The limited number of link-encryption (IDE) streams that a given set of
host bridges supports is a platform specific detail. Provide
pci_ide_init_nr_streams() as a generic facility for either platform TSM
drivers, or PCI core native IDE, to report the number available streams.
After invoking pci_ide_init_nr_streams() an "available_secure_streams"
attribute appears in PCI host bridge sysfs to convey that count.
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Samuel Ortiz <sameo@xxxxxxxxxxxx>
Cc: Alexey Kardashevskiy <aik@xxxxxxx>
Cc: Xu Yilun <yilun.xu@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
.../ABI/testing/sysfs-devices-pci-host-bridge | 12 ++++
drivers/pci/ide.c | 58 ++++++++++++++++++++
drivers/pci/pci.h | 3 +
drivers/pci/probe.c | 12 ++++
include/linux/pci.h | 8 +++
5 files changed, 92 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-pci-host-bridge b/Documentation/ABI/testing/sysfs-devices-pci-host-bridge
index 51dc9eed9353..4624469e56d4 100644
--- a/Documentation/ABI/testing/sysfs-devices-pci-host-bridge
+++ b/Documentation/ABI/testing/sysfs-devices-pci-host-bridge
@@ -20,6 +20,7 @@ What: pciDDDD:BB/streamH.R.E:DDDD:BB:DD:F
Date: December, 2024
Contact: linux-pci@xxxxxxxxxxxxxxx
Description:
+<<<<<<< current
(RO) When a platform has established a secure connection, PCIe
IDE, between two Partner Ports, this symlink appears. The
primary function is to account the stream slot / resources
@@ -30,3 +31,14 @@ Description:
assigned Selective IDE Stream Register Block in the Root Port
and Endpoint, and H represents a platform specific pool of
stream resources shared by the Root Ports in a host bridge.
+
+What: pciDDDD:BB/available_secure_streams
+Date: December, 2024
+Contact: linux-pci@xxxxxxxxxxxxxxx
+Description:
+ (RO) When a host bridge has Root Ports that support PCIe IDE
+ (link encryption and integrity protection) there may be a
+ limited number of streams that can be used for establishing new
+ secure links. This attribute decrements upon secure link setup,
+ and increments upon secure link teardown. The in-use stream
+ count is determined by counting stream symlinks.
diff --git a/drivers/pci/ide.c b/drivers/pci/ide.c
index b2091f6260e6..0c72985e6a65 100644
--- a/drivers/pci/ide.c
+++ b/drivers/pci/ide.c
@@ -439,3 +439,61 @@ void pci_ide_stream_disable(struct pci_dev *pdev, struct pci_ide *ide)
pci_write_config_dword(pdev, pos + PCI_IDE_SEL_CTL, 0);
}
EXPORT_SYMBOL_GPL(pci_ide_stream_disable);
+
+static ssize_t available_secure_streams_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_host_bridge *hb = to_pci_host_bridge(dev);
+ int avail;
+
+ if (hb->nr_ide_streams < 0)
+ return -ENXIO;
+
+ avail = hb->nr_ide_streams -
+ bitmap_weight(hb->ide_stream_map, hb->nr_ide_streams);
+ return sysfs_emit(buf, "%d\n", avail);
+}
+static DEVICE_ATTR_RO(available_secure_streams);
+
+static struct attribute *pci_ide_attrs[] = {
+ &dev_attr_available_secure_streams.attr,
+ NULL,
+};
+
+static umode_t pci_ide_attr_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct pci_host_bridge *hb = to_pci_host_bridge(dev);
+
+ if (a == &dev_attr_available_secure_streams.attr)
+ if (hb->nr_ide_streams < 0)
+ return 0;
+
+ return a->mode;
+}
+
+struct attribute_group pci_ide_attr_group = {
+ .attrs = pci_ide_attrs,
+ .is_visible = pci_ide_attr_visible,
+};
+
+/**
+ * pci_init_nr_ide_streams() - size the pool of IDE Stream resources
+ * @hb: host bridge boundary for the stream pool
+ * @nr: number of streams
+ *
+ * Enable IDE Stream establishment by setting the number of stream
+ * resources available at the host bridge. Platform init code must set
+ * this before the first pci_ide_stream_alloc() call.
+ *
+ * The "PCI_IDE" symbol namespace is required because this is typically
+ * a detail that is settled in early PCI init, i.e. only an expert or
+ * test module should consume this export.
+ */
+void pci_ide_init_nr_streams(struct pci_host_bridge *hb, int nr)
+{
+ hb->nr_ide_streams = nr;
+ sysfs_update_group(&hb->dev.kobj, &pci_ide_attr_group);
+}
+EXPORT_SYMBOL_NS_GPL(pci_ide_init_nr_streams, "PCI_IDE");
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index b38bdd91e742..6c050eb9a91b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -458,8 +458,11 @@ static inline void pci_npem_remove(struct pci_dev *dev) { }
#ifdef CONFIG_PCI_IDE
void pci_ide_init(struct pci_dev *dev);
+extern struct attribute_group pci_ide_attr_group;
+#define PCI_IDE_ATTR_GROUP (&pci_ide_attr_group)
#else
static inline void pci_ide_init(struct pci_dev *dev) { }
+#define PCI_IDE_ATTR_GROUP NULL
#endif
#ifdef CONFIG_PCI_TSM
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index e1c915629864..a383cc32c84b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -633,6 +633,16 @@ static void pci_release_host_bridge_dev(struct device *dev)
kfree(bridge);
}
+static const struct attribute_group *pci_host_bridge_groups[] = {
+ PCI_IDE_ATTR_GROUP,
+ NULL,
+};
+
+static const struct device_type pci_host_bridge_type = {
+ .groups = pci_host_bridge_groups,
+ .release = pci_release_host_bridge_dev,
+};
+
static void pci_init_host_bridge(struct pci_host_bridge *bridge)
{
INIT_LIST_HEAD(&bridge->windows);
@@ -652,6 +662,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
bridge->native_dpc = 1;
bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET;
bridge->native_cxl_error = 1;
+ bridge->dev.type = &pci_host_bridge_type;
device_initialize(&bridge->dev);
}
@@ -665,7 +676,6 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
return NULL;
pci_init_host_bridge(bridge);
- bridge->dev.release = pci_release_host_bridge_dev;
return bridge;
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 0f9d6aece346..c2f18f31f7a7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -660,6 +660,14 @@ void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
void (*release_fn)(struct pci_host_bridge *),
void *release_data);
+#ifdef CONFIG_PCI_IDE
+void pci_ide_init_nr_streams(struct pci_host_bridge *hb, int nr);
+#else
+static inline void pci_ide_init_nr_streams(struct pci_host_bridge *hb, int nr)
+{
+}
+#endif
+
int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge);
#define PCI_REGION_FLAG_MASK 0x0fU /* These bits of resource flags tell us the PCI region flags */
