream *new_stream, *cur_stream;
> +	struct rb_node **new_node, *parent_node = NULL;
> +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
> +
> +	master->streams = kcalloc(fwspec->num_ids,
> +				  sizeof(*master->streams), GFP_KERNEL);
> +	if (!master->streams)
> +		return -ENOMEM;
> +	master->num_streams = fwspec->num_ids;
> +
> +	mutex_lock(&smmu->streams_mutex);
> +	for (i = 0; i < fwspec->num_ids && !ret; i++) {
> +		u32 sid = fwspec->ids[i];
> +
> +		new_stream = &master->streams[i];
> +		new_stream->id = sid;
> +		new_stream->master = master;
> +
> +		/*
> +		 * Check the SIDs are in range of the SMMU and our stream table
> +		 */
> +		if (!arm_smmu_sid_in_range(smmu, sid)) {
> +			ret = -ERANGE;
> +			break;
> +		}
> +
> +		/* Ensure l2 strtab is initialised */
> +		if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
> +			ret = arm_smmu_init_l2_strtab(smmu, sid);
> +			if (ret)
> +				break;
> +		}
> +
> +		/* Insert into SID tree */
> +		new_node = &(smmu->streams.rb_node);
> +		while (*new_node) {
> +			cur_stream = rb_entry(*new_node, struct arm_smmu_stream,
> +					      node);
> +			parent_node = *new_node;
> +			if (cur_stream->id > new_stream->id) {
> +				new_node = &((*new_node)->rb_left);
> +			} else if (cur_stream->id < new_stream->id) {
> +				new_node = &((*new_node)->rb_right);
> +			} else {
> +				dev_warn(master->dev,
> +					 "stream %u already in tree\n",
> +					 cur_stream->id);
> +				ret = -EINVAL;
> +				break;
> +			}
> +		}
> +
> +		if (!ret) {
> +			rb_link_node(&new_stream->node, parent_node, new_node);
> +			rb_insert_color(&new_stream->node, &smmu->streams);
> +		}
> +	}
> +
> +	if (ret) {
> +		for (; i > 0; i--)
> +			rb_erase(&master->streams[i].node, &smmu->streams);
> +		kfree(master->streams);
> +	}
> +	mutex_unlock(&smmu->streams_mutex);
> +
> +	return ret;
> +}
> +
> +static void arm_smmu_remove_master(struct arm_smmu_master *master)
> +{
> +	int i;
> +	struct arm_smmu_device *smmu = master->smmu;
> +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
> +
> +	if (!smmu || !master->streams)
> +		return;
> +
> +	mutex_lock(&smmu->streams_mutex);
> +	for (i = 0; i < fwspec->num_ids; i++)
> +		rb_erase(&master->streams[i].node, &smmu->streams);
> +	mutex_unlock(&smmu->streams_mutex);
> +
> +	kfree(master->streams);
> +}
> +
>  static struct iommu_ops arm_smmu_ops;
>  
>  static struct iommu_device *arm_smmu_probe_device(struct device *dev)
>  {
> -	int i, ret;
> +	int ret;
>  	struct arm_smmu_device *smmu;
>  	struct arm_smmu_master *master;
>  	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> @@ -2344,27 +2460,12 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
>  
>  	master->dev = 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 */
> -	for (i = 0; i < master->num_sids; i++) {
> -		u32 sid = master->sids[i];
> -
> -		if (!arm_smmu_sid_in_range(smmu, sid)) {
> -			ret = -ERANGE;
> -			goto err_free_master;
> -		}
> -
> -		/* Ensure l2 strtab is initialised */
> -		if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
> -			ret = arm_smmu_init_l2_strtab(smmu, sid);
> -			if (ret)
> -				goto err_free_master;
> -		}
> -	}
> +	ret = arm_smmu_insert_master(smmu, master);
> +	if (ret)
> +		goto err_free_master;
>  
>  	device_property_read_u32(dev, "pasid-num-bits", &master->ssid_bits);
>  	master->ssid_bits = min(smmu->ssid_bits, master->ssid_bits);
> @@ -2403,6 +2504,7 @@ static void arm_smmu_release_device(struct device *dev)
>  	WARN_ON(arm_smmu_master_sva_enabled(master));
>  	arm_smmu_detach_dev(master);
>  	arm_smmu_disable_pasid(master);
> +	arm_smmu_remove_master(master);
>  	kfree(master);
>  	iommu_fwspec_free(dev);
>  }
> @@ -2825,6 +2927,9 @@ static int arm_smmu_init_structures(struct arm_smmu_device *smmu)
>  {
>  	int ret;
>  
> +	mutex_init(&smmu->streams_mutex);
> +	smmu->streams = RB_ROOT;
> +
>  	ret = arm_smmu_init_queues(smmu);
>  	if (ret)
>  		return ret;
>