[PATCH 1/2] drm/xe: Add configfs to enable survivability mode
Lucas De Marchi
lucas.demarchi at intel.com
Tue Apr 1 01:03:11 UTC 2025
On Thu, Mar 27, 2025 at 12:12:01PM +0530, Riana Tauro wrote:
>Registers a configfs subsystem called 'xe' to userspace. The user can
>use this to modify exposed attributes for a device.
>
>Attribute exposed:
>
>/config/xe/<device>/survivability_mode : Enables survivability mode
>
>The attributes can be modified by creating the device directory under the
>configfs directory
>
>mount -t configfs none /config
>mkdir /config/xe/0000:03:00.0
>
>echo 0000:03:00.0 > /sys/bus/pci/drivers/xe/unbind
>echo 1 > /config/xe/0000:03:00.0/survivability_mode
>echo 0000:03:00.0 > /sys/bus/pci/drivers/xe/bind
>
>Signed-off-by: Riana Tauro <riana.tauro at intel.com>
>---
> drivers/gpu/drm/xe/Makefile | 1 +
> drivers/gpu/drm/xe/xe_configfs.c | 174 +++++++++++++++++++++++++++++++
> drivers/gpu/drm/xe/xe_configfs.h | 11 ++
> drivers/gpu/drm/xe/xe_module.c | 5 +
> 4 files changed, 191 insertions(+)
> create mode 100644 drivers/gpu/drm/xe/xe_configfs.c
> create mode 100644 drivers/gpu/drm/xe/xe_configfs.h
>
>diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
>index cd464fe26eb8..190176c2e10d 100644
>--- a/drivers/gpu/drm/xe/Makefile
>+++ b/drivers/gpu/drm/xe/Makefile
>@@ -28,6 +28,7 @@ $(obj)/generated/%_wa_oob.c $(obj)/generated/%_wa_oob.h: $(obj)/xe_gen_wa_oob \
> xe-y += xe_bb.o \
> xe_bo.o \
> xe_bo_evict.o \
>+ xe_configfs.o \
> xe_devcoredump.o \
> xe_device.o \
> xe_device_sysfs.o \
>diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
>new file mode 100644
>index 000000000000..59e1bc4c5f76
>--- /dev/null
>+++ b/drivers/gpu/drm/xe/xe_configfs.c
>@@ -0,0 +1,174 @@
>+// SPDX-License-Identifier: MIT
>+/*
>+ * Copyright © 2025 Intel Corporation
>+ */
>+
>+#include <linux/configfs.h>
>+#include <linux/init.h>
>+#include <linux/module.h>
>+#include <linux/pci.h>
>+
>+#include "xe_configfs.h"
>+#include "xe_module.h"
>+
>+/**
>+ * DOC: XE Configfs Support
>+ *
>+ * Overview
>+ * =========
>+ *
>+ * Configfs is a filesystem-based manager of kernel objects. XE KMD registers a
>+ * configfs subsystem called 'xe' that allows user to configure various attributes
>+ * See Documentation/filesystems/configfs.rst for more information about how configfs works.
>+ *
>+ * Create devices
>+ * ===============
>+ *
>+ * To use configfs exposed by Xe, mount the configfs directory and create the device directory
>+ *
>+ * $ mount -t configfs none /config
nit: once upon a time I think the "standard" was to have a /config. Same
thing as for debugfs. Nowadays I think pretty much every distro settled
on /sys/kernel/{debug,config} for debugfs and configfs. Mine even gets
mounted automatically:
# grep Where /usr/lib/systemd/system/sys-kernel-config.mount
Where=/sys/kernel/config
>+ * $ mkdir /config/xe/0000:03:00.0
>+ *
>+ * Configure Attributes
>+ * ====================
>+ *
>+ * /config/xe/<device>/survivability mode : Enables survivability mode if supported by device
* <configfs>/xe/<device>/survivability_mode: Enable survivability mode if supported by device
>+ *
>+ * Unbind : echo 0000:03:00.0 > /sys/bus/pci/drivers/xe/unbind
please, no unbind. The unbind part is part of "the previous time the
driver was attached/bound to the device".
>+ * Enable survivability mode : echo 1 > /config/xe/0000:03:00.0/survivability_mode
>+ * Bind : echo 0000:03:00.0 > /sys/bus/pci/drivers/xe/bind
are these extra spaces to try to align anything?
>+ *
>+ * The device enters survivability mode if supported
>+ *
trailing line.
>+ */
>+
>+struct xe_config_device {
>+ struct config_group group;
>+
>+ /** @survivability_mode: enables survivability mode when set */
I don't think we should kernel-doc this. But if we are, then it should
be proper kernel-doc, including the doc about the struct and not leaving
members undocumented.
