[PATCH v4 09/10] PCI/TSM: Report active IDE streams

[Dan Williams <dan.j.williams@intel.com>]

Given that the platform TSM owns IDE Stream ID allocation, report the
active streams via the TSM class device. Establish a symlink from the
class device to the PCI endpoint device consuming the stream, named by
the Stream ID.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 Documentation/ABI/testing/sysfs-class-tsm | 10 ++++++++
 drivers/pci/ide.c                         |  4 ++++
 drivers/virt/coco/tsm-core.c              | 28 +++++++++++++++++++++++
 include/linux/pci-ide.h                   |  2 ++
 include/linux/tsm.h                       |  4 ++++
 5 files changed, 48 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-tsm b/Documentation/ABI/testing/sysfs-class-tsm
index 2949468deaf7..6fc1a5ac6da1 100644
--- a/Documentation/ABI/testing/sysfs-class-tsm
+++ b/Documentation/ABI/testing/sysfs-class-tsm
@@ -7,3 +7,13 @@ Description:
 		signals when the PCI layer is able to support establishment of
 		link encryption and other device-security features coordinated
 		through a platform tsm.
+
+What:		/sys/class/tsm/tsmN/streamH.R.E
+Contact:	linux-pci@vger.kernel.org
+Description:
+		(RO) When a host bridge has established a secure connection via
+		the platform TSM, symlink appears. The primary function of this
+		is have a system global review of TSM resource consumption
+		across host bridges. The link points to the endpoint PCI device
+		and matches the same link published by the host bridge. See
+		Documentation/ABI/testing/sysfs-devices-pci-host-bridge.
diff --git a/drivers/pci/ide.c b/drivers/pci/ide.c
index cafbc740a9da..923b0db4803c 100644
--- a/drivers/pci/ide.c
+++ b/drivers/pci/ide.c
@@ -5,6 +5,7 @@
 
 #define dev_fmt(fmt) "PCI/IDE: " fmt
 #include <linux/pci.h>
+#include <linux/tsm.h>
 #include <linux/sysfs.h>
 #include <linux/pci-ide.h>
 #include <linux/bitfield.h>
@@ -271,6 +272,9 @@ void pci_ide_stream_release(struct pci_ide *ide)
 	if (ide->partner[PCI_IDE_EP].enable)
 		pci_ide_stream_disable(pdev, ide);
 
+	if (ide->tsm_dev)
+		tsm_ide_stream_unregister(ide);
+
 	if (ide->partner[PCI_IDE_RP].setup)
 		pci_ide_stream_teardown(rp, ide);
 
diff --git a/drivers/virt/coco/tsm-core.c b/drivers/virt/coco/tsm-core.c
index 093824dc68dd..b0ef9089e0f2 100644
--- a/drivers/virt/coco/tsm-core.c
+++ b/drivers/virt/coco/tsm-core.c
@@ -2,14 +2,17 @@
 /* Copyright(c) 2024 Intel Corporation. All rights reserved. */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#define dev_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/tsm.h>
 #include <linux/idr.h>
+#include <linux/pci.h>
 #include <linux/rwsem.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/cleanup.h>
 #include <linux/pci-tsm.h>
+#include <linux/pci-ide.h>
 
 static struct class *tsm_class;
 static DECLARE_RWSEM(tsm_rwsem);
@@ -140,6 +143,31 @@ void tsm_unregister(struct tsm_dev *tsm_dev)
 }
 EXPORT_SYMBOL_GPL(tsm_unregister);
 
+/* must be invoked between tsm_register / tsm_unregister */
+int tsm_ide_stream_register(struct pci_ide *ide)
+{
+	struct pci_dev *pdev = ide->pdev;
+	struct pci_tsm *tsm = pdev->tsm;
+	struct tsm_dev *tsm_dev = tsm->ops->owner;
+	int rc;
+
+	rc = sysfs_create_link(&tsm_dev->dev.kobj, &pdev->dev.kobj,
+				 ide->name);
+	if (rc == 0)
+		ide->tsm_dev = tsm_dev;
+	return rc;
+}
+EXPORT_SYMBOL_GPL(tsm_ide_stream_register);
+
+void tsm_ide_stream_unregister(struct pci_ide *ide)
+{
+	struct tsm_dev *tsm_dev = ide->tsm_dev;
+
+	sysfs_remove_link(&tsm_dev->dev.kobj, ide->name);
+	ide->tsm_dev = NULL;
+}
+EXPORT_SYMBOL_GPL(tsm_ide_stream_unregister);
+
 static void tsm_release(struct device *dev)
 {
 	struct tsm_dev *tsm_dev = container_of(dev, typeof(*tsm_dev), dev);
diff --git a/include/linux/pci-ide.h b/include/linux/pci-ide.h
index 89c1ef0de841..36290bdaf51f 100644
--- a/include/linux/pci-ide.h
+++ b/include/linux/pci-ide.h
@@ -42,6 +42,7 @@ struct pci_ide_partner {
  * @host_bridge_stream: track platform Stream ID
  * @stream_id: unique Stream ID (within Partner Port pairing)
  * @name: name of the established Selective IDE Stream in sysfs
+ * @tsm_dev: For TSM established IDE, the TSM device context
  *
  * Negative @stream_id values indicate "uninitialized" on the
  * expectation that with TSM established IDE the TSM owns the stream_id
@@ -53,6 +54,7 @@ struct pci_ide {
 	u8 host_bridge_stream;
 	int stream_id;
 	const char *name;
+	struct tsm_dev *tsm_dev;
 };
 
 int pci_ide_domain(struct pci_dev *pdev);
diff --git a/include/linux/tsm.h b/include/linux/tsm.h
index ce95589a5d5b..4eba45a754ec 100644
--- a/include/linux/tsm.h
+++ b/include/linux/tsm.h
@@ -120,4 +120,8 @@ const char *tsm_name(const struct tsm_dev *tsm_dev);
 struct tsm_dev *find_tsm_dev(int id);
 const struct pci_tsm_ops *tsm_pci_ops(const struct tsm_dev *tsm_dev);
 const struct attribute_group *tsm_pci_group(const struct tsm_dev *tsm_dev);
+struct pci_dev;
+struct pci_ide;
+int tsm_ide_stream_register(struct pci_ide *ide);
+void tsm_ide_stream_unregister(struct pci_ide *ide);
 #endif /* __TSM_H */
-- 
2.50.1