diff mbox series

[v11,3/4] PCI/DOE: Expose the DOE features via sysfs

Message ID 20240614001244.925401-3-alistair.francis@wdc.com (mailing list archive)
State Superseded
Delegated to: Bjorn Helgaas
Headers show
Series [v11,1/4] PCI/DOE: Rename DOE protocol to feature | expand

Commit Message

Alistair Francis June 14, 2024, 12:12 a.m. UTC
The PCIe 6 specification added support for the Data Object
Exchange (DOE).
When DOE is supported the DOE Discovery Feature must be implemented per
PCIe r6.1 sec 6.30.1.1. The protocol allows a requester to obtain
information about the other DOE features supported by the device.

The kernel is already querying the DOE features supported and cacheing
the values. Expose the values in sysfs to allow user space to
determine which DOE features are supported by the PCIe device.

By exposing the information to userspace tools like lspci can relay the
information to users. By listing all of the supported features we can
allow userspace to parse the list, which might include
vendor specific features as well as yet to be supported features.

As the DOE Discovery feature must always be supported we treat it as a
special named attribute case. This allows the usual PCI attribute_group
handling to correctly create the doe_features directory when registering
pci_doe_sysfs_group (otherwise it doesn't and sysfs_add_file_to_group()
will seg fault).

After this patch is supported you can see something like this when
attaching a DOE device

$ ls /sys/devices/pci0000:00/0000:00:02.0//doe*
0001:01        0001:02        doe_discovery

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
v11:
 - Gracefully handle multiple entried of same feature
 - Minor fixes and code cleanups
v10:
 - Rebase to use DEFINE_SYSFS_GROUP_VISIBLE and remove
   special setup function
v9:
 - Add a teardown function
 - Rename functions to be clearer
 - Tidy up the commit message
 - Remove #ifdef from header
v8:
 - Inlucde an example in the docs
 - Fixup removing a file that wasn't added
 - Remove a blank line
v7:
 - Fixup the #ifdefs to keep the test robot happy
v6:
 - Use "feature" instead of protocol
 - Don't use any devm_* functions
 - Add two more patches to the series
v5:
 - Return the file name as the file contents
 - Code cleanups and simplifications
v4:
 - Fixup typos in the documentation
 - Make it clear that the file names contain the information
 - Small code cleanups
 - Remove most #ifdefs
 - Remove extra NULL assignment
v3:
 - Expose each DOE feature as a separate file
v2:
 - Add documentation
 - Code cleanups

 Documentation/ABI/testing/sysfs-bus-pci |  28 ++++
 drivers/pci/doe.c                       | 179 ++++++++++++++++++++++++
 drivers/pci/pci-sysfs.c                 |  13 ++
 drivers/pci/pci.h                       |  10 ++
 4 files changed, 230 insertions(+)

Comments

Jonathan Cameron June 14, 2024, 8:59 a.m. UTC | #1
On Fri, 14 Jun 2024 10:12:43 +1000
Alistair Francis <alistair23@gmail.com> wrote:

> The PCIe 6 specification added support for the Data Object
> Exchange (DOE).
> When DOE is supported the DOE Discovery Feature must be implemented per
> PCIe r6.1 sec 6.30.1.1. The protocol allows a requester to obtain
> information about the other DOE features supported by the device.
> 
> The kernel is already querying the DOE features supported and cacheing
> the values. Expose the values in sysfs to allow user space to
> determine which DOE features are supported by the PCIe device.
> 
> By exposing the information to userspace tools like lspci can relay the
> information to users. By listing all of the supported features we can
> allow userspace to parse the list, which might include
> vendor specific features as well as yet to be supported features.
> 
> As the DOE Discovery feature must always be supported we treat it as a
> special named attribute case. This allows the usual PCI attribute_group
> handling to correctly create the doe_features directory when registering
> pci_doe_sysfs_group (otherwise it doesn't and sysfs_add_file_to_group()
> will seg fault).
> 
> After this patch is supported you can see something like this when
> attaching a DOE device
> 
> $ ls /sys/devices/pci0000:00/0000:00:02.0//doe*
> 0001:01        0001:02        doe_discovery
> 
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Hi Alistair,

One question inline.  Feels like I'm either missing something or
the code has evolved in a fashion that left us with a pointless check
on attr visibility.

