diff mbox series

[v4,06/14] iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC

Message ID d0edfde78e75b6941589392e618f6d43b3f10e6b.1735933254.git.nicolinc@nvidia.com (mailing list archive)
State New
Headers show
Series iommufd: Add vIOMMU infrastructure (Part-3: vEVENTQ) | expand

Commit Message

Nicolin Chen Jan. 3, 2025, 7:43 p.m. UTC
Introduce a new IOMMUFD_OBJ_VEVENTQ object for vIOMMU Event Queue that
provides user space (VMM) another FD to read the vIOMMU Events.

Allow a vIOMMU object to allocate vEVENTQs, with a condition that each
vIOMMU can only have one single vEVENTQ per type.

Add iommufd_veventq_alloc() with iommufd_veventq_ops for the new ioctl.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/iommufd_private.h |  58 +++++++++++
 include/linux/iommufd.h                 |   3 +
 include/uapi/linux/iommufd.h            |  31 ++++++
 drivers/iommu/iommufd/eventq.c          | 129 ++++++++++++++++++++++++
 drivers/iommu/iommufd/main.c            |   7 ++
 drivers/iommu/iommufd/viommu.c          |   2 +
 6 files changed, 230 insertions(+)

Comments

Baolu Lu Jan. 6, 2025, 2:50 a.m. UTC | #1
On 1/4/25 03:43, Nicolin Chen wrote:
> Introduce a new IOMMUFD_OBJ_VEVENTQ object for vIOMMU Event Queue that
> provides user space (VMM) another FD to read the vIOMMU Events.
> 
> Allow a vIOMMU object to allocate vEVENTQs, with a condition that each
> vIOMMU can only have one single vEVENTQ per type.
> 
> Add iommufd_veventq_alloc() with iommufd_veventq_ops for the new ioctl.
> 
> Signed-off-by: Nicolin Chen<nicolinc@nvidia.com>
> ---
>   drivers/iommu/iommufd/iommufd_private.h |  58 +++++++++++
>   include/linux/iommufd.h                 |   3 +
>   include/uapi/linux/iommufd.h            |  31 ++++++
>   drivers/iommu/iommufd/eventq.c          | 129 ++++++++++++++++++++++++
>   drivers/iommu/iommufd/main.c            |   7 ++
>   drivers/iommu/iommufd/viommu.c          |   2 +
>   6 files changed, 230 insertions(+)

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
diff mbox series

Patch

diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index dfbc5cfbd164..9410f6275b5a 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -547,6 +547,50 @@  static inline int iommufd_hwpt_replace_device(struct iommufd_device *idev,
 	return iommu_group_replace_domain(idev->igroup->group, hwpt->domain);
 }
 
+/*
+ * An iommufd_veventq object represents an interface to deliver vIOMMU events to
+ * the user space. It is created/destroyed by the user space and associated with
+ * vIOMMU object(s) during the allocations.
+ */
+struct iommufd_veventq {
+	struct iommufd_eventq common;
+	struct iommufd_viommu *viommu;
+	struct list_head node; /* for iommufd_viommu::veventqs */
+
+	unsigned int type;
+};
+
+static inline struct iommufd_veventq *
+eventq_to_veventq(struct iommufd_eventq *eventq)
+{
+	return container_of(eventq, struct iommufd_veventq, common);
+}
+
+static inline struct iommufd_veventq *
+iommufd_get_veventq(struct iommufd_ucmd *ucmd, u32 id)
+{
+	return container_of(iommufd_get_object(ucmd->ictx, id,
+					       IOMMUFD_OBJ_VEVENTQ),
+			    struct iommufd_veventq, common.obj);
+}
+
+int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd);
+void iommufd_veventq_destroy(struct iommufd_object *obj);
+void iommufd_veventq_abort(struct iommufd_object *obj);
+
+/* An iommufd_vevent represents a vIOMMU event in an iommufd_veventq */
+struct iommufd_vevent {
+	struct list_head node; /* for iommufd_eventq::deliver */
+	ssize_t data_len;
+	u64 event_data[] __counted_by(data_len);
+};
+
+static inline int iommufd_vevent_handler(struct iommufd_veventq *veventq,
+					  struct iommufd_vevent *vevent)
+{
+	return iommufd_eventq_notify(&veventq->common, &vevent->node);
+}
+
 static inline struct iommufd_viommu *
 iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
 {
@@ -555,6 +599,20 @@  iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
 			    struct iommufd_viommu, obj);
 }
 
