[PATCH v4 08/12] iommu/arm-smmu-v3: Support IOMMU_VIOMMU_ALLOC

Jason Gunthorpe
2024-10-31T00:21:08Z

From: Nicolin Chen <nicolinc@nvidia.com>

Add a new driver-type for ARM SMMUv3 to enum iommu_viommu_type. Implement
an arm_vsmmu_alloc().

As an initial step, copy the VMID from s2_parent. A followup series is
required to give the VIOMMU object it's own VMID that will be used in all
nesting configurations.

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 | 45 +++++++++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 1 +
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 13 ++++++
include/uapi/linux/iommufd.h | 4 ++
4 files changed, 63 insertions(+)

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 3d2671031c9bb5..60dd9e90759571 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
@@ -29,3 +29,48 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type)

return info;
}
+
+static const struct iommufd_viommu_ops arm_vsmmu_ops = {
+};
+
+struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
+ struct iommu_domain *parent,
+ struct iommufd_ctx *ictx,
+ unsigned int viommu_type)
+{
+ struct arm_smmu_device *smmu =
+ iommu_get_iommu_dev(dev, struct arm_smmu_device, iommu);
+ struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+ struct arm_smmu_domain *s2_parent = to_smmu_domain(parent);
+ struct arm_vsmmu *vsmmu;
+
+ if (viommu_type != IOMMU_VIOMMU_TYPE_ARM_SMMUV3)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ if (!(smmu->features & ARM_SMMU_FEAT_NESTING))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ if (s2_parent->smmu != master->smmu)
+ return ERR_PTR(-EINVAL);
+
+ /*
+ * Must support some way to prevent the VM from bypassing the cache
+ * because VFIO currently does not do any cache maintenance. canwbs
+ * indicates the device is fully coherent and no cache maintenance is
+ * ever required, even for PCI No-Snoop.
+ */
+ if (!arm_smmu_master_canwbs(master))
+ return ERR_PTR(-EOPNOTSUPP);
+
+ vsmmu = iommufd_viommu_alloc(ictx, struct arm_vsmmu, core,
+ &arm_vsmmu_ops);
+ if (IS_ERR(vsmmu))
+ return ERR_CAST(vsmmu);
+
+ vsmmu->smmu = smmu;
+ vsmmu->s2_parent = s2_parent;
+ /* FIXME Move VMID allocation from the S2 domain allocation to here */
+ vsmmu->vmid = s2_parent->s2_cfg.vmid;
+
+ return &vsmmu->core;
+}
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 b4b03206afbf48..c425fb923eb3de 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -3517,6 +3517,7 @@ static struct iommu_ops arm_smmu_ops = {
.dev_disable_feat = arm_smmu_dev_disable_feature,
.page_response = arm_smmu_page_response,
.def_domain_type = arm_smmu_def_domain_type,
+ .viommu_alloc = arm_vsmmu_alloc,
.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 c9e5290e995a64..3b8013afcec0de 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -10,6 +10,7 @@

#include <linux/bitfield.h>
#include <linux/iommu.h>
+#include <linux/iommufd.h>
#include <linux/kernel.h>
#include <linux/mmzone.h>
#include <linux/sizes.h>
@@ -976,10 +977,22 @@ tegra241_cmdqv_probe(struct arm_smmu_device *smmu)
}
#endif /* CONFIG_TEGRA241_CMDQV */

+struct arm_vsmmu {
+ struct iommufd_viommu core;
+ struct arm_smmu_device *smmu;
+ struct arm_smmu_domain *s2_parent;
+ u16 vmid;
+};
+
#if IS_ENABLED(CONFIG_ARM_SMMU_V3_IOMMUFD)
void *arm_smmu_hw_info(struct device *dev, u32 *length, u32 *type);
+struct iommufd_viommu *arm_vsmmu_alloc(struct device *dev,
+ struct iommu_domain *parent,
+ struct iommufd_ctx *ictx,
+ unsigned int viommu_type);
#else
#define arm_smmu_hw_info NULL
+#define arm_vsmmu_alloc NULL
#endif /* CONFIG_ARM_SMMU_V3_IOMMUFD */

#endif /* _ARM_SMMU_V3_H */
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index b227ac16333fe1..27c5117db985b2 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -400,10 +400,12 @@ struct iommu_hwpt_vtd_s1 {
* enum iommu_hwpt_data_type - IOMMU HWPT Data Type
* @IOMMU_HWPT_DATA_NONE: no data
* @IOMMU_HWPT_DATA_VTD_S1: Intel VT-d stage-1 page table
+ * @IOMMU_HWPT_DATA_ARM_SMMUV3: ARM SMMUv3 Context Descriptor Table
*/
enum iommu_hwpt_data_type {
IOMMU_HWPT_DATA_NONE = 0,
IOMMU_HWPT_DATA_VTD_S1 = 1,
+ IOMMU_HWPT_DATA_ARM_SMMUV3 = 2,
};

/**
@@ -843,9 +845,11 @@ struct iommu_fault_alloc {
/**
* enum iommu_viommu_type - Virtual IOMMU Type
* @IOMMU_VIOMMU_TYPE_DEFAULT: Reserved for future use
+ * @IOMMU_VIOMMU_TYPE_ARM_SMMUV3: ARM SMMUv3 driver specific type
*/
enum iommu_viommu_type {
IOMMU_VIOMMU_TYPE_DEFAULT = 0,
+ IOMMU_VIOMMU_TYPE_ARM_SMMUV3 = 1,
};

/**
--
2.43.0