Jonathan

> diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
> index defc4be81bd4..9858b709c020 100644
> --- a/drivers/pci/doe.c
> +++ b/drivers/pci/doe.c

> +static umode_t pci_doe_features_sysfs_attr_visible(struct kobject *kobj,
> +						   struct attribute *a, int n)
> +{
> +	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> +	struct pci_doe_mb *doe_mb;
> +	unsigned long index, j;
> +	unsigned long vid, type;
> +	void *entry;
> +
> +	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
> +		xa_for_each(&doe_mb->feats, j, entry) {

I'm confused.  What is the intent here?

Given every DOE should have the discovery entry any call of this function
that actually finds a DOE should return a->mode, so why search the
actual entries? 

Given absence of the files anyway (due to the directory visible checks)
if there are no DOEs, why not drop this function completely?

> +			vid = xa_to_value(entry) >> 8;
> +			type = xa_to_value(entry) & 0xFF;
> +
> +			if (vid == 0x01 && type == 0x00) {
> +				/*
> +				 * This is the DOE discovery protocol
> +				 * Every DOE instance must support this, so we
> +				 * give it a useful name.
> +				 */
> +				return a->mode;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
Lukas Wunner June 14, 2024, 4:28 p.m. UTC | #2
On Fri, Jun 14, 2024 at 10:12:43AM +1000, Alistair Francis wrote:
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -16,6 +16,7 @@
>  #include <linux/kernel.h>
>  #include <linux/sched.h>
>  #include <linux/pci.h>
> +#include <linux/pci-doe.h>
>  #include <linux/stat.h>
>  #include <linux/export.h>
>  #include <linux/topology.h>

I'm not seeing any symbols used here which are defined in pci-doe.h.
Am I missing something?

If not this additional #include can be dropped.


> @@ -1143,6 +1144,9 @@ static void pci_remove_resource_files(struct pci_dev *pdev)
>  {
>  	int i;
>  
> +	if (IS_ENABLED(CONFIG_PCI_DOE))
> +		pci_doe_sysfs_teardown(pdev);
> +

No need to constrain to "if (IS_ENABLED(CONFIG_PCI_DOE))" as you're
defining an empty static inline in the header file.


> @@ -1227,6 +1231,12 @@ static int pci_create_resource_files(struct pci_dev *pdev)
>  	int i;
>  	int retval;
>  
> +	if (IS_ENABLED(CONFIG_PCI_DOE)) {
> +		retval = pci_doe_sysfs_init(pdev);
> +		if (retval)
> +			return retval;
> +	}
> +

Same here.

Note that pci_{create,remove}_resource_files() is not the right place
to dynamically add sysfs attributes.  These functions are called very
late to postpone exposure of ROM resources until they're enumerated.
You want to add your sysfs attributes right after device_add() has been
called and you want to remove them right before device_del() is called.

See here for an example how it's done correctly:

https://lore.kernel.org/all/20240528131940.16924-3-mariusz.tkaczyk@linux.intel.com/

(Search for the call to pci_npem_create() in pci_device_add() and
pci_npem_remove() in pci_destroy_dev().)


> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -189,6 +189,7 @@ extern const struct attribute_group *pci_dev_groups[];
>  extern const struct attribute_group *pci_dev_attr_groups[];
>  extern const struct attribute_group *pcibus_groups[];
>  extern const struct attribute_group *pci_bus_groups[];
> +extern const struct attribute_group pci_doe_sysfs_group;
>  #else
>  static inline int pci_create_sysfs_dev_files(struct pci_dev *pdev) { return 0; }
>  static inline void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { }
> @@ -196,6 +197,7 @@ static inline void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { }
>  #define pci_dev_attr_groups NULL
>  #define pcibus_groups NULL
>  #define pci_bus_groups NULL
> +#define pci_doe_sysfs_group NULL
>  #endif

You only need the "extern const struct ..." definition, not the
NULL definition.  The reason we have these NULL definitions is
because we're referencing the attribute groups in files which
are compiled even if CONFIG_SYSFS=n.  But I believe that's not
the case here.