+static inline struct iommufd_veventq *
+iommufd_viommu_find_veventq(struct iommufd_viommu *viommu, u32 type)
+{
+	struct iommufd_veventq *veventq, *next;
+
+	lockdep_assert_held(&viommu->veventqs_rwsem);
+
+	list_for_each_entry_safe(veventq, next, &viommu->veventqs, node) {
+		if (veventq->type == type)
+			return veventq;
+	}
+	return NULL;
+}
+
 int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
 void iommufd_viommu_destroy(struct iommufd_object *obj);
 int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd);
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 11110c749200..8948b1836940 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -34,6 +34,7 @@  enum iommufd_object_type {
 	IOMMUFD_OBJ_FAULT,
 	IOMMUFD_OBJ_VIOMMU,
 	IOMMUFD_OBJ_VDEVICE,
+	IOMMUFD_OBJ_VEVENTQ,
 #ifdef CONFIG_IOMMUFD_TEST
 	IOMMUFD_OBJ_SELFTEST,
 #endif
@@ -93,6 +94,8 @@  struct iommufd_viommu {
 	const struct iommufd_viommu_ops *ops;
 
 	struct xarray vdevs;
+	struct list_head veventqs;
+	struct rw_semaphore veventqs_rwsem;
 
 	unsigned int type;
 };
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 34810f6ae2b5..0a08aa82e7cc 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -55,6 +55,7 @@  enum {
 	IOMMUFD_CMD_VIOMMU_ALLOC = 0x90,
 	IOMMUFD_CMD_VDEVICE_ALLOC = 0x91,
 	IOMMUFD_CMD_IOAS_CHANGE_PROCESS = 0x92,
+	IOMMUFD_CMD_VEVENTQ_ALLOC = 0x93,
 };
 
 /**
@@ -1012,4 +1013,34 @@  struct iommu_ioas_change_process {
 #define IOMMU_IOAS_CHANGE_PROCESS \
 	_IO(IOMMUFD_TYPE, IOMMUFD_CMD_IOAS_CHANGE_PROCESS)
 
+/**
+ * enum iommu_veventq_type - Virtual Event Queue Type
+ * @IOMMU_VEVENTQ_TYPE_DEFAULT: Reserved for future use
+ */
+enum iommu_veventq_type {
+	IOMMU_VEVENTQ_TYPE_DEFAULT = 0,
+};
+
+/**
+ * struct iommu_veventq_alloc - ioctl(IOMMU_VEVENTQ_ALLOC)
+ * @size: sizeof(struct iommu_veventq_alloc)
+ * @flags: Must be 0
+ * @viommu: virtual IOMMU ID to associate the vEVENTQ with
+ * @type: Type of the vEVENTQ. Must be defined in enum iommu_veventq_type
+ * @out_veventq_id: The ID of the new vEVENTQ
+ * @out_veventq_fd: The fd of the new vEVENTQ. User space must close the
+ *                  successfully returned fd after using it
+ *
+ * Explicitly allocate a virtual event queue interface for a vIOMMU. A vIOMMU
+ * can have multiple FDs for different types, but is confined to one per @type.
+ */
+struct iommu_veventq_alloc {
+	__u32 size;
+	__u32 flags;
+	__u32 viommu_id;
+	__u32 type;
+	__u32 out_veventq_id;
+	__u32 out_veventq_fd;
+};
+#define IOMMU_VEVENTQ_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VEVENTQ_ALLOC)
 #endif
diff --git a/drivers/iommu/iommufd/eventq.c b/drivers/iommu/iommufd/eventq.c
index e386b6c3e6ab..bf0c04f571a7 100644
--- a/drivers/iommu/iommufd/eventq.c
+++ b/drivers/iommu/iommufd/eventq.c
@@ -346,6 +346,73 @@  static const struct iommufd_eventq_ops iommufd_fault_ops = {
 	.write = &iommufd_fault_fops_write,
 };
 
+/* IOMMUFD_OBJ_VEVENTQ Functions */
+
+void iommufd_veventq_abort(struct iommufd_object *obj)
+{
+	struct iommufd_eventq *eventq =
+		container_of(obj, struct iommufd_eventq, obj);
+	struct iommufd_veventq *veventq = eventq_to_veventq(eventq);
+	struct iommufd_viommu *viommu = veventq->viommu;
+	struct iommufd_vevent *cur, *next;
+
+	lockdep_assert_held_write(&viommu->veventqs_rwsem);
+
+	list_for_each_entry_safe(cur, next, &eventq->deliver, node) {
+		list_del(&cur->node);
+		kfree(cur);
+	}
+
+	refcount_dec(&viommu->obj.users);
+	mutex_destroy(&eventq->mutex);
+	list_del(&veventq->node);
+}
+
+void iommufd_veventq_destroy(struct iommufd_object *obj)
+{
+	struct iommufd_veventq *veventq = eventq_to_veventq(
+		container_of(obj, struct iommufd_eventq, obj));
+
+	down_write(&veventq->viommu->veventqs_rwsem);
+	iommufd_veventq_abort(obj);
+	up_write(&veventq->viommu->veventqs_rwsem);
+}
+
+static ssize_t iommufd_veventq_fops_read(struct iommufd_eventq *eventq,
+					 char __user *buf, size_t count,
+					 loff_t *ppos)
+{
+	size_t done = 0;
+	int rc = 0;
+
+	if (*ppos)
+		return -ESPIPE;
+
+	mutex_lock(&eventq->mutex);
+	while (!list_empty(&eventq->deliver) && count > done) {
+		struct iommufd_vevent *cur = list_first_entry(
+			&eventq->deliver, struct iommufd_vevent, node);
+
+		if (cur->data_len > count - done)
+			break;
+
+		if (copy_to_user(buf + done, cur->event_data, cur->data_len)) {
+			rc = -EFAULT;
+			break;
+		}
+		done += cur->data_len;
+		list_del(&cur->node);
+		kfree(cur);
+	}
+	mutex_unlock(&eventq->mutex);
+
+	return done == 0 ? rc : done;
+}
+
+static const struct iommufd_eventq_ops iommufd_veventq_ops = {
+	.read = &iommufd_veventq_fops_read,
+};
+
 /* Common Event Queue Functions */
 
