diff mbox series

[v4,09/12] iommu/arm-smmu-v3: Support IOMMU_DOMAIN_NESTED

Message ID 9-v4-9e99b76f3518+3a8-smmuv3_nesting_jgg@nvidia.com (mailing list archive)
State New
Headers show
Series Initial support for SMMUv3 nested translation | expand

Commit Message

Jason Gunthorpe Oct. 31, 2024, 12:20 a.m. UTC
For SMMUv3 a IOMMU_DOMAIN_NESTED is composed of a S2 iommu_domain acting
as the parent and a user provided STE fragment that defines the CD table
and related data with addresses translated by the S2 iommu_domain.

The kernel only permits userspace to control certain allowed bits of the
STE that are safe for user/guest control.

IOTLB maintenance is a bit subtle here, the S1 implicitly includes the S2
translation, but there is no way of knowing which S1 entries refer to a
range of S2.

For the IOTLB we follow ARM's guidance and issue a CMDQ_OP_TLBI_NH_ALL to
flush all ASIDs from the VMID after flushing the S2 on any change to the
S2.

The IOMMU_DOMAIN_NESTED can only be created from inside a VIOMMU as the
invalidation path relies on the VIOMMU to translate virtual stream ID used
in the invalidation commands for the CD table and ATS.

Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Donald Dutile <ddutile@redhat.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     | 157 ++++++++++++++++++
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  17 +-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  26 +++
 include/uapi/linux/iommufd.h                  |  20 +++
 4 files changed, 219 insertions(+), 1 deletion(-)