Thanks,

Lukas
Lukas Wunner June 15, 2024, 1:05 p.m. UTC | #3
On Fri, Jun 14, 2024 at 10:12:43AM +1000, Alistair Francis wrote:
> --- a/drivers/pci/doe.c
> +++ b/drivers/pci/doe.c
[...]
> +#ifdef CONFIG_SYSFS
> +static ssize_t doe_discovery_show(struct device *dev,
> +				  struct device_attribute *attr,
> +				  char *buf)
> +{
> +	return sysfs_emit(buf, "0001:00\n");
> +}
> +DEVICE_ATTR_RO(doe_discovery);

If you want to use "0001:00" as filename but can't because
"0001:00_show()" would not be a valid function name in C,
I think there's no harm in manually expanding the macro to:

struct device_attribute dev_attr_doe_discovery = \
	__ATTR(0001:00, 0444, pci_doe_sysfs_feature_show, NULL);

That also avoids the need to have an extra doe_discovery_show()
function.

Intuitively, when I saw there's a "doe_discovery" attribute,
my first thought was: "Oh maybe I need to write something there
to (re-)initiate DOE discovery?"


> +static umode_t pci_doe_features_sysfs_attr_visible(struct kobject *kobj,
> +						   struct attribute *a, int n)
> +{
> +	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> +	struct pci_doe_mb *doe_mb;
> +	unsigned long index, j;
> +	unsigned long vid, type;
> +	void *entry;
> +
> +	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
> +		xa_for_each(&doe_mb->feats, j, entry) {
> +			vid = xa_to_value(entry) >> 8;
> +			type = xa_to_value(entry) & 0xFF;
> +
> +			if (vid == 0x01 && type == 0x00) {

Wherever possible, PCI_VENDOR_ID_PCI_SIG and PCI_DOE_PROTOCOL_DISCOVERY
macros should be used in lieu of 0x0001 and 0x00.

> +				/*
> +				 * This is the DOE discovery protocol
> +				 * Every DOE instance must support this, so we
> +				 * give it a useful name.
> +				 */
> +				return a->mode;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}

I agree with Jonathan that at first glance one would assume that
this function just always returns a->mode.


> +static bool pci_doe_features_sysfs_group_visible(struct kobject *kobj)
> +{
> +	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> +	struct pci_doe_mb *doe_mb;
> +	unsigned long index;
> +
> +	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
> +		if (!xa_empty(&doe_mb->feats))
> +			return true;
> +	}
> +
> +	return false;

So in principle, doe_mb->feats should never be empty because the
discovery protocol is always supported, right?  Wouldn't it then
suffice to just check for:

+	if (!xa_empty(&pdev->doe_mbs))
+		return true;

Or alternatively:

+	return !xa_empty(&pdev->doe_mbs);

Thanks,

Lukas
Alistair Francis June 26, 2024, 3:59 a.m. UTC | #4
On Fri, Jun 14, 2024 at 6:59 PM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Fri, 14 Jun 2024 10:12:43 +1000
> Alistair Francis <alistair23@gmail.com> wrote:
>
> > The PCIe 6 specification added support for the Data Object
> > Exchange (DOE).
> > When DOE is supported the DOE Discovery Feature must be implemented per
> > PCIe r6.1 sec 6.30.1.1. The protocol allows a requester to obtain
> > information about the other DOE features supported by the device.
> >
> > The kernel is already querying the DOE features supported and cacheing
> > the values. Expose the values in sysfs to allow user space to
> > determine which DOE features are supported by the PCIe device.
> >
> > By exposing the information to userspace tools like lspci can relay the
> > information to users. By listing all of the supported features we can
> > allow userspace to parse the list, which might include
> > vendor specific features as well as yet to be supported features.
> >
> > As the DOE Discovery feature must always be supported we treat it as a
> > special named attribute case. This allows the usual PCI attribute_group
> > handling to correctly create the doe_features directory when registering
> > pci_doe_sysfs_group (otherwise it doesn't and sysfs_add_file_to_group()
> > will seg fault).
> >
> > After this patch is supported you can see something like this when
> > attaching a DOE device
> >
> > $ ls /sys/devices/pci0000:00/0000:00:02.0//doe*
> > 0001:01        0001:02        doe_discovery
> >
> > Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> Hi Alistair,
>
> One question inline.  Feels like I'm either missing something or
> the code has evolved in a fashion that left us with a pointless check
> on attr visibility.

