[PATCH 12/14] iommufd: Add IOMMU_HWPT_ALLOC

Jason Gunthorpe
2023-02-25T00:28:13Z

This allows userspace to manually create HWPTs on IOAS's and then use
those HWPTs as inputs to iommufd_device_attach/replace().

Following series will extend this to allow creating iommu_domains with
driver specific parameters.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/iommufd/hw_pagetable.c | 46 +++++++++++++++++++++++++
drivers/iommu/iommufd/iommufd_private.h | 9 +++++
drivers/iommu/iommufd/main.c | 3 ++
include/uapi/linux/iommufd.h | 26 ++++++++++++++
4 files changed, 84 insertions(+)

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 2584f9038b29a2..a1f87193057385 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -3,6 +3,7 @@
* Copyright (c) 2021-2022, NVIDIA CORPORATION & AFFILIATES
*/
#include <linux/iommu.h>
+#include <uapi/linux/iommufd.h>

#include "iommufd_private.h"

@@ -121,3 +122,48 @@ iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,
iommufd_object_abort_and_destroy(ictx, &hwpt->obj);
return ERR_PTR(rc);
}
+
+int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_hwpt_alloc *cmd = ucmd->cmd;
+ struct iommufd_hw_pagetable *hwpt;
+ struct iommufd_device *idev;
+ struct iommufd_ioas *ioas;
+ int rc;
+
+ if (cmd->flags)
+ return -EOPNOTSUPP;
+
+ idev = iommufd_get_device(ucmd, cmd->dev_id);
+ if (IS_ERR(idev))
+ return PTR_ERR(idev);
+
+ ioas = iommufd_get_ioas(ucmd, cmd->pt_id);
+ if (IS_ERR(ioas)) {
+ rc = PTR_ERR(idev);
+ goto out_put_idev;
+ }
+
+ mutex_lock(&ioas->mutex);
+ hwpt = iommufd_hw_pagetable_alloc(ucmd->ictx, ioas, idev, false);
+ mutex_unlock(&ioas->mutex);
+ if (IS_ERR(hwpt)) {
+ rc = PTR_ERR(idev);
+ goto out_put_ioas;
+ }
+
+ cmd->out_hwpt_id = hwpt->obj.id;
+ rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+ if (rc)
+ goto out_hwpt;
+ iommufd_object_finalize(ucmd->ictx, &hwpt->obj);
+ goto out_put_ioas;
+
+out_hwpt:
+ iommufd_object_abort_and_destroy(ucmd->ictx, &hwpt->obj);
+out_put_ioas:
+ iommufd_put_object(&ioas->obj);
+out_put_idev:
+ iommufd_put_object(&idev->obj);
+ return rc;
+}
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index cfcda73942b533..c9acc70d84f794 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -261,6 +261,7 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
struct iommufd_hw_pagetable *
iommufd_hw_pagetable_detach(struct iommufd_device *idev);
void iommufd_hw_pagetable_destroy(struct iommufd_object *obj);
+int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd);

static inline void iommufd_hw_pagetable_put(struct iommufd_ctx *ictx,
struct iommufd_hw_pagetable *hwpt)
@@ -296,6 +297,14 @@ struct iommufd_device {
bool enforce_cache_coherency;
};

+static inline struct iommufd_device *
+iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id)
+{
+ return container_of(iommufd_get_object(ucmd->ictx, id,
+ IOMMUFD_OBJ_DEVICE),
+ struct iommufd_device, obj);
+}
+
void iommufd_device_destroy(struct iommufd_object *obj);

struct iommufd_access {
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 9cba592d0482e7..694da191e4b155 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -261,6 +261,7 @@ static int iommufd_option(struct iommufd_ucmd *ucmd)

union ucmd_buffer {
struct iommu_destroy destroy;
+ struct iommu_hwpt_alloc hwpt;
struct iommu_ioas_alloc alloc;
struct iommu_ioas_allow_iovas allow_iovas;
struct iommu_ioas_copy ioas_copy;
@@ -292,6 +293,8 @@ struct iommufd_ioctl_op {
}
static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct iommu_destroy, id),
+ IOCTL_OP(IOMMU_HWPT_ALLOC, iommufd_hwpt_alloc, struct iommu_hwpt_alloc,
+ __reserved),
IOCTL_OP(IOMMU_IOAS_ALLOC, iommufd_ioas_alloc_ioctl,
struct iommu_ioas_alloc, out_ioas_id),
IOCTL_OP(IOMMU_IOAS_ALLOW_IOVAS, iommufd_ioas_allow_iovas,
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 98ebba80cfa1fc..ccd36acad36a3f 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -45,6 +45,7 @@ enum {
IOMMUFD_CMD_IOAS_UNMAP,
IOMMUFD_CMD_OPTION,
IOMMUFD_CMD_VFIO_IOAS,
+ IOMMUFD_CMD_HWPT_ALLOC,
};

/**
@@ -344,4 +345,29 @@ struct iommu_vfio_ioas {
__u16 __reserved;
};
#define IOMMU_VFIO_IOAS _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VFIO_IOAS)
+
+/**
+ * struct iommu_hwpt_alloc - ioctl(IOMMU_HWPT_ALLOC)
+ * @size: sizeof(struct iommu_hwpt_alloc)
+ * @flags: Must be 0
+ * @dev_id: The device to allocate this HWPT for
+ * @pt_id: The IOAS to connect this HWPT to
+ * @out_hwpt_id: The ID of the new HWPT
+ * @__reserved: Must be 0
+ *
+ * Explicitly allocate a hardware page table object. This is the same object
+ * type that is returned by iommufd_device_attach() and represents the
+ * underlying iommu driver's iommu_domain kernel object.
+ *
+ * A normal HWPT will be created with the mappings from the given IOAS.
+ */
+struct iommu_hwpt_alloc {
+ __u32 size;
+ __u32 flags;
+ __u32 dev_id;
+ __u32 pt_id;
+ __u32 out_hwpt_id;
+ __u32 __reserved;
+};
+#define IOMMU_HWPT_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_ALLOC)
#endif
--
2.39.1