Comments

Zhangfei Gao Oct. 31, 2024, 6:21 a.m. UTC | #1
On Thu, 31 Oct 2024 at 08:21, Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> For SMMUv3 a IOMMU_DOMAIN_NESTED is composed of a S2 iommu_domain acting
> as the parent and a user provided STE fragment that defines the CD table
> and related data with addresses translated by the S2 iommu_domain.
>
> The kernel only permits userspace to control certain allowed bits of the
> STE that are safe for user/guest control.
>
> IOTLB maintenance is a bit subtle here, the S1 implicitly includes the S2
> translation, but there is no way of knowing which S1 entries refer to a
> range of S2.
>
> For the IOTLB we follow ARM's guidance and issue a CMDQ_OP_TLBI_NH_ALL to
> flush all ASIDs from the VMID after flushing the S2 on any change to the
> S2.
>
> The IOMMU_DOMAIN_NESTED can only be created from inside a VIOMMU as the
> invalidation path relies on the VIOMMU to translate virtual stream ID used
> in the invalidation commands for the CD table and ATS.
>
> Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Reviewed-by: Donald Dutile <ddutile@redhat.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     | 157 ++++++++++++++++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  17 +-
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  26 +++
>  include/uapi/linux/iommufd.h                  |  20 +++
>  4 files changed, 219 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> index 60dd9e90759571..0b9fffc5b2f09b 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> @@ -30,7 +30,164 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type)
>         return info;
>  }
>
> +static void arm_smmu_make_nested_cd_table_ste(
> +       struct arm_smmu_ste *target, struct arm_smmu_master *master,
> +       struct arm_smmu_nested_domain *nested_domain, bool ats_enabled)
> +{
> +       arm_smmu_make_s2_domain_ste(
> +               target, master, nested_domain->vsmmu->s2_parent, ats_enabled);
> +
> +       target->data[0] = cpu_to_le64(STRTAB_STE_0_V |
> +                                     FIELD_PREP(STRTAB_STE_0_CFG,
> +                                                STRTAB_STE_0_CFG_NESTED));
> +       target->data[0] |= nested_domain->ste[0] &
> +                          ~cpu_to_le64(STRTAB_STE_0_CFG);
> +       target->data[1] |= nested_domain->ste[1];
> +}
> +
> +/*
> + * Create a physical STE from the virtual STE that userspace provided when it
> + * created the nested domain. Using the vSTE userspace can request:
> + * - Non-valid STE
> + * - Abort STE
> + * - Bypass STE (install the S2, no CD table)
> + * - CD table STE (install the S2 and the userspace CD table)
> + */
> +static void arm_smmu_make_nested_domain_ste(
> +       struct arm_smmu_ste *target, struct arm_smmu_master *master,
> +       struct arm_smmu_nested_domain *nested_domain, bool ats_enabled)
> +{
> +       unsigned int cfg =
> +               FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(nested_domain->ste[0]));
> +
> +       /*
> +        * Userspace can request a non-valid STE through the nesting interface.
> +        * We relay that into an abort physical STE with the intention that
> +        * C_BAD_STE for this SID can be generated to userspace.
> +        */
> +       if (!(nested_domain->ste[0] & cpu_to_le64(STRTAB_STE_0_V)))
> +               cfg = STRTAB_STE_0_CFG_ABORT;
> +
> +       switch (cfg) {
> +       case STRTAB_STE_0_CFG_S1_TRANS:
> +               arm_smmu_make_nested_cd_table_ste(target, master, nested_domain,
> +                                                 ats_enabled);
> +               break;
> +       case STRTAB_STE_0_CFG_BYPASS:
> +               arm_smmu_make_s2_domain_ste(target, master,
> +                                           nested_domain->vsmmu->s2_parent,
> +                                           ats_enabled);
> +               break;
> +       case STRTAB_STE_0_CFG_ABORT:
> +       default:
> +               arm_smmu_make_abort_ste(target);
> +               break;
> +       }
> +}
> +
> +static int arm_smmu_attach_dev_nested(struct iommu_domain *domain,
> +                                     struct device *dev)
> +{
> +       struct arm_smmu_nested_domain *nested_domain =
> +               to_smmu_nested_domain(domain);
> +       struct arm_smmu_master *master = dev_iommu_priv_get(dev);
> +       struct arm_smmu_attach_state state = {
> +               .master = master,
> +               .old_domain = iommu_get_domain_for_dev(dev),
> +               .ssid = IOMMU_NO_PASID,
> +               /* Currently invalidation of ATC is not supported */
> +               .disable_ats = true,
> +       };
> +       struct arm_smmu_ste ste;
> +       int ret;
> +
> +       if (nested_domain->vsmmu->smmu != master->smmu)
> +               return -EINVAL;
> +       if (arm_smmu_ssids_in_use(&master->cd_table))
> +               return -EBUSY;
> +
> +       mutex_lock(&arm_smmu_asid_lock);
> +       ret = arm_smmu_attach_prepare(&state, domain);
> +       if (ret) {
> +               mutex_unlock(&arm_smmu_asid_lock);
> +               return ret;
> +       }
> +
> +       arm_smmu_make_nested_domain_ste(&ste, master, nested_domain,
> +                                       state.ats_enabled);
> +       arm_smmu_install_ste_for_dev(master, &ste);
> +       arm_smmu_attach_commit(&state);
> +       mutex_unlock(&arm_smmu_asid_lock);
> +       return 0;
> +}
> +
> +static void arm_smmu_domain_nested_free(struct iommu_domain *domain)
> +{
> +       kfree(to_smmu_nested_domain(domain));
> +}
> +
> +static const struct iommu_domain_ops arm_smmu_nested_ops = {
> +       .attach_dev = arm_smmu_attach_dev_nested,
> +       .free = arm_smmu_domain_nested_free,
> +};
> +
> +static int arm_smmu_validate_vste(struct iommu_hwpt_arm_smmuv3 *arg)
> +{
> +       unsigned int cfg;
> +
> +       if (!(arg->ste[0] & cpu_to_le64(STRTAB_STE_0_V))) {
> +               memset(arg->ste, 0, sizeof(arg->ste));
> +               return 0;
> +       }
> +
> +       /* EIO is reserved for invalid STE data. */
> +       if ((arg->ste[0] & ~STRTAB_STE_0_NESTING_ALLOWED) ||
> +           (arg->ste[1] & ~STRTAB_STE_1_NESTING_ALLOWED))
> +               return -EIO;
> +
> +       cfg = FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(arg->ste[0]));
> +       if (cfg != STRTAB_STE_0_CFG_ABORT && cfg != STRTAB_STE_0_CFG_BYPASS &&
> +           cfg != STRTAB_STE_0_CFG_S1_TRANS)
> +               return -EIO;
> +       return 0;
> +}
> +
> +static struct iommu_domain *
> +arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
> +                             const struct iommu_user_data *user_data)
> +{
> +       struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
> +       struct arm_smmu_nested_domain *nested_domain;
> +       struct iommu_hwpt_arm_smmuv3 arg;
> +       int ret;
> +
> +       if (flags)
> +               return ERR_PTR(-EOPNOTSUPP);

This check fails when using user page fault, with flags =
IOMMU_HWPT_FAULT_ID_VALID (4)
Strange, the check is not exist in last version?

iommufd_viommu_alloc_hwpt_nested ->
viommu->ops->alloc_domain_nested(viommu, flags, user_data) ->
arm_vsmmu_alloc_domain_nested