It's the second :)

>
> Jonathan
>
> > diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
> > index defc4be81bd4..9858b709c020 100644
> > --- a/drivers/pci/doe.c
> > +++ b/drivers/pci/doe.c
>
> > +static umode_t pci_doe_features_sysfs_attr_visible(struct kobject *kobj,
> > +                                                struct attribute *a, int n)
> > +{
> > +     struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> > +     struct pci_doe_mb *doe_mb;
> > +     unsigned long index, j;
> > +     unsigned long vid, type;
> > +     void *entry;
> > +
> > +     xa_for_each(&pdev->doe_mbs, index, doe_mb) {
> > +             xa_for_each(&doe_mb->feats, j, entry) {
>
> I'm confused.  What is the intent here?

I feel like this was required at some point, but you are right, it
doesn't seem useful now

>
> Given every DOE should have the discovery entry any call of this function
> that actually finds a DOE should return a->mode, so why search the
> actual entries?
>
> Given absence of the files anyway (due to the directory visible checks)
> if there are no DOEs, why not drop this function completely?

Done!

Alistair

>
> > +                     vid = xa_to_value(entry) >> 8;
> > +                     type = xa_to_value(entry) & 0xFF;
> > +
> > +                     if (vid == 0x01 && type == 0x00) {
> > +                             /*
> > +                              * This is the DOE discovery protocol
> > +                              * Every DOE instance must support this, so we
> > +                              * give it a useful name.
> > +                              */
> > +                             return a->mode;
> > +                     }
> > +             }
> > +     }
> > +
> > +     return 0;
> > +}
>
>
>
Alistair Francis Aug. 6, 2024, 6:36 a.m. UTC | #5
On Sat, 2024-06-15 at 15:05 +0200, Lukas Wunner wrote:
> On Fri, Jun 14, 2024 at 10:12:43AM +1000, Alistair Francis wrote:
> > --- a/drivers/pci/doe.c
> > +++ b/drivers/pci/doe.c
> [...]
> > +#ifdef CONFIG_SYSFS
> > +static ssize_t doe_discovery_show(struct device *dev,
> > +				  struct device_attribute *attr,
> > +				  char *buf)
> > +{
> > +	return sysfs_emit(buf, "0001:00\n");
> > +}
> > +DEVICE_ATTR_RO(doe_discovery);
> 
> If you want to use "0001:00" as filename but can't because
> "0001:00_show()" would not be a valid function name in C,
> I think there's no harm in manually expanding the macro to:
> 
> struct device_attribute dev_attr_doe_discovery = \
> 	__ATTR(0001:00, 0444, pci_doe_sysfs_feature_show, NULL);
> 
> That also avoids the need to have an extra doe_discovery_show()
> function.
> 
> Intuitively, when I saw there's a "doe_discovery" attribute,
> my first thought was: "Oh maybe I need to write something there
> to (re-)initiate DOE discovery?"