 static ssize_t iommufd_eventq_fops_read(struct file *filep, char __user *buf,
@@ -473,3 +540,65 @@  int iommufd_fault_alloc(struct iommufd_ucmd *ucmd)
 
 	return rc;
 }
+
+int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_veventq_alloc *cmd = ucmd->cmd;
+	struct iommufd_veventq *veventq;
+	struct iommufd_viommu *viommu;
+	int fdno;
+	int rc;
+
+	if (cmd->flags || cmd->type == IOMMU_VEVENTQ_TYPE_DEFAULT)
+		return -EOPNOTSUPP;
+
+	viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+	if (IS_ERR(viommu))
+		return PTR_ERR(viommu);
+	down_write(&viommu->veventqs_rwsem);
+
+	if (iommufd_viommu_find_veventq(viommu, cmd->type)) {
+		rc = -EEXIST;
+		goto out_unlock_veventqs;
+	}
+
+	veventq = __iommufd_object_alloc(ucmd->ictx, veventq,
+					 IOMMUFD_OBJ_VEVENTQ, common.obj);
+	if (IS_ERR(veventq)) {
+		rc = PTR_ERR(veventq);
+		goto out_unlock_veventqs;
+	}
+
+	veventq->type = cmd->type;
+	veventq->viommu = viommu;
+	refcount_inc(&viommu->obj.users);
+	list_add_tail(&veventq->node, &viommu->veventqs);
+
+	fdno = iommufd_eventq_init(&veventq->common, "[iommufd-viommu-event]",
+				   ucmd->ictx, &iommufd_veventq_ops);
+	if (fdno < 0) {
+		rc = fdno;
+		goto out_abort;
+	}
+
+	cmd->out_veventq_id = veventq->common.obj.id;
+	cmd->out_veventq_fd = fdno;
+
+	rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+	if (rc)
+		goto out_put_fdno;
+
+	iommufd_object_finalize(ucmd->ictx, &veventq->common.obj);
+	fd_install(fdno, veventq->common.filep);
+	goto out_unlock_veventqs;
+
+out_put_fdno:
+	put_unused_fd(fdno);
+	fput(veventq->common.filep);
+out_abort:
+	iommufd_object_abort_and_destroy(ucmd->ictx, &veventq->common.obj);
+out_unlock_veventqs:
+	up_write(&viommu->veventqs_rwsem);
+	iommufd_put_object(ucmd->ictx, &viommu->obj);
+	return rc;
+}
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 49be19305d98..985661a4af07 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -310,6 +310,7 @@  union ucmd_buffer {
 	struct iommu_vdevice_alloc vdev;
 	struct iommu_vfio_ioas vfio_ioas;
 	struct iommu_viommu_alloc viommu;
+	struct iommu_veventq_alloc veventq;
 #ifdef CONFIG_IOMMUFD_TEST
 	struct iommu_test_cmd test;
 #endif
@@ -367,6 +368,8 @@  static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 __reserved),
 	IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
 		 struct iommu_viommu_alloc, out_viommu_id),
+	IOCTL_OP(IOMMU_VEVENTQ_ALLOC, iommufd_veventq_alloc,
+		 struct iommu_veventq_alloc, out_veventq_fd),
 #ifdef CONFIG_IOMMUFD_TEST
 	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
@@ -502,6 +505,10 @@  static const struct iommufd_object_ops iommufd_object_ops[] = {
 	[IOMMUFD_OBJ_FAULT] = {
 		.destroy = iommufd_fault_destroy,
 	},
+	[IOMMUFD_OBJ_VEVENTQ] = {
+		.destroy = iommufd_veventq_destroy,
+		.abort = iommufd_veventq_abort,
+	},
 	[IOMMUFD_OBJ_VIOMMU] = {
 		.destroy = iommufd_viommu_destroy,
 	},
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 69b88e8c7c26..01df2b985f02 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -59,6 +59,8 @@  int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
 	viommu->ictx = ucmd->ictx;
 	viommu->hwpt = hwpt_paging;
 	refcount_inc(&viommu->hwpt->common.obj.users);
+	INIT_LIST_HEAD(&viommu->veventqs);
+	init_rwsem(&viommu->veventqs_rwsem);
 	/*
 	 * It is the most likely case that a physical IOMMU is unpluggable. A
 	 * pluggable IOMMU instance (if exists) is responsible for refcounting