Thanks
Jason Gunthorpe Nov. 4, 2024, 5:19 p.m. UTC | #2
On Thu, Oct 31, 2024 at 02:21:11PM +0800, Zhangfei Gao wrote:

> > +static struct iommu_domain *
> > +arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
> > +                             const struct iommu_user_data *user_data)
> > +{
> > +       struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
> > +       struct arm_smmu_nested_domain *nested_domain;
> > +       struct iommu_hwpt_arm_smmuv3 arg;
> > +       int ret;
> > +
> > +       if (flags)
> > +               return ERR_PTR(-EOPNOTSUPP);
> 
> This check fails when using user page fault, with flags =
> IOMMU_HWPT_FAULT_ID_VALID (4)
> Strange, the check is not exist in last version?
> 
> iommufd_viommu_alloc_hwpt_nested ->
> viommu->ops->alloc_domain_nested(viommu, flags, user_data) ->
> arm_vsmmu_alloc_domain_nested

It should permit IOMMU_HWPT_FAULT_ID_VALID, I'll add this hunk:

--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
@@ -178,12 +178,18 @@ arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
                              const struct iommu_user_data *user_data)
 {
        struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
+       const u32 SUPPORTED_FLAGS = IOMMU_HWPT_FAULT_ID_VALID;
        struct arm_smmu_nested_domain *nested_domain;
        struct iommu_hwpt_arm_smmuv3 arg;
        bool enable_ats = false;
        int ret;
 
-       if (flags)
+       /*
+        * Faults delivered to the nested domain are faults that originated by
+        * the S1 in the domain. The core code will match all PASIDs when
+        * delivering the fault due to user_pasid_table
+        */
+       if (flags & ~SUPPORTED_FLAGS)
                return ERR_PTR(-EOPNOTSUPP);
 
        ret = iommu_copy_struct_from_user(&arg, user_data,

Thanks,
Jason
Zhangfei Gao Nov. 6, 2024, 5:39 a.m. UTC | #3
On Mon, 4 Nov 2024 at 17:19, Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> On Thu, Oct 31, 2024 at 02:21:11PM +0800, Zhangfei Gao wrote:
>
> > > +static struct iommu_domain *
> > > +arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
> > > +                             const struct iommu_user_data *user_data)
> > > +{
> > > +       struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
> > > +       struct arm_smmu_nested_domain *nested_domain;
> > > +       struct iommu_hwpt_arm_smmuv3 arg;
> > > +       int ret;
> > > +
> > > +       if (flags)
> > > +               return ERR_PTR(-EOPNOTSUPP);
> >
> > This check fails when using user page fault, with flags =
> > IOMMU_HWPT_FAULT_ID_VALID (4)
> > Strange, the check is not exist in last version?
> >
> > iommufd_viommu_alloc_hwpt_nested ->
> > viommu->ops->alloc_domain_nested(viommu, flags, user_data) ->
> > arm_vsmmu_alloc_domain_nested
>
> It should permit IOMMU_HWPT_FAULT_ID_VALID, I'll add this hunk:
>
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> @@ -178,12 +178,18 @@ arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
>                               const struct iommu_user_data *user_data)
>  {
>         struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
> +       const u32 SUPPORTED_FLAGS = IOMMU_HWPT_FAULT_ID_VALID;
>         struct arm_smmu_nested_domain *nested_domain;
>         struct iommu_hwpt_arm_smmuv3 arg;
>         bool enable_ats = false;
>         int ret;
>
> -       if (flags)
> +       /*
> +        * Faults delivered to the nested domain are faults that originated by
> +        * the S1 in the domain. The core code will match all PASIDs when
> +        * delivering the fault due to user_pasid_table
> +        */
> +       if (flags & ~SUPPORTED_FLAGS)
>                 return ERR_PTR(-EOPNOTSUPP);

Thanks Jason, this works
diff mbox series

Patch

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
index 60dd9e90759571..0b9fffc5b2f09b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
@@ -30,7 +30,164 @@  void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type)
 	return info;
 }
 