I prefer the `doe_discovery` as it's clear what the protocol is, but if
it's preferred I can change it to `0001:00`

Alistair

> 
> 
> > +static umode_t pci_doe_features_sysfs_attr_visible(struct kobject
> > *kobj,
> > +						   struct
> > attribute *a, int n)
> > +{
> > +	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> > +	struct pci_doe_mb *doe_mb;
> > +	unsigned long index, j;
> > +	unsigned long vid, type;
> > +	void *entry;
> > +
> > +	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
> > +		xa_for_each(&doe_mb->feats, j, entry) {
> > +			vid = xa_to_value(entry) >> 8;
> > +			type = xa_to_value(entry) & 0xFF;
> > +
> > +			if (vid == 0x01 && type == 0x00) {
> 
> Wherever possible, PCI_VENDOR_ID_PCI_SIG and
> PCI_DOE_PROTOCOL_DISCOVERY
> macros should be used in lieu of 0x0001 and 0x00.
> 
> > +				/*
> > +				 * This is the DOE discovery
> > protocol
> > +				 * Every DOE instance must support
> > this, so we
> > +				 * give it a useful name.
> > +				 */
> > +				return a->mode;
> > +			}
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> 
> I agree with Jonathan that at first glance one would assume that
> this function just always returns a->mode.
> 
> 
> > +static bool pci_doe_features_sysfs_group_visible(struct kobject
> > *kobj)
> > +{
> > +	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
> > +	struct pci_doe_mb *doe_mb;
> > +	unsigned long index;
> > +
> > +	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
> > +		if (!xa_empty(&doe_mb->feats))
> > +			return true;
> > +	}
> > +
> > +	return false;
> 
> So in principle, doe_mb->feats should never be empty because the
> discovery protocol is always supported, right?  Wouldn't it then
> suffice to just check for:
> 
> +	if (!xa_empty(&pdev->doe_mbs))
> +		return true;
> 
> Or alternatively:
> 
> +	return !xa_empty(&pdev->doe_mbs);
> 
> Thanks,
> 
> Lukas
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index ecf47559f495..65a3238ab701 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -500,3 +500,31 @@  Description:
 		console drivers from the device.  Raw users of pci-sysfs
 		resourceN attributes must be terminated prior to resizing.
 		Success of the resizing operation is not guaranteed.
+
+What:		/sys/bus/pci/devices/.../doe_features
+Date:		May 2024
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		This directory contains a list of the supported
+		Data Object Exchange (DOE) features. The features are
+		the file name. The contents of each file is the raw vendor id and
+		data object feature values.
+
+		The value comes from the device and specifies the vendor and
+		data object type supported. The lower (RHS of the colon) is
+		the data object type in hex. The upper (LHS of the colon)
+		is the vendor ID.
+
+		As all DOE devices must support the DOE discovery protocol, if
+		DOE is supported you will at least see the doe_discovery file, with
+		this contents
+
+		# cat doe_features/doe_discovery
+		0001:00
+
+		If the device supports other protocols you will see other files
+		as well. For example is CMA/SPDM and secure CMA/SPDM are supported
+		the doe_features directory will look like this
+
+		# ls doe_features
+		0001:01        0001:02        doe_discovery
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index defc4be81bd4..9858b709c020 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -14,6 +14,7 @@ 
 
 #include <linux/bitfield.h>
 #include <linux/delay.h>
+#include <linux/device.h>
 #include <linux/jiffies.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
@@ -47,6 +48,7 @@ 
  * @wq: Wait queue for work item
  * @work_queue: Queue of pci_doe_work items
  * @flags: Bit array of PCI_DOE_FLAG_* flags
+ * @sysfs_attrs: Array of sysfs device attributes
  */
 struct pci_doe_mb {
 	struct pci_dev *pdev;
@@ -56,6 +58,10 @@  struct pci_doe_mb {
 	wait_queue_head_t wq;
 	struct workqueue_struct *work_queue;
 	unsigned long flags;
+
+#ifdef CONFIG_SYSFS
+	struct device_attribute *sysfs_attrs;
+#endif
 };
 
 struct pci_doe_feature {
@@ -92,6 +98,179 @@  struct pci_doe_task {
 	struct pci_doe_mb *doe_mb;
 };
 