>+ bool survivability_mode;
>+
>+ /** @lock: protects attributes */
>+ struct mutex lock;
>+};
>+
>+static struct xe_config_device *to_xe_config_device(struct config_item *item)
>+{
>+ return container_of(to_config_group(item), struct xe_config_device, group);
>+}
>+
>+static ssize_t survivability_mode_show(struct config_item *item, char *page)
>+{
>+ struct xe_config_device *dev = to_xe_config_device(item);
>+
>+ return sprintf(page, "%d\n", dev->survivability_mode);
>+}
>+
>+static ssize_t survivability_mode_store(struct config_item *item, const char *page, size_t len)
>+{
>+ struct xe_config_device *dev = to_xe_config_device(item);
>+ bool survivability_mode;
>+ int ret;
>+
>+ ret = kstrtobool(page, &survivability_mode);
>+ if (ret)
>+ return ret;
>+
>+ mutex_lock(&dev->lock);
>+ dev->survivability_mode = survivability_mode;
>+ mutex_unlock(&dev->lock);
>+
>+ return len;
>+}
>+
>+CONFIGFS_ATTR(, survivability_mode);
>+
>+static struct configfs_attribute *xe_config_device_attrs[] = {
>+ &attr_survivability_mode,
>+ NULL,
>+};
>+
>+static void xe_config_device_release(struct config_item *item)
>+{
>+ struct xe_config_device *dev = to_xe_config_device(item);
>+
>+ mutex_destroy(&dev->lock);
>+ kfree(dev);
>+}
>+
>+static struct configfs_item_operations xe_config_device_ops = {
>+ .release = xe_config_device_release,
>+};
>+
>+static const struct config_item_type xe_config_device_type = {
>+ .ct_item_ops = &xe_config_device_ops,
>+ .ct_attrs = xe_config_device_attrs,
>+ .ct_owner = THIS_MODULE,
>+};
>+
>+static struct config_group *xe_config_make_device_group(struct config_group *group,
>+ const char *name)
>+{
>+ unsigned int domain, bus, slot, function;
>+ struct xe_config_device *dev;
>+ struct pci_dev *pdev;
>+ int ret;
>+
>+ ret = sscanf(name, "%04x:%02x:%02x.%x", &domain, &bus, &slot, &function);
>+ if (ret != 4)
>+ return ERR_PTR(-EINVAL);
>+
>+ pdev = pci_get_domain_bus_and_slot(domain, bus, PCI_DEVFN(slot, function));
>+ if (!pdev)
>+ return ERR_PTR(-EINVAL);
>+
>+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
>+ if (!dev)
>+ return ERR_PTR(-ENOMEM);
>+
>+ config_group_init_type_name(&dev->group, name, &xe_config_device_type);
>+
>+ mutex_init(&dev->lock);
>+
>+ return &dev->group;
>+}
>+
>+static struct configfs_group_operations xe_config_device_group_ops = {
>+ .make_group = xe_config_make_device_group,
>+};
>+
>+static const struct config_item_type xe_configfs_type = {
>+ .ct_group_ops = &xe_config_device_group_ops,
>+ .ct_owner = THIS_MODULE,
Rodrigo, ^
this is what makes the config side take a ref on the module, as it
should.
>+};
>+
>+static struct configfs_subsystem xe_configfs = {
>+ .su_group = {
>+ .cg_item = {
>+ .ci_namebuf = "xe",
>+ .ci_type = &xe_configfs_type,
>+ },
>+ },
>+};
>+
>+int __init xe_configfs_init(void)
>+{
>+ struct config_group *root = &xe_configfs.su_group;
>+ int ret = 0;
pointless init as it's overwritten below.
>+
>+ config_group_init(root);
>+ mutex_init(&xe_configfs.su_mutex);
>+ ret = configfs_register_subsystem(&xe_configfs);
>+ if (ret) {
>+ pr_err("Error %d while registering %s subsystem\n",
>+ ret, root->cg_item.ci_namebuf);
return ret;
>+ }
>+
>+ return ret;
return 0;
A bunch of nits above, but looking pretty good.
thanks
Lucas De Marchi
>+}
>+
>+void __exit xe_configfs_exit(void)
>+{
>+ configfs_unregister_subsystem(&xe_configfs);
>+}
>+
>diff --git a/drivers/gpu/drm/xe/xe_configfs.h b/drivers/gpu/drm/xe/xe_configfs.h
>new file mode 100644
>index 000000000000..2c30be9a2c7e
>--- /dev/null
>+++ b/drivers/gpu/drm/xe/xe_configfs.h
>@@ -0,0 +1,11 @@
>+/* SPDX-License-Identifier: MIT */
>+/*
>+ * Copyright © 2025 Intel Corporation
>+ */
>+#ifndef _XE_CONFIGFS_H_
>+#define _XE_CONFIGFS_H_
>+
>+int xe_configfs_init(void);
>+void xe_configfs_exit(void);
>+
>+#endif
>diff --git a/drivers/gpu/drm/xe/xe_module.c b/drivers/gpu/drm/xe/xe_module.c
>index 475acdba2b55..15b3cf22193c 100644
>--- a/drivers/gpu/drm/xe/xe_module.c
>+++ b/drivers/gpu/drm/xe/xe_module.c
>@@ -11,6 +11,7 @@
> #include <drm/drm_module.h>
>
> #include "xe_drv.h"
>+#include "xe_configfs.h"
> #include "xe_hw_fence.h"
> #include "xe_pci.h"
> #include "xe_pm.h"
>@@ -91,6 +92,10 @@ static const struct init_funcs init_funcs[] = {
> {
> .init = xe_check_nomodeset,
> },
>+ {
>+ .init = xe_configfs_init,
>+ .exit = xe_configfs_exit,
>+ },
> {
> .init = xe_hw_fence_module_init,
> .exit = xe_hw_fence_module_exit,
>--
>2.47.1
>
More information about the Intel-xe
mailing list