+static void arm_smmu_make_nested_cd_table_ste(
+	struct arm_smmu_ste *target, struct arm_smmu_master *master,
+	struct arm_smmu_nested_domain *nested_domain, bool ats_enabled)
+{
+	arm_smmu_make_s2_domain_ste(
+		target, master, nested_domain->vsmmu->s2_parent, ats_enabled);
+
+	target->data[0] = cpu_to_le64(STRTAB_STE_0_V |
+				      FIELD_PREP(STRTAB_STE_0_CFG,
+						 STRTAB_STE_0_CFG_NESTED));
+	target->data[0] |= nested_domain->ste[0] &
+			   ~cpu_to_le64(STRTAB_STE_0_CFG);
+	target->data[1] |= nested_domain->ste[1];
+}
+
+/*
+ * Create a physical STE from the virtual STE that userspace provided when it
+ * created the nested domain. Using the vSTE userspace can request:
+ * - Non-valid STE
+ * - Abort STE
+ * - Bypass STE (install the S2, no CD table)
+ * - CD table STE (install the S2 and the userspace CD table)
+ */
+static void arm_smmu_make_nested_domain_ste(
+	struct arm_smmu_ste *target, struct arm_smmu_master *master,
+	struct arm_smmu_nested_domain *nested_domain, bool ats_enabled)
+{
+	unsigned int cfg =
+		FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(nested_domain->ste[0]));
+
+	/*
+	 * Userspace can request a non-valid STE through the nesting interface.
+	 * We relay that into an abort physical STE with the intention that
+	 * C_BAD_STE for this SID can be generated to userspace.
+	 */
+	if (!(nested_domain->ste[0] & cpu_to_le64(STRTAB_STE_0_V)))
+		cfg = STRTAB_STE_0_CFG_ABORT;
+
+	switch (cfg) {
+	case STRTAB_STE_0_CFG_S1_TRANS:
+		arm_smmu_make_nested_cd_table_ste(target, master, nested_domain,
+						  ats_enabled);
+		break;
+	case STRTAB_STE_0_CFG_BYPASS:
+		arm_smmu_make_s2_domain_ste(target, master,
+					    nested_domain->vsmmu->s2_parent,
+					    ats_enabled);
+		break;
+	case STRTAB_STE_0_CFG_ABORT:
+	default:
+		arm_smmu_make_abort_ste(target);
+		break;
+	}
+}
+
+static int arm_smmu_attach_dev_nested(struct iommu_domain *domain,
+				      struct device *dev)
+{
+	struct arm_smmu_nested_domain *nested_domain =
+		to_smmu_nested_domain(domain);
+	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	struct arm_smmu_attach_state state = {
+		.master = master,
+		.old_domain = iommu_get_domain_for_dev(dev),
+		.ssid = IOMMU_NO_PASID,
+		/* Currently invalidation of ATC is not supported */
+		.disable_ats = true,
+	};
+	struct arm_smmu_ste ste;
+	int ret;
+
+	if (nested_domain->vsmmu->smmu != master->smmu)
+		return -EINVAL;
+	if (arm_smmu_ssids_in_use(&master->cd_table))
+		return -EBUSY;
+
+	mutex_lock(&arm_smmu_asid_lock);
+	ret = arm_smmu_attach_prepare(&state, domain);
+	if (ret) {
+		mutex_unlock(&arm_smmu_asid_lock);
+		return ret;
+	}
+
+	arm_smmu_make_nested_domain_ste(&ste, master, nested_domain,
+					state.ats_enabled);
+	arm_smmu_install_ste_for_dev(master, &ste);
+	arm_smmu_attach_commit(&state);
+	mutex_unlock(&arm_smmu_asid_lock);
+	return 0;
+}
+
+static void arm_smmu_domain_nested_free(struct iommu_domain *domain)
+{
+	kfree(to_smmu_nested_domain(domain));
+}
+
+static const struct iommu_domain_ops arm_smmu_nested_ops = {
+	.attach_dev = arm_smmu_attach_dev_nested,
+	.free = arm_smmu_domain_nested_free,
+};
+
+static int arm_smmu_validate_vste(struct iommu_hwpt_arm_smmuv3 *arg)
+{
+	unsigned int cfg;
+
+	if (!(arg->ste[0] & cpu_to_le64(STRTAB_STE_0_V))) {
+		memset(arg->ste, 0, sizeof(arg->ste));
+		return 0;
+	}
+
+	/* EIO is reserved for invalid STE data. */
+	if ((arg->ste[0] & ~STRTAB_STE_0_NESTING_ALLOWED) ||
+	    (arg->ste[1] & ~STRTAB_STE_1_NESTING_ALLOWED))
+		return -EIO;
+
+	cfg = FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(arg->ste[0]));
+	if (cfg != STRTAB_STE_0_CFG_ABORT && cfg != STRTAB_STE_0_CFG_BYPASS &&
+	    cfg != STRTAB_STE_0_CFG_S1_TRANS)
+		return -EIO;
+	return 0;
+}
+
+static struct iommu_domain *
+arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
+			      const struct iommu_user_data *user_data)
+{
+	struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
+	struct arm_smmu_nested_domain *nested_domain;
+	struct iommu_hwpt_arm_smmuv3 arg;
+	int ret;
+
+	if (flags)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	ret = iommu_copy_struct_from_user(&arg, user_data,
+					  IOMMU_HWPT_DATA_ARM_SMMUV3, ste);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = arm_smmu_validate_vste(&arg);
+	if (ret)
+		return ERR_PTR(ret);
+
+	nested_domain = kzalloc(sizeof(*nested_domain), GFP_KERNEL_ACCOUNT);
+	if (!nested_domain)
+		return ERR_PTR(-ENOMEM);
+
+	nested_domain->domain.type = IOMMU_DOMAIN_NESTED;
+	nested_domain->domain.ops = &arm_smmu_nested_ops;
+	nested_domain->vsmmu = vsmmu;
+	nested_domain->ste[0] = arg.ste[0];
+	nested_domain->ste[1] = arg.ste[1] & ~cpu_to_le64(STRTAB_STE_1_EATS);
+
+	return &nested_domain->domain;
+}
+
 static const struct iommufd_viommu_ops arm_vsmmu_ops = {
+	.alloc_domain_nested = arm_vsmmu_alloc_domain_nested,
 };
 
 struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
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 c425fb923eb3de..53f12b9d78ab21 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -295,6 +295,7 @@  static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
 	case CMDQ_OP_TLBI_NH_ASID:
 		cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
 		fallthrough;
+	case CMDQ_OP_TLBI_NH_ALL:
 	case CMDQ_OP_TLBI_S12_VMALL:
 		cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
 		break;
@@ -2230,6 +2231,15 @@  static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
 	}
 	__arm_smmu_tlb_inv_range(&cmd, iova, size, granule, smmu_domain);
 
+	if (smmu_domain->nest_parent) {
+		/*
+		 * When the S2 domain changes all the nested S1 ASIDs have to be
+		 * flushed too.
+		 */
+		cmd.opcode = CMDQ_OP_TLBI_NH_ALL;
+		arm_smmu_cmdq_issue_cmd_with_sync(smmu_domain->smmu, &cmd);
+	}
+
 	/*
 	 * Unfortunately, this can't be leaf-only since we may have
 	 * zapped an entire table.
@@ -2644,6 +2654,8 @@  to_smmu_domain_devices(struct iommu_domain *domain)
 	if ((domain->type & __IOMMU_DOMAIN_PAGING) ||
 	    domain->type == IOMMU_DOMAIN_SVA)
 		return to_smmu_domain(domain);
+	if (domain->type == IOMMU_DOMAIN_NESTED)
+		return to_smmu_nested_domain(domain)->vsmmu->s2_parent;
 	return NULL;
 }
 
@@ -2716,7 +2728,8 @@  int arm_smmu_attach_prepare(struct arm_smmu_attach_state *state,
 		 * enabled if we have arm_smmu_domain, those always have page
 		 * tables.
 		 */
-		state->ats_enabled = arm_smmu_ats_supported(master);
+		state->ats_enabled = !state->disable_ats &&
+				     arm_smmu_ats_supported(master);
 	}
 
 	if (smmu_domain) {
@@ -3122,6 +3135,7 @@  arm_smmu_domain_alloc_user(struct device *dev, u32 flags,
 			goto err_free;
 		}
 		smmu_domain->stage = ARM_SMMU_DOMAIN_S2;
+		smmu_domain->nest_parent = true;
 	}
 
 	smmu_domain->domain.type = IOMMU_DOMAIN_UNMANAGED;
@@ -3518,6 +3532,7 @@  static struct iommu_ops arm_smmu_ops = {
 	.page_response		= arm_smmu_page_response,
 	.def_domain_type	= arm_smmu_def_domain_type,
 	.viommu_alloc		= arm_vsmmu_alloc,
+	.user_pasid_table	= 1,
 	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
 	.owner			= THIS_MODULE,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
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 3b8013afcec0de..3fabe187ea7815 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -244,6 +244,7 @@  static inline u32 arm_smmu_strtab_l2_idx(u32 sid)
 #define STRTAB_STE_0_CFG_BYPASS		4
 #define STRTAB_STE_0_CFG_S1_TRANS	5
 #define STRTAB_STE_0_CFG_S2_TRANS	6
+#define STRTAB_STE_0_CFG_NESTED		7
 