+#ifdef CONFIG_SYSFS
+static ssize_t doe_discovery_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	return sysfs_emit(buf, "0001:00\n");
+}
+DEVICE_ATTR_RO(doe_discovery);
+
+static struct attribute *pci_doe_sysfs_feature_attrs[] = {
+	&dev_attr_doe_discovery.attr,
+	NULL
+};
+
+static umode_t pci_doe_features_sysfs_attr_visible(struct kobject *kobj,
+						   struct attribute *a, int n)
+{
+	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+	struct pci_doe_mb *doe_mb;
+	unsigned long index, j;
+	unsigned long vid, type;
+	void *entry;
+
+	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
+		xa_for_each(&doe_mb->feats, j, entry) {
+			vid = xa_to_value(entry) >> 8;
+			type = xa_to_value(entry) & 0xFF;
+
+			if (vid == 0x01 && type == 0x00) {
+				/*
+				 * This is the DOE discovery protocol
+				 * Every DOE instance must support this, so we
+				 * give it a useful name.
+				 */
+				return a->mode;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static bool pci_doe_features_sysfs_group_visible(struct kobject *kobj)
+{
+	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+	struct pci_doe_mb *doe_mb;
+	unsigned long index;
+
+	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
+		if (!xa_empty(&doe_mb->feats))
+			return true;
+	}
+
+	return false;
+}
+DEFINE_SYSFS_GROUP_VISIBLE(pci_doe_features_sysfs)
+
+const struct attribute_group pci_doe_sysfs_group = {
+	.name	    = "doe_features",
+	.attrs	    = pci_doe_sysfs_feature_attrs,
+	.is_visible = SYSFS_GROUP_VISIBLE(pci_doe_features_sysfs),
+};
+
+static ssize_t pci_doe_sysfs_feature_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	return sysfs_emit(buf, "%s\n", attr->attr.name);
+}
+
+static void pci_doe_sysfs_feature_remove(struct pci_dev *pdev,
+					 struct pci_doe_mb *doe_mb)
+{
+	struct device_attribute *attrs = doe_mb->sysfs_attrs;
+	struct device *dev = &pdev->dev;
+	unsigned long i;
+	void *entry;
+
+	if (!attrs)
+		return;
+
+	doe_mb->sysfs_attrs = NULL;
+	xa_for_each(&doe_mb->feats, i, entry) {
+		if (attrs[i].show)
+			sysfs_remove_file_from_group(&dev->kobj, &attrs[i].attr,
+						     pci_doe_sysfs_group.name);
+		kfree(attrs[i].attr.name);
+	}
+	kfree(attrs);
+}
+
+static int pci_doe_sysfs_feature_populate(struct pci_dev *pdev,
+					  struct pci_doe_mb *doe_mb)
+{
+	struct device *dev = &pdev->dev;
+	struct device_attribute *attrs;
+	unsigned long num_features = 0;
+	unsigned long vid, type;
+	unsigned long i;
+	void *entry;
+	int ret;
+
+	xa_for_each(&doe_mb->feats, i, entry)
+		num_features++;
+
+	attrs = kcalloc(num_features, sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		return -ENOMEM;
+
+	doe_mb->sysfs_attrs = attrs;
+	xa_for_each(&doe_mb->feats, i, entry) {
+		sysfs_attr_init(&attrs[i].attr);
+		vid = xa_to_value(entry) >> 8;
+		type = xa_to_value(entry) & 0xFF;
+
+		if (vid == 0x01 && type == 0x00) {
+			/* DOE Discovery, manually displayed by `dev_attr_doe_discovery` */
+			continue;
+		}
+
+		attrs[i].attr.name = kasprintf(GFP_KERNEL,
+					       "%04lx:%02lx", vid, type);
+		if (!attrs[i].attr.name) {
+			ret = -ENOMEM;
+			goto fail;
+		}
+
+		attrs[i].attr.mode = 0444;
+		attrs[i].show = pci_doe_sysfs_feature_show;
+
+		ret = sysfs_add_file_to_group(&dev->kobj, &attrs[i].attr,
+					      pci_doe_sysfs_group.name);
+		if (ret) {
+			attrs[i].show = NULL;
+			if (ret != -EEXIST)
+				goto fail;
+			else
+				kfree(attrs[i].attr.name);
+		}
+	}
+
+	return 0;
+
+fail:
+	pci_doe_sysfs_feature_remove(pdev, doe_mb);
+	return ret;
+}
+
+void pci_doe_sysfs_teardown(struct pci_dev *pdev)
+{
+	struct pci_doe_mb *doe_mb;
+	unsigned long index;
+
+	xa_for_each(&pdev->doe_mbs, index, doe_mb)
+		pci_doe_sysfs_feature_remove(pdev, doe_mb);
+}
+
+int pci_doe_sysfs_init(struct pci_dev *pdev)
+{
+	struct pci_doe_mb *doe_mb;
+	unsigned long index;
+	int ret;
+
+	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
+		ret = pci_doe_sysfs_feature_populate(pdev, doe_mb);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+#endif
+
 static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout)
 {
 	if (wait_event_timeout(doe_mb->wq,
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 40cfa716392f..b5db191cb29f 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -16,6 +16,7 @@ 
 #include <linux/kernel.h>
 #include <linux/sched.h>
 #include <linux/pci.h>
+#include <linux/pci-doe.h>
 #include <linux/stat.h>
 #include <linux/export.h>
 #include <linux/topology.h>
@@ -1143,6 +1144,9 @@  static void pci_remove_resource_files(struct pci_dev *pdev)
 {
 	int i;
 
