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

Auger Eric
2020-09-08T09:47:37Z

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