 #define STRTAB_STE_0_S1FMT		GENMASK_ULL(5, 4)
 #define STRTAB_STE_0_S1FMT_LINEAR	0
@@ -295,6 +296,15 @@  static inline u32 arm_smmu_strtab_l2_idx(u32 sid)
 
 #define STRTAB_STE_3_S2TTB_MASK		GENMASK_ULL(51, 4)
 
+/* These bits can be controlled by userspace for STRTAB_STE_0_CFG_NESTED */
+#define STRTAB_STE_0_NESTING_ALLOWED                                         \
+	cpu_to_le64(STRTAB_STE_0_V | STRTAB_STE_0_CFG | STRTAB_STE_0_S1FMT | \
+		    STRTAB_STE_0_S1CTXPTR_MASK | STRTAB_STE_0_S1CDMAX)
+#define STRTAB_STE_1_NESTING_ALLOWED                            \
+	cpu_to_le64(STRTAB_STE_1_S1DSS | STRTAB_STE_1_S1CIR |   \
+		    STRTAB_STE_1_S1COR | STRTAB_STE_1_S1CSH |   \
+		    STRTAB_STE_1_S1STALLD)
+
 /*
  * Context descriptors.
  *
@@ -514,6 +524,7 @@  struct arm_smmu_cmdq_ent {
 			};
 		} cfgi;
 
+		#define CMDQ_OP_TLBI_NH_ALL     0x10
 		#define CMDQ_OP_TLBI_NH_ASID	0x11
 		#define CMDQ_OP_TLBI_NH_VA	0x12
 		#define CMDQ_OP_TLBI_EL2_ALL	0x20
@@ -815,10 +826,18 @@  struct arm_smmu_domain {
 	struct list_head		devices;
 	spinlock_t			devices_lock;
 	bool				enforce_cache_coherency : 1;
+	bool				nest_parent : 1;
 
 	struct mmu_notifier		mmu_notifier;
 };
 
+struct arm_smmu_nested_domain {
+	struct iommu_domain domain;
+	struct arm_vsmmu *vsmmu;
+
+	__le64 ste[2];
+};
+
 /* The following are exposed for testing purposes. */
 struct arm_smmu_entry_writer_ops;
 struct arm_smmu_entry_writer {
@@ -863,6 +882,12 @@  static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
 	return container_of(dom, struct arm_smmu_domain, domain);
 }
 
+static inline struct arm_smmu_nested_domain *
+to_smmu_nested_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct arm_smmu_nested_domain, domain);
+}
+
 extern struct xarray arm_smmu_asid_xa;
 extern struct mutex arm_smmu_asid_lock;
 
@@ -909,6 +934,7 @@  struct arm_smmu_attach_state {
 	struct iommu_domain *old_domain;
 	struct arm_smmu_master *master;
 	bool cd_needs_ats;
+	bool disable_ats;
 	ioasid_t ssid;
 	/* Resulting state */
 	bool ats_enabled;
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 27c5117db985b2..47ee35ce050b63 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -396,6 +396,26 @@  struct iommu_hwpt_vtd_s1 {
 	__u32 __reserved;
 };
 
+/**
+ * struct iommu_hwpt_arm_smmuv3 - ARM SMMUv3 nested STE
+ *                                (IOMMU_HWPT_DATA_ARM_SMMUV3)
+ *
+ * @ste: The first two double words of the user space Stream Table Entry for
+ *       the translation. Must be little-endian.
+ *       Allowed fields: (Refer to "5.2 Stream Table Entry" in SMMUv3 HW Spec)
+ *       - word-0: V, Cfg, S1Fmt, S1ContextPtr, S1CDMax
+ *       - word-1: S1DSS, S1CIR, S1COR, S1CSH, S1STALLD
+ *
+ * -EIO will be returned if @ste is not legal or contains any non-allowed field.
+ * Cfg can be used to select a S1, Bypass or Abort configuration. A Bypass
+ * nested domain will translate the same as the nesting parent. The S1 will
+ * install a Context Descriptor Table pointing at userspace memory translated
+ * by the nesting parent.
+ */
+struct iommu_hwpt_arm_smmuv3 {
+	__aligned_le64 ste[2];
+};
+
 /**
  * enum iommu_hwpt_data_type - IOMMU HWPT Data Type
  * @IOMMU_HWPT_DATA_NONE: no data