+	if (IS_ENABLED(CONFIG_PCI_DOE))
+		pci_doe_sysfs_teardown(pdev);
+
 	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
 		struct bin_attribute *res_attr;
 
@@ -1227,6 +1231,12 @@  static int pci_create_resource_files(struct pci_dev *pdev)
 	int i;
 	int retval;
 
+	if (IS_ENABLED(CONFIG_PCI_DOE)) {
+		retval = pci_doe_sysfs_init(pdev);
+		if (retval)
+			return retval;
+	}
+
 	/* Expose the PCI resources from this device as files */
 	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
 
@@ -1661,6 +1671,9 @@  const struct attribute_group *pci_dev_attr_groups[] = {
 #endif
 #ifdef CONFIG_PCIEASPM
 	&aspm_ctrl_attr_group,
+#endif
+#ifdef CONFIG_PCI_DOE
+	&pci_doe_sysfs_group,
 #endif
 	NULL,
 };
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index fd44565c4756..3aee231dcb0c 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -189,6 +189,7 @@  extern const struct attribute_group *pci_dev_groups[];
 extern const struct attribute_group *pci_dev_attr_groups[];
 extern const struct attribute_group *pcibus_groups[];
 extern const struct attribute_group *pci_bus_groups[];
+extern const struct attribute_group pci_doe_sysfs_group;
 #else
 static inline int pci_create_sysfs_dev_files(struct pci_dev *pdev) { return 0; }
 static inline void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { }
@@ -196,6 +197,7 @@  static inline void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { }
 #define pci_dev_attr_groups NULL
 #define pcibus_groups NULL
 #define pci_bus_groups NULL
+#define pci_doe_sysfs_group NULL
 #endif
 
 extern unsigned long pci_hotplug_io_size;
@@ -333,6 +335,14 @@  static inline void pci_doe_destroy(struct pci_dev *pdev) { }
 static inline void pci_doe_disconnected(struct pci_dev *pdev) { }
 #endif
 
+#if defined(CONFIG_PCI_DOE) && defined(CONFIG_SYSFS)
+int pci_doe_sysfs_init(struct pci_dev *pci_dev);
+void pci_doe_sysfs_teardown(struct pci_dev *pdev);
+#else
+static inline int pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
+static inline void pci_doe_sysfs_teardown(struct pci_dev *pdev) { }
+#endif
+
 /**
  * pci_dev_set_io_state - Set the new error state if